JP2009025673A - Image forming apparatus - Google Patents
Image forming apparatus Download PDFInfo
- Publication number
- JP2009025673A JP2009025673A JP2007190238A JP2007190238A JP2009025673A JP 2009025673 A JP2009025673 A JP 2009025673A JP 2007190238 A JP2007190238 A JP 2007190238A JP 2007190238 A JP2007190238 A JP 2007190238A JP 2009025673 A JP2009025673 A JP 2009025673A
- Authority
- JP
- Japan
- Prior art keywords
- transfer
- transfer belt
- intermediate transfer
- roller
- electrostatic bias
- 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
Links
Abstract
Description
本発明は、中間転写ベルトからトナー像を用紙上へ転写する電子写真方式の画像形成装置に関する。 The present invention relates to an electrophotographic image forming apparatus for transferring a toner image from an intermediate transfer belt onto a sheet.
電子写真方式の画像形成装置においては、近年の印刷の高速化への対応を考えると、転写部で中間転写ベルトと用紙の接触時間をローラ転写よりも長く取りやすい点で、ベルト転写方式が優位である。 In the electrophotographic image forming apparatus, considering the recent increase in printing speed, the belt transfer system is superior in that the contact time between the intermediate transfer belt and the paper is longer than the roller transfer at the transfer section. It is.
中間転写ベルトからトナー像を用紙上へ転写する電子写真方式の画像形成装置で、とりわけ第二転写時に用紙を中間転写ベルトと転写ベルトで挟持するベルト転写方式において、安定したトナーの転写を実現する技術に関しては特許文献１に記載がある。 Achieves stable toner transfer in an electrophotographic image forming apparatus that transfers a toner image from an intermediate transfer belt onto paper, particularly in a belt transfer system in which the paper is sandwiched between the intermediate transfer belt and the transfer belt during the second transfer. The technique is described in Patent Document 1.
この特許文献１に記載された技術では、中間転写ベルトに転写されたトナー像を転写材に二次転写するとき、バイアス印加ローラとアースローラを下流側に設けられた二次転写ローラ側に移動し、下流側に設けられた二次転写ローラの位置で二次転写ベルトを中間転写ベルトに食い込ませて転写材に一定の圧力を加えながら搬送し、中間転写ベルトや二次転写ベルトと転写材との間に隙間が空いて転写効率にむらを起こして画像むらが生じたり、搬送不足による搬送不良が発生することを防止するものであり、転写紙等に転写した画像に虫食い画像が発生したり、転写チリにより画像の一部に欠損が生じることを防ぐことができる。 In the technique described in Patent Document 1, when the toner image transferred to the intermediate transfer belt is secondarily transferred to the transfer material, the bias application roller and the earth roller are moved to the secondary transfer roller side provided on the downstream side. Then, the secondary transfer belt is bitten into the intermediate transfer belt at the position of the secondary transfer roller provided on the downstream side and conveyed while applying a certain pressure to the transfer material. To prevent uneven transfer efficiency and uneven image transfer, or poor transport due to insufficient transport, resulting in worm-eaten images on images transferred to transfer paper, etc. In addition, it is possible to prevent a part of the image from being lost due to transfer dust.
しかしながら特許文献１の技術では、アースローラからバイアス印加ローラの間は転写紙に略一定の静電バイアスが印加されるため、例えば低温低湿環境下で各種ローラの抵抗値が高くなった場合には、トナーの転写に必要な電流を得るためにより多くの電圧を印加することとなり、転写紙が中間転写ベルトから剥離する際に過剰な電界が与えられて放電に伴う画像不良を発生させる恐れがあった。 However, in the technique of Patent Document 1, since a substantially constant electrostatic bias is applied to the transfer paper between the earth roller and the bias application roller, for example, when the resistance values of various rollers increase in a low temperature and low humidity environment. Therefore, more voltage is applied to obtain the current required for toner transfer, and an excessive electric field is applied when the transfer paper is peeled off from the intermediate transfer belt, which may cause image defects due to discharge. It was.
本発明の目的は、中間転写ベルトからトナー像を用紙上へ転写する電子写真方式の画像形成装置で、とりわけ第二転写時に用紙を中間転写ベルトと転写ベルトで挟持するベルト転写方式において、安定したトナーの転写を実現し、画像の乱れのない高画質画像が得られる画像形成装置を提供することにある。 An object of the present invention is an electrophotographic image forming apparatus that transfers a toner image from an intermediate transfer belt onto a sheet, and more particularly in a belt transfer system in which a sheet is sandwiched between an intermediate transfer belt and a transfer belt during a second transfer. An object of the present invention is to provide an image forming apparatus that realizes toner transfer and obtains a high-quality image without image distortion.
本発明の請求項１記載の画像形成装置では、像担持手段と、該像担持手段上に潜像を形成する潜像形成手段と、前記像担持手段上に形成された潜像にトナーを付着させる現像手段と、前記像担持手段上のトナー画像が転写される中間転写ベルトと、該中間転写ベルトを駆動する駆動ローラと、前記像担持手段上のトナー画像を前記中間転写ベルトに転写する第一の転写手段と、用紙を搬送する用紙搬送手段と、前記中間転写ベルト上のトナー画象を前記用紙搬送手段により搬送されている用紙に転写する第二の転写手段と、該用紙上のトナー画像を溶融定着する定着手段とを有する電子写真方式の画像形成装置において、前記第二の転写手段は、前記中間転写ベルト上のトナーを静電気的に前記用紙へ転写する第一の静電バイアス付与部及び第二の静電バイアス付与部からなり、前記第一の静電バイアス部で印加される静電バイアス値と、前記第二の静電バイアス部で印加される静電バイアス値が異なることを特徴とする。 In the image forming apparatus according to the first aspect of the present invention, the image carrying means, the latent image forming means for forming a latent image on the image carrying means, and the toner is attached to the latent image formed on the image carrying means. Developing means, an intermediate transfer belt to which the toner image on the image carrying means is transferred, a driving roller for driving the intermediate transfer belt, and a toner image on the image carrying means transferred to the intermediate transfer belt. One transfer means, a paper transport means for transporting the paper, a second transfer means for transferring the toner image on the intermediate transfer belt to the paper transported by the paper transport means, and the toner on the paper In the electrophotographic image forming apparatus having a fixing unit for fusing and fixing an image, the second transfer unit applies a first electrostatic bias for electrostatically transferring the toner on the intermediate transfer belt to the sheet. And The electrostatic bias value applied by the first electrostatic bias unit is different from the electrostatic bias value applied by the second electrostatic bias unit. To do.
請求項２に係るものは、請求項１記載の画像形成装置において、前記第二の転写手段は、前記中間転写ベルトのトナー画像保持裏面側に配される転写対向部材と、該転写対向部材と対向して前記中間転写ベルトと共に前記用紙を所定の押し付け力で挟む転写部材とからなり、前記転写部材は、前記転写対向部材と対向して所定の押し付け力を付与しかつ前記転写対向部材との間に静電バイアスを印加する第一の静電バイアス付与部としての第一押し付けローラと、前記転写対向部材と対向して所定の押し付け力を付与しかつ前記転写対向部材との間に静電バイアスを印加する第二の静電バイアス付与部としての第二押し付けローラと、これら第一ならびに第二押し付けローラを囲むように配され、前記第一ならびに第二押し付けローラと前記中間転写ベルトに挟持されかつ前記中間転写ベルトの搬送方向に搬送される無端状の転写ベルトからなることを特徴とする。 According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the second transfer unit includes a transfer counter member disposed on a toner image holding back surface side of the intermediate transfer belt, the transfer counter member, And a transfer member that sandwiches the sheet with a predetermined pressing force together with the intermediate transfer belt, the transfer member facing the transfer facing member and applying a predetermined pressing force, and the transfer facing member. A first pressing roller serving as a first electrostatic bias applying unit that applies an electrostatic bias therebetween, and a predetermined pressing force is applied to face the transfer facing member and the electrostatic force is applied between the transfer facing member. A second pressing roller as a second electrostatic bias applying unit for applying a bias, and arranged to surround the first and second pressing rollers, the first and second pressing rollers, It is held between the transfer belt and characterized by comprising an endless transfer belt which is conveyed in the conveying direction of the intermediate transfer belt.
請求項３に係るものは、請求項１記載の画像形成装置において、前記第二の転写手段は、前記中間転写ベルトのトナー画像保持裏面側に配される転写対向部材と該転写対向部材と対向して前記中間転写ベルトと共に前記用紙を所定の押し付け力で挟持する転写部材とからなり、前記転写部材は、前記転写対向部材と対向して所定の押し付け力を付与しかつ前記転写対向部材との間に静電バイアスを印加する第一の静電バイアス付与部としての第一押し付けパッドと、前記転写対向部材と対向して所定の押し付け力を付与しかつ前記転写対向部材との間に静電バイアスを印加する第二の静電バイアス付与部としての第二押し付けパッドと、該第一ならびに第二押し付けパッドを囲むように配され、前記第一ならびに第二押し付けパッドと前記中間転写ベルトに挟持されかつ前記中間転写ベルトの搬送方向に搬送される無端状の転写ベルトからなることを特徴とする。 According to a third aspect of the present invention, in the image forming apparatus according to the first aspect, the second transfer unit is opposite to the transfer counter member disposed on the toner image holding back surface side of the intermediate transfer belt and the transfer counter member. And a transfer member that clamps the sheet with a predetermined pressing force together with the intermediate transfer belt, the transfer member facing the transfer facing member and applying a predetermined pressing force, and the transfer facing member. A first pressing pad serving as a first electrostatic bias applying unit that applies an electrostatic bias therebetween, and a predetermined pressing force is applied to the transfer facing member and electrostatically applied between the transfer facing member. A second pressing pad as a second electrostatic bias applying unit for applying a bias; and the first and second pressing pads are arranged so as to surround the first and second pressing pads. Characterized by comprising an endless transfer belt which is transported in the transport direction of the sandwiched transfer belt and the intermediate transfer belt.
請求項４に係るものは、請求項３記載の画像形成装置において、前記転写対向部材は前記中間転写ベルトの搬送と共に回動する転写対向ローラでありかつ前記第一及び第二押し付けパッドは絶縁部材を介して一体に形成された転写パッドを構成しかつ前記転写パッドの前記転写対向ローラとの押し付け面の形状が前記転写対向ローラの外周形状と略一致することを特徴とする。 According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the transfer counter member is a transfer counter roller that rotates along with the conveyance of the intermediate transfer belt, and the first and second pressing pads are insulating members. And the shape of the pressing surface of the transfer pad against the transfer counter roller substantially coincides with the outer peripheral shape of the transfer counter roller.
請求項５に係るものは、請求項１から４のいずれかに記載の画像形成装置において、前記第一の静電バイアス付与部は静電バイアス出力が定電流に制御されかつ前記第二の静電バイアス付与部は静電バイアス出力が定電圧に制御されることを特徴とする。 According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the first electrostatic bias applying unit has an electrostatic bias output controlled to a constant current and the second static bias applying unit. The electric bias applying unit is characterized in that the electrostatic bias output is controlled to a constant voltage.
本発明は、第一の静電バイアス付与部でトナーの転写に必要な静電バイアスを印加し、第二の静電バイアス付与部で、用紙に転写されたトナー像を乱さない静電バイアスを印加できるので、第二の転写手段におけるトナーの転写部において画像不良のない安定した転写を実現できる。 In the present invention, the first electrostatic bias applying unit applies an electrostatic bias necessary for toner transfer, and the second electrostatic bias applying unit applies an electrostatic bias that does not disturb the toner image transferred to the paper. Since it can be applied, stable transfer without image defects can be realized in the toner transfer portion of the second transfer means.
以下本発明を実施するための最良の形態を、図に示す実施例を参照して説明する。 The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.
図１は本発明に係る中間転写ベルトユニットを用いる画像形成装置の一例を示す側面断面図である。
本例の画像形成装置１は、各色の現像ユニットを中間転写ベルト２０の上方に配置し、中間転写ベルト２０上にトナーによるカラー像を形成し、そのカラー像を用紙堆積手段４から搬送される用紙に転写し、定着器６０で熱と圧力でトナーを溶融定着してカラー画像を形成する。
FIG. 1 is a side sectional view showing an example of an image forming apparatus using an intermediate transfer belt unit according to the present invention.
In the image forming apparatus 1 of this example, each color developing unit is disposed above the intermediate transfer belt 20, forms a color image with toner on the intermediate transfer belt 20, and the color image is conveyed from the paper stacking unit 4. The toner image is transferred to a sheet, and the toner is melted and fixed by heat and pressure in the fixing device 60 to form a color image.
この装置におけるカラー画像の作像プロセスを図１を参照して説明する。
現像ユニットは４式あり、各々像担持体として感光体ドラムを備えており、それぞれ、黒色トナーを有するＫ現像ユニット５０１、シアン色トナーを有するＣ現像ユニット５０２、マゼンタ色トナーを有するＭ現像ユニット５０３、イエロー色トナーを有するＹ現像ユニット５０４である。Ｋ現像ユニットは、トナーを貯めるトナーホッパ５３、トナー層を形成し、感光体ドラム５４上にトナーを現像する現像ローラ５２、感光体ドラム５４上をクリーニングするドラムクリーナ５７、感光体ドラム５４上を帯電させる帯電器５５、感光体ドラム５４上に静電潜像を書き込む露光器５６で構成される。他の色の現像ユニットも同様である。
A color image forming process in this apparatus will be described with reference to FIG.
There are four types of developing units, each including a photosensitive drum as an image carrier, and each includes a K developing unit 501 having black toner, a C developing unit 502 having cyan toner, and an M developing unit 503 having magenta toner. Y developing unit 504 having yellow toner. The K developing unit forms a toner hopper 53 for storing toner, a toner layer, a developing roller 52 for developing toner on the photosensitive drum 54, a drum cleaner 57 for cleaning the photosensitive drum 54, and charging the photosensitive drum 54. And an exposure unit 56 for writing an electrostatic latent image on the photosensitive drum 54. The same applies to the developing units of other colors.
中間転写ベルト２０は、第一の従動ローラ２１、第二の従動ローラ２６、転写従動ローラ３１等に張架され、駆動ローラ３で搬送される。 The intermediate transfer belt 20 is stretched around the first driven roller 21, the second driven roller 26, the transfer driven roller 31, and the like, and is conveyed by the driving roller 3.
画像を形成する場合、感光体ドラム５４上を帯電器５５で帯電させ、露光器５６で画像に応じた光をあてて、感光体ドラム５４上の電位を落とす。その部位が感光体ドラム５４の回転により、現像ローラ５２に達し、トナー層と接すると帯電しているトナーが画像位置に付着する。第一の転写手段である一次転写ローラ５８は、感光体ドラム５４に対向して中間転写ベルト２０内側に配置される。感光体ドラム５４上のトナー画像は、一次転写ローラ５８が中間転写ベルト２０当接する第一転写部で、中間転写ベルト２０上に転写される。 When an image is formed, the surface of the photosensitive drum 54 is charged by the charger 55, and light corresponding to the image is applied by the exposure device 56 to drop the potential on the photosensitive drum 54. The portion reaches the developing roller 52 by the rotation of the photosensitive drum 54, and when it comes into contact with the toner layer, the charged toner adheres to the image position. A primary transfer roller 58 serving as a first transfer unit is disposed inside the intermediate transfer belt 20 so as to face the photosensitive drum 54. The toner image on the photosensitive drum 54 is transferred onto the intermediate transfer belt 20 at the first transfer portion where the primary transfer roller 58 contacts the intermediate transfer belt 20.
各現像ユニットの感光体ドラム上のトナー画像は、中間転写ベルト２０上に転写され、カラーのトナー画像が形成される。そして、中間転写ベルト２０の搬送により、中間転写ベルト２０と転写ベルト３２と当接する第二転写部で搬送されてきた用紙上にトナー画像が転写される。ベルトクリーナ９１は中間転写ベルト２０上の残留トナーを除去する。 The toner image on the photosensitive drum of each developing unit is transferred onto the intermediate transfer belt 20 to form a color toner image. As the intermediate transfer belt 20 is conveyed, the toner image is transferred onto the sheet conveyed by the second transfer unit that contacts the intermediate transfer belt 20 and the transfer belt 32. The belt cleaner 91 removes residual toner on the intermediate transfer belt 20.
用紙搬送経路８は、用紙を堆積する用紙堆積手段４から、ピックローラ９、分離ローラ１１を経て、転写ベルト３２と中間転写ベルト２０の間を通過し、搬送ベルト８１から定着器６０へ至る。 The sheet conveyance path 8 passes from the sheet accumulation unit 4 that accumulates sheets, passes between the transfer belt 32 and the intermediate transfer belt 20 via the pick roller 9 and the separation roller 11, and reaches the fixing device 60 from the conveyance belt 81.
定着器６０は、バックアップローラ６４、弾性ローラ６３、加熱ローラ６２、定着ベルト６１を有する。定着ベルト６１は、弾性ローラ６３と加熱ローラ６２に掛け渡され、加熱ローラ６２あるいは他のローラの回転により搬送される。 The fixing device 60 includes a backup roller 64, an elastic roller 63, a heating roller 62, and a fixing belt 61. The fixing belt 61 is stretched over the elastic roller 63 and the heating roller 62 and is conveyed by the rotation of the heating roller 62 or other rollers.
用紙はバックアップローラ６４により弾性ローラ６３側に押し付けられる。加熱ローラ６２は、金属の中空シャフト内にハロゲンヒータ等の加熱手段を有し、定着ベルト６１を加熱する。弾性ローラ６３表面は、シリコンゴム等の弾性材で形成され、バックアップローラ６４の押し付けにより、ニップ部を弾性ローラ６３側に凸とし、用紙が定着ベルト６１に巻きつくのを防止する。そして、トナー画像が転写された用紙は、搬送ベルト８１により定着器６０に搬送され、熱と圧力によりトナーを溶融定着しカラー画像を形成する。 The sheet is pressed against the elastic roller 63 side by the backup roller 64. The heating roller 62 has heating means such as a halogen heater in a metal hollow shaft, and heats the fixing belt 61. The surface of the elastic roller 63 is formed of an elastic material such as silicon rubber, and the nip portion is convex toward the elastic roller 63 by pressing the backup roller 64 to prevent the paper from being wound around the fixing belt 61. The sheet on which the toner image is transferred is conveyed to the fixing device 60 by the conveying belt 81, and the toner is melted and fixed by heat and pressure to form a color image.
図２は上述した画像形成装置の中間転写ベルトユニットの一例を示す図である。
本例の中間転写ベルト２０は、駆動ローラ３、第一の従動ローラ２１、第二の従動ローラ２６、転写対向部材としての従動転写ローラ３１に張り渡され、駆動手段２５により回転する駆動ローラ３により図中矢印Ａ方向に搬送される。第二の従動ローラ２６は図示されていない荷重付与手段により中間転写ベルト２０に張力を与え、駆動ローラ３と中間転写ベルト２０の間に摩擦搬送力を発生させる。
FIG. 2 is a diagram illustrating an example of the intermediate transfer belt unit of the image forming apparatus described above.
The intermediate transfer belt 20 of this example is stretched over a driving roller 3, a first driven roller 21, a second driven roller 26, and a driven transfer roller 31 as a transfer facing member, and is rotated by a driving means 25. Is conveyed in the direction of arrow A in FIG. The second driven roller 26 applies tension to the intermediate transfer belt 20 by a load applying means (not shown), and generates a friction conveying force between the driving roller 3 and the intermediate transfer belt 20.
駆動ローラ３と第二の従動ローラ２６で形成される面は、図示されていない現像手段が配置され、中間転写ベルト２０を介して対向する一次転写ローラ（図示せず）等第一の転写手段を構成する。 The surface formed by the drive roller 3 and the second driven roller 26 is provided with a developing means (not shown), and a first transfer means such as a primary transfer roller (not shown) opposed via the intermediate transfer belt 20. Configure.
第二の転写手段は第一の静電バイアス付与部としての第一押し付けローラ３０ａと、第二の静電バイアス付与部としての第二押し付けローラ３０ｂとを有し、図示されていないばね等の加圧手段により、従動転写ローラ３１に対向して中間転写ベルト２０に押し付けられる。第一押し付けローラ３０ａならびに第二押し付けローラ３０ｂは、例えば発泡性ゴムのような柔らかい材質の材料で形成され、従動転写ローラ３１に押し付けられると、従動転写ローラ３１の外周形状に沿うように変形する。 The second transfer means includes a first pressing roller 30a as a first electrostatic bias applying unit and a second pressing roller 30b as a second electrostatic bias applying unit, such as a spring not shown. The pressing unit is pressed against the intermediate transfer belt 20 so as to face the driven transfer roller 31. The first pressing roller 30a and the second pressing roller 30b are formed of a soft material such as foamable rubber, for example. When pressed against the driven transfer roller 31, the first pressing roller 30a and the second pressing roller 30b are deformed so as to follow the outer peripheral shape of the driven transfer roller 31. .
転写ベルト３２は第一押し付けローラ３０ａならびに第二押し付けローラ３０ｂを内包するように配置され、中間転写ベルト２０の移動に伴い、従動搬送される。用紙は図中矢印Ｂ方向から搬送され、転写ベルト３２と中間転写ベルト２０の間を搬送される。 The transfer belt 32 is disposed so as to include the first pressing roller 30a and the second pressing roller 30b, and is driven and conveyed as the intermediate transfer belt 20 moves. The sheet is conveyed from the direction of arrow B in the figure, and is conveyed between the transfer belt 32 and the intermediate transfer belt 20.
本実施例の構成により、第二転写部において用紙と中間転写ベルトの接触領域を安定して保持することができるので、高速印刷において安定した転写性能を確保することができる。 With the configuration of this embodiment, the contact area between the sheet and the intermediate transfer belt can be stably held in the second transfer portion, so that stable transfer performance can be ensured in high-speed printing.
図３は上述した画像形成装置の第二転写部の側断面構成図である。
本例においては、第二の転写手段は第一押し付けローラ３０ａならびに第二押し付けローラ３０ｂを有し、図示していないばね等の加圧手段により、従動転写ローラ３１に対向して中間転写ベルト２０に押し付けられる。転写ベルト３２は第一押し付けローラ３０ａならびに第二押し付けローラ３０ｂを内包するように配置され、中間転写ベルト２０の移動に伴い、従動搬送される。転写ベルト３２は転写ベルトガイドローラ３３、３４、３５により張架され、安定したベルト搬送が実現される。なお、転写ベルトガイドローラ３３を駆動源（図示せず）により回動させることによって転写ベルト３２に中間転写ベルト２０との速度差を所定の範囲に制御することによって、中間転写ベルト２０の搬送負荷を低減させた上で、第二転写部での転写画像の品質を確保することができる。
FIG. 3 is a side sectional view of the second transfer portion of the image forming apparatus described above.
In this example, the second transfer unit includes a first pressing roller 30a and a second pressing roller 30b. The intermediate transfer belt 20 is opposed to the driven transfer roller 31 by a pressing unit such as a spring (not shown). Pressed against. The transfer belt 32 is disposed so as to include the first pressing roller 30a and the second pressing roller 30b, and is driven and conveyed as the intermediate transfer belt 20 moves. The transfer belt 32 is stretched by transfer belt guide rollers 33, 34, and 35 to realize stable belt conveyance. The transfer load of the intermediate transfer belt 20 is controlled by rotating the transfer belt guide roller 33 by a drive source (not shown) to control the speed difference between the transfer belt 32 and the intermediate transfer belt 20 within a predetermined range. In addition, the quality of the transfer image at the second transfer portion can be ensured.
用紙は図中矢印Ｂ方向から搬送され、転写ベルト３２と中間転写ベルト２０の間を挟持、搬送される。従動転写ローラ３１、中間転写ベルト２０、転写ベルト３２および、第一押し付けローラ３０ａならびに第二押し付けローラ３０ｂは電気抵抗値が調整されており、用紙が転写ベルト３２と中間転写ベルト２０の間を挟持、搬送されている間に従動転写ローラ３１と第一押し付けローラ３０ａならびに第二押し付けローラ３０ｂの間に所定の静電バイアスが印加され、中間転写ベルト２０上の帯電トナーを静電力によって用紙へ転写する。 The sheet is conveyed from the direction of arrow B in the figure, and is nipped and conveyed between the transfer belt 32 and the intermediate transfer belt 20. The driven transfer roller 31, the intermediate transfer belt 20, the transfer belt 32, the first pressing roller 30 a, and the second pressing roller 30 b have electric resistance values adjusted, and the sheet sandwiches between the transfer belt 32 and the intermediate transfer belt 20. A predetermined electrostatic bias is applied between the driven transfer roller 31, the first pressing roller 30a and the second pressing roller 30b while being conveyed, and the charged toner on the intermediate transfer belt 20 is transferred to the sheet by electrostatic force. To do.
本例においては、用紙の挿入側に配置された第一押し付けローラ３０ａは第一転写バイアス印加ユニット３００ａに、用紙の排出側に配置された第二押し付けローラ３０ｂは第一転写バイアス印加ユニット３００ｂに電気的に接続されており、夫々従動転写ローラ３１との間に静電転写バイアスを印加する。さらに本実施例においては、第一転写バイアス印加ユニット３００ａは出力が一定電流となるように制御されており、中間転写ベルト２０上の帯電トナーを用紙へ転写するのに必要な電流を確保し、トナーの転写を確実にする。一方、第二転写バイアス印加ユニット３００ｂでは出力が一定電圧となるように制御されており、中間転写ベルト２０上に転写された帯電トナーが飛散しないような静電界を形成し、例えば低温低湿環境下で従動転写ローラ３１ならびに第一押し付けローラ３０ａの抵抗値が上昇して一定電流制御された第一転写バイアスユニットの出力電圧が高くなることに起因した、転写ニップ部出口での放電によるトナーの飛散を防止でき、第二転写部でのトナー像の安定形勢を実現する。トナーを保持した用紙は、図中矢印Ｃの方向へ搬送される。 In this example, the first pressing roller 30a disposed on the paper insertion side is connected to the first transfer bias applying unit 300a, and the second pressing roller 30b disposed on the paper discharging side is connected to the first transfer bias applying unit 300b. They are electrically connected, and an electrostatic transfer bias is applied to each of the driven transfer rollers 31. Further, in this embodiment, the first transfer bias applying unit 300a is controlled so that the output becomes a constant current, and secures a current necessary for transferring the charged toner on the intermediate transfer belt 20 to the sheet. Ensure toner transfer. On the other hand, in the second transfer bias applying unit 300b, the output is controlled to be a constant voltage, and an electrostatic field is formed so that the charged toner transferred onto the intermediate transfer belt 20 does not scatter, for example, in a low temperature and low humidity environment. As a result, the resistance value of the driven transfer roller 31 and the first pressing roller 30a is increased and the output voltage of the first transfer bias unit controlled at a constant current is increased. The toner image can be stably formed at the second transfer portion. The sheet holding the toner is conveyed in the direction of arrow C in the figure.
本構成により、使用環境によらず第二転写部でのトナー像の安定形成を実現し、また、第二転写部において用紙と中間転写ベルトの接触領域を安定して保持することができるので、高速印刷において安定した転写性能を確保することができる。 With this configuration, the toner image can be stably formed in the second transfer portion regardless of the use environment, and the contact area between the sheet and the intermediate transfer belt can be stably held in the second transfer portion. Stable transfer performance can be ensured in high-speed printing.
さらに、第二転写部のニップ部を形成する従動転写ローラ３１と第一押し付けローラ３０ａならびに第二押し付けローラ３０ｂの接触領域に形成される転写電界中を搬送される前に、転写ベルトガイドローラ３５および中間転写ベルトガイドローラ３７により中間転写ベルト２０と用紙（図示せず）が挟持、搬送されるので、第二転写部のニップ部直前の用紙のばたつきが防止され、用紙のばたつきによる電界の不安定に起因した放電を防止することができる。このため、中間転写ベルト２０上のトナー像の放電による飛散りを防止することができる。 Further, before being conveyed through the transfer electric field formed in the contact area between the driven transfer roller 31 forming the nip portion of the second transfer portion, the first pressing roller 30a, and the second pressing roller 30b, the transfer belt guide roller 35 is transferred. Further, since the intermediate transfer belt 20 and the paper (not shown) are sandwiched and conveyed by the intermediate transfer belt guide roller 37, flapping of the paper immediately before the nip portion of the second transfer portion is prevented, and electric field is prevented from being fluttered by the paper. Discharge due to stability can be prevented. For this reason, it is possible to prevent scattering of the toner image on the intermediate transfer belt 20 due to discharge.
図４は本発明の実施例２に係る画像形成装置の中間転写ベルトユニットを示す図である。なお以下では、実施例１と異なる点を中心に説明する。
本実施例装置は、第二の転写手段は転写パッド３０’を有し、図示していないばね等の加圧手段により、従動転写ローラ３１に対向して中間転写ベルト２０に押し付けられる。転写ベルト３２は転写パッド３０’を内包するように配置され、中間転写ベルト２０の移動に伴い、従動搬送される。用紙は図中矢印Ｂ方向から搬送され、転写ベルト３２と中間転写ベルト２０の間を搬送される。
FIG. 4 is a view showing an intermediate transfer belt unit of the image forming apparatus according to Embodiment 2 of the present invention. In the following description, differences from the first embodiment will be mainly described.
In this embodiment, the second transfer means has a transfer pad 30 ′ and is pressed against the intermediate transfer belt 20 so as to face the driven transfer roller 31 by a pressing means such as a spring (not shown). The transfer belt 32 is disposed so as to include the transfer pad 30 ′, and is driven and conveyed as the intermediate transfer belt 20 moves. The sheet is conveyed from the direction of arrow B in the figure, and is conveyed between the transfer belt 32 and the intermediate transfer belt 20.
さらに本実施例においては、転写パッド３０’は従動転写ローラ３１との押し付け面の形状が前記転写対向ローラの外周形状と略一致するように形成されかつ、用紙の挿入側に電気抵抗の調整された第一押し付けパッド３０ａ、排出側に電気抵抗の調整された第一押し付けパッド３０ｂ、ならびに、その間に電気的絶縁部材３０ｃを具備している。 Further, in this embodiment, the transfer pad 30 'is formed so that the shape of the pressing surface with the driven transfer roller 31 substantially matches the outer peripheral shape of the transfer counter roller, and the electric resistance is adjusted on the paper insertion side. Further, the first pressing pad 30a, the first pressing pad 30b whose electric resistance is adjusted on the discharge side, and the electrically insulating member 30c are provided therebetween.
そして本構成により、第二転写部において用紙と中間転写ベルトの接触領域を安定して保持することができるので、高速印刷において安定した転写性能を確保することができる。 With this configuration, the contact area between the sheet and the intermediate transfer belt can be stably held in the second transfer portion, so that stable transfer performance can be ensured in high-speed printing.
図５は実施例２の第二転写部の側断面構成図である。これについても実施例１と異なる点を中心に説明する。
本例においては、第二の転写手段は転写パッド３０’を有し、図示していないばね等の加圧手段により、従動転写ローラ３１に対向して中間転写ベルト２０に押し付けられる。転写ベルト３２は転写パッド３０’を内包するように配置され、中間転写ベルト２０の移動に伴い、従動搬送される。本実施例においては、転写ベルト３２は転写ベルトガイドローラ３３、３４、３５により張架され、安定したベルト搬送が実現される。潤滑剤付与部材３８が転写ベルト３２の内面に接触するように配置されており、転写ベルト３２の搬送に伴って転写ベルト３２の内面に潤滑剤を塗布し、転写パッド３０’と転写ベルト３２の摺動抵抗を低減させる。
FIG. 5 is a side cross-sectional configuration diagram of the second transfer portion of the second embodiment. This will also be described focusing on differences from the first embodiment.
In this example, the second transfer means has a transfer pad 30 ′, and is pressed against the intermediate transfer belt 20 so as to face the driven transfer roller 31 by a pressing means such as a spring (not shown). The transfer belt 32 is disposed so as to include the transfer pad 30 ′, and is driven and conveyed as the intermediate transfer belt 20 moves. In this embodiment, the transfer belt 32 is stretched by transfer belt guide rollers 33, 34, and 35, and stable belt conveyance is realized. The lubricant applying member 38 is disposed so as to contact the inner surface of the transfer belt 32, and a lubricant is applied to the inner surface of the transfer belt 32 as the transfer belt 32 is conveyed, so that the transfer pad 30 ′ and the transfer belt 32 are in contact with each other. Reduce sliding resistance.
なお、転写ベルトガイドローラ３３を駆動源（図示せず）により回動させることによって転写ベルト３２に中間転写ベルト２０と同速で搬送されるように搬送力を付与し、中間転写ベルト２０の搬送負荷を低減させることができる。 The transfer belt guide roller 33 is rotated by a drive source (not shown) to apply a transport force to the transfer belt 32 so that the transfer belt 32 is transported at the same speed as the intermediate transfer belt 20. The load can be reduced.
用紙は図中矢印Ｂ方向から搬送され、転写ベルト３２と中間転写ベルト２０の間を挟持、搬送される。従動転写ローラ３１、中間転写ベルト２０、転写ベルト３２および、転写パッド３０’は電気抵抗値が調整されており、用紙が転写ベルト３２と中間転写ベルト２０の間を挟持、搬送されている間に従動転写ローラ３１と転写パッド３０の間に所定の電位が付与され、中間転写ベルト２０上の帯電トナーを静電力によって用紙へ転写する。 The sheet is conveyed from the direction of arrow B in the figure, and is nipped and conveyed between the transfer belt 32 and the intermediate transfer belt 20. The driven transfer roller 31, the intermediate transfer belt 20, the transfer belt 32, and the transfer pad 30 'are adjusted in electric resistance value, and the sheet is sandwiched and conveyed between the transfer belt 32 and the intermediate transfer belt 20. A predetermined potential is applied between the driven transfer roller 31 and the transfer pad 30, and the charged toner on the intermediate transfer belt 20 is transferred to the sheet by electrostatic force.
さらに本実施例においては、転写パッド３０’は、用紙の挿入側に電気抵抗の調整された第一押し付けパッド３０ａ、排出側に電気抵抗の調整された第一押し付けパッド３０ｂ、ならびに、その間に電気的絶縁部材３０ｃを具備している。 Further, in the present embodiment, the transfer pad 30 ′ includes a first pressing pad 30 a having an adjusted electric resistance on the paper insertion side, a first pressing pad 30 b having an adjusted electric resistance on the discharge side, and an electric circuit therebetween. The insulating member 30c is provided.
また本実施例においては、用紙の挿入側に配置された第一押し付けパッド３０ａは第一転写バイアス印加ユニット３００ａに、用紙の排出側に配置された第二押し付けパッド３０ｂは第一転写バイアス印加ユニット３００ｂに電気的に接続されており、それぞれ従動転写ローラ３１との間に静電転写バイアスを印加する。 In this embodiment, the first pressing pad 30a arranged on the paper insertion side is the first transfer bias applying unit 300a, and the second pressing pad 30b arranged on the paper discharging side is the first transfer bias applying unit. 300 b is electrically connected, and an electrostatic transfer bias is applied to each of the driven transfer rollers 31.
さらに本実施例においては、第一転写バイアス印加ユニット３００ａは出力が一定電流となるように制御されており、中間転写ベルト２０上の帯電トナーを用紙へ転写するのに必要な電流を確保し、トナーの転写を確実にする。一方、第二転写バイアス印加ユニット３００ｂでは出力が一定電圧となるように制御されており、中間転写ベルト２０上に転写された帯電トナーが飛散しないような静電界を形成し、例えば低温低湿環境下で従動転写ローラ３１ならびに第一押し付けパッド３０ａの抵抗値が上昇して一定電流制御された第一転写バイアスユニットの出力電圧が高くなることに起因した、転写ニップ部出口での放電によるトナーの飛散を防止でき、第二転写部でのトナー像の安定形成を実現する。トナーを保持した用紙は、図中矢印Ｃの方向へ搬送される。 Further, in this embodiment, the first transfer bias applying unit 300a is controlled so that the output becomes a constant current, and secures a current necessary for transferring the charged toner on the intermediate transfer belt 20 to the sheet. Ensure toner transfer. On the other hand, in the second transfer bias applying unit 300b, the output is controlled to be a constant voltage, and an electrostatic field is formed so that the charged toner transferred onto the intermediate transfer belt 20 does not scatter, for example, in a low temperature and low humidity environment. As a result, the resistance value of the driven transfer roller 31 and the first pressing pad 30a is increased, and the output voltage of the first transfer bias unit controlled at a constant current is increased. The toner image can be stably formed at the second transfer portion. The sheet holding the toner is conveyed in the direction of arrow C in the figure.
本構成により、使用環境によらず第二転写部でのトナー像の安定形成を実現し、また、第二転写部において用紙と中間転写ベルトの接触領域を安定して保持することができるので、高速印刷において安定した転写性能を確保することができる。 With this configuration, the toner image can be stably formed in the second transfer portion regardless of the use environment, and the contact area between the sheet and the intermediate transfer belt can be stably held in the second transfer portion. Stable transfer performance can be ensured in high-speed printing.
なお本実施例では、第二転写部において中間転写ベルトと用紙が押し付けローラと転写対向ローラに所定の押し付け力を付与され続けながら挟持、搬送されるので、安定した転写を実現できる。さらに、押し付けローラと中間転写ベルトの間には転写ベルトおよび対向転写ベルトが配され、中間転写ベルトと同方向に搬送されるので、中間転写ベルトの搬送力を小さく押さえ、駆動モータへの負荷を低減することができる。さらに、二次転写部を従動転写ローラと転写パッドで中間転写ベルトと用紙を挟持する構成とすることで、二次転写時の中間転写ベルトと用紙の接触部における面圧分布を略一定にすることができるので、搬送中に用紙を変形させる力が作用せず、用紙搬送の安定性を一層向上させることができる。 In this embodiment, since the intermediate transfer belt and the sheet are nipped and conveyed in the second transfer unit while a predetermined pressing force is continuously applied to the pressing roller and the transfer opposing roller, stable transfer can be realized. In addition, a transfer belt and a counter transfer belt are arranged between the pressing roller and the intermediate transfer belt, and are conveyed in the same direction as the intermediate transfer belt. Therefore, the conveyance force of the intermediate transfer belt is reduced to reduce the load on the drive motor. Can be reduced. Further, the secondary transfer unit is configured such that the intermediate transfer belt and the paper are sandwiched by the driven transfer roller and the transfer pad, so that the surface pressure distribution at the contact portion between the intermediate transfer belt and the paper at the time of secondary transfer is made substantially constant. Therefore, the force for deforming the sheet during the conveyance does not act, and the stability of the sheet conveyance can be further improved.
本発明により、中間転写ベルトからトナー像を用紙上へ転写する電子写真方式の画像形成装置で、とりわけ第二転写時に用紙を中間転写ベルトと転写ベルトで挟持するベルト転写方式において、第二転写部において用紙の挿入側に配置された第一押し付けローラは第一転写バイアス印加ユニットに、用紙の排出側に配置された第二押し付けローラは第一転写バイアス印加ユニットに電気的に接続されており、夫々従動転写ローラとの間に静電転写バイアスを印加し、さらに、第一転写バイアス印加ユニットは出力が一定電流となるように制御されており、中間転写ベルト上の帯電トナーを用紙へ転写するのに必要な電流を確保し、トナーの転写を確実にする一方、第二転写バイアス印加ユニットでは出力が一定電圧となるように制御され、中間転写ベルト上に転写された帯電トナーが飛散しないような静電界を形成するので、例えば低温低湿環境下で従動転写ローラならびに第一押し付けローラの抵抗値が上昇して一定電流制御された第一転写バイアスユニットの出力電圧が高くなることに起因した転写ニップ部出口での放電によるトナーの飛散を防止でき、第二転写部でのトナー像の安定形形成を実現できる。 According to the present invention, in an electrophotographic image forming apparatus that transfers a toner image from an intermediate transfer belt onto a sheet, in particular in a belt transfer system in which a sheet is sandwiched between the intermediate transfer belt and the transfer belt during the second transfer, The first pressing roller disposed on the paper insertion side is electrically connected to the first transfer bias application unit, and the second pressing roller disposed on the paper discharge side is electrically connected to the first transfer bias application unit, An electrostatic transfer bias is applied between each of the driven transfer rollers, and the first transfer bias applying unit is controlled so that the output becomes a constant current, and transfers the charged toner on the intermediate transfer belt to the sheet. The second transfer bias application unit is controlled so that the output becomes a constant voltage while ensuring the current necessary for the transfer and ensuring toner transfer. Since the electrostatic field is formed so that the charged toner transferred onto the transfer belt does not scatter, for example, the resistance value of the driven transfer roller and the first pressing roller is increased in a low temperature and low humidity environment, and the first transfer is controlled at a constant current. It is possible to prevent scattering of toner due to discharge at the exit of the transfer nip due to an increase in the output voltage of the bias unit, and to realize stable formation of a toner image at the second transfer portion.
さらに、第二の転写手段は従動転写ローラとの押し付け面の形状が前記転写対向ローラの外周形状と略一致するように形成された転写パッドを有し、かつ、用紙の挿入側に電気抵抗の調整された第一押し付けパッド、排出側に電気抵抗の調整された第一押し付けパッド、ならびに、その間に電気的絶縁部材を具備することによって、第二転写部において用紙と中間転写ベルトの接触領域を安定して保持することができるので、高速印刷において安定した転写性能を確保することができる。 Further, the second transfer means has a transfer pad formed so that the shape of the pressing surface with the driven transfer roller substantially coincides with the outer peripheral shape of the transfer counter roller, and an electric resistance is provided on the paper insertion side. By providing the adjusted first pressing pad, the first pressing pad whose electric resistance is adjusted on the discharge side, and the electrical insulation member therebetween, the contact area between the sheet and the intermediate transfer belt is provided in the second transfer portion. Since it can be stably held, stable transfer performance can be ensured in high-speed printing.
すなわち、本発明の画像形成装置では、第一の静電バイアス付与部でトナーの転写に必要な静電バイアスを印加し、第二の静電バイアス付与部で、用紙に転写されたトナー像を乱さない静電バイアスを印加できるので、第二の転写手段におけるトナーの転写部において画像不良のない安定した転写を実現できる。 That is, in the image forming apparatus of the present invention, the first electrostatic bias applying unit applies an electrostatic bias necessary for toner transfer, and the second electrostatic bias applying unit applies the toner image transferred to the sheet. Since an electrostatic bias without disturbance can be applied, stable transfer without image defects can be realized in the toner transfer portion of the second transfer unit.
また、転写対向部材は前記中間転写ベルトの搬送と共に回動する転写対向ローラであり、かつ、前記第一および第二押し付けパッドは絶縁部材を介して一体に形成された押し付け転写パッドを構成し、かつ、前記転写パッドの前記転写対向ローラとの押し付け面の形状が前記転写対向ローラの外周形状と略一致させることで、二次転写時の中間転写ベルトと用紙の接触部における面圧分布を略一定にでき、圧力分布の変動に伴う画像欠陥を防止することができる。 Further, the transfer counter member is a transfer counter roller that rotates along with the conveyance of the intermediate transfer belt, and the first and second pressing pads constitute a pressing transfer pad formed integrally with an insulating member, In addition, the surface pressure distribution at the contact portion between the intermediate transfer belt and the sheet at the time of secondary transfer is substantially reduced by making the shape of the pressing surface of the transfer pad with the transfer counter roller substantially coincide with the outer peripheral shape of the transfer counter roller. It is possible to make the image constant and to prevent image defects due to fluctuations in pressure distribution.
さらに、第一の静電バイアス付与部は静電バイアス出力を定電流に制御し、かつ第二の静電バイアス付与部は静電バイアス出力を定電圧に制御することにより、転写に必要な電流の安定化と、用紙の剥離での放電の防止を確実に行うことができる。 Furthermore, the first electrostatic bias applying unit controls the electrostatic bias output to a constant current, and the second electrostatic bias applying unit controls the electrostatic bias output to a constant voltage, so that the current required for transfer is controlled. Stabilization and prevention of discharge due to sheet peeling can be reliably performed.
２０：中間転写ベルト
２１：第一の従動ローラ
２３：フライホイール
２５：駆動手段
２６：第二の従動ローラ
３０：転写ローラ
３０’：転写パッド
３１：従動転写ローラ
３２：転写ベルト
３３、３４、３５：転写ベルトガイドローラ
３７：対向転写ベルトガイドローラ
３８：潤滑剤付与部材
５２：現像ローラ
５４：感光体ドラム
５５：帯電器
５６：露光器
５７：ドラムクリーナ
５８：一次転写ローラ
６０：定着器
６１：定着ベルト
６２：加熱ローラ
６３：加圧ローラ
６４：バックアップローラ
８１：搬送ベルト
９１：ベルトクリーナ
５０１〜５０４：現像ユニット
20: intermediate transfer belt 21: first driven roller 23: flywheel 25: driving means 26: second driven roller 30: transfer roller 30 ′: transfer pad 31: driven transfer roller 32: transfer belt 33, 34, 35 : Transfer belt guide roller 37: Opposite transfer belt guide roller 38: Lubricant application member 52: Development roller 54: Photosensitive drum 55: Charger 56: Exposure unit 57: Drum cleaner 58: Primary transfer roller 60: Fixing unit 61: Fixing belt 62: Heating roller 63: Pressure roller 64: Backup roller 81: Conveying belt 91: Belt cleaner 501 to 504: Developing unit
Claims (5)
前記第二の転写手段は、前記中間転写ベルト上のトナーを静電気的に前記用紙へ転写する第一の静電バイアス付与部及び第二の静電バイアス付与部からなり、前記第一の静電バイアス部で印加される静電バイアス値と、前記第二の静電バイアス部で印加される静電バイアス値が異なることを特徴とする画像形成装置。 An image carrying means; a latent image forming means for forming a latent image on the image carrying means; a developing means for attaching toner to the latent image formed on the image carrying means; and a toner image on the image carrying means. An intermediate transfer belt to which the toner image is transferred, a driving roller for driving the intermediate transfer belt, a first transfer means for transferring the toner image on the image carrying means to the intermediate transfer belt, and a paper conveying means for conveying the paper An electrophotographic system comprising: a second transfer unit that transfers a toner image on the intermediate transfer belt to a sheet conveyed by the sheet conveyance unit; and a fixing unit that melts and fixes the toner image on the sheet In the image forming apparatus,
The second transfer unit includes a first electrostatic bias applying unit and a second electrostatic bias applying unit that electrostatically transfer the toner on the intermediate transfer belt to the paper, and the first electrostatic bias applying unit. An image forming apparatus, wherein an electrostatic bias value applied by a bias unit is different from an electrostatic bias value applied by the second electrostatic bias unit.
前記第二の転写手段は、前記中間転写ベルトのトナー画像保持裏面側に配される転写対向部材と、該転写対向部材と対向して前記中間転写ベルトと共に前記用紙を所定の押し付け力で挟む転写部材とからなり、
前記転写部材は、前記転写対向部材と対向して所定の押し付け力を付与しかつ前記転写対向部材との間に静電バイアスを印加する第一の静電バイアス付与部としての第一押し付けローラと、前記転写対向部材と対向して所定の押し付け力を付与しかつ前記転写対向部材との間に静電バイアスを印加する第二の静電バイアス付与部としての第二押し付けローラと、これら第一ならびに第二押し付けローラを囲むように配され、前記第一ならびに第二押し付けローラと前記中間転写ベルトに挟持されかつ前記中間転写ベルトの搬送方向に搬送される無端状の転写ベルトからなることを特徴とする画像形成装置。 The image forming apparatus according to claim 1.
The second transfer means includes a transfer facing member disposed on a toner image holding back surface side of the intermediate transfer belt, and a transfer that faces the transfer facing member and sandwiches the sheet with the intermediate transfer belt with a predetermined pressing force. Consisting of parts,
A first pressing roller as a first electrostatic bias applying unit that applies a predetermined pressing force to the transfer member facing the transfer counter member and applies an electrostatic bias to the transfer counter member; A second pressing roller as a second electrostatic bias applying unit that applies a predetermined pressing force to the transfer facing member and applies an electrostatic bias to the transfer facing member; And an endless transfer belt which is disposed so as to surround the second pressing roller and is sandwiched between the first and second pressing rollers and the intermediate transfer belt and conveyed in the conveying direction of the intermediate transfer belt. An image forming apparatus.
前記第二の転写手段は、前記中間転写ベルトのトナー画像保持裏面側に配される転写対向部材と該転写対向部材と対向して前記中間転写ベルトと共に前記用紙を所定の押し付け力で挟持する転写部材とからなり、
前記転写部材は、前記転写対向部材と対向して所定の押し付け力を付与しかつ前記転写対向部材との間に静電バイアスを印加する第一の静電バイアス付与部としての第一押し付けパッドと、前記転写対向部材と対向して所定の押し付け力を付与しかつ前記転写対向部材との間に静電バイアスを印加する第二の静電バイアス付与部としての第二押し付けパッドと、該第一ならびに第二押し付けパッドを囲むように配され、前記第一ならびに第二押し付けパッドと前記中間転写ベルトに挟持されかつ前記中間転写ベルトの搬送方向に搬送される無端状の転写ベルトからなることを特徴とする画像形成装置。 The image forming apparatus according to claim 1.
The second transfer unit includes a transfer facing member disposed on a toner image holding back surface side of the intermediate transfer belt, and a transfer that faces the transfer facing member and holds the sheet together with the intermediate transfer belt with a predetermined pressing force. Consisting of parts,
A first pressing pad serving as a first electrostatic bias applying unit that applies a predetermined pressing force to the transfer member facing the transfer counter member and applies an electrostatic bias to the transfer counter member; A second pressing pad as a second electrostatic bias applying unit that applies a predetermined pressing force to the transfer facing member and applies an electrostatic bias to the transfer facing member; And an endless transfer belt which is disposed so as to surround the second pressing pad and is sandwiched between the first and second pressing pads and the intermediate transfer belt and conveyed in the conveying direction of the intermediate transfer belt. An image forming apparatus.
前記転写対向部材は前記中間転写ベルトの搬送と共に回動する転写対向ローラでありかつ前記第一及び第二押し付けパッドは絶縁部材を介して一体に形成された転写パッドを構成しかつ前記転写パッドの前記転写対向ローラとの押し付け面の形状が前記転写対向ローラの外周形状と略一致することを特徴とする画像形成装置。 The image forming apparatus according to claim 3.
The transfer counter member is a transfer counter roller that rotates along with the conveyance of the intermediate transfer belt, and the first and second pressing pads constitute a transfer pad that is integrally formed via an insulating member, and the transfer pad An image forming apparatus, wherein a shape of a pressing surface with the transfer counter roller substantially matches an outer peripheral shape of the transfer counter roller.
前記第一の静電バイアス付与部は静電バイアス出力が定電流に制御されかつ前記第二の静電バイアス付与部は静電バイアス出力が定電圧に制御されることを特徴とする画像形成装置。
5. The image forming apparatus according to claim 1, wherein:
The first electrostatic bias applying unit has an electrostatic bias output controlled to a constant current, and the second electrostatic bias applying unit has an electrostatic bias output controlled to a constant voltage. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007190238A JP2009025673A (en) | 2007-07-20 | 2007-07-20 | Image forming apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007190238A JP2009025673A (en) | 2007-07-20 | 2007-07-20 | Image forming apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2009025673A true JP2009025673A (en) | 2009-02-05 |
Family
ID=40397510
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2007190238A Pending JP2009025673A (en) | 2007-07-20 | 2007-07-20 | Image forming apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2009025673A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011065081A (en) * | 2009-09-18 | 2011-03-31 | Canon Inc | Image forming apparatus |
| JP2011242521A (en) * | 2010-05-17 | 2011-12-01 | Sharp Corp | Transfer device |
| JP2017090699A (en) * | 2015-11-11 | 2017-05-25 | 株式会社リコー | Image forming apparatus |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004184984A (en) * | 2002-11-20 | 2004-07-02 | Ricoh Co Ltd | Image forming apparatus and process cartridge |
| JP2005017558A (en) * | 2003-06-25 | 2005-01-20 | Ricoh Co Ltd | Image forming apparatus and image forming method |
| JP2006243596A (en) * | 2005-03-07 | 2006-09-14 | Konica Minolta Business Technologies Inc | Image forming apparatus |
-
2007
- 2007-07-20 JP JP2007190238A patent/JP2009025673A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004184984A (en) * | 2002-11-20 | 2004-07-02 | Ricoh Co Ltd | Image forming apparatus and process cartridge |
| JP2005017558A (en) * | 2003-06-25 | 2005-01-20 | Ricoh Co Ltd | Image forming apparatus and image forming method |
| JP2006243596A (en) * | 2005-03-07 | 2006-09-14 | Konica Minolta Business Technologies Inc | Image forming apparatus |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011065081A (en) * | 2009-09-18 | 2011-03-31 | Canon Inc | Image forming apparatus |
| JP2011242521A (en) * | 2010-05-17 | 2011-12-01 | Sharp Corp | Transfer device |
| JP2017090699A (en) * | 2015-11-11 | 2017-05-25 | 株式会社リコー | Image forming apparatus |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7352987B2 (en) | Fixing device and image forming apparatus for holding a recording medium by electrostatic force | |
| JP2010008968A (en) | Transfer device and image forming apparatus including the same | |
| JP2008216294A (en) | Fixing device and image forming apparatus | |
| US8457537B2 (en) | Image forming apparatus for transferring a toner image onto a recording material | |
| JPH11352800A (en) | Image forming device | |
| JP2008145460A (en) | Image forming apparatus | |
| JP2013024895A (en) | Fixing device and image formation device | |
| JP2009025673A (en) | Image forming apparatus | |
| JP4466295B2 (en) | Image forming apparatus | |
| JP4927612B2 (en) | Fixing apparatus and image forming apparatus | |
| US11334005B2 (en) | Tiltable steering assembly to adjust position of endless belt in imaging system | |
| JP6264199B2 (en) | Image forming system | |
| JP4517796B2 (en) | Image forming apparatus and fixing apparatus | |
| US8737883B2 (en) | Charging device and image forming apparatus | |
| JP2016133565A (en) | Image forming apparatus and image forming system | |
| JP2006243536A (en) | Image forming apparatus | |
| JP2006171503A (en) | Fixing device and image forming apparatus having the same | |
| JP4282977B2 (en) | Image forming apparatus and color image forming apparatus | |
| JPH09281824A (en) | Belt fixing device | |
| US10459385B2 (en) | Fixing device and image forming apparatus | |
| JP2007328203A (en) | Image forming apparatus | |
| JP2008241862A (en) | Image forming apparatus and image forming method | |
| JP2009169156A (en) | Fixing device, and image forming apparatus including the same | |
| JP2006267910A (en) | Image forming apparatus | |
| JP2003241482A (en) | Image forming apparatus |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Effective date: 20100517 Free format text: JAPANESE INTERMEDIATE CODE: A621 |
|
| A131 | Notification of reasons for refusal |
Effective date: 20120307 Free format text: JAPANESE INTERMEDIATE CODE: A131 |
|
| A02 | Decision of refusal |
Effective date: 20120627 Free format text: JAPANESE INTERMEDIATE CODE: A02 |