JPH09244355A - Charging device, image recording device, and process cartridge - Google Patents

Charging device, image recording device, and process cartridge

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Publication number
JPH09244355A
JPH09244355A JP8079622A JP7962296A JPH09244355A JP H09244355 A JPH09244355 A JP H09244355A JP 8079622 A JP8079622 A JP 8079622A JP 7962296 A JP7962296 A JP 7962296A JP H09244355 A JPH09244355 A JP H09244355A
Authority
JP
Japan
Prior art keywords
charging
voltage
charger
charged
image
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP8079622A
Other languages
Japanese (ja)
Inventor
Yasunori Kono
康則 児野
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Priority to JP8079622A priority Critical patent/JPH09244355A/en
Publication of JPH09244355A publication Critical patent/JPH09244355A/en
Pending legal-status Critical Current

Links

Abstract

PROBLEM TO BE SOLVED: To compatibly control the fine electric potential irregularity on a surface of a body to be charged and prevent defective charging attributable to application of an AC bias by providing first and second charging devices along the moving direction of the body to be charged, and specifying the setting of the charging characteristic of the charging devices. SOLUTION: A charging device is provided with first and second charging devices 2A, 2B along the moving direction of a body 1 to be charged (photosensitive body), and has the charging characteristic in which the relationship between the DC voltage and the potential of the body to be charged is approximately proportional when the DC voltage of either polarity is applied to each of the charging devices 2A, 2B. Regarding the potential fluctuation ΔV on the surface of the body to be charged which is generated attributable to the applied AC voltage, the charging characteristic is set so that the potential fluctuations ΔV1, ΔV2 at the charging devices 2A, 2B satisfy the inequality of ΔV1>ΔV2. The potential fluctuation ΔV is calculated by the formula where τ(sec) is the time constant of the charging device, f(Hz) is the frequency of the AC voltage to be applied, and NAC(V) is the effective voltage of the AC voltage.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は、帯電装置、画像記
録装置及びプロセスカートリッジに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device, an image recording device and a process cartridge.

【０００２】より詳しくは、電圧を印加した帯電器（接
触帯電部材）を被帯電体に接触させて被帯電体を帯電
（除電も含む）する接触帯電方式の帯電装置、該帯電装
置を用いた画像記録装置やプロセスカートリッジに関す
る。More specifically, a contact charging type charging device for charging a charged body by contacting a charged body (contact charging member) to which a voltage has been applied (contact charging member), and the charging device is used. The present invention relates to an image recording device and a process cartridge.

【０００３】[0003]

【従来の技術】例えば、電子写真方式・静電記録方式等
の複写機・プリンタなど、電子写真感光体・静電記録誘
電体等の像担持体に該像担持体を帯電する工程を含む作
像プロセスを適用して画像形成を実行する画像記録装置
においては、被帯電体としての像担持体を一様に帯電処
理する手段機器として従来一般にコロナ帯電装置が利用
されていた。2. Description of the Related Art For example, in a copying machine or printer of electrophotographic type, electrostatic recording type, etc., a process including a step of charging an image bearing member such as an electrophotographic photosensitive member or an electrostatic recording dielectric substance. 2. Description of the Related Art In an image recording apparatus that executes image formation by applying an image process, a corona charging device has been generally used as a device for uniformly charging an image bearing member as a member to be charged.

【０００４】これは、コロナ帯電器を被帯電体に非接触
に対向配設し、高圧を印加したコロナ帯電器から発生す
るコロナシャワーに被帯電体面をさらすことで被帯電体
面を所定の極性・電位に帯電させるものである。This is because a corona charger is disposed so as to face a member to be charged without contact, and the surface of the member to be charged is exposed to a corona shower generated from a corona charger to which a high voltage is applied so that the surface of the member to be charged has a predetermined polarity. It is charged to a potential.

【０００５】近年は、コロナ帯電装置よりも低オゾン・
低電力等の利点を有することから、中・低速機種の画像
記録装置などには接触帯電装置（直接帯電装置）が実用
されるようになってきている。In recent years, the ozone level is lower than that of corona charging devices.
A contact charging device (direct charging device) has been put into practical use for image recording devices of medium and low speed models because it has advantages such as low power consumption.

【０００６】これは、被帯電体に、所定の電圧を印加し
た帯電器を当接させて被帯電体面を所定の極性・電位に
帯電させるものである。接触帯電器は導電性の部材であ
り、弾性ローラ（ローラ帯電器）、ブレード（ブレード
帯電器）、磁気ブラシ（磁気ブラシ帯電器）、ファーブ
ラシ（ファーブラシ帯電器）等の形態のものが用いられ
る。In this method, a charging device to which a predetermined voltage is applied is brought into contact with the charged body to charge the surface of the charged body to a predetermined polarity and potential. The contact charger is a conductive member and is in the form of an elastic roller (roller charger), blade (blade charger), magnetic brush (magnetic brush charger), fur brush (fur brush charger), or the like. To be

【０００７】磁気ブラシ帯電器は、給電電極を兼ねる回
転或は非回転の担持部材に磁気拘束して担持させた導電
性磁性粒子の磁気ブラシ部を有し、該磁気ブラシ部を被
帯電体に接触させ、担持部材に給電するものである。The magnetic brush charger has a magnetic brush portion of conductive magnetic particles magnetically restrained and held by a rotating or non-rotating supporting member that also serves as a power feeding electrode. They are brought into contact with each other to supply power to the supporting member.

【０００８】ファーブラシ帯電器は、給電電極を兼ねる
回転或は非回転の担持部材に担持させた導電性繊維のブ
ラシ部を有し、該導電性繊維ブラシ部を被帯電体に接触
させ、担持部材に給電するものである。The fur brush charger has a brush portion of conductive fibers carried on a rotating or non-rotating carrier member which also serves as a power feeding electrode, and the conductive fiber brush portion is brought into contact with a member to be charged and carried. It supplies power to the members.

【０００９】磁気ブラシ帯電器やファーブラシ帯電器は
帯電、接触の安定性という点から好ましく用いられる。The magnetic brush charger and the fur brush charger are preferably used from the viewpoint of stability of charging and contact.

【００１０】接触帯電には、放電現象による帯電が支配
的である系と、被帯電体面に対する電荷の直接注入（充
電）による帯電が支配的である系（電荷注入接触帯電方
式）がある。The contact charging includes a system in which charging due to a discharge phenomenon is dominant and a system in which charging due to direct injection (charging) of charges to the surface of an object to be charged is dominant (charge injection contact charging system).

【００１１】電荷注入接触帯電方式については例えば特
開平６−３９２１号公報に開示されている。これは上記
のような接触帯電器に電圧を印加し、表面に電荷注入層
を設けた、被帯電体としての感光体上のフロート電極に
該感光体面に接触させた接触帯電器から電荷を注入して
帯電を行なう方法である。具体的には、特開平６−３９
２１号公報では、電荷注入層として、感光体表面にアク
リル樹脂に導電フィラー（導電性粒子）であるアンチモ
ンドープで導電化したＳｎＯ2 を分散したものを塗工し
て用いることが可能であるとの記述がある。The charge injection contact charging method is disclosed in, for example, Japanese Patent Laid-Open No. 6-3921. This is because a voltage is applied to the contact charger as described above, and a charge injection layer is provided on the surface of the photoreceptor. Is a method of charging. Specifically, JP-A-6-39
According to Japanese Patent Laid-Open No. 21-21, it is possible to use, as the charge injection layer, an acrylic resin coated with a dispersion of SnO 2 which is conductive with antimony dope, which is a conductive filler (conductive particles), applied to the surface of the photoreceptor. There is a description.

【００１２】このような電荷注入接触帯電方式は、放電
現象を用いないため、所望する感光体表面電位に等しい
直流電圧を接触帯電器に印加することで感光体を該所望
の表面電位に帯電可能であり、またオゾンの発生もな
い。Since such a charge injection contact charging method does not use a discharge phenomenon, the photoreceptor can be charged to the desired surface potential by applying a DC voltage equal to the desired photoreceptor surface potential to the contact charger. In addition, no ozone is generated.

【００１３】[0013]

【発明が解決しようとする課題】接触帯電装置におい
て、接触帯電器に対する印加電圧は、直流電圧（ＤＣバ
イアス）のみとする「ＤＣ印加方式」と、ＤＣバイアス
と交流電圧（ＡＣバイアス）を重畳した振動電圧（時間
とともに電圧値が周期的に変化する電圧）を印加する
「ＡＣ印加方式」がある。In the contact charging device, the voltage applied to the contact charger is a "DC applying method" in which only a DC voltage (DC bias) is applied, and a DC bias and an AC voltage (AC bias) are superimposed. There is an “AC application method” in which an oscillating voltage (a voltage whose voltage value changes periodically with time) is applied.

【００１４】ＤＣ印加方式の場合、接触帯電器の汚染や
変性、環境変動等に起因する抵抗上昇の影響が帯電不良
となって現れやすい。これに比べて、ＡＣ印加方式の場
合は、ＡＣバイアスを印加し高電位差を生むことで、高
抵抗化した接触帯電器であっても、帯電均一性・帯電安
定性がある。In the case of the DC application method, the influence of resistance increase due to contamination or modification of the contact charger, environmental change, etc. is likely to appear as charging failure. On the other hand, in the case of the AC application method, by applying an AC bias to generate a high potential difference, even a contact charger having a high resistance has charging uniformity and charging stability.

【００１５】しかしながら、ＡＣ印加方式の場合も、Ａ
Ｃバイアスを印加したことに起因する被帯電体表面の細
かな電位ムラの帯電不良があり、被帯電体としての像担
持体の帯電を接触帯電方式・ＡＣ印加方式にした電子写
真装置等の画像記録装置においては、このＡＣバイアス
を印加したことに起因する細かな電位ムラによる「かぶ
り」（ＡＣかぶり）が出力画像に発生して記録画像の品
質を低下させることがある。However, in the case of the AC application method, A
An image of an electrophotographic apparatus or the like in which there is a charging failure due to fine potential unevenness on the surface of the charged object due to the application of the C bias, and the image carrier as the charged object is charged by the contact charging method or the AC applying method. In the recording apparatus, "fog" (AC fog) due to fine potential unevenness due to the application of the AC bias may occur in the output image and deteriorate the quality of the recorded image.

【００１６】「かぶり」とは、本来非画像部（白紙部）
であるはずのところが、わずかに現像され画像部との光
学的コントラストをそこなう画像不良である。The "fog" originally means a non-image part (blank part).
However, it is an image defect that is slightly developed and impairs the optical contrast with the image area.

【００１７】電荷注入による接触帯電方式においては、
接触帯電器から被帯電体に直接電荷を注入し帯電を行な
うため、印加バイアスに対してリニアに被帯電体を帯電
することができる。従って、ＤＣバイアスのみでも帯電
可能であるが、画像記録装置にあっては繰り返し印字す
ることにより接触帯電器が徐々に汚染されていく等によ
り抵抗上昇して帯電不良による画像不良が発生する。Ａ
Ｃ印加方式にすることで、高抵抗化した接触帯電器であ
っても、より安定した帯電が可能となるが、その反面、
ＡＣバイアスを印加したときはＡＣバイアスに起因する
像担持体表面の細かな電位ムラを生じて画像ムラやかぶ
りを生じさ画像品質を低下させることがある。In the contact charging method by charge injection,
Since the charge is directly injected from the contact charger to the charged body, the charged body can be charged linearly with respect to the applied bias. Therefore, although the charging can be performed only with the DC bias, in the image recording apparatus, the resistance is increased due to the contact charger being gradually contaminated by repeated printing, and the image failure due to the charging failure occurs. A
By adopting the C application method, more stable charging is possible even with a contact charger having a high resistance, but on the other hand,
When an AC bias is applied, fine potential unevenness on the surface of the image carrier due to the AC bias may occur, resulting in image unevenness and fog, which may deteriorate image quality.

【００１８】即ち、電荷注入接触帯電方式においては接
触帯電器電圧とほぼ等しい電位に被帯電体が帯電される
ため、ＡＣバイアスを重畳して迅速に安定して帯電を行
おうとすると微小な電位ムラを生じやすい。That is, in the charge injection contact charging method, the charged body is charged to a potential almost equal to the voltage of the contact charger, and therefore, when an attempt is made to superimpose an AC bias and to perform stable charging quickly, a minute potential unevenness occurs. Prone to

【００１９】この電位ムラを生じないような帯電器構成
をとると、電荷注入能力が低く、画像記録装置にあって
は、帯電不良による、かぶりや帯電不良によるゴースト
画像が現れ画像品位を低下させる。If the charger is constructed so as not to cause this potential unevenness, the charge injection capability will be low, and in the image recording apparatus, a ghost image will appear due to fog or improper charging due to poor charging, thus degrading the image quality. .

【００２０】本発明は、電荷注入接触帯電方式・ＡＣ印
加方式の帯電装置、該帯電装置を使用した画像記録装置
やプロセスカートリッジについて、接触帯電器にＡＣバ
イアスを印加したことに起因する被帯電体表面の細かな
電位ムラの抑制（帯電均一性）と、帯電不良の防止（帯
電安定性）を両立させること、画像記録装置やプロセス
カートリッジにあっては、該帯電均一性と帯電安定性の
両立により高品位な画像記録を長期に渡り安定に維持さ
せることを目的とする。The present invention relates to a charge injection contact charging type / AC applying type charging device, an image recording apparatus and a process cartridge using the charging device, which are to be charged by applying an AC bias to the contact charging device. Suppression of small surface potential unevenness (charging uniformity) and prevention of charging failure (charging stability) are both achieved. In image recording devices and process cartridges, both charging uniformity and charging stability are compatible. The purpose is to maintain high-quality image recording stably over a long period of time.

【００２１】[0021]

【課題を解決するための手段】本発明は下記の構成を特
徴とする、帯電装置、画像記録装置及びプロセスカート
リッジである。The present invention is a charging device, an image recording device and a process cartridge having the following features.

【００２２】（１）直流電圧と交流電圧を重畳した電圧
が印加され、被帯電体に接触して該被帯電体を帯電する
帯電器を有する帯電装置において、被帯電体移動方向に
沿って、少なくとも、第１の帯電器と、それよりも被帯
電体移動方向下流側の第２の帯電器を有し、該第１と第
２の両帯電器についてそれぞれ一方極性の直流電圧を印
加したときの直流電圧と被帯電体電位の関係がおよそ比
例関係にある帯電特性を有し、帯電器の時定数をτ（ｓ
ｅｃ）、印加する交流電圧の周波数をｆ（Ｈｚ）、交流
電圧の実効電圧をＶAC（Ｖ）、とするとき、(1) In a charging device having a charger to which a voltage in which a DC voltage and an AC voltage are superposed is applied to contact a charged body to charge the charged body, along a moving direction of the charged body, When at least a first charger and a second charger downstream of the first charger in the moving direction of the body to be charged are provided, and a DC voltage of one polarity is applied to each of the first and second chargers. Has a charging characteristic in which the relationship between the DC voltage and the potential of the body to be charged is approximately proportional, and the time constant of the charger is τ (s
ec), when the frequency of the applied AC voltage is f (Hz) and the effective voltage of the AC voltage is V AC (V),

【００２３】[0023]

【数５】 で算定される、印加交流電圧に起因して発生する被帯電
体表面の電位変動ΔＶに関して、第１の帯電器における
該電位変動ΔＶ１と、第２の帯電器における該電位変動
ΔＶ２とが、ΔＶ１＞ΔＶ２となるように第１と第２の
両帯電器の帯電特性が設定されていることを特徴とする
帯電装置。(Equation 5) With respect to the potential fluctuation ΔV on the surface of the member to be charged that is caused by the applied AC voltage calculated in step A, the potential fluctuation ΔV1 in the first charger and the potential fluctuation ΔV2 in the second charger are ΔV1. A charging device characterized in that the charging characteristics of both the first and second chargers are set so that> ΔV2.

【００２４】（２）直流電圧と交流電圧を重畳した電圧
が印加され、被帯電体に接触して該被帯電体を帯電する
帯電器を有する帯電装置において、帯電器は、被帯電体
移動方向に沿って、少なくとも、第１の給電部材による
第１の帯電部と、それよりも被帯電体移動方向下流側の
第２の給電部材による第２の帯電部を有し、該第１と第
２の両帯電部についてそれぞれ一方極性の直流電圧を印
加したときの直流電圧と被帯電体電位の関係がおよそ比
例関係にある帯電特性を有し、帯電部の時定数をτ（ｓ
ｅｃ）、給電部材に印加する交流電圧の周波数をｆ（Ｈ
ｚ）、交流電圧の実効電圧をＶAC（Ｖ）、とするとき、(2) In a charging device having a charger to which a voltage obtained by superimposing a DC voltage and an AC voltage is applied to contact a charged body to charge the charged body, the charger is a moving direction of the charged body. Along with, at least a first charging portion by the first power feeding member and a second charging portion by the second power feeding member on the downstream side in the moving direction of the body to be charged from the first charging portion, and the first charging portion and the first charging portion. The two charging units have charging characteristics such that the relationship between the DC voltage and the potential of the body to be charged when a DC voltage of one polarity is applied is approximately proportional, and the time constant of the charging unit is τ (s
ec), the frequency of the AC voltage applied to the power feeding member is f (H
z), when the effective voltage of the AC voltage is V AC (V),

【００２５】[0025]

【数６】 で算定される、印加交流電圧に起因して発生する被帯電
体表面の電位変動ΔＶに関して、第１の帯電部における
該電位変動ΔＶ１と、第２の帯電部における該電位変動
ΔＶ２とが、ΔＶ１＞ΔＶ２となるように第１と第２の
両帯電部の帯電特性が設定されていることを特徴とする
帯電装置。(Equation 6) With respect to the potential fluctuation ΔV on the surface of the charged body generated due to the applied AC voltage calculated in step A, the potential fluctuation ΔV1 in the first charging portion and the potential fluctuation ΔV2 in the second charging portion are ΔV1. A charging device characterized in that the charging characteristics of both the first and second charging units are set so that> ΔV2.

【００２６】（３）帯電器は、担持部材に磁気拘束して
担持させた導電磁性粒子の磁気ブラシ部を有し、該磁気
ブラシ部を被帯電体に接触させた磁気ブラシ帯電器であ
ることを特徴とする（１）または（２）に記載の帯電装
置。(3) The charging device is a magnetic brush charging device having a magnetic brush part of conductive magnetic particles magnetically restrained and carried on a carrying member, and the magnetic brush part is brought into contact with an object to be charged. The charging device as described in (1) or (2) above.

【００２７】（４）帯電器は、導電性繊維のブラシ部を
有し、該導電性繊維ブラシ部を被帯電体に接触させたフ
ァーブラシ帯電器であることを特徴とする（１）または
（２）に記載の帯電装置。(4) The charger is a fur brush charger having a conductive fiber brush portion, and the conductive fiber brush portion is brought into contact with an object to be charged (1) or ( The charging device according to 2).

【００２８】（５）被帯電体が表面抵抗１０9 〜１０14
Ω／ｃｍの低抵抗層を有することを特徴とする（１）な
いし（４）のいずれか１つに記載の帯電装置。(5) The body to be charged has a surface resistance of 10 9 to 10 14
The charging device according to any one of (1) to (4), which has a low resistance layer of Ω / cm.

【００２９】（６）被帯電体が絶縁性材料に導電性粒子
を分散した表面層を有することを特徴とする（１）ない
し（５）のいずれか１つに記載の帯電装置。(6) The charging device according to any one of (1) to (5), wherein the member to be charged has a surface layer in which conductive particles are dispersed in an insulating material.

【００３０】（７）導電性粒子がＳｎＯ2 であることを
特徴とする（６）に記載の帯電装置。(7) The charging device as described in (6), characterized in that the conductive particles are SnO 2 .

【００３１】（８）被帯電体が画像記録装置における像
担持体であることを特徴とする（１）ないし（７）の何
れか１つに記載の帯電装置。(8) The charging device according to any one of (1) to (7), wherein the member to be charged is an image carrier in the image recording device.

【００３２】（９）像担持体に該像担持体を帯電する工
程を有する作像プロセスを適用して画像形成を実行する
画像記録装置において、像担持体の帯電工程手段が、直
流電圧と交流電圧を重畳した電圧が印加され、像担持体
に接触して該像担持体を帯電する帯電器を有する帯電装
置であり、像担持体移動方向に沿って、少なくとも、第
１の帯電器と、それよりも像担持体移動方向下流側の第
２の帯電器を有し、該第１と第２の両帯電器についてそ
れぞれ一方極性の直流電圧を印加したときの直流電圧と
像担持体電位の関係がおよそ比例関係にある帯電特性を
有し、帯電器の時定数をτ（ｓｅｃ）、印加する交流電
圧の周波数をｆ（Ｈｚ）、交流電圧の実効電圧をＶ
AC（Ｖ）、とするとき、(9) In an image recording apparatus for performing image formation by applying an image forming process having a step of charging the image carrier, the charging process means of the image carrier has a DC voltage and an AC voltage. A charging device having a charger to which a voltage superimposed with a voltage is applied and which charges the image carrier by contacting the image carrier, and at least a first charger along the moving direction of the image carrier, There is a second charger on the downstream side of the moving direction of the image carrier, and a DC voltage and an image carrier potential when a DC voltage of one polarity is applied to the first and second chargers, respectively. The relationship is approximately proportional, and the time constant of the charger is τ (sec), the frequency of the applied AC voltage is f (Hz), and the effective voltage of the AC voltage is V.
When using AC (V),

【００３３】[0033]

【数７】 で算定される、印加交流電圧に起因して発生する像担持
体表面の電位変動ΔＶに関して、第１の帯電器における
該電位変動ΔＶ１と、第２の帯電器における該電位変動
ΔＶ２とが、ΔＶ１＞ΔＶ２となるように第１と第２の
両帯電器の帯電特性が設定されていることを特徴とする
画像記録装置。(Equation 7) With respect to the potential fluctuation ΔV on the surface of the image carrier that occurs due to the applied AC voltage, the potential fluctuation ΔV1 in the first charger and the potential fluctuation ΔV2 in the second charger are ΔV1. An image recording apparatus, wherein the charging characteristics of both the first and second chargers are set so that> ΔV2.

【００３４】（１０）像担持体に該像担持体を帯電する
工程を有する作像プロセスを適用して画像形成を実行す
る画像記録装置において、像担持体の帯電工程手段が、
直流電圧と交流電圧を重畳した電圧が印加され、像担持
体に接触して該像担持体を帯電する帯電器を有する帯電
装置において、帯電器は、像担持体移動方向に沿って、
少なくとも、第１の給電部材による第１の帯電部と、そ
れよりも像担持体移動方向下流側の第２の給電部材によ
る第２の帯電部を有し、該第１と第２の両帯電部につい
てそれぞれ一方極性の直流電圧を印加したときの直流電
圧と像担持体電位の関係がおよそ比例関係にある帯電特
性を有し、帯電部の時定数をτ（ｓｅｃ）、給電部材に
印加する交流電圧の周波数をｆ（Ｈｚ）、交流電圧の実
効電圧をＶAC（Ｖ）、とするとき、(10) In an image recording apparatus for performing image formation by applying an image forming process having a step of charging the image carrier, the image carrier charging process means
In a charging device having a charger to which a voltage obtained by superimposing a DC voltage and an AC voltage is applied and which contacts the image carrier to charge the image carrier, the charger is configured to move along the moving direction of the image carrier.
At least a first charging unit formed by the first power supply member and a second charging unit formed by a second power supply member downstream of the first charging unit in the moving direction of the image carrier are provided, and both the first charging unit and the second charging unit are provided. Each part has a charging characteristic in which the relationship between the DC voltage and the potential of the image carrier is approximately proportional when a DC voltage of one polarity is applied, and the time constant of the charging part is τ (sec) and is applied to the feeding member. When the frequency of the AC voltage is f (Hz) and the effective voltage of the AC voltage is V AC (V),

【００３５】[0035]

【数８】 で算定される、印加交流電圧に起因して発生する像担持
体表面の電位変動ΔＶに関して、第１の帯電部における
該電位変動ΔＶ１と、第２の帯電部における該電位変動
ΔＶ２とが、ΔＶ１＞ΔＶ２となるように第１と第２の
両帯電部の帯電特性が設定されていることを特徴とする
画像記録装置。(Equation 8) With respect to the potential fluctuation ΔV on the surface of the image carrier that occurs due to the applied AC voltage calculated in step A, the potential fluctuation ΔV1 in the first charging portion and the potential fluctuation ΔV2 in the second charging portion are ΔV1. An image recording apparatus, wherein the charging characteristics of both the first and second charging units are set so that> ΔV2.

【００３６】（１１）像担持体が光導電性であり、この
像担持体に、該像担持体を帯電する工程、その帯電面に
露光により静電潜像を形成する工程、該静電潜像を帯電
したトナーにより可視化する工程を有する作像プロセス
で画像形成が実行されることを特徴とする（９）または
（１０）に記載の画像記録装置。(11) The image carrier is photoconductive, and the process of charging the image carrier on the image carrier, the process of forming an electrostatic latent image on the charged surface by exposure, the electrostatic latent image The image recording apparatus according to (9) or (10), wherein image formation is performed in an image forming process including a step of visualizing an image with charged toner.

【００３７】（１２）帯電器は、担持部材に磁気拘束し
て担持させた導電磁性粒子の磁気ブラシ部を有し、該磁
気ブラシ部を像担持体に接触させた磁気ブラシ帯電器で
あることを特徴とする（９）ないし（１１）のいずれか
１つに記載の画像記録装置。(12) The charging device is a magnetic brush charging device having a magnetic brush portion of conductive magnetic particles magnetically restrained and carried by a carrying member, and the magnetic brush portion being in contact with the image carrier. The image recording apparatus described in any one of (9) to (11).

【００３８】（１３）帯電器は、導電性繊維のブラシ部
を有し、該導電性繊維ブラシ部を像担持体に接触させた
ファーブラシ帯電器であることを特徴とする（９）ない
し（１１）のいずれか１つに記載の画像記録装置。(13) The charging device is a fur brush charging device having a brush portion of conductive fiber, and the conductive fiber brush portion is in contact with the image carrier. The image recording apparatus according to any one of 11).

【００３９】（１４）像担持体が表面抵抗１０9 〜１０
14Ω／ｃｍの低抵抗層を有することを特徴とする（９）
ないし（１３）のいずれか１つに記載の画像記録装置。(14) The image bearing member has a surface resistance of 10 9 to 10
Characterized by having a low resistance layer of 14 Ω / cm (9)
The image recording apparatus described in any one of (1) to (13).

【００４０】（１５）像担持体が絶縁性材料に導電性粒
子を分散した表面層を有することを特徴とする（９）な
いし（１４）のいずれか１つに記載の画像記録装置。(15) The image recording apparatus described in any one of (9) to (14), wherein the image carrier has a surface layer in which conductive particles are dispersed in an insulating material.

【００４１】（１６）導電性粒子がＳｎＯ2 であること
を特徴とする（１５）に記載の画像記録装置。(16) The image recording apparatus as described in (15), wherein the conductive particles are SnO 2 .

【００４２】（１７）少なくとも、像担持体と、（１）
ないし（８）の何れか１つに記載の帯電装置の少なくと
も帯電器を包含して画像記録装置本体に対して着脱され
ることを特徴とするプロセスカートリッジ。(17) At least an image carrier, and (1)
(8) A process cartridge including at least a charger of the charging device described in any one of (8) to (8) and being attached to and detached from an image recording apparatus main body.

【００４３】〈作 用〉 １）本発明は、電荷注入接触帯電方式の帯電系が抵抗と
コンデンサの時定数を有する帯電特性を持つことを利用
し、ＡＣ印加方式において印加ＡＣバイアスが被帯電体
表面に与える電位変動（電位振れ巾）ΔＶ、つまり印加
ＡＣバイアスに起因する被帯電体表面の細かな電位ムラ
を、実質的に悪影響しない一定量以下に抑えながら、し
かも帯電性を向上させるものである。<Operation> 1) The present invention utilizes the fact that the charging system of the charge injection contact charging system has charging characteristics having time constants of a resistor and a capacitor, and in the AC applying system, the applied AC bias is an object to be charged. The potential fluctuation (potential fluctuation range) ΔV applied to the surface, that is, the minute potential unevenness on the surface of the charged object due to the applied AC bias is suppressed to a fixed amount or less that does not substantially adversely affect, and yet the charging property is improved. is there.

【００４４】２）即ち、上記本発明において、2) That is, in the present invention,

【００４５】[0045]

【数９】 は、電荷注入接触帯電方式・ＡＣ印加方式で被帯電体を
帯電処理した場合のＡＣバイアスに起因して定常的に発
生する被帯電体表面の電位振れ巾ΔＶ（Ｖ）、つまり印
加ＡＣバイアスに起因する被帯電体表面の細かな電位ム
ラを意味する。[Equation 9] Is the potential fluctuation width ΔV (V) of the surface of the charged body that is constantly generated due to the AC bias when the charged body is charged by the charge injection contact charging method / AC applying method. It means a small potential unevenness on the surface of the body to be charged.

【００４６】この電位振れ巾（電位ムラ）ΔＶが小さい
程ＡＣバイアスによるかぶりは低下するが、同時に帯電
安定性は低下し、被帯電体の繰り返し帯電（印字）を行
ったときには、帯電不良を生じやすくなる。The smaller the potential fluctuation width (potential unevenness) ΔV, the lower the fog caused by the AC bias, but at the same time, the charging stability is lowered, and when the charged member is repeatedly charged (printed), a charging failure occurs. It will be easier.

【００４７】そこで本発明においては、被帯電体（像担
持体）移動方向に沿って、少なくとも、第１の帯電器
と、それよりも被帯電体移動方向下流側の第２の帯電器
を具備させ、第１の帯電器における該電位振れ巾ΔＶ１
と、第２の帯電器における該電位振れ巾ΔＶ２とが、Δ
Ｖ１＞ΔＶ２となるように第１と第２の両帯電器の帯電
特性を設定して、あるいは、帯電器に、被帯電体移動方
向に沿って、少なくとも、第１の給電部材による第１の
帯電部と、それよりも被帯電体移動方向下流側の第２の
給電部材による第２の帯電部を具備させ、第１の帯電部
における該電位振れ巾ΔＶ１と、第２の帯電部における
該電位振れ巾ΔＶ２とが、ΔＶ１＞ΔＶ２となるように
第１と第２の両帯電部の帯電特性を設定して、第２の帯
電器（第２の帯電部）よりも被帯電体移動方向上流側で
ある第１の帯電器（第１の帯電部）での被帯電体の帯電
は帯電性能を優先させて被帯電体電位を瞬時に上げるが
高い電位振れ巾ΔＶ１を生じる構成をとり、この第１の
帯電器よりも被帯電体移動方向下流側である第２の帯電
器での被帯電体の帯電はＡＣバイアスを印加したことに
起因する細かな電位ムラを被帯電体上に実質的に残さな
いよう十分低い電位振れ巾ΔＶ２（１００Ｖ以下が望ま
しい）となる状態で帯電する２重帯電の構成にする。Therefore, in the present invention, at least a first charger is provided along the moving direction of the charged body (image carrier), and a second charger is provided downstream of the first charger in the moving direction of the charged body. The potential fluctuation width ΔV1 in the first charger.
And the potential fluctuation range ΔV2 in the second charger is Δ
The charging characteristics of both the first and second charging devices are set so that V1> ΔV2, or the charging device is provided with at least the first charging member along the moving direction of the member to be charged. The charging section and the second charging section by the second power feeding member on the downstream side in the moving direction of the charged body are provided, and the potential fluctuation width ΔV1 of the first charging section and the second charging section of the second charging section are provided. The charging characteristics of both the first and second charging units are set so that the potential fluctuation range ΔV2 is ΔV1> ΔV2, and the direction of movement of the body to be charged is greater than that of the second charger (second charging unit). The charging of the body to be charged by the first charger (first charging unit) on the upstream side instantly raises the potential of the body to be charged by prioritizing the charging performance, but a high potential fluctuation range ΔV1 is generated. Charging of the member to be charged by the second charger which is downstream of the first charger in the moving direction of the member to be charged. A double charging configuration is used in which the potential fluctuation width ΔV2 (preferably 100 V or less) is sufficiently low so that the minute potential unevenness due to the application of the AC bias is not substantially left on the charged body. .

【００４８】第１と第２の帯電器（帯電部）における電
位振れ巾ΔＶ１，ΔＶ２は、第１と第２の帯電器それぞ
れにおいて印加ＡＣバイアスの実効電圧ＶACの倍数、周
波数ｆ、時定数τを調整することにより所望に調整でき
る。The first potential swing width ΔV1 in the second charger (charging unit), the [Delta] V2, the effective voltage V AC multiples of the applied AC bias in each of the first and second charger, the frequency f, the time constant It can be adjusted as desired by adjusting τ.

【００４９】これにより、電荷注入接触帯電方式・ＡＣ
印加方式の帯電装置、該帯電装置を使用した画像記録装
置やプロセスカートリッジについて、接触帯電器にＡＣ
バイアスを印加したことに起因する被帯電体表面の細か
な電位ムラの抑制（帯電均一性）と、帯電不良の防止
（帯電安定性）を両立させることができて、画像記録装
置やプロセスカートリッジにあっては、該帯電均一性と
帯電安定性の両立により高品位な画像記録を長期に渡り
安定に維持させることができる。As a result, the charge injection contact charging system AC
Regarding the charging type charging device, the image recording device and the process cartridge using the charging device, the contact charging device has an AC
It is possible to achieve both the suppression of minute potential unevenness on the surface of the member to be charged due to applying a bias (charging uniformity) and the prevention of charging failure (charging stability), making it suitable for image recording devices and process cartridges. Accordingly, high-quality image recording can be stably maintained for a long period of time by satisfying both the charging uniformity and the charging stability.

【００５０】３）また接触帯電器は特に磁気ブラシ帯電
器を使用することにより、かぶりがなく、帯電均一性に
も優れた帯電を行うことができ、優れた画像記録を可能
にする。接触帯電であっても、放電現象による帯電が支
配的である系においては、接触帯電器と被帯電体の電位
差は最小放電開始電圧（常温常圧において３２５Ｖ）以
下には成りえないため本発明の構成をとる効果はない
が、被帯電体面に対する電荷の直接注入（充電）による
帯電が支配的である系においては、接触帯電器に印加し
たＤＣバイアスとほぼ等しい電位に被帯電体が帯電され
るため、ＡＣバイアスを重畳し、迅速に安定して帯電を
行おうとすると、前述したように微小な帯電ムラを生じ
やすい。本発明は、このような電荷注入による帯電方式
において、ＡＣバイアスを印加するときに非常に有効な
構成を提供するものである。これは接触帯電器が磁気ブ
ラシ帯電器のみでなく、ファーブラシ帯電器やローラ帯
電器等の形態の部材であっても被帯電体が印加ＤＣバイ
アスとほぼ等しく帯電される帯電装置において共通して
有効である。ただ、磁気ブラシ帯電器のように、より均
一に細かく被帯電体に接触できる部材の方が、接触によ
る帯電ムラも少なく、本発明の構成を取ることでＡＣバ
イアスによるムラも少なく、より優れた帯電を実現可能
である。3) Further, by using a magnetic brush charger as the contact charger, it is possible to perform charging without fogging and with excellent charging uniformity, and it is possible to perform excellent image recording. Even in the case of contact charging, in a system where charging due to a discharge phenomenon is dominant, the potential difference between the contact charger and the body to be charged cannot be less than the minimum discharge starting voltage (325 V at room temperature and normal pressure). However, in a system in which charging by direct injection (charging) of charges to the surface of the charged body is dominant, the charged body is charged to a potential almost equal to the DC bias applied to the contact charger. Therefore, if an AC bias is superposed to quickly and stably perform charging, minute charging unevenness is likely to occur as described above. The present invention provides a very effective configuration when an AC bias is applied in such a charge injection charging system. This is common not only in the magnetic brush charger but also in the charging device in which the charged body is charged almost equal to the applied DC bias even if the contact charger is a member such as a fur brush charger or a roller charger. It is valid. However, a member such as a magnetic brush charger that can contact the member to be charged more uniformly and finely has less charging unevenness due to contact, and by adopting the configuration of the present invention, less unevenness due to AC bias is more excellent. Charging is possible.

【００５１】[0051]

【発明の実施の形態】BEST MODE FOR CARRYING OUT THE INVENTION

〈実施形態例１〉（図１〜図８） （１）画像記録装置例の概略（図１） 図１は本発明に従う画像記録装置例の概略構成図であ
る。本例の画像記録装置は、転写式電子写真方式・プロ
セスカートリッジ着脱方式のレーザービームプリンタで
ある。<Embodiment 1> (FIGS. 1 to 8) (1) Outline of image recording apparatus example (FIG. 1) FIG. 1 is a schematic configuration diagram of an image recording apparatus example according to the present invention. The image recording apparatus of this example is a laser beam printer of a transfer type electrophotographic type and a process cartridge attaching / detaching type.

【００５２】１は像担持体（被帯電体）としての回転ド
ラム型の電子写真感光体であり、中心支軸を中心に矢示
の時計方向ａに所定の周速度（プロセススピード）、本
例では１００ｍｍ／ｓｅｃをもって回転駆動される。本
例の感光体は表面に電荷注入層を設けたＯＰＣ感光体
（有機感光体）である。これについては（３）項で詳述
する。Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member as an image bearing member (charged member), which has a predetermined peripheral speed (process speed) in a clockwise direction a as shown by an arrow around a central support shaft. Is rotated at 100 mm / sec. The photoreceptor of this example is an OPC photoreceptor (organic photoreceptor) having a charge injection layer provided on the surface. This will be described in detail in section (3).

【００５３】２Ａ・２Ｂは該感光体１に対する第１の接
触帯電器と、これよりも感光体回転方向下流側の第２の
接触帯電器であり、本例の第１及び第２の帯電器２Ａ・
２Ｂはそれぞれ矢示の時計方向ｂに回転駆動されるスリ
ーブ回転タイプの磁気ブラシ帯電器である。これについ
ては（４）項で詳述する。Reference numerals 2A and 2B are a first contact charger for the photosensitive member 1 and a second contact charger downstream of the photosensitive member 1 in the rotating direction of the photosensitive member. The first and second chargers of the present embodiment. 2A
Reference numeral 2B denotes a sleeve rotation type magnetic brush charger which is rotationally driven in the clockwise direction b shown by the arrow. This will be described in detail in section (4).

【００５４】この第１と第２の磁気ブラシ帯電器２Ａ・
２Ｂにそれぞれ帯電バイアス印加電源Ｓ１・Ｓ２から帯
電バイアスとして所定の直流バイアスと交流バイアスの
重畳電圧が印加され（ＡＣ印加方式）、回転感光体表面
が所定の極性・電位に電荷注入方式で接触帯電処理され
る。本例においてはほぼ−７００Ｖに帯電処理される。The first and second magnetic brush chargers 2A
A superposed voltage of a predetermined DC bias and an AC bias is applied as a charging bias from each of the charging bias applying power sources S1 and S2 to 2B (AC applying method), and the surface of the rotating photoconductor is contact charged by a charge injection method to a predetermined polarity and potential. It is processed. In this example, the charging process is performed at about -700V.

【００５５】その回転感光体１の帯電処理面に対して露
光器としてのレーザースキャナ７によりレーザービーム
走査露光Ｌがなされて目的の画像情報に対応した静電潜
像が形成される。レーザースキャナ７は目的の画像情報
の時系列電気デジタル画素信号に対応して変調されたレ
ーザー光Ｌを出力する。７ａはレーザースキャナ７から
の出力レーザー光Ｌを回転感光体１の画像露光部に偏向
するミラーである。A laser beam scanning exposure L is applied to the charged surface of the rotating photosensitive member 1 by a laser scanner 7 as an exposing device to form an electrostatic latent image corresponding to desired image information. The laser scanner 7 outputs the laser light L modulated corresponding to the time series electric digital pixel signal of the target image information. Reference numeral 7a is a mirror for deflecting the output laser light L from the laser scanner 7 to the image exposure portion of the rotating photoconductor 1.

【００５６】その回転感光体面の静電潜像が現像器３に
よりトナー画像として現像される。本例の場合は反転現
像器であり、静電潜像の露光明部にトナーが付着して潜
像の現像がなされる。３ａは回転現像スリーブ、３ｂは
該現像スリーブ内に挿入配設したマグネットローラ、Ｓ
３は現像スリーブ３ａに対する現像バイアス印加電源で
ある。現像スリーブ３ａは感光体１の表面と０．３ｍｍ
隔てて対向しており、矢示の反時計方向に回転駆動され
てその周面に負に摩擦帯電されたトナーが薄層として塗
布されて感光体との対向部（現像部）へ搬送される。現
像スリーブ３ａには現像バイアス印加電源Ｓ３により、
本例の場合は、−５００ＶのＤＣ電圧と、周波数２．０
ＫＨｚ、ピーク間電圧１．６ｋＶのＡＣ電圧を重畳した
現像バイアスを印加することで、感光体１の静電潜像の
露光明部に現像スリーブ３ａ側のトナーが電界により選
択的に付着して静電潜像のトナー現像がなされる。The electrostatic latent image on the surface of the rotating photoconductor is developed as a toner image by the developing device 3. In the case of this example, the reversal developing device is used to develop the latent image by adhering toner to the exposed bright portion of the electrostatic latent image. 3a is a rotary developing sleeve, 3b is a magnet roller inserted in the developing sleeve, and S is a developing roller.
Reference numeral 3 is a power source for applying a developing bias to the developing sleeve 3a. The developing sleeve 3a is 0.3 mm from the surface of the photoreceptor 1.
Opposite to each other, the toner is driven to rotate counterclockwise as indicated by the arrow and negatively frictionally charged toner is applied to its peripheral surface as a thin layer and conveyed to a portion (developing portion) facing the photoconductor. . A developing bias applying power source S3 applies to the developing sleeve 3a.
In the case of this example, a DC voltage of -500V and a frequency of 2.0
By applying a developing bias superposed with an AC voltage of KHz and a peak-to-peak voltage of 1.6 kV, the toner on the developing sleeve 3a side selectively adheres to the exposed bright portion of the electrostatic latent image of the photoconductor 1 by the electric field. Toner development of the electrostatic latent image is performed.

【００５７】回転感光体１面のトナー画像は感光体１と
転写器４との対向部である転写部Ｔにおいて、該転写部
Ｔに不図示の給紙機構部から所定のタイミングで給紙さ
れた記録材（転写材）Ｐに対して転写される。転写器４
は本例の場合は感光体に当接させた転写ローラであり、
この転写ローラ４に転写バイアス印加電源Ｓ４からトナ
ーの帯電極性とは逆極性の所定電圧の転写バイアスが印
加されて、転写部Ｔに導入された記録材Ｐの表面側に感
光体１面側のトナー画像が静電的に転写される。The toner image on the surface of the rotating photoconductor 1 is fed to the transfer unit T at a predetermined timing from a paper feeding mechanism unit (not shown) at a transfer unit T which is an opposing portion of the photoconductor 1 and the transfer unit 4. It is transferred onto the recording material (transfer material) P. Transfer device 4
In the case of this example, is a transfer roller that is in contact with the photoconductor,
A transfer bias of a predetermined voltage opposite to the charging polarity of the toner is applied to the transfer roller 4 from the transfer bias applying power source S4, and the surface of the recording material P introduced into the transfer portion T is exposed to the surface of the photoreceptor 1. The toner image is electrostatically transferred.

【００５８】転写部Ｔを通ってトナー画像の転写を受け
た記録材Ｐは回転感光体面から分離されて定着器５に導
入され、トナー画像の定着処理を受けてプリントとして
出力される。The recording material P which has received the transfer of the toner image through the transfer portion T is separated from the surface of the rotating photoconductor and is introduced into the fixing device 5, where it is subjected to the fixing processing of the toner image and output as a print.

【００５９】また記録材分離後の回転感光体の面はクリ
ーニング器６により転写残りトナー等の付着残留物の除
去を受けて清浄面化され、繰り返して作像に供される。After the recording material is separated, the surface of the rotating photoconductor is cleaned by a cleaning device 6 to remove adhering residues such as residual toner after transfer, and is repeatedly used for image formation.

【００６０】（２）プロセスカートリッジ１０ １０はプリンタ本体内の所定の部位に対して着脱自在に
装着されるプロセスカートリッジである。本例のもの
は、像担持体としての感光体１と、接触帯電部材として
の第１及び第２の磁気ブラシ帯電器２Ａ・２Ｂと、現像
器３と、クリーニング器６の４つのプロセス機器を所定
の相互配置関係をもって一体的にカートリッジ筐体内に
組み付けてプロセスカートリッジ１０としてある。(2) Process cartridge 10 10 is a process cartridge which is detachably attached to a predetermined portion in the printer body. In this example, four process devices including a photoconductor 1 as an image carrier, first and second magnetic brush chargers 2A and 2B as contact charging members, a developing device 3, and a cleaning device 6 are provided. The process cartridge 10 is integrally assembled in a cartridge housing with a predetermined mutual arrangement relationship.

【００６１】このプロセスカートリッジ１０をプリンタ
本体内の所定の部位に対して装着することで、該プロセ
スカートリッジ１０とプリンタ本体側とが機械的・電気
的に所定に結合状態になり、プリンタが画像形成動作可
能状態になる。８・８はプロセスカートリッジ１０の着
脱ガイド部材兼保持部材である。By mounting the process cartridge 10 on a predetermined portion in the printer body, the process cartridge 10 and the printer body side are mechanically and electrically connected in a predetermined state, and the printer forms an image. Ready to operate. Reference numeral 8 denotes a detachable guide member / holding member for the process cartridge 10.

【００６２】（３）感光体１（図２） 本例で使用の感光体１は前述したように、表面に電荷注
入層を設けたＯＰＣ感光体（有機感光体）である。(3) Photoreceptor 1 (FIG. 2) As described above, the photoreceptor 1 used in this example is an OPC photoreceptor (organic photoreceptor) having a charge injection layer on its surface.

【００６３】図２は該感光体１の層構成模型図である。
１１はアルミニウム製のドラム基体（Ａｌドラム基体）
であり、その上に、下引き層１２、正電荷注入防止層１
３、電荷発生層１４、電荷輸送層１５を順次に重ねて塗
工することで一般的なＯＰＣ感光体層を形成し、更にそ
の上に電荷注入層１６を塗布して形成具備させたもので
ある。FIG. 2 is a schematic diagram of the layer structure of the photoconductor 1.
11 is an aluminum drum base (Al drum base)
And on top of that, the undercoat layer 12 and the positive charge injection prevention layer 1
3, a charge generation layer 14 and a charge transport layer 15 are sequentially laminated and applied to form a general OPC photoreceptor layer, and a charge injection layer 16 is further applied and formed thereon. is there.

【００６４】本例における電荷注入層１６は、光硬化型
のアクリル樹脂に、導電性粒子としてのＳｎＯ2 超微粒
子１６ａ（径が約０．０３μｍ）、４フッ化エチレン樹
脂（テフロン）などの滑剤、重合開始剤等を混合分散
し、塗工後、光硬化法により膜形成したものである。電
荷注入層１６の抵抗値としては１×１０9 〜１×１０14
（Ω・ｃｍ）の範囲が適当である。The charge injection layer 16 in this example is composed of a photo-curing acrylic resin, SnO 2 ultrafine particles 16a (having a diameter of about 0.03 μm) as conductive particles, and a lubricant such as tetrafluoroethylene resin (Teflon). , A polymerization initiator and the like are mixed and dispersed, and after coating, a film is formed by a photo-curing method. The resistance value of the charge injection layer 16 is 1 × 10 9 to 1 × 10 14
The range of (Ω · cm) is appropriate.

【００６５】感光体層はＣｄＳや、Ｓｉ，Ｓｅなど無機
物半導体を用いることもできる。For the photosensitive layer, an inorganic semiconductor such as CdS, Si or Se can be used.

【００６６】（４）第１と第２の磁気ブラシ帯電器２Ａ
・２Ｂ（図３・図４） 図３は第１と第２の磁気ブラシ帯電器２Ａ・２Ｂ部分の
構成模型図である。この両磁気ブラシ帯電器２Ａ・２Ｂ
は何れも同様構成のスリーブ回転タイプの磁気ブラシ帯
電器である。(4) First and second magnetic brush charger 2A
2B (FIGS. 3 and 4) FIG. 3 is a structural model view of the first and second magnetic brush chargers 2A and 2B. Both magnetic brush chargers 2A and 2B
Is a sleeve rotation type magnetic brush charger having the same configuration.

【００６７】即ち、何れも、固定支持させたマグネット
ローラ２ａと、このマグネットローラ２ａの外回りに同
心に回転自由に外嵌させた、表面の平均粗さＲａ１．２
μｍの非磁性の導電性帯電スリーブ２ｂと、この帯電ス
リーブ２ｂの外周面に帯電スリーブ内部のマグネットロ
ーラ２ａの磁力により吸着保持させて形成させた導電性
磁性粒子の磁気ブラシ層２ｃからなる。That is, in both cases, the average roughness Ra1.2 of the surface of the magnet roller 2a, which is fixed and supported, and the outer surface of which is concentrically and rotatably fitted around the outer circumference of the magnet roller 2a.
It comprises a non-magnetic conductive charging sleeve 2b of μm and a magnetic brush layer 2c of conductive magnetic particles formed on the outer peripheral surface of the charging sleeve 2b by being attracted and held by the magnetic force of the magnet roller 2a inside the charging sleeve.

【００６８】マグネットローラ２ａは帯電スリーブ表面
上で半径方向の磁束密度のピークが６００Ｇを発生する
磁極を４極有するものを使用し、感光体１側に一つの磁
極が向くようにマグネットローラ２ａを固定支持させ
た。As the magnet roller 2a, one having four magnetic poles having a radial magnetic flux density peak of 600 G on the surface of the charging sleeve is used, and the magnet roller 2a is oriented so that one magnetic pole faces the photoreceptor 1. It was fixed and supported.

【００６９】磁気ブラシ層２ｃを構成させる導電性磁性
粒子は、所定の抵抗値、形状及び磁気特性を有する必要
がある。例えば、平均粒径が３０μｍ、体積抵抗のオー
ダが１×１０6 （Ωｃｍ）のフェライト粒子であり、飽
和磁化が６０（Ａ・ｍ2 ／ｋｇ）のものを使用した。The conductive magnetic particles forming the magnetic brush layer 2c must have a predetermined resistance value, shape and magnetic characteristics. For example, ferrite particles having an average particle size of 30 μm, a volume resistance order of 1 × 10 6 (Ωcm), and a saturation magnetization of 60 (A · m 2 / kg) were used.

【００７０】導電性磁性粒子の抵抗測定は、底面積２２
８ｍｍ2 の筒状の容器に導電性磁性粒子を２ｇ充填して
１５Ｋｇで加圧し、上下から１００Ｖの電圧を印加して
この系に流れる電流から算出し正規化したもので定義し
た。The resistance of conductive magnetic particles is measured by measuring the bottom area 22.
2 g of the conductive magnetic particles were filled in a cylindrical container of 8 mm 2 and pressurized at 15 kg, and a voltage of 100 V was applied from the top and bottom to calculate from the current flowing in this system and defined as normalized.

【００７１】導電性磁性粒子としては、フェライト、マ
グネタイトなど磁性金属粒子や、またこれらの磁性粒子
を樹脂で決着したものも使用可能である。抵抗値は１×
１０4 〜１×１０7 Ωｃｍのものが適当である。粒径に
ついては５〜５０μｍが適性であった。また、複数の磁
性粒子を混合し用いることで帯電性の向上も図ることが
可能である。本発明において、帯電ニップの構成、導電
性磁性粒子の抵抗、流刑は磁気ブラシを構成したとき
に、帯電器全体として後述するある一定の条件を満足す
るように適切な特性をもつ必要がある。As the conductive magnetic particles, it is possible to use magnetic metal particles such as ferrite and magnetite, or particles obtained by fixing these magnetic particles with a resin. Resistance value is 1 ×
A value of 10 4 to 1 × 10 7 Ωcm is suitable. Regarding the particle size, 5 to 50 μm was suitable. Further, it is possible to improve the charging property by mixing and using a plurality of magnetic particles. In the present invention, the configuration of the charging nip, the resistance of the conductive magnetic particles, and the expulsion must have appropriate characteristics so that the charger as a whole satisfies certain conditions described below.

【００７２】導電性磁性粒子の平均粒径は、水平方向最
大弦長で示し、測定法は顕微鏡法により、粒子３００個
以上をランダムに選び、その径を実測して算術平均をと
ることによって算出した。The average particle diameter of the conductive magnetic particles is indicated by the maximum chord length in the horizontal direction. The measuring method is a microscope method in which 300 or more particles are randomly selected, and the diameter is measured to calculate the arithmetic mean. did.

【００７３】導電性磁性粒子の磁気特性測定には理研電
子株式会社の直流磁化Ｂ−Ｈ特性自動記録装置ＢＨＨ−
５０を用いることができる。この際、直径（内径）６．
５ｍｍ、高さ１０ｍｍの円柱状の容器に導電性磁性粒子
を荷重約２ｇ重程度で充填し、容器内で粒子が動かない
ようにしてそのＢ−Ｈカーブから飽和磁化を測定する。To measure the magnetic properties of the conductive magnetic particles, a DC magnetization BH characteristic automatic recorder BHH- manufactured by Riken Denshi Co., Ltd.
50 can be used. At this time, the diameter (inner diameter) 6.
A columnar container having a height of 5 mm and a height of 10 mm is filled with conductive magnetic particles under a load of about 2 g, and the saturation magnetization is measured from the BH curve while keeping the particles from moving in the container.

【００７４】而して、上記の第１と第２の磁気ブラシ帯
電器２Ａ・２Ｂをそれぞれ、感光体１と略並行にして、
帯電スリーブ２ｂの表面と感光体１の表面との離間距離
が０．５ｍｍになるように長手方向の端部をスペーサ部
材（不図示）を介して感光体の端部表面に当接して配設
することで、磁気ブラシ層２ｃを感光体１面に所定幅の
帯電部（帯電ニップ部）ｎ１・ｎ２を形成させて接触さ
せてある。Then, the above-mentioned first and second magnetic brush chargers 2A and 2B are arranged substantially parallel to the photoconductor 1 respectively,
The end portion in the longitudinal direction is disposed in contact with the end surface of the photoconductor through a spacer member (not shown) so that the distance between the surface of the charging sleeve 2b and the surface of the photoconductor 1 is 0.5 mm. By doing so, the magnetic brush layer 2c is formed in contact with the surface of the photoconductor 1 by forming charging portions (charging nip portions) n1 and n2 having a predetermined width.

【００７５】第１と第２の磁気ブラシ帯電器２Ａ・２Ｂ
の帯電スリーブ２ｂはそれぞれ帯電部ｎ１・ｎ２におい
て感光体１の回転方向ａとは逆方向である矢示の時計方
向ｂに感光体１の回転周速度１００ｍｍ／ｓｅｃと同じ
周速度で回転駆動され、これに伴い磁気ブラシ層２ｃも
同方向に回転して感光体１面を摺擦する。First and second magnetic brush chargers 2A and 2B
The charging sleeve 2b is rotationally driven in the charging portions n1 and n2 in the clockwise direction b indicated by the arrow, which is the opposite direction to the rotation direction a of the photoconductor 1, at the same peripheral speed as the peripheral speed of rotation of the photoconductor 1 of 100 mm / sec. Along with this, the magnetic brush layer 2c also rotates in the same direction and rubs the surface of the photoreceptor 1.

【００７６】そして帯電時に、第１の磁気ブラシ帯電器
２Ａの帯電スリーブ２ｂに対して帯電バイアス印加電源
Ｓ１から ＤＣバイアス； −７００Ｖ ＡＣバイアス； 実効電圧１０００Ｖ、周波数１００
０Ｈｚ、矩形波 の重畳電圧が印加されることで、磁気ブラシ層２ｃの導
電性磁性粒子を通して帯電部ｎ１において感光体１の電
荷注入層１６に電荷が注入（充電）され、感光体表面は
この第１の磁気ブラシ帯電器２Ａに対する上記印加帯電
バイアスのＤＣバイアスとほぼ同電位に帯電される。During charging, DC bias from the charging bias applying power source S1 to the charging sleeve 2b of the first magnetic brush charger 2A; -700V AC bias; effective voltage 1000V, frequency 100.
By applying a superposed voltage of 0 Hz and a rectangular wave, charges are injected (charged) into the charge injection layer 16 of the photoconductor 1 at the charging portion n1 through the conductive magnetic particles of the magnetic brush layer 2c, and the surface of the photoconductor is The first magnetic brush charger 2A is charged to substantially the same potential as the DC bias of the applied charging bias.

【００７７】また、第２の磁気ブラシ帯電器２Ｂの帯電
スリーブ２ｂに対して帯電バイアス印加電源Ｓ２から ＤＣバイアス； −７００Ｖ ＡＣバイアス； 実効電圧５００Ｖ、周波数１０００
Ｈｚ、矩形波 の重畳電圧が印加されることで、磁気ブラシ層２ｃの導
電性磁性粒子を通して帯電部ｎ２において感光体１の電
荷注入層１６に電荷が注入（充電）され、感光体表面は
この第２の磁気ブラシ帯電器２Ｂに対する上記印加帯電
バイアスのＤＣバイアスとほぼ同電位に帯電される。A DC bias from the charging bias applying power source S2 to the charging sleeve 2b of the second magnetic brush charger 2B; -700V AC bias; effective voltage 500V, frequency 1000.
When a superimposed voltage of Hz and a rectangular wave is applied, charges are injected (charged) into the charge injection layer 16 of the photoconductor 1 at the charging portion n2 through the conductive magnetic particles of the magnetic brush layer 2c, and the surface of the photoconductor is The second magnetic brush charger 2B is charged to substantially the same potential as the DC bias of the applied charging bias.

【００７８】即ち、回転感光体１は第１の磁気ブラシ帯
電器２Ａによる帯電に次いで第２の磁気ブラシ帯電器２
Ｂによる帯電の２重の帯電処理を受ける。That is, the rotary photoreceptor 1 is charged by the first magnetic brush charger 2A and then the second magnetic brush charger 2 is charged.
It undergoes a double charging process of charging by B.

【００７９】この場合、後述するように、第１の磁気ブ
ラシ帯電器２Ａによる感光体１の帯電は、帯電性能を優
先して高い電位振れ巾ΔＶ１を生じるように、次の第２
の磁気ブラシ帯電器２Ｂによる感光体１の帯電は、第１
の磁気ブラシ帯電器２Ａによる帯電で生じたＡＣバイア
スによる電位ムラを抑えるよう低い電位振れ巾ΔＶ１で
帯電するように、第１と第２の磁気ブラシ帯電器２Ａ・
２Ｂのそれぞれに印加する帯電バイアスを上記のように
設定してある。In this case, as will be described later, the charging of the photoconductor 1 by the first magnetic brush charger 2A is performed in the following second step so that a high potential fluctuation range ΔV1 is generated by giving priority to the charging performance.
The charging of the photoconductor 1 by the magnetic brush charger 2B of
The first and second magnetic brush chargers 2A and 2A so as to charge with a low potential fluctuation width ΔV1 so as to suppress potential unevenness due to the AC bias generated by the magnetic brush charger 2A.
The charging bias applied to each of 2B is set as described above.

【００８０】図４の（ａ）は第１または第２の磁気ブラ
シ帯電器２Ａ・２Ｂの帯電回路系の構成模型図、（ｂ）
はその等価回路図である。FIG. 4A is a structural model diagram of the charging circuit system of the first or second magnetic brush chargers 2A and 2B, and FIG.
Is an equivalent circuit diagram thereof.

【００８１】電荷注入帯電は、中抵抗の接触帯電部材で
中抵抗の表面抵抗を持つ被帯電体（感光体）表面に電荷
注入を行なうものであり、本例においては感光体表面材
質の持つトラップ電位に電荷を注入するものではなく、
電荷注入層１６の導電性粒子（ＳｎＯ2 ）１６ａに電荷
を充電して帯電を行なう方式であり、図４の（ｂ）の等
価回路のように、電荷輸送層１５を誘電体とし、アルミ
ニウムドラム基体１１と、電荷注入層１６内の導電性粒
子１６ａを両電極板とする微小なコンデンサーに対し
て、接触帯電部材２Ａ（２Ｂ）で電荷を充電する理論に
基づくものである。この際、導電性粒子１６ａは互いに
電気的には独立であり、一種の微小なフロート電極を形
成している。このため、マクロ的には感光体表面は均一
電位に充電、帯電されているように見えるが、実際には
微小な無数の充電された導電性粒子であるＳｎＯ2 が感
光体表面を覆っているような状況となっている。このた
め、レーザー光によって画像露光Ｌを行なっても、露光
暗部ではそれぞれのＳｎＯ2粒子１６ａは電気的に独立
なため、静電潜像を保持することが可能になる。In the charge injection charging, a contact charging member having a medium resistance is used to inject charges to the surface of a charged body (photoreceptor) having a surface resistance of medium resistance. In this example, a trap of the surface material of the photoreceptor is used. Not to inject charge into the potential,
This is a method in which the conductive particles (SnO 2 ) 16a of the charge injection layer 16 are charged by charging, and the charge transport layer 15 is a dielectric and the aluminum drum is used as in the equivalent circuit of FIG. This is based on the theory that the contact charging member 2A (2B) charges the base 11 and the minute capacitor having the conductive particles 16a in the charge injection layer 16 as both electrode plates. At this time, the conductive particles 16a are electrically independent of each other and form a kind of minute float electrode. For this reason, the surface of the photoconductor looks macroscopically charged and charged to a uniform potential, but in reality SnO 2 which is a myriad of charged conductive particles covers the surface of the photoconductor. The situation is as follows. Therefore, even if the image exposure L is performed with the laser light, the SnO 2 particles 16a are electrically independent in the dark portion of the exposure, so that the electrostatic latent image can be held.

【００８２】（５）帯電特性（図５〜図８） 電荷注入による帯電方式において、被帯電体としての感
光体１の帯電特性は、接触帯電器２に直流電圧を印加し
たときの感光体電位の上昇する過程を観測することによ
り把握することができる。(5) Charging Characteristics (FIGS. 5 to 8) In the charging method by charge injection, the charging characteristics of the photosensitive member 1 as the member to be charged are the photosensitive member potential when a DC voltage is applied to the contact charger 2. It can be understood by observing the rising process of.

【００８３】実際の帯電過程を等価回路に当てはめて考
えると、図４の（ａ）における電源Ｓ１（Ｓ２）−磁気
ブラシ帯電器２Ａ（２Ｂ）−感光体１の帯電系は、図４
の（ｂ）の等価回路のように、感光体１はコンデンサと
して、磁気ブラシ帯電器２Ａ（２Ｂ）は抵抗として表さ
れ、帯電はこのコンデンサと抵抗の直列回路に従い充電
が行なわれると考えることができる。When the actual charging process is applied to the equivalent circuit, the charging system of the power source S1 (S2) -magnetic brush charger 2A (2B) -photoreceptor 1 in FIG.
Like the equivalent circuit of (b), the photoconductor 1 is represented as a capacitor and the magnetic brush charger 2A (2B) is represented as a resistor, and it can be considered that charging is performed according to a series circuit of this capacitor and the resistor. it can.

【００８４】そこで、接触帯電器としての磁気ブラシ帯
電器２を介して被帯電体としての感光体１に印加する直
流電圧をＶ（Ｖ）、時定数をτ（ｓｅｃ）、印加後経過
時間をｔ（ｓｅｃ）とするとき、感光体１の充電電圧Ｖ
ｄ（Ｖ）は以下の式で表される。Therefore, the DC voltage applied to the photoconductor 1 as the member to be charged through the magnetic brush charger 2 as the contact charger is V (V), the time constant is τ (sec), and the elapsed time after the application is When t (sec), the charging voltage V of the photoconductor 1
d (V) is represented by the following formula.

【００８５】 Ｖｄ＝Ｖ（１−ｅｘｐ（−ｔ／τ）） ・・・・・・（１）式 または、 ｌｎ｜Ｖ−Ｖｄ｜＝−ｔ／τ＋ｌｎＶ ・・・・・・（２）式 （２）式からｌｎ｜Ｖ−Ｖｄ｜とｔの関係において直線
関係が得られることが予想できる。Vd = V (1-exp (−t / τ)) Equation (1) or ln | V−Vd | = −t / τ + lnV Equation (2) From the equation (2), it can be expected that a linear relationship can be obtained in the relationship between ln | V-Vd | and t.

【００８６】図５の（ａ）は、磁気ブラシ帯電器２のス
リーブ２ｂに直流電圧のみを印加し感光体１を複数回連
続して回転したときの感光体表面の電位が上昇していく
経過を示している。周回を重ねる毎に表面電位が増加し
ていくことが確認できる。FIG. 5A shows a process in which the potential of the surface of the photoconductor rises when only the DC voltage is applied to the sleeve 2b of the magnetic brush charger 2 and the photoconductor 1 is continuously rotated a plurality of times. Is shown. It can be confirmed that the surface potential increases with each lap.

【００８７】感光体１の帯電は磁気ブラシ帯電器２に接
触している間のみ断続的に行われるため、時間に対し帯
電現象を捕らえるためには正味の帯電時間を計算する必
要がある。図５の（ｂ）は磁気ブラシ帯電器２と感光体
１との接触部である帯電ニップ部内通過時間ｔnip （ｓ
ｅｃ）を感光体周回ごとに累積することによりバイアス
印加からの帯電時間を求めた。Since the charging of the photosensitive member 1 is intermittently performed only while it is in contact with the magnetic brush charger 2, it is necessary to calculate the net charging time in order to catch the charging phenomenon with respect to time. FIG. 5B shows the passage time tnip (s) in the charging nip portion, which is the contact portion between the magnetic brush charger 2 and the photoconductor 1.
The charging time from the bias application was obtained by accumulating ec) for each rotation of the photoreceptor.

【００８８】帯電ニップ部通過時間ｔnip は感光体１の
周速度Ｖｐｓ（ｍｍ／ｓｅｃ）と正味の帯電ニップ部巾
Ｌnip （ｍｍ）から、ｔnip ＝Ｌnip ／Ｖｐｓで求めら
れる。The passage time tnip of the charging nip portion can be obtained from the peripheral speed Vps (mm / sec) of the photosensitive member 1 and the net width Lnip (mm) of the charging nip portion as tnip = Lnip / Vps.

【００８９】また、帯電ニップ部巾Ｌnip 巾に関して、
磁気ブラシ帯電器２の磁気ブラシ層２ｃと感光体１の接
触は周方向について不均一であるため、正味の帯電に寄
与する帯電ニップ部巾は見かけ接触しているニップ巾よ
り狭い。Regarding the charging nip width Lnip,
Since the contact between the magnetic brush layer 2c of the magnetic brush charger 2 and the photoconductor 1 is non-uniform in the circumferential direction, the width of the charging nip portion that contributes to net charging is narrower than the width of the apparent contact nip portion.

【００９０】そこで、本発明においては、正味のニップ
巾は、感光体１表面と磁気ブラシ帯電器２Ａ（２Ｂ）の
スリーブ２ｂ間の抵抗分布から正確に求める。方法とし
ては感光体１上にニップに対し充分小さな電極を取り付
け、その電極とスリーブ２ｂ間の抵抗値を測定する。電
極は長手方向長さ５０ｍｍ、周方向巾０．５ｍｍ、厚さ
０．１μｍとし、真空蒸着法により形成した。電極は長
手方向と平行になるよう配慮し調整した。抵抗分布の測
定は、スリーブ２ｂ、感光体１共に回転した状態で、感
光体１上に形成した電極とスリーブ２ｂ間に３００Ｖの
電圧を印加し、この系の抵抗を時系列に測定し、感光体
周速から周方向位置を計算し、ニップ内の抵抗分布を求
めた。本例では、この抵抗分布の半値巾をニップの実効
的巾と定義した。正味のニップ巾は２〜５ｍｍの値であ
った。Therefore, in the present invention, the net nip width is accurately obtained from the resistance distribution between the surface of the photoconductor 1 and the sleeve 2b of the magnetic brush charger 2A (2B). As a method, a sufficiently small electrode is attached to the nip on the photoconductor 1 and the resistance value between the electrode and the sleeve 2b is measured. The electrode had a length of 50 mm in the longitudinal direction, a width of 0.5 mm in the circumferential direction, and a thickness of 0.1 μm, and was formed by a vacuum deposition method. The electrodes were adjusted so as to be parallel to the longitudinal direction. To measure the resistance distribution, a voltage of 300 V is applied between the electrode formed on the photoconductor 1 and the sleeve 2b while the sleeve 2b and the photoconductor 1 are rotated, and the resistance of this system is measured in time series. The circumferential position was calculated from the body speed and the resistance distribution in the nip was obtained. In this example, the full width at half maximum of this resistance distribution is defined as the effective width of the nip. The net nip width was a value of 2-5 mm.

【００９１】そうして求められた帯電ニップ部通過時間
を感光体の周回毎累積することで帯電時間をもとめ、図
５の（ｂ）における縦軸は印加バイアスと感光体表面電
位の差の絶対値の自然対数、つまり（２）式の左辺ｌｎ
｜Ｖ−Ｖｄ｜を計算し、プロットした。図５の（ｂ）の
グラフよりほぼ直線関係が得られているので、帯電の過
程が前述の等価回路に従い起きていることが確認でき
る。The charging time is obtained by accumulating the thus obtained charging nip portion passing time for each revolution of the photoconductor, and the vertical axis in FIG. 5B shows the absolute difference between the applied bias and the photoconductor surface potential. Natural logarithm of the value, that is, left side ln of equation (2)
| V-Vd | was calculated and plotted. Since a nearly linear relationship is obtained from the graph of FIG. 5B, it can be confirmed that the charging process occurs according to the equivalent circuit described above.

【００９２】図５の（ｂ）の関係から、第１及び第２の
磁気ブラシ帯電器２Ａ・２Ｂにおける充電過程の時定数
τを求めることができる。こうして求められた時定数τ
は後述するかぶり除去と帯電性維持のための構成を設定
するために重要な値である。From the relationship of FIG. 5B, the time constant τ of the charging process in the first and second magnetic brush chargers 2A and 2B can be obtained. The time constant τ obtained in this way
Is an important value for setting a configuration for removing fog and maintaining chargeability, which will be described later.

【００９３】前述の通り、電荷注入による帯電方式にお
いてＤＣ＋ＡＣの重畳バイアスを用いる場合はＡＣバイ
アスによる電位ムラが生じ画像中にかぶりが生じる。更
に帯電性の維持と両立しないという問題がある。接触帯
電器である磁気ブラシ帯電器２Ａ・２Ｂに印加したバイ
アスに等しい電位に感光体１を帯電できるため、ＡＣバ
イアスのムラを感光体１に与えやすい構成になってい
る。実際その周期が画像記録上充分小さい場合において
も、微小な帯電ムラを生じているためかぶりとなって現
れると考えられる。As described above, when a DC + AC superimposing bias is used in the charging method by charge injection, potential unevenness occurs due to the AC bias, and fog occurs in the image. Further, there is a problem that it is incompatible with the maintenance of chargeability. Since the photoconductor 1 can be charged to a potential equal to the bias applied to the magnetic brush chargers 2A and 2B, which are contact chargers, the AC bias unevenness is easily applied to the photoconductor 1. In fact, even if the cycle is sufficiently small for image recording, it is considered that fogging occurs because minute charging unevenness occurs.

【００９４】本発明では電荷注入による帯電方式が前述
の抵抗とコンデンサの時定数を有する帯電特性を持つこ
とを利用し、感光体表面に与える電位変動を一定量以下
に抑えながら、帯電性を向上できる構成をとる。The present invention utilizes the fact that the charging method by charge injection has the above-mentioned charging characteristics having the time constants of the resistor and the capacitor, and improves the charging property while suppressing the potential fluctuation applied to the surface of the photoconductor to a certain amount or less. Take a possible configuration.

【００９５】前述の等価回路において、定常的に発生す
る電圧の変動分ΔＶ（感光体表面の電位振れ巾）は以下
の式（３）で表わされる。In the above-mentioned equivalent circuit, the variation ΔV (potential fluctuation range on the surface of the photoconductor) which is constantly generated is expressed by the following equation (3).

【００９６】[0096]

【数１０】 ここで、ＶAC（Ｖ）は印加ＡＣバイアスの実効電圧を、
ｆ（Ｈｚ）は印加ＡＣバイアスの周波数を、τ（ｓｅ
ｃ）は前述の方法で求められる帯電装置の時定数を示
す。(Equation 10) Where V AC (V) is the effective voltage of the applied AC bias,
f (Hz) is the frequency of the applied AC bias, τ (se
c) shows the time constant of the charging device obtained by the above method.

【００９７】図５の（ｂ）において、直線の傾きから時
定数τを決定するが、実際の充電過程は完全に線形では
ない。この場合、ここで用いるＡＣバイアスの実効値の
電圧量と等しい量の電位差（印加ＤＣバイアスと表面電
位の差）のときの接線の傾きから時定数を求める必要が
ある。In FIG. 5B, the time constant τ is determined from the slope of the straight line, but the actual charging process is not completely linear. In this case, it is necessary to obtain the time constant from the slope of the tangent line when the potential difference (difference between the applied DC bias and the surface potential) is equal to the effective voltage amount of the AC bias used here.

【００９８】本発明者の検討の結果、このようにして求
められる感光体表面の電位振れ巾ΔＶとかぶりの相関が
得られた。図６はこの感光体表面の電位振れ巾ΔＶとか
ぶりの関係をグラフに表わしたものである。As a result of the study by the present inventor, the correlation between the potential fluctuation width ΔV of the surface of the photosensitive member and the fog thus obtained was obtained. FIG. 6 is a graph showing the relationship between the potential fluctuation range ΔV on the surface of the photoconductor and the fog.

【００９９】かぶりは、記録前の記録紙の反射率と記録
後の非画像部の反射率の差をとり、数値化して評価し
た。The fogging was evaluated by taking the difference between the reflectance of the recording paper before recording and the reflectance of the non-image area after recording and digitizing it.

【０１００】電位振れ巾ΔＶが小さい程ＡＣバイアスに
よるかぶりは低下するが、同時に帯電安定性は低下し、
繰り返し印字を行ったときは帯電不良を生じやすくな
る。As the potential fluctuation width ΔV is smaller, the fogging due to the AC bias is reduced, but at the same time, the charging stability is reduced.
When printing is repeated, charging failure tends to occur.

【０１０１】本例においては、第１の磁気ブラシ帯電器
２Ａによる感光体１の帯電は、帯電性能を優先して高い
電位振れ巾ΔＶ１を生じるように、次の第２の磁気ブラ
シ帯電器２Ｂによる感光体１の帯電は、第１の磁気ブラ
シ帯電器２Ａによる帯電で生じたＡＣバイアスによる電
位ムラを抑えるよう低い電位振れ巾ΔＶ１（１００Ｖ以
下が望ましい）で帯電するように、第１と第２の磁気ブ
ラシ帯電器２Ａ・２Ｂのそれぞれに印加する帯電バイア
スを設定した。In this example, the charging of the photoconductor 1 by the first magnetic brush charger 2A is performed so that a high potential fluctuation range ΔV1 is generated by giving priority to the charging performance. The photoreceptor 1 is charged by the first and the first magnetic brush chargers 2A so as to be charged with a low potential fluctuation width ΔV1 (preferably 100 V or less) so as to suppress potential unevenness due to the AC bias generated by the charging. The charging bias applied to each of the two magnetic brush chargers 2A and 2B was set.

【０１０２】これにより、電荷注入接触帯電方式・ＡＣ
印加方式の帯電系について、接触帯電器にＡＣバイアス
を印加したことに起因する被帯電体表面の細かな電位ム
ラの抑制（帯電均一性）と、帯電不良の防止（帯電安定
性）を両立させることができて、画像記録装置やプロセ
スカートリッジにあっては、該帯電均一性と帯電安定性
の両立により高品位な画像記録を長期に渡り安定に維持
させることができる。As a result, the charge injection contact charging method / AC
With respect to the charging system of the application system, it is possible to both suppress small potential unevenness on the surface of the member to be charged (charging uniformity) due to the application of an AC bias to the contact charger and prevent charging failure (charging stability). Therefore, in the image recording apparatus and the process cartridge, high-quality image recording can be stably maintained for a long period of time by achieving both the charging uniformity and the charging stability.

【０１０３】次に、比較例とともに本発明の優位性を説
明する。Next, the superiority of the present invention will be described together with a comparative example.

【０１０４】表１は、比較例１・比較例２とともに実施
例１の時定数、ＡＣ電圧の実効電圧の倍数、周波数、そ
して（３）式から算出される感光体表面の電位振れ巾Δ
Ｖ、及び実際画像記録を行ったときのかぶりの数値をま
とめたものである。比較例１及び比較例２は磁気ブラシ
帯電器を１器だけにしたものである。Table 1 shows Comparative Example 1 and Comparative Example 2 together with the time constant of Example 1, the multiple of the effective voltage of the AC voltage, the frequency, and the potential fluctuation range Δ of the photosensitive member surface calculated from the equation (3).
The values of V and fogging when actual image recording is performed are summarized. In Comparative Example 1 and Comparative Example 2, only one magnetic brush charger is used.

【０１０５】[0105]

【表１】 比較例１；比較例１の条件においては、電位振れ巾ΔＶ
は１２４Ｖ（図７）になり、ＡＣかぶりが大きく画像不
良が生じている。しかし、印字耐久に対しては初期の帯
電電位を維持しており安定性としては満足している。[Table 1] Comparative Example 1; Under the conditions of Comparative Example 1, the potential fluctuation range ΔV
Is 124 V (FIG. 7), AC fogging is large, and an image defect occurs. However, with respect to printing durability, the initial charging potential was maintained and the stability was satisfactory.

【０１０６】比較例２；比較例２の条件においては、Ｖ
ACを５００Ｖに低下したため、電位振れ巾ΔＶは６２Ｖ
に減少し（図８）、かぶりも１．８％で良好である。し
かし、印字を続けるにつれて、帯電電位が減少し帯電不
良を生じていた。Comparative Example 2; Under the conditions of Comparative Example 2, V
Since the AC voltage is reduced to 500V, the potential fluctuation width ΔV is 62V.
(Fig. 8), and the fogging is also good at 1.8%. However, as the printing was continued, the charging potential decreased, and charging failure occurred.

【０１０７】比較例１・比較例２に示すように、ＡＣか
ぶりの防止（帯電均一性）と帯電安定性の両立は難しい
ことがわかる。As shown in Comparative Examples 1 and 2, it is understood that it is difficult to achieve both AC fog prevention (charging uniformity) and charging stability.

【０１０８】実施例１；第１の磁気ブラシ帯電器２Ａで
は電位振れ巾ΔＶ１が１２４Ｖであるため、帯電安定性
は優れているが、そのままではかぶりが問題になる。し
かしこの第１の磁気ブラシ帯電器２Ａの感光体下流側の
第２の磁気ブラシ帯電器２Ｂにより電位振れ巾ΔＶ２が
６２Ｖにまで改善されＡＣバイアスによるかぶりも１．
８％にまで減少し、優れた帯電系を構成することができ
た。Example 1 In the first magnetic brush charger 2A, since the potential fluctuation width ΔV1 is 124 V, the charging stability is excellent, but fogging becomes a problem as it is. However, the second magnetic brush charger 2B on the downstream side of the photoconductor of the first magnetic brush charger 2A improves the potential fluctuation width ΔV2 to 62V, and the fog caused by the AC bias is 1.
It was reduced to 8%, and an excellent charging system could be constructed.

【０１０９】以上、本実施例においては、第１と第２の
磁気ブラシ帯電器２Ａ・２Ｂを具備させ、帯電系の時定
数と、印加するＡＣバイアスから計算される感光体表面
の電位振れ巾ΔＶについて、第１の磁気ブラシ帯電器２
ＡのΔＶ１を、該第１の磁気ブラシ帯電器２Ａよりも感
光体回転方向下流側の第２の磁気ブラシ帯電器２ＢのΔ
Ｖ２より小さく構成することにより、ＡＣバイアスによ
る画像劣化を生じることなく、帯電安定性に優れた画像
記録が可能である。As described above, in this embodiment, the first and second magnetic brush chargers 2A and 2B are provided, and the potential fluctuation range of the surface of the photoconductor calculated from the time constant of the charging system and the applied AC bias. Regarding ΔV, the first magnetic brush charger 2
ΔV1 of A is Δ of the second magnetic brush charger 2B downstream of the first magnetic brush charger 2A in the photoconductor rotation direction.
By configuring the voltage V2 to be smaller than V2, it is possible to record an image having excellent charging stability without causing image deterioration due to the AC bias.

【０１１０】〈実施形態例２〉（図９・図１０） 図９は本例のプリンタの概略構成図である。本例のプリ
ンタも上述実施形態例１のプリンタと同じく、感光体１
の帯電処理手段として第１と第２の２つの磁気ブラシ帯
電器２Ａ・２Ｂを配設してある。<Embodiment 2> (FIGS. 9 and 10) FIG. 9 is a schematic configuration diagram of a printer of this embodiment. The printer of this example is also the same as the printer of the above-described first embodiment with the photoconductor 1
The first and second magnetic brush chargers 2A and 2B are provided as the charging processing means.

【０１１１】ただし、第２の磁気ブラシ帯電器２Ｂにつ
いては、磁気ブラシ層２ｃを構成させる導電磁性粒子
を、平均粒径５０（μｍ）、体積比抵抗１×１０7 （Ω
・ｃｍ）のものに変更した。However, in the second magnetic brush charger 2B, the conductive magnetic particles forming the magnetic brush layer 2c have an average particle size of 50 (μm) and a volume resistivity of 1 × 10 7 (Ω).
・ Changed to cm.

【０１１２】また、第１の磁気ブラシ帯電器２Ａと第２
の磁気ブラシ帯電器２Ｂに対する帯電バイアス印加電源
Ｓは共通にして両者に同じＤＣ＋ＡＣの帯電バイアス ＤＣバイアス； −７００Ｖ ＡＣバイアス； 実効電圧１０００Ｖ、周波数１００
０Ｈｚ、矩形波 を印加した。２０は第１と第２の磁気ブラシ帯電器２Ａ
と２Ｂとの区画カバーである。その他の装置構成・条件
は実施形態例１と同じである。The first magnetic brush charger 2A and the second magnetic brush charger 2A
The same charging bias applying power source S to the magnetic brush charger 2B is used for both DC and AC charging bias DC bias; -700V AC bias; effective voltage 1000V, frequency 100
A rectangular wave of 0 Hz was applied. 20 is the first and second magnetic brush chargers 2A
And 2B are compartment covers. Other device configurations and conditions are the same as those in the first embodiment.

【０１１３】即ち本例では、第２の磁気ブラシ帯電器２
Ｂについて、磁気ブラシ層２ｃを構成させる導電磁性粒
子を、第１の磁気ブラシ帯電器２Ａとは異ならせて、該
第２の磁気ブラシ帯電器２Ｂの帯電系の時定数を０．０
０８秒に設定し、ＡＣバイアスに対しかぶりを生じにく
い構成をとっている。That is, in this example, the second magnetic brush charger 2
Regarding B, the conductive magnetic particles forming the magnetic brush layer 2c are made different from those of the first magnetic brush charger 2A, and the time constant of the charging system of the second magnetic brush charger 2B is 0.0.
The time is set to 08 seconds, and the structure is such that fogging is less likely to occur with respect to the AC bias.

【０１１４】先の比較例１・２及び本実施例２の感光体
表面の電位振れ巾ΔＶの計算結果及び本実施例の結果を
まとめ以下の表２に表わす。Table 2 below summarizes the calculation results of the potential fluctuation range ΔV on the surface of the photoconductors of Comparative Examples 1 and 2 and this Example 2 and the results of this Example.

【０１１５】[0115]

【表２】 比較例１・２いずれにおいても、かぶり防止と帯電安定
性が両立しないが、本実施例２では第１の磁気ブラシ帯
電器２Ａに対してこれよりも感光体回転方向下流側であ
る第２の磁気ブラシ２Ｂの帯電系の時定数を０．００８
と遅くすることで、第２の磁気ブラシ帯電器２Ｂの電位
振れ巾ΔＶを第１の磁気ブラシ帯電器２Ａの電位振れ巾
ΔＶ＝１２４Ｖより小さい６４Ｖに減少させかぶりを
１．８％と適切な範囲にまで減少することができた。[Table 2] In both Comparative Examples 1 and 2, the fogging prevention and the charging stability are not compatible, but in the present Example 2, the second magnetic brush charger 2A, which is on the downstream side of the first magnetic brush charger 2A in the rotation direction of the photoconductor. The time constant of the charging system of the magnetic brush 2B is 0.008.
By slowing down, the potential swing width ΔV of the second magnetic brush charger 2B is reduced to 64V which is smaller than the potential swing width ΔV = 124V of the first magnetic brush charger 2A, and the fog is appropriately 1.8%. Could be reduced to range.

【０１１６】第１や第２の磁気ブラシ帯電器２Ａ・２Ｂ
の帯電系の時定数を調節するためには、電源−磁気ブラ
シ帯電器−感光体の帯電系の中で、この系の抵抗あるい
は静電容量を調節することにより同様の効果が得られ
る。First and second magnetic brush chargers 2A and 2B
In order to adjust the time constant of the charging system, the same effect can be obtained by adjusting the resistance or capacitance of this system in the charging system of power source-magnetic brush charger-photoreceptor.

【０１１７】本実施例では、磁気ブラシ層２ｃを構成す
る導電磁性粒子の抵抗と粒径を調整したが、他にも、ス
リーブ２ｂと感光体１の間隔を調節する、あるいは感光
体容量を調節すること等により達成される。In this embodiment, the resistance and particle size of the conductive magnetic particles forming the magnetic brush layer 2c are adjusted, but in addition, the distance between the sleeve 2b and the photosensitive member 1 is adjusted, or the photosensitive member capacity is adjusted. It is achieved by doing.

【０１１８】導電磁性粒子の粒径も系全体の抵抗を左右
する。磁気ブラシ層２ｃを構成している導電磁性粒子と
感光体１の間には接触抵抗が存在し、小粒径の導電磁性
粒子ほど感光体１に密に接触できるため接触抵抗が小さ
い。The particle size of the conductive magnetic particles also affects the resistance of the entire system. There is a contact resistance between the electroconductive magnetic particles forming the magnetic brush layer 2c and the photoconductor 1, and the electroconductive particles having a smaller particle size can be brought into closer contact with the photoconductor 1 so that the contact resistance is smaller.

【０１１９】本実施例２においては、粒子抵抗を高くし
た他に、粒径の大きな導電磁性粒子で磁気ブラシ層２ｃ
を構成したことにより、導電磁性粒子と感光体の接触抵
抗が増加し下流側の第２の磁気ブラシ帯電器２Ｂの帯電
系の時定数を遅くし、ＡＣかぶりを防止しながら、帯電
安定性をもたせた構成をとる。In the second embodiment, in addition to increasing the particle resistance, the magnetic brush layer 2c is made of conductive magnetic particles having a large particle size.
By configuring the above, the contact resistance between the conductive magnetic particles and the photoconductor increases, the time constant of the charging system of the second magnetic brush charger 2B on the downstream side is delayed, and the AC fogging is prevented and the charging stability is improved. Take the configuration that has been given.

【０１２０】〈実施形態例３〉（図１１） 本例は１器の磁気ブラシ帯電器２で本発明の構成を実現
したもので、図１１のように、１器の磁気ブラシ帯電器
２の帯電ニップ部における、感光体回転方向上流側部分
（第１の帯電部）ｎ１と、下流側部分（第２の帯電部）
ｎ２にそれぞれ異なる帯電特性をもたせて帯電安定性と
ＡＣかぶり防止を両立させるものである。<Embodiment 3> (FIG. 11) In this example, the configuration of the present invention is realized by one magnetic brush charger 2. As shown in FIG. In the charging nip portion, an upstream side portion (first charging portion) n1 and a downstream side portion (second charging portion) in the photoconductor rotating direction.
By making n2 have different charging characteristics, both charging stability and AC fog prevention are achieved.

【０１２１】即ち、磁気ブラシ帯電器２の帯電ニップ部
における、感光体回転方向上流側部分ｎ１のスリーブ２
ｂと感光体１電極（第１の給電部材）２７を設け、この
電極２７には第１の電圧印加手段Ｓ１で ＤＣバイアス； −７００Ｖ ＡＣバイアス； 実効電圧７５０Ｖ、周波数１０００
Ｈｚ の帯電バイアスを印加する。That is, in the charging nip portion of the magnetic brush charger 2, the sleeve 2 of the upstream side portion n1 in the photoconductor rotating direction.
b and a photoreceptor 1 electrode (first power supply member) 27 are provided, and a DC bias of -700V AC bias; an effective voltage of 750V and a frequency of 1000 are applied to the electrode 27 by the first voltage applying means S1.
Apply a charging bias of Hz.

【０１２２】また磁気ブラシ帯電器２のスリーブ（第２
の給電部材）２ｂには第２の電圧印加手段Ｓ２で ＤＣバイアス； −７００Ｖ ＡＣバイアス； 実効電圧５００Ｖ、周波数１０００
Ｈｚ の帯電バイアスを印加する。The sleeve of the magnetic brush charger 2 (second
The power supply member 2b of the second voltage applying means S2 to the DC bias; -700V AC bias; effective voltage 500V, frequency 1000
Apply a charging bias of Hz.

【０１２３】２８は磁気ブラシ帯電器２を覆わせたカバ
ー部材である。Reference numeral 28 is a cover member which covers the magnetic brush charger 2.

【０１２４】これにより、磁気ブラシ帯電器２の帯電ニ
ップ部における、感光体回転方向上流側部分ｎ１では電
極２７に印加した上記帯電バイアスにより感光体１の帯
電安定性を満足し、下流側部分ｎ２ではスリーブ２ｂに
印加した上記帯電バイアスにより上流側部分ｎ２で生じ
た電位ムラを低減する。As a result, in the charging nip portion of the magnetic brush charger 2, the charging stability of the photosensitive member 1 is satisfied by the charging bias applied to the electrode 27 in the upstream portion n1 in the photosensitive member rotating direction, and the downstream portion n2. Then, the potential unevenness generated in the upstream side portion n2 is reduced by the charging bias applied to the sleeve 2b.

【０１２５】表３は、比較例１・２と本実施例３のバイ
アス条件、かぶり、帯電安定性の評価についてまとめた
ものである。Table 3 summarizes the evaluation of the bias conditions, fog, and charging stability of Comparative Examples 1 and 2 and Example 3.

【０１２６】[0126]

【表３】 比較例１と同２ではＡＣかぶり防止と帯電安定性を共に
満足することはできないが、本実施例３では、帯電ニッ
プ部上流に位置した電極２７による帯電の電位振れ巾Δ
Ｖ１より、下流に配置したスリーブ２ｂによる帯電の電
位振れ巾ΔＶ２を小さく設定することで、ＡＣかぶり防
止と帯電安定性を満足する。[Table 3] In Comparative Examples 1 and 2, both the AC fog prevention and the charging stability cannot be satisfied, but in Example 3, the potential fluctuation range Δ of the charging by the electrode 27 located upstream of the charging nip portion is Δ.
AC fogging prevention and charging stability are satisfied by setting the potential fluctuation width ΔV2 of charging by the sleeve 2b arranged downstream of V1 to be smaller.

【０１２７】また、本実施例３のような連続した帯電ニ
ップ部内で上流側ｎ１と下流側ｎ２各々の時定数を求め
る方法について補足する。電極２７あるいはスリーブ２
ｂによる時定数を求める時、給電を一方のみに行い、他
方をフロート状態にし帯電電位の上昇過程を前述の方法
により解析することで定義できる。また、帯電ニップ幅
については、前述のように、抵抗分布から上流側、下流
側の二つの抵抗ピークが求められるので各ピークに対し
半値幅を計算することにより定義できる。Further, a method for obtaining the time constants of the upstream side n1 and the downstream side n2 in the continuous charging nip portion as in the third embodiment will be supplemented. Electrode 27 or sleeve 2
When the time constant by b is obtained, it can be defined by supplying power to only one side, leaving the other side in a floating state, and analyzing the process of increasing the charging potential by the method described above. As described above, the charging nip width can be defined by calculating the half-value width for each peak because two resistance peaks on the upstream side and the downstream side are obtained from the resistance distribution.

【０１２８】本実施例３の構成は帯電器２は１器で済
み、第１及び第２・・の２器以上の帯電器を配設する場
合よりもスペース的に有利となる。In the structure of the third embodiment, only one charger 2 is required, which is more advantageous in space than the case where two or more chargers of the first and second ..

【０１２９】〈その他〉 １）本発明の帯電装置は、実施形態例の画像記録装置に
おける像担持体の帯電処理に限らず、広く被帯電体の接
触帯電処理手段として有効であることはもちろんであ
る。<Others> 1) The charging device of the present invention is not limited to the charging process of the image carrier in the image recording apparatus of the embodiment, but is of course widely effective as the contact charging process means for the charged object. is there.

【０１３０】２）接触帯電器は実施形態例に示した磁気
ブラシ帯電器に限られず、ファーブラシ帯電器や導電性
ゴムや導電性スポンジを用いた帯電ローラ・帯電ブレー
ドなど他の接触帯電部材であってもよいし、回転しない
構成の帯電器であってもよい。2) The contact charging device is not limited to the magnetic brush charging device shown in the embodiment, but may be another contact charging member such as a fur brush charging device or a charging roller or charging blade using conductive rubber or conductive sponge. It may be provided or may be a charger having a configuration that does not rotate.

【０１３１】磁気ブラシ帯電器にしても、マグネットロ
ーラ２ａが回転するものや、マグネットローラ２ａの表
面を必要に応じて給電用電極として導電性処理してその
面に直接に導電性磁性粒子を磁気拘束させて磁気ブラシ
層２ｃを形成保持させ、マグネットローラを回転させる
構成のもの等にすることもできる。回転しないタイプの
磁気ブラシ帯電器とすることもできる。Even in the case of a magnetic brush charger, the magnet roller 2a rotates, or the surface of the magnet roller 2a is subjected to a conductive treatment as a power feeding electrode if necessary, and the conductive magnetic particles are directly magnetized on the surface. The magnetic brush layer 2c may be constrained to be formed and held, and the magnet roller may be rotated. It may be a non-rotating type magnetic brush charger.

【０１３２】３）第１と第２の接触帯電器２Ａ・２Ｂは
実施形態例のようにどちらも磁気ブラシ帯電器とする以
外にも、例えば、一方を磁気ブラシ帯電器、他方をファ
ーブラシ帯電器にする等、互いに異なるタイプの帯電器
にすることもできる。3) The first and second contact chargers 2A and 2B are both magnetic brush chargers as in the embodiment, and for example, one is a magnetic brush charger and the other is a fur brush charger. It is also possible to use different types of chargers such as a container.

【０１３３】また帯電器を被帯電体移動方向に３器以上
配設することもできる。It is also possible to arrange three or more chargers in the moving direction of the body to be charged.

【０１３４】４）被帯電体は注入帯電方式の場合には表
面抵抗が１０9 〜１０14Ω・ｃｍの層を持つことが望ま
しい。像担持体としては、実施形態例のＯＰＣ感光体上
にＳｎＯ2 等の導電性粒子を分散させた表層（電荷注入
層）をコーティングしたＯＣＬ感光体の他にも、α−Ｓ
ｉ（アモルファスシリコン、非晶質シリコン）の表層を
有する感光体など電荷注入帯電性を有するものを用いる
ことができる。4) In the case of the injection charging method, it is desirable that the member to be charged has a layer having a surface resistance of 10 9 to 10 14 Ω · cm. As the image bearing member, in addition to the OCL photosensitive member in which the surface layer (charge injection layer) in which conductive particles such as SnO 2 are dispersed is coated on the OPC photosensitive member of the embodiment, α-S
It is possible to use a photoreceptor having a charge injection charging property such as a photoreceptor having a surface layer of i (amorphous silicon, amorphous silicon).

【０１３５】５）画像記録装置における像坦持体の帯電
面に対する情報書き込み手段としての画像露光手段は、
実施形態例で示した様なデジタル的な潜像を形成するレ
ーザ走査露光手段に限定されるものではなく、通常のア
ナログ的な画像露光やＬＥＤなどの他の発光素子でも構
わないし、蛍光燈等の発光素子と液晶シャッタ等の組み
合わせによるものなど、画像情報に対応した静電潜像を
形成できるものであるなら構わない。5) The image exposure means as the information writing means for the charged surface of the image carrier in the image recording device is
The present invention is not limited to the laser scanning exposure means for forming a digital latent image as shown in the embodiment, but may be a normal analog image exposure or another light emitting element such as an LED, a fluorescent lamp or the like. It is possible to form an electrostatic latent image corresponding to image information, such as a combination of the above light emitting element and a liquid crystal shutter.

【０１３６】また像担持体は静電記録誘電体などであっ
てもよい。この場合は、該誘電体面を所定の極性・電位
に一様に一次帯電した後、除電針ヘッド、電子銃等の除
電手段で選択的に除電して目的の静電潜像を書き込み形
成する。Further, the image carrier may be an electrostatic recording dielectric or the like. In this case, after the primary surface of the dielectric surface is uniformly charged to a predetermined polarity and potential, the target electrostatic latent image is written and formed by selectively neutralizing with a neutralizing means such as a neutralizing needle head or an electron gun.

【０１３７】静電潜像の現像方式・手段は任意であり、
実施形態例の反転現像でなく、正規現像方式であっても
勿論よい。The developing system and means of the electrostatic latent image are arbitrary,
Of course, the regular development method may be used instead of the reversal development of the embodiment.

【０１３８】６）また、転写方法としては、実施形態例
に示したローラ転写だけでなく、ブレード転写やその他
の接触転写帯電方式、更に転写ドラムや転写ベルトや中
間転写体などを用いて、単色画像形成ばかりでなく多重
転写等により多色、フルカラー画像を形成する画像記録
装置にも適応可能な事は言うまでもない。6) As the transfer method, not only the roller transfer shown in the embodiment, but also blade transfer and other contact transfer charging methods, and further, a transfer drum, a transfer belt, an intermediate transfer member, or the like is used. It goes without saying that the present invention can be applied not only to image formation but also to an image recording apparatus that forms a multicolor or full-color image by multiple transfer or the like.

【０１３９】７）接触帯電器に対する印加帯電バイアス
の交流バイアス成分の波形としては、正弦波、矩形波、
三角波等適宜使用可能である。また、直流電源を周期的
にオン／オフすることによって形成された矩形波であっ
てもよい。このように交流電圧の波形としては周期的に
その電圧値が変化するようなバイアスが使用できる。7) The waveform of the AC bias component of the charging bias applied to the contact charger is a sine wave, a rectangular wave,
A triangular wave or the like can be appropriately used. Further, it may be a rectangular wave formed by periodically turning on / off the DC power supply. Thus, as the waveform of the AC voltage, a bias whose voltage value periodically changes can be used.

【０１４０】８）プロセスカートリッジ１０は実施形態
例のものに限らず、任意の作像プロセス機器の組み合わ
せをもって構成することができる。8) The process cartridge 10 is not limited to that of the embodiment, but can be constructed by combining any image forming process equipment.

【０１４１】９）また、像担持体としての電子写真感光
体や静電記録誘電体を回動ベルト型にし、これに帯電・
潜像形成・現像の工程手段により所要の画像情報に対応
したトナー像を形成させ、そのトナー像形成部を閲読表
示部に位置させて画像表示させ、像担持体は繰り返して
表示画像の形成に使用する画像表示装置もある。本発明
の画像記録装置にはこのような画像表示装置も含む。9) Further, the electrophotographic photosensitive member or the electrostatic recording dielectric as the image bearing member is of a rotating belt type, and is charged / charged on the rotating belt type.
A toner image corresponding to the required image information is formed by means of the latent image forming / developing process means, the toner image forming portion is positioned in the reading display portion to display an image, and the image carrier repeatedly forms the display image. There is also an image display device used. The image recording device of the present invention includes such an image display device.

【０１４２】[0142]

【発明の効果】以上説明したように本発明によれば、電
荷注入接触帯電方式・ＡＣ印加方式の帯電装置、該帯電
装置を使用した画像記録装置やプロセスカートリッジに
ついて、接触帯電器にＡＣバイアスを印加したことに起
因する被帯電体表面の細かな電位ムラの抑制（帯電均一
性）と、帯電不良の防止（帯電安定性）を両立させるこ
とができて、画像記録装置やプロセスカートリッジにあ
っては、該帯電均一性と帯電安定性の両立により高品位
な画像記録を長期に渡り安定に維持させることができ
る。As described above, according to the present invention, an AC bias is applied to a contact charger in a charge injection contact charging type / AC applying type charging device, and an image recording device and a process cartridge using the charging device. In the image recording device and the process cartridge, it is possible to achieve both suppression of fine potential unevenness on the surface of the charged object due to application (charging uniformity) and prevention of charging failure (charging stability). Can maintain high-quality image recording stably for a long period of time by satisfying both the charging uniformity and the charging stability.

【図面の簡単な説明】[Brief description of drawings]

【図１】実施形態例１における画像記録装置の構成略図FIG. 1 is a schematic diagram of a configuration of an image recording apparatus according to a first embodiment.

【図２】感光体の層構成模型図FIG. 2 is a schematic diagram of a layer configuration of a photoreceptor.

【図３】第１と第２の磁気ブラシ帯電器部分の構成模型
図FIG. 3 is a structural model diagram of first and second magnetic brush charger portions.

【図４】（ａ）は帯電回路系の模型図、（ｂ）はその等
価回路図4A is a model diagram of a charging circuit system, and FIG. 4B is an equivalent circuit diagram thereof.

【図５】（ａ）は帯電時の感光体表面電位の経過を表わ
すグラフ、（ｂ）は帯電特性グラフ5A is a graph showing the course of the surface potential of the photosensitive member during charging, and FIG. 5B is a charging characteristic graph.

【図６】ΔＶとかぶりの関係を表わすグラフFIG. 6 is a graph showing the relationship between ΔV and fogging.

【図７】比較例１の電位ムラ計算結果FIG. 7: Potential unevenness calculation result of Comparative Example 1

【図８】比較例２の電位ムラ計算結果FIG. 8: Potential unevenness calculation result of Comparative Example 2

【図９】実施形態例２における画像記録装置の構成略図FIG. 9 is a schematic configuration diagram of an image recording apparatus according to a second embodiment.

【図１０】実施例２の電位ムラ計算結果FIG. 10: Potential unevenness calculation result of Example 2

【図１１】実施形態例３における磁気ブラシ帯電器の構
成略図FIG. 11 is a schematic configuration diagram of a magnetic brush charger according to the third embodiment.

【符号の説明】 １ 被帯電体としての像担持体（電子写真感光体） ２Ａ・２Ｂ 接触帯電部材としての第１及び第２の磁
気ブラシ帯電器 ２ａ マグネットローラ ２ｂ 帯電スリーブ ２ｃ 磁気ブラシ層 ３ 現像器 ４ 転写器（転写ローラ） ５ 定着器 ６ クリーニング器 ７ 露光器（レーザービームスキャナ） １０ プロセスカートリッジ ２７ 電極（第１の給電部材） Ｓ１〜Ｓ４ バイアス印加電源[Description of Reference Signs] 1 image carrier (electrophotographic photoreceptor) 2A and 2B as charged body 1st and 2nd magnetic brush charger 2a as contact charging member magnet roller 2b charging sleeve 2c magnetic brush layer 3 development Device 4 Transfer device (transfer roller) 5 Fixing device 6 Cleaning device 7 Exposure device (laser beam scanner) 10 Process cartridge 27 Electrode (first power supply member) S1 to S4 Bias application power source

Claims (17)

【特許請求の範囲】[Claims] 【請求項１】 直流電圧と交流電圧を重畳した電圧が印
加され、被帯電体に接触して該被帯電体を帯電する帯電
器を有する帯電装置において、 被帯電体移動方向に沿って、少なくとも、第１の帯電器
と、それよりも被帯電体移動方向下流側の第２の帯電器
を有し、 該第１と第２の両帯電器についてそれぞれ一方極性の直
流電圧を印加したときの直流電圧と被帯電体電位の関係
がおよそ比例関係にある帯電特性を有し、 帯電器の時定数をτ（ｓｅｃ）、 印加する交流電圧の周波数をｆ（Ｈｚ）、 交流電圧の実効電圧をＶAC（Ｖ）、とするとき、 【数１】 で算定される、印加交流電圧に起因して発生する被帯電
体表面の電位変動ΔＶに関して、第１の帯電器における
該電位変動ΔＶ１と、第２の帯電器における該電位変動
ΔＶ２とが、ΔＶ１＞ΔＶ２となるように第１と第２の
両帯電器の帯電特性が設定されていることを特徴とする
帯電装置。1. A charging device having a charger to which a voltage in which a DC voltage and an AC voltage are superposed is applied to contact a member to be charged to charge the member, at least along a moving direction of the member to be charged. , A first charger and a second charger on the downstream side in the moving direction of the body to be charged relative to the first charger, and when a DC voltage of one polarity is applied to each of the first and second chargers. It has charging characteristics that the relationship between the DC voltage and the potential of the body to be charged is approximately proportional. The time constant of the charger is τ (sec), the frequency of the applied AC voltage is f (Hz), and the effective voltage of the AC voltage is If V AC (V), then With respect to the potential fluctuation ΔV on the surface of the member to be charged that is caused by the applied AC voltage calculated in step A, the potential fluctuation ΔV1 in the first charger and the potential fluctuation ΔV2 in the second charger are ΔV1. A charging device characterized in that the charging characteristics of both the first and second chargers are set so that> ΔV2. 【請求項２】 直流電圧と交流電圧を重畳した電圧が印
加され、被帯電体に接触して該被帯電体を帯電する帯電
器を有する帯電装置において、 帯電器は、被帯電体移動方向に沿って、少なくとも、第
１の給電部材による第１の帯電部と、それよりも被帯電
体移動方向下流側の第２の給電部材による第２の帯電部
を有し、 該第１と第２の両帯電部についてそれぞれ一方極性の直
流電圧を印加したときの直流電圧と被帯電体電位の関係
がおよそ比例関係にある帯電特性を有し、 帯電部の時定数をτ（ｓｅｃ）、 給電部材に印加する交流電圧の周波数をｆ（Ｈｚ）、 交流電圧の実効電圧をＶAC（Ｖ）、とするとき、 【数２】 で算定される、印加交流電圧に起因して発生する被帯電
体表面の電位変動ΔＶに関して、第１の帯電部における
該電位変動ΔＶ１と、第２の帯電部における該電位変動
ΔＶ２とが、ΔＶ１＞ΔＶ２となるように第１と第２の
両帯電部の帯電特性が設定されていることを特徴とする
帯電装置。2. A charging device comprising a charger to charge a charged body by contacting the charged body with a voltage in which a DC voltage and an AC voltage are superposed on each other. Along with at least a first charging portion formed by the first power supply member and a second charging portion formed by a second power supply member downstream of the first charging portion in the moving direction of the body to be charged, the first and second charging portions are provided. The charging characteristics are such that the relationship between the DC voltage and the potential of the body to be charged when a DC voltage of one polarity is applied to both charging sections is approximately proportional, and the time constant of the charging section is τ (sec). When the frequency of the AC voltage applied to is f (Hz) and the effective voltage of the AC voltage is V AC (V), With respect to the potential fluctuation ΔV on the surface of the charged body generated due to the applied AC voltage calculated in step A, the potential fluctuation ΔV1 in the first charging portion and the potential fluctuation ΔV2 in the second charging portion are ΔV1. A charging device characterized in that the charging characteristics of both the first and second charging units are set so that> ΔV2. 【請求項３】 帯電器は、担持部材に磁気拘束して担持
させた導電磁性粒子の磁気ブラシ部を有し、該磁気ブラ
シ部を被帯電体に接触させた磁気ブラシ帯電器であるこ
とを特徴とする請求項１または２に記載の帯電装置。3. The charging device is a magnetic brush charging device having a magnetic brush portion of conductive magnetic particles magnetically bound to and carried by a carrying member, and the magnetic brush portion being in contact with an object to be charged. The charging device according to claim 1, wherein the charging device is a charging device. 【請求項４】 帯電器は、導電性繊維のブラシ部を有
し、該導電性繊維ブラシ部を被帯電体に接触させたファ
ーブラシ帯電器であることを特徴とする請求項１または
２に記載の帯電装置。4. The fur brush charger, wherein the charger has a brush portion of a conductive fiber, and the conductive fiber brush portion is in contact with an object to be charged. The charging device described. 【請求項５】 被帯電体が表面抵抗１０9 〜１０14Ω／
ｃｍの低抵抗層を有することを特徴とする請求項１ない
し４のいずれか１つに記載の帯電装置。5. The charged body has a surface resistance of 10 9 to 10 14 Ω /
The charging device according to any one of claims 1 to 4, wherein the charging device has a low resistance layer of cm. 【請求項６】 被帯電体が絶縁性材料に導電性粒子を分
散した表面層を有することを特徴とする請求項１ないし
５のいずれか１つに記載の帯電装置。6. The charging device according to claim 1, wherein the member to be charged has a surface layer in which conductive particles are dispersed in an insulating material. 【請求項７】 導電性粒子がＳｎＯ2 であることを特徴
とする請求項６に記載の帯電装置。7. The charging device according to claim 6, wherein the conductive particles are SnO 2 . 【請求項８】 被帯電体が画像記録装置における像担持
体であることを特徴とする請求項１ないし７の何れか１
つに記載の帯電装置。8. The object to be charged is an image carrier in an image recording apparatus.
The charging device according to any one of the above. 【請求項９】 像担持体に該像担持体を帯電する工程を
有する作像プロセスを適用して画像形成を実行する画像
記録装置において、 像担持体の帯電工程手段が、直流電圧と交流電圧を重畳
した電圧が印加され、像担持体に接触して該像担持体を
帯電する帯電器を有する帯電装置であり、 像担持体移動方向に沿って、少なくとも、第１の帯電器
と、それよりも像担持体移動方向下流側の第２の帯電器
を有し、 該第１と第２の両帯電器についてそれぞれ一方極性の直
流電圧を印加したときの直流電圧と像担持体電位の関係
がおよそ比例関係にある帯電特性を有し、 帯電器の時定数をτ（ｓｅｃ）、 印加する交流電圧の周波数をｆ（Ｈｚ）、 交流電圧の実効電圧をＶAC（Ｖ）、とするとき、 【数３】 で算定される、印加交流電圧に起因して発生する像担持
体表面の電位変動ΔＶに関して、第１の帯電器における
該電位変動ΔＶ１と、第２の帯電器における該電位変動
ΔＶ２とが、ΔＶ１＞ΔＶ２となるように第１と第２の
両帯電器の帯電特性が設定されていることを特徴とする
画像記録装置。9. An image recording apparatus for performing image formation by applying an image forming process including a step of charging an image carrier to the image carrier, wherein a charging step means of the image carrier has a DC voltage and an AC voltage. A charging device having a charger to which an overlapping voltage is applied to contact the image carrier to charge the image carrier, wherein at least a first charger and the charger are provided along the moving direction of the image carrier. A second charger on the downstream side in the moving direction of the image carrier, and a relationship between the DC voltage and the potential of the image carrier when a DC voltage of one polarity is applied to each of the first and second chargers. Has a charging characteristic that is approximately in proportion, where the time constant of the charger is τ (sec), the frequency of the applied AC voltage is f (Hz), and the effective voltage of the AC voltage is VAC (V). , [Equation 3] With respect to the potential fluctuation ΔV on the surface of the image carrier that occurs due to the applied AC voltage, the potential fluctuation ΔV1 in the first charger and the potential fluctuation ΔV2 in the second charger are ΔV1. An image recording apparatus, wherein the charging characteristics of both the first and second chargers are set so that> ΔV2. 【請求項１０】 像担持体に該像担持体を帯電する工程
を有する作像プロセスを適用して画像形成を実行する画
像記録装置において、 像担持体の帯電工程手段が、直流電圧と交流電圧を重畳
した電圧が印加され、像担持体に接触して該像担持体を
帯電する帯電器を有する帯電装置において、 帯電器は、像担持体移動方向に沿って、少なくとも、第
１の給電部材による第１の帯電部と、それよりも像担持
体移動方向下流側の第２の給電部材による第２の帯電部
を有し、 該第１と第２の両帯電部についてそれぞれ一方極性の直
流電圧を印加したときの直流電圧と像担持体電位の関係
がおよそ比例関係にある帯電特性を有し、 帯電部の時定数をτ（ｓｅｃ）、 給電部材に印加する交流電圧の周波数をｆ（Ｈｚ）、 交流電圧の実効電圧をＶAC（Ｖ）、とするとき、 【数４】 で算定される、印加交流電圧に起因して発生する像担持
体表面の電位変動ΔＶに関して、第１の帯電部における
該電位変動ΔＶ１と、第２の帯電部における該電位変動
ΔＶ２とが、ΔＶ１＞ΔＶ２となるように第１と第２の
両帯電部の帯電特性が設定されていることを特徴とする
画像記録装置。10. An image recording apparatus for performing image formation by applying an image forming process including a step of charging an image carrier to the image carrier, wherein a charging step means of the image carrier has a DC voltage and an AC voltage. In a charging device having a charger that is applied with a voltage that superposes on the image carrier to charge the image carrier, the charger includes at least a first power supply member along the moving direction of the image carrier. And a second charging portion by a second power feeding member on the downstream side in the moving direction of the image carrier with respect to the first charging portion, and a direct current of one polarity for each of the first and second charging portions. It has a charging characteristic in which the relationship between the DC voltage when a voltage is applied and the image carrier potential is approximately proportional, the time constant of the charging section is τ (sec), and the frequency of the AC voltage applied to the power supply member is f ( Hz), the effective voltage of AC voltage is V AC (V) , And when, With respect to the potential fluctuation ΔV on the surface of the image carrier that occurs due to the applied AC voltage calculated in step A, the potential fluctuation ΔV1 in the first charging portion and the potential fluctuation ΔV2 in the second charging portion are ΔV1. An image recording apparatus, wherein the charging characteristics of both the first and second charging units are set so that> ΔV2. 【請求項１１】 像担持体が光導電性であり、この像担
持体に、該像担持体を帯電する工程、その帯電面に露光
により静電潜像を形成する工程、該静電潜像を帯電した
トナーにより可視化する工程を有する作像プロセスで画
像形成が実行されることを特徴とする請求項９または１
０に記載の画像記録装置。11. The image bearing member is photoconductive, and the step of charging the image bearing member on the image bearing member, the step of forming an electrostatic latent image on the charged surface by exposure, the electrostatic latent image. 10. The image formation is performed by an image forming process including a step of visualizing the toner with a charged toner.
The image recording device according to item 0. 【請求項１２】 帯電器は、担持部材に磁気拘束して担
持させた導電磁性粒子の磁気ブラシ部を有し、該磁気ブ
ラシ部を像担持体に接触させた磁気ブラシ帯電器である
ことを特徴とする請求項９ないし１１のいずれか１つに
記載の画像記録装置。12. The charging device is a magnetic brush charging device having a magnetic brush part of conductive magnetic particles magnetically restrained and carried on a carrying member, and the magnetic brush part is brought into contact with an image carrier. The image recording apparatus according to any one of claims 9 to 11, which is characterized in that. 【請求項１３】 帯電器は、導電性繊維のブラシ部を有
し、該導電性繊維ブラシ部を像担持体に接触させたファ
ーブラシ帯電器であることを特徴とする請求項９ないし
１１のいずれか１つに記載の画像記録装置。13. The fur brush charger, wherein the charger has a brush portion of a conductive fiber, and the conductive fiber brush portion is in contact with the image carrier. The image recording apparatus according to any one of claims. 【請求項１４】 像担持体が表面抵抗１０9 〜１０14Ω
／ｃｍの低抵抗層を有することを特徴とする請求項９な
いし１３のいずれか１つに記載の画像記録装置。14. The image bearing member has a surface resistance of 10 9 to 10 14 Ω.
The image recording apparatus according to any one of claims 9 to 13, which has a low resistance layer of / cm. 【請求項１５】 像担持体が絶縁性材料に導電性粒子を
分散した表面層を有することを特徴とする請求項９ない
し１４のいずれか１つに記載の画像記録装置。15. The image recording apparatus according to claim 9, wherein the image carrier has a surface layer in which conductive particles are dispersed in an insulating material. 【請求項１６】 導電性粒子がＳｎＯ2 であることを特
徴とする請求項１５に記載の画像記録装置。16. The image recording apparatus according to claim 15, wherein the conductive particles are SnO 2 . 【請求項１７】 少なくとも、像担持体と、請求項１な
いし８の何れか１つに記載の帯電装置の少なくとも帯電
器を包含して画像記録装置本体に対して着脱されること
を特徴とするプロセスカートリッジ。17. An image carrier and at least a charger of the charging device according to claim 1, which is attached to and detached from the main body of the image recording device. Process cartridge.
JP8079622A 1996-03-07 1996-03-07 Charging device, image recording device, and process cartridge Pending JPH09244355A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8079622A JPH09244355A (en) 1996-03-07 1996-03-07 Charging device, image recording device, and process cartridge

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8079622A JPH09244355A (en) 1996-03-07 1996-03-07 Charging device, image recording device, and process cartridge

Publications (1)

Publication Number Publication Date
JPH09244355A true JPH09244355A (en) 1997-09-19

Family

ID=13695176

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8079622A Pending JPH09244355A (en) 1996-03-07 1996-03-07 Charging device, image recording device, and process cartridge

Country Status (1)

Country Link
JP (1) JPH09244355A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09288401A (en) * 1996-04-23 1997-11-04 Canon Inc Contact electrifying member and contact electrifying device
JPH09288400A (en) * 1996-04-23 1997-11-04 Canon Inc Contact electrifying member and contact electrifying device
US6947688B2 (en) * 2002-07-04 2005-09-20 Canon Kabushiki Kaisha Image-forming apparatus including first and second charging members with a target potential charging feature

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09288401A (en) * 1996-04-23 1997-11-04 Canon Inc Contact electrifying member and contact electrifying device
JPH09288400A (en) * 1996-04-23 1997-11-04 Canon Inc Contact electrifying member and contact electrifying device
US6947688B2 (en) * 2002-07-04 2005-09-20 Canon Kabushiki Kaisha Image-forming apparatus including first and second charging members with a target potential charging feature

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