JP3090986B2 - Fixing device self-bias application circuit - Google Patents
Fixing device self-bias application circuitInfo
- Publication number
- JP3090986B2 JP3090986B2 JP03218109A JP21810991A JP3090986B2 JP 3090986 B2 JP3090986 B2 JP 3090986B2 JP 03218109 A JP03218109 A JP 03218109A JP 21810991 A JP21810991 A JP 21810991A JP 3090986 B2 JP3090986 B2 JP 3090986B2
- Authority
- JP
- Japan
- Prior art keywords
- diode
- roller
- fixing device
- resistor
- self
- 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.)
- Expired - Fee Related
Links
Landscapes
- Fixing For Electrophotography (AREA)
- Control Or Security For Electrophotography (AREA)
Description
【０００１】[0001]
【産業上の利用分野】熱ローラ定着装置を用いる電子写
真記録装置でローラにセルフバイアスを印加する回路に
関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit for applying a self-bias to a roller in an electrophotographic recording apparatus using a heat roller fixing device.
【０００２】[0002]
【従来の技術】従来、熱ローラ定着装置を用いる電子写
真装置において、記録媒体（紙）上の現像剤たるトナー
が加熱ローラにオフセットするのを防止するため、トナ
ーと同極性の電位をローラに与え、ローラとトナーが反
発するようにした構成が使われる場合がある。ローラに
電位を与えるにはローラに電源から電圧を印加する方式
と、記録媒体とローラが擦れることによる摩擦帯電を用
いる方式とがある。特に、摩擦帯電を用いる方式は別名
セルフバイアス方式とも呼ばれ、ローラとアース間に整
流素子たるダイオードが挿入された簡易な構成のために
広く用いられている。このダイオードは逆電圧を印加す
ると逆耐圧を越えたところでブレークダウンが発生し定
電圧特性を示すものである。このように構成されたロー
ラと記録媒体が摩擦するとローラが帯電し、順方向の電
荷はアースに流れ、逆方向の電荷はローラに蓄積され
る。ある程度の電荷が蓄積されると上述のようにダイオ
ードのブレークダウンが発生するので、ローラの電位は
一定に保たれる。これによって、トナーはローラから静
電気的反発力を受け、オフセットが防止されることとな
る。2. Description of the Related Art Conventionally, in an electrophotographic apparatus using a heat roller fixing device, in order to prevent toner as a developer on a recording medium (paper) from offsetting to a heating roller, a potential having the same polarity as the toner is applied to the roller. In some cases, a configuration in which the roller and the toner are repelled is used. To apply a potential to the roller, there are a method in which a voltage is applied to the roller from a power supply, and a method in which frictional charging is performed by rubbing between the recording medium and the roller. In particular, a system using triboelectric charging is also called a self-bias system, and is widely used because of a simple configuration in which a diode as a rectifying element is inserted between a roller and ground. When a reverse voltage is applied to the diode, breakdown occurs when the reverse voltage is exceeded, and the diode exhibits constant voltage characteristics. When the recording medium rubs against the roller configured as described above, the roller is charged, the forward charge flows to the ground, and the reverse charge is accumulated on the roller. When a certain amount of charge is accumulated, the breakdown of the diode occurs as described above, so that the potential of the roller is kept constant. As a result, the toner receives an electrostatic repulsive force from the roller, and the offset is prevented.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら上記従来
例では、定着装置ユニットをサービスマンやユーザが交
換するとき、ダイオードの端部やローラに手を触れる可
能性がある。このとき人間が帯電していると、ダイオー
ドに過大電流が流れ、ダイオードを破壊することがあっ
た。However, in the above-mentioned conventional example, when a serviceman or a user replaces the fixing device unit, there is a possibility that the end of the diode or the roller is touched by a hand. At this time, if a person is charged, an excessive current may flow through the diode, possibly destroying the diode.
【０００４】ダイオードの静電破壊は過大電流によるも
ので、例えばダイオードの内部抵抗を１ＫΩとすると、
２５ＫＶに帯電した人体からの放電では２５Ａのピーク
電流が流れることになる。しかし、セルフバイアスに用
いるダイオードは逆耐圧１ＫＶ電流数百ｍＡ程度の小型
ダイオードなので２５Ａもピーク電流が流れると接合部
が破壊されてしまうのである。The electrostatic breakdown of a diode is caused by an excessive current. For example, if the internal resistance of a diode is 1 KΩ,
In a discharge from a human body charged to 25 KV, a peak current of 25 A flows. However, since the diode used for the self-bias is a small diode having a reverse breakdown voltage of 1 KV and a current of about several hundred mA, the junction is destroyed when a peak current of 25 A flows.
【０００５】本発明は上記問題点を解決し、定着装置の
保守点検時等におけるダイオードの過電流破壊を防止す
ることのできる定着装置セルフバイアス印加回路を提供
することを目的としている。SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixing device self-bias applying circuit which can solve the above-mentioned problems and can prevent overcurrent destruction of a diode during maintenance and inspection of the fixing device.
【０００６】[0006]
【課題を解決するための手段】本発明によれば上記目的
は、互いに圧接して配設された加熱ローラと加圧ローラ
の芯金に、一端を接地した整流素子を接続して、現像剤
を加熱ローラ側から引き離し加圧ローラ側へ引き付ける
方向のバイアス電圧を印加せしめる定着装置セルフバイ
アス印加回路において、上記整流素子に抵抗素子を直列
に接続し、上記整流素子と上記抵抗素子を圧着により接
続したことにより達成される。SUMMARY OF THE INVENTION According to the present invention, there is provided an image forming apparatus, comprising: connecting a rectifying element, one end of which is grounded, to a core of a heating roller and a core of a pressure roller which are disposed in pressure contact with each other; In the fixing device self-bias applying circuit for applying a bias voltage in a direction to separate the rectifying element from the heating roller side and to attract the pressing roller side, a resistance element is connected in series to the rectification element, and the rectification element and the resistance element are connected by crimping.
It is achieved by continuing .
【０００７】[0007]
【作用】本発明によれば、定着装置の保守点検時等にお
いて人間が帯電していた場合、ローラや整流素子端部に
手を触れると整流素子に大電流が流れようとするが、該
整流素子には抵抗素子が直列に接続されているので電流
を制限する。したがって、整流素子の過電流破壊が防止
される。According to the present invention, when a person is charged during maintenance or inspection of a fixing device, a large current tends to flow through the rectifying element by touching the roller or the end of the rectifying element. Since a resistance element is connected to the element in series, the current is limited. Therefore, overcurrent destruction of the rectifying element is prevented.
【０００８】[0008]
【実施例】本発明の第一実施例及び第二実施例を図面に
基づいて説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment and a second embodiment of the present invention will be described with reference to the drawings.
【０００９】〈第一実施例〉図１において、１は定着装
置の加熱ローラである。該加熱ローラ１は内部にハロゲ
ンヒータを有するアルミニウム製のローラでその表面は
絶縁コートされている。また、該加熱ローラ１の端部に
は二点で接触するばね２が配設されており、該ばね２に
は１００ＫΩ程度のカーボン抵抗３及び逆耐圧６００Ｖ
〜２ＫＶ程度の整流素子たるダイオード４が直列に接続
され、ダイオード４はアノード側が接地されている。一
方、上記加熱ローラ１の下方には中心部の芯金上に高抵
抗の導電スポンジを有した加圧ローラ５が圧接するよう
に配設されており、該加圧ローラ５の芯金の端部には接
点６が接続されている。該接点６には１００ＫΩ程度の
カーボン抵抗７と上記ダイオード４と同様のダイオード
８が直列に接続されており、ダイオード８はカソード側
が接地されている。<First Embodiment> In FIG. 1, reference numeral 1 denotes a heating roller of a fixing device. The heating roller 1 is an aluminum roller having a halogen heater inside, and the surface thereof is coated with insulation. A spring 2 is provided at the end of the heating roller 1 so as to contact at two points. The spring 2 has a carbon resistance 3 of about 100 KΩ and a reverse withstand voltage of 600V.
A diode 4 as a rectifying element of about 2 KV is connected in series, and the anode side of the diode 4 is grounded. On the other hand, below the heating roller 1, a pressure roller 5 having a high-resistance conductive sponge is disposed on the core metal at the center so as to be in pressure contact with the core metal. The contact 6 is connected to the portion. A carbon resistor 7 of about 100 KΩ and a diode 8 similar to the diode 4 are connected in series to the contact 6, and the cathode of the diode 8 is grounded.
【００１０】以上のような本実施例装置において加熱ロ
ーラ１と加圧ローラ５の間をトナーの載った紙が通過す
るとトナーが溶融し定着される。このとき紙とローラ
１，５の摩擦によりローラ１，５は帯電する。ダイオー
ド４，８の順方向に電流を流す電荷はすぐアースに逃げ
てしまうが、逆方向に電流を流す電荷はダイオードで阻
止され、ローラ上に残る。In the above-described apparatus of the present embodiment, when the paper carrying the toner passes between the heating roller 1 and the pressure roller 5, the toner is melted and fixed. At this time, the rollers 1 and 5 are charged by friction between the paper and the rollers 1 and 5. Charges that flow current in the forward direction of the diodes 4 and 8 immediately escape to the ground, but charges that flow current in the reverse direction are blocked by the diode and remain on the roller.
【００１１】図１の接続では加熱ローラ１には正電荷、
加圧ローラ５には負電荷が残る。紙の上のトナーが正電
荷を有していると加熱ローラ１から反発力を受け、加圧
ローラ５には吸引力を受けるのでトナーは加熱ローラ１
にオフセットしなくなる。In the connection of FIG. 1, the heating roller 1 has a positive charge,
Negative charges remain on the pressure roller 5. If the toner on the paper has a positive charge, it receives a repulsive force from the heating roller 1 and a suction force to the pressure roller 5, so that the toner is
Will no longer be offset.
【００１２】図１の構成で、加熱ローラ１や加圧ローラ
５の芯金には定着ユニットの交換時にサービスマンやユ
ーザが手を触れる可能性がある。このとき抵抗３，７が
無いと、人間が帯電していたときに大電流がダイオード
を通ってアースに流れ、ダイオードが破壊する。しか
し、本実施例装置では１００ＫΩ程度の抵抗が接続され
ていることによって電流を制限するので、ダイオードの
破壊が防止される。In the configuration shown in FIG. 1, there is a possibility that a serviceman or a user may touch the cores of the heating roller 1 and the pressure roller 5 when replacing the fixing unit. At this time, if the resistors 3 and 7 are not provided, when a person is charged, a large current flows through the diode to the ground, and the diode is destroyed. However, in the device of the present embodiment, the current is limited by the connection of the resistance of about 100 KΩ, so that the breakdown of the diode is prevented.
【００１３】なお、抵抗３，７にカーボン抵抗を用いて
いるのはカーボン抵抗がラッシュ電流に強いからであ
る。実験の結果、金属皮膜抵抗では一回放電すると抵抗
値が変化してしまった。The reason why carbon resistors are used for the resistors 3 and 7 is that the carbon resistors are strong against rush current. As a result of the experiment, the resistance value of the metal film resistor changed after one discharge.
【００１４】図２は実際に抵抗、ダイオードを実装する
方法を示したものである。抵抗３とダイオード４を直列
に接続し、その接続部は閉端接続子９で圧着接続してい
る。ハンダ付けでもよいが作業性の点では圧着方が良
い。FIG. 2 shows a method of actually mounting a resistor and a diode. The resistor 3 and the diode 4 are connected in series, and the connection is crimp-connected with a closed-end connector 9. Although soldering may be used, crimping is preferable in terms of workability.
【００１５】ダイオード４の片端には丸型端子１０、抵
抗３の片端には丸型端子１１が圧着される。丸型端子１
０はビスでフレームに固定され、丸型端子１１はビスで
ばね２に固定される。A round terminal 10 is crimped to one end of the diode 4 and a round terminal 11 is crimped to one end of the resistor 3. Round terminal 1
Numeral 0 is fixed to the frame with screws, and round terminal 11 is fixed to spring 2 with screws.
【００１６】この抵抗３、ダイオード４を直線状に配置
しているのはもし丸型端子１１がダイオード４のリード
線に近付いていると、静電気が印加されたとき、電流が
抵抗３を通らず、丸型端子１１からダイオード４に放電
してしまうからである。このような可能性があるときは
点線１２のように絶縁チューブを被らせて沿面距離を確
保し、放電を防止すると効果がある。The reason why the resistor 3 and the diode 4 are linearly arranged is that if the round terminal 11 is close to the lead wire of the diode 4, the current does not pass through the resistor 3 when static electricity is applied. This is because the diode 4 is discharged from the round terminal 11. When there is such a possibility, it is effective to cover the insulating tube as shown by the dotted line 12 to secure the creepage distance and prevent discharge.
【００１７】〈第二実施例〉次に、図３に基づいて本発
明の第二実施例を説明する。なお、第一実施例との共通
箇所には同一符号を付して説明を省略する。<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted.
【００１８】本実施例は、ダイオード３，８に接続する
抵抗を一つにしたところが第一実施例と異なる。図３に
示すように、ダイオード３，８の接地側に抵抗１３を接
続して接地させたものである。このように接続すること
によって抵抗の数を減らすことができる。The present embodiment differs from the first embodiment in that only one resistor is connected to the diodes 3 and 8. As shown in FIG. 3, a resistor 13 is connected to the ground side of the diodes 3 and 8 and grounded. This connection reduces the number of resistors.
【００１９】以上の実施例においては熱ローラ定着方式
の定着装置について説明したが、本発明は圧力定着方式
の定着装置に用いても同様の効果を奏する。In the above embodiment, the fixing device of the heat roller fixing type has been described. However, the present invention has the same effect when used in a fixing device of the pressure fixing type.
【００２０】[0020]
【発明の効果】以上説明したように、本発明によれば、
セルフバイアス用のダイオードに直列に１００ＫΩ程度
の抵抗を接続することで静電気放電時の電流を十分に小
さく制限でき、ダイオードの過電流破壊を防止すること
ができる。As described above, according to the present invention,
By connecting a resistor of about 100 KΩ in series with the self-biasing diode, the current at the time of electrostatic discharge can be limited to a sufficiently small value, and overcurrent destruction of the diode can be prevented.
【００２１】また、通常動作時はダイオードに流れる電
流は１μＡ程度で、１００ＫΩの抵抗による電圧ドロッ
プは０．１Ｖ程度であり、バイアス電圧６００Ｖ〜２Ｋ
Ｖに対し十分小さな値でオフセット防止に関してもまっ
たく問題ない。さらに本発明は、整流素子に抵抗素子を
直列に接続するに際し、整流素子と抵抗素子を圧着によ
り接続することとしたので、整流素子と抵抗素子の実装
作業性を向上させることができ、またハンダ等の熱を伴
わないので素子の熱劣化を防止することができる。 During normal operation, the current flowing through the diode is about 1 μA, the voltage drop due to a 100 KΩ resistor is about 0.1 V, and the bias voltage is 600 V to 2 K.
With a sufficiently small value for V, there is no problem with respect to offset prevention. Furthermore, the present invention provides a rectifier with a resistance element.
When connecting in series, connect the rectifying element and the resistance element by crimping.
Rectifier and resistor elements
Workability can be improved, and the heat
Since it is not known, thermal deterioration of the element can be prevented.
【図１】本発明の第一実施例装置の概略構成を示す図で
ある。FIG. 1 is a diagram showing a schematic configuration of an apparatus according to a first embodiment of the present invention.
【図２】図１装置における整流素子と抵抗素子の実装手
法を示す図である。FIG. 2 is a diagram showing a mounting method of a rectifying element and a resistive element in the apparatus of FIG.
【図３】本発明の第二実施例装置の概略構成を示す図で
ある。FIG. 3 is a diagram showing a schematic configuration of an apparatus according to a second embodiment of the present invention.
１ 加熱ローラ ３，７ 抵抗素子（カーボン抵抗） ４，８ 整流素子（ダイオード） ５ 加圧ローラ DESCRIPTION OF SYMBOLS 1 Heating roller 3,7 Resistance element (carbon resistance) 4,8 Rectification element (diode) 5 Pressure roller
フロントページの続き (56)参考文献 特開 平３−145682（ＪＰ，Ａ) 特開 昭51−126770（ＪＰ，Ａ) 実開 昭57−202238（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.7，ＤＢ名) G03G 15/20 H01G 1/00 Continued on the front page (56) References JP-A-3-145682 (JP, A) JP-A-51-126770 (JP, A) JP-A-57-202238 (JP, U) (58) Fields investigated (Int) .Cl. 7 , DB name) G03G 15/20 H01G 1/00
Claims (1)
加圧ローラの芯金に、一端を接地した整流素子を接続し
て、現像剤を加熱ローラ側から引き離し加圧ローラ側へ
引き付ける方向のバイアス電圧を印加せしめる定着装置
セルフバイアス印加回路において、上記整流素子に抵抗
素子を直列に接続し、上記整流素子と上記抵抗素子を圧
着により接続したことを特徴とする定着装置セルフバイ
アス印加回路。1. A direction in which a rectifying element whose one end is grounded is connected to a core of a heating roller and a pressure roller which are disposed in pressure contact with each other, and the developer is separated from the heating roller side and is attracted to the pressure roller side. In the fixing device self-bias applying circuit for applying a bias voltage of, a resistor is connected in series to the rectifier, and the rectifier and the resistor are compressed.
A self-bias applying circuit for the fixing device, wherein the self-bias applying circuit is connected to the fixing device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03218109A JP3090986B2 (en) | 1991-08-05 | 1991-08-05 | Fixing device self-bias application circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03218109A JP3090986B2 (en) | 1991-08-05 | 1991-08-05 | Fixing device self-bias application circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0540426A JPH0540426A (en) | 1993-02-19 |
| JP3090986B2 true JP3090986B2 (en) | 2000-09-25 |
Family
ID=16714773
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03218109A Expired - Fee Related JP3090986B2 (en) | 1991-08-05 | 1991-08-05 | Fixing device self-bias application circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3090986B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7082273B2 (en) * | 2002-01-02 | 2006-07-25 | Kabushiki Kaisha Toshiba | Image forming apparatus with electricity eliminating member |
| JP5528053B2 (en) * | 2009-10-19 | 2014-06-25 | キヤノン株式会社 | Image forming apparatus |
| JP6007591B2 (en) * | 2012-05-22 | 2016-10-12 | 富士ゼロックス株式会社 | Grounding device, fixing device, image forming device |
| JP6136833B2 (en) * | 2013-10-07 | 2017-05-31 | 富士ゼロックス株式会社 | Fixing apparatus and image forming apparatus |
-
1991
- 1991-08-05 JP JP03218109A patent/JP3090986B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0540426A (en) | 1993-02-19 |
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