JP2005242121A - Image forming apparatus - Google Patents

Image forming apparatus Download PDF

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JP2005242121A
JP2005242121A JP2004053659A JP2004053659A JP2005242121A JP 2005242121 A JP2005242121 A JP 2005242121A JP 2004053659 A JP2004053659 A JP 2004053659A JP 2004053659 A JP2004053659 A JP 2004053659A JP 2005242121 A JP2005242121 A JP 2005242121A
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belt
endless belt
image
roller
recording paper
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Kenichi Mukai
健一 向井
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Kyocera Document Solutions Inc
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Kyocera Mita Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a tandem type image forming apparatus equipped with an endless belt such as an intermediate transfer belt and a recording paper conveying belt, a transfer roller which is installed opposite an image carrier across the endless belt, and a driving roller which is wound with the endless belt to drive it and provided with a zigzag preventing pulley guiding a zigzag preventing belt provided on one end surface of the endless belt to limit meandering of the endless belt or/and a driven roller, the endless belt such as the intermediate transfer belt and recording paper conveying belt being prevented from meandering by a simple and inexpensive method to form an image which is free of color slurring. <P>SOLUTION: At least one transfer roller has a specified angle to the axis of the image carrier, and the endless belt is arranged to be put close to the meandering preventing pulley. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、電子写真方式を利用した複写機、プリンタ、ファクシミリ、それらの複合機などの画像形成装置に係り、特に、複数の感光体ドラム（像担持体）を中間転写ベルトや記録紙搬送ベルトなどの無端ベルトの搬送方向に設け、前記複数の感光体ドラム（像担持体）上に形成されたトナー像を中間転写ベルト、または搬送ベルトで搬送される記録紙に色ズレ無く転写できるようにした、タンデム型の画像形成装置に関するものである。   BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine using an electrophotographic method, and more particularly, a plurality of photosensitive drums (image carriers) are used as an intermediate transfer belt or a recording paper transport belt. The toner images formed on the plurality of photosensitive drums (image carriers) can be transferred to the intermediate transfer belt or the recording paper conveyed by the conveyance belt without color misalignment. The present invention relates to a tandem type image forming apparatus.

使用するトナーの色に対応し、感光体ドラム（像担持体）、帯電器、プリント用露光器、トナー供給容器などで構成される複数の電子写真プロセス部材を並べて配置し、転写部材の送りに同期させて、各色の電子写真プロセス部材で画像を形成して転写部材上で色重ねを行うタンデム型カラー画像形成装置は、高速のカラー画像形成装置として注目されている。   Corresponding to the color of toner to be used, a plurality of electrophotographic process members composed of a photosensitive drum (image carrier), a charger, an exposure device for printing, a toner supply container, etc. are arranged side by side to feed the transfer member A tandem-type color image forming apparatus that forms an image with electrophotographic process members of each color and performs color superimposition on a transfer member in synchronism has attracted attention as a high-speed color image forming apparatus.

このタンデム型カラー画像形成装置にも、各電子写真プロセス部材で形成されたトナー像を一度中間転写ベルトなどの転写部材に転写した後で記録紙に転写する方式のもの、搬送ベルトで記録紙を搬送し、各電子写真プロセス部材で形成されたトナー像を直接記録紙上に転写する方式のものなどがある。   In this tandem type color image forming apparatus, the toner image formed by each electrophotographic process member is once transferred to a transfer member such as an intermediate transfer belt and then transferred to the recording paper. There is a system in which a toner image formed by each electrophotographic process member is directly transferred onto a recording sheet.

これら２方式にはそれぞれ得失があるが、どちらの方式でも、各色の電子写真プロセス部材で形成されたトナー像を、中間転写ベルト、または記録紙上で正確に色重ねできないと色ズレを起こす。しかしながら、中間転写ベルトや記録紙搬送ベルトなどは、その駆動方法が悪いと蛇行が生じ、その蛇行によって色ズレが生じる。   Each of these two methods has advantages and disadvantages, but in either method, a color shift occurs when the toner image formed by each color electrophotographic process member cannot be accurately overlaid on the intermediate transfer belt or the recording paper. However, the intermediate transfer belt, the recording paper conveyance belt, and the like meander when the driving method is poor, and color deviation occurs due to the meandering.

そのため従来では、例えば図３に示したように、中間転写ベルトや記録紙搬送ベルトなどの無端ベルト６０の端部に蛇行防止ベルト６１と、無端ベルト６０を張架する駆動または従動ローラ１１の端部に、蛇行防止ベルト６１の幅方向への移動範囲を規制する蛇行防止プーリ６２を設けて蛇行を防止したり、中間転写ベルトや記録紙搬送ベルトなどの無端ベルトを懸架したローラの両端部に寄り止めガイドを設け、無端ベルト６０の端部を接触させながら搬送して蛇行を防止するなどの方法がとられていた。   Therefore, conventionally, for example, as shown in FIG. 3, the end of an endless belt 60 such as an intermediate transfer belt or a recording paper conveying belt and an end of a drive or driven roller 11 that stretches the endless belt 60 and the endless belt 60 are stretched. A meandering prevention pulley 62 for restricting the range of movement of the meandering prevention belt 61 in the width direction is provided to prevent meandering, or at both ends of a roller on which an endless belt such as an intermediate transfer belt or a recording paper conveyance belt is suspended. A method has been adopted in which a slip-off guide is provided and the end of the endless belt 60 is conveyed while being brought into contact to prevent meandering.

しかしながら、図３に示した蛇行防止ベルト６１と蛇行防止プーリ６２を用いる方法でも、駆動または従動ローラ１１と蛇行防止プーリ６２の間、及び蛇行防止ベルト６１と蛇行防止プーリ６２の間のクリアランス６３により、約０．５ｍｍ程度の移動が可能であり、また、ローラの両端部に寄り止めガイドを設ける方法でも、寄り止めガイドの間隔と無端ベルト６０の幅が一致していないと、広いところでは無端ベルト６０が蛇行可能状態になり、また、狭いところでは無端ベルト６０が寄り止めガイドを乗り越えてしまい、主走査方向の画像の色ズレを起こすといった問題があった。   However, even in the method using the meandering prevention belt 61 and the meandering prevention pulley 62 shown in FIG. 3, the clearance 63 between the drive or driven roller 11 and the meandering prevention pulley 62 and between the meandering prevention belt 61 and the meandering prevention pulley 62. In addition, even if the guides are provided at both ends of the roller, if the distance between the guides does not match the width of the endless belt 60, the endless belt 60 is endless in a wide area. There is a problem that the belt 60 can be meandered, and the endless belt 60 gets over the detent guide in a narrow area, causing a color shift of the image in the main scanning direction.

こういった問題に対処するための従来技術として例えば特許文献１には、スプロケットを用いて像担持体ベルトを駆動するようにした画像形成装置において、像担持体ベルトに設けた穴がスプロケットより大きいために生じる蛇行を防止するため、像担持体ベルトに当接して像担持体ベルトの進行方向と直交する方向に対して傾斜させた帯電ローラ、現像ローラ、転写ローラ、クリーニングブレードなどの当接部材で像担持体ベルトを一方に寄せ、蛇行が生じないようにすることが示されている。   As a conventional technique for coping with such a problem, for example, Patent Document 1 discloses that in an image forming apparatus in which an image carrier belt is driven using a sprocket, a hole provided in the image carrier belt is larger than a sprocket. Contact members such as a charging roller, a developing roller, a transfer roller, and a cleaning blade that are in contact with the image carrier belt and are inclined with respect to a direction perpendicular to the traveling direction of the image carrier belt to prevent meandering It is shown that the image carrier belt is moved to one side to prevent meandering.

また、特許文献２には、両側縁周長をＬ１、Ｌ２としたとき、Ｌ１＞Ｌ２なる差を有する無端状の転写材搬送ベルトを用い、周長が短いＬ２側に位置して強い圧力Ｐ１を有する第１の付勢部材を配置すると共に、周長が長いＬ１側に位置して弱い圧力Ｐ２を有する第２の付勢部材を配置する転写材搬送手段が平行に設けられ、かつ少なくとも１本が一端に向けて径を徐々に大きくして形成したテーパローラとして転写ベルトを片側に寄せるようにする、転写材搬送手段が、平行に設けられた駆動ローラを含む２本以上のローラ、および平行でない斜めローラを含む複数のローラとして転写ベルトを片側に寄せるようにする、などの方法で転写ベルトを一端側に寄せるようにして蛇行を防止するようにした画像形成装置が示されている。   Patent Document 2 uses an endless transfer material conveyance belt having a difference of L1> L2 when the peripheral lengths of both side edges are L1 and L2, and a strong pressure P1 located on the L2 side where the peripheral length is short. And a transfer material conveying means for arranging a second urging member having a weak pressure P2 located on the L1 side having a long circumference is provided in parallel. Two or more rollers including a driving roller provided in parallel and a transfer material conveying means for bringing the transfer belt to one side as a tapered roller formed with a diameter gradually increasing toward one end, and in parallel There is shown an image forming apparatus in which meandering is prevented by moving the transfer belt toward one end by a method such as moving the transfer belt toward one side as a plurality of rollers including oblique rollers that are not.

さらに特許文献３には、転写材搬送ベルトの両側縁周長を異ならせる、転写材搬送ベルトを張架するローラを非平行にする、テーパローラを用いる、などの手段で転写材搬送ベルトを一方に寄らせるようにした画像形成装置が示されている。   Further, in Patent Document 3, the transfer material conveyance belt is changed to one side by means such as making the peripheral lengths of both sides of the transfer material conveyance belt different, making the roller for stretching the transfer material conveyance belt non-parallel, or using a taper roller. An image forming apparatus adapted to approach is shown.

特開平９−２８１８４８号公報JP-A-9-281848 特開平６−２７８８９４号公報JP-A-6-278894 特開昭６４−２０７０号公報JP-A 64-2070

しかしながら、特許文献１に示された技術は、像担持体ベルトはその内周に接するローラで駆動されており、この駆動方向と異なる方向の力を像担持ベルトにローラと対向する位置で加えると、像担持ベルトに無理がかかり、像担持ベルトにねじれが生じたりしてその耐久性を損ねる恐れがある。   However, in the technique disclosed in Patent Document 1, the image carrier belt is driven by a roller in contact with the inner periphery of the image carrier belt, and when a force in a direction different from the driving direction is applied to the image carrier belt at a position facing the roller. There is a risk that the image bearing belt may be overworked and the image bearing belt may be twisted to impair its durability.

また、特許文献２、特許文献３に示された画像形成装置における、両側縁周長を異ならせる方法とテーパローラを用いる方法とでは、ベルト表面の速度が幅方向で異なるため、各プロセスで作像した画像がベルトの下流側に進むにつれて速度差分、主走査方向で斜めになってしまう。すなわち、無端ベルト上流側に配置された感光体により描かれた画像は、ベルトへの転写時は、感光体と作像プロセスのアライメントに等しく転写される。ところが、端部周長の差により、端部周長の長い方の表面速度は速く、端部周長の短い方の表面速度は遅いため、ベルトが下流側に進むにつれ、転写された画像は転写時のアライメントから斜めになってしまう。さらに、平行に設けられた駆動ローラの間に平行でない斜めローラを設ける方法は、特別に設けた斜めローラを用意する必要があって高価になる。   Further, in the image forming apparatuses disclosed in Patent Document 2 and Patent Document 3, the belt surface speed is different in the width direction between the method in which the peripheral lengths of both sides are different and the method in which the taper roller is used. As the processed image advances to the downstream side of the belt, the difference in speed becomes oblique in the main scanning direction. That is, the image drawn by the photoconductor disposed on the upstream side of the endless belt is transferred equally to the alignment between the photoconductor and the image forming process when transferred to the belt. However, due to the difference in the edge circumference, the surface speed of the longer edge circumference is faster, and the surface speed of the shorter edge circumference is slower, so as the belt advances downstream, the transferred image is It becomes diagonal from the alignment at the time of transfer. Furthermore, the method of providing a non-parallel oblique roller between the drive rollers provided in parallel requires a specially provided oblique roller and is expensive.

そのため本発明においては、簡単、安価な方法で、中間転写ベルトや記録紙搬送ベルトなどの無端ベルトの蛇行を防止し、色ズレのない画像を形成できるようにした画像形成装置を提供することが課題である。   Therefore, in the present invention, it is possible to provide an image forming apparatus capable of preventing meandering of an endless belt such as an intermediate transfer belt or a recording paper transport belt and forming an image without color misregistration by a simple and inexpensive method. It is a problem.

上記課題を解決するため本発明においては、
使用する複数色のトナーのそれぞれに対応させて設けられ、電子写真プロセスによりトナー像を担持する像担持体と、該像担持体の配列方向を搬送方向とし、各像担持体上に形成されたトナー像を転写する中間転写ベルト、または記録紙を搬送してトナー像を転写させる搬送ベルトなどの無端ベルトと、該無端ベルトを挟んで前記各像担持体のそれぞれに相対して設置された転写ローラと、前記無端ベルトを張架して駆動すると共に、前記無端ベルトの端面に設けられた蛇行防止ベルトをガイドし、前記無端ベルトの蛇行を制限する蛇行防止プーリとを設けた駆動ローラまたは／及び従動ローラとを備えた画像形成装置において、
前記少なくとも一つの転写ローラを前記像担持体の軸方向に対して所定角度を持たせ、前記無端ベルトが一側に寄せられるよう配置したことを特徴とする。 In order to solve the above problems, in the present invention,
An image carrier that is provided corresponding to each of a plurality of color toners to be used and carries a toner image by an electrophotographic process, and an arrangement direction of the image carrier is a transport direction, and is formed on each image carrier. An endless belt such as an intermediate transfer belt for transferring a toner image or a conveying belt for transferring a recording paper by transferring a recording paper, and a transfer disposed opposite to each of the image carriers with the endless belt interposed therebetween. A driving roller provided with a roller and a meander-preventing pulley that drives the endless belt in a stretched manner, guides a meandering-preventing belt provided on an end surface of the endless belt, and restricts the meandering of the endless belt; And an image forming apparatus provided with a driven roller,
The at least one transfer roller has a predetermined angle with respect to the axial direction of the image carrier, and is arranged so that the endless belt is brought close to one side.

また、前記転写ローラに持たせた所定角度による前記無端ベルトの寄せ量を、前記蛇行防止プーリと蛇行防止ベルトによって前記無担ベルトが異常走行しないような値としたことを特徴とする。   Further, the amount of movement of the endless belt at a predetermined angle given to the transfer roller is set to a value that prevents the unsupported belt from running abnormally by the meandering prevention pulley and the meandering prevention belt.

このように、前記少なくとも一つの転写ローラを前記像担持体の軸方向に対して所定角度を持たせ、前記無端ベルトが一側に寄せられるよう配置することにより、転写ローラという画像形成装置に用いられ、かつ、駆動ローラとベルトへの力の作用位置が異なる転写ローラを用いて無端ベルトの蛇行を防止できるから、無端ベルトの耐久性を損ねることがなく、無端ベルトにスプロケットを設けたり両側縁周長を異ならせる、テーパローラを用いるなどの、無端ベルトの下流側に進むにつれて速度差分、主走査方向で斜めになってしまうような方法を取る必要が無く、また、特別な斜めローラというコストを上げる方法も必要ないから、簡単、安価な方法で、中間転写ベルトや記録紙搬送ベルトなどの無端ベルトの蛇行を防止して色ズレを防止した画像形成装置を提供することができる。   In this way, the at least one transfer roller has a predetermined angle with respect to the axial direction of the image carrier, and is arranged so that the endless belt is brought close to one side, thereby being used for an image forming apparatus called a transfer roller. In addition, the endless belt can be prevented from meandering by using a transfer roller with a different position of the force applied to the drive roller and the belt, so that the endless belt is not impaired and sprockets are provided on the endless belt. There is no need to adopt a method that makes the circumference different, or uses a tapered roller, etc., so that the speed difference becomes oblique in the main scanning direction as it goes downstream of the endless belt, and the cost of a special oblique roller is reduced. Since there is no need for a lifting method, a simple and inexpensive method prevents meandering of endless belts such as intermediate transfer belts and recording paper transport belts to prevent color misregistration. It is possible to provide an image forming apparatus.

また、前記転写ローラに持たせた所定角度による前記無端ベルトの寄せ量を、前記蛇行防止プーリと蛇行防止ベルトによって前記無担ベルトが寄り止めガイドを乗り越えてしまうような異常走行をしないような値としたことにより、無理なく蛇行を防止できる画像形成装置を提供することができる。   Further, the amount of movement of the endless belt at a predetermined angle given to the transfer roller is a value that does not cause an abnormal running in which the unsupported belt passes over the detent guide by the meandering prevention pulley and the meandering prevention belt. Therefore, it is possible to provide an image forming apparatus that can prevent meandering without difficulty.

以下、図面を参照して本発明の好適な実施例を例示的に詳しく説明する。但しこの実施例に記載されている構成部品の寸法、材質、形状、その相対的配置等は特に特定的な記載がない限りは、この発明の範囲をそれに限定する趣旨ではなく、単なる説明例に過ぎない。   Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

図１は、本発明になる画像形成装置の一例を概略的に示す断面図、図２は本発明になる画像形成装置における転写材搬送ベルトの蛇行防止機構の概略図である。   FIG. 1 is a sectional view schematically showing an example of an image forming apparatus according to the present invention, and FIG. 2 is a schematic view of a meandering prevention mechanism for a transfer material conveying belt in the image forming apparatus according to the present invention.

図中１は画像形成装置、２は画像形成装置のハウジング（筐体）、３Ｍ、３Ｃ、３Ｙ、３Ｂはマゼンタ（Ｍ）、シアン（Ｃ）、イエロー（Ｙ）、ブラック（Ｂ）のそれぞれに対応して設けられた現像装置、４Ｍ、４Ｃ、４Ｙ、４Ｂはマゼンタ（Ｍ）、シアン（Ｃ）、イエロー（Ｙ）、ブラック（Ｂ）のそれぞれに対応して設けられた感光体ドラム、５Ｍ、５Ｃ、５Ｙ、５Ｂは同じく主帯電器、６Ｍ、６Ｃ、６Ｙ、６Ｂは同じくＬＥＤプリントヘッドユニット、７Ｍ、７Ｃ、７Ｙ、７Ｂは同じくトナー供給容器、８は一端面に前記図３に示したような蛇行防止ベルト６１を設けた無端ベルトとしての記録紙搬送ベルト、９Ｍ、９Ｃ、９Ｙ、９Ｂは同じく転写ローラ、１０は蛇行防止プーリを備えた駆動ローラ、１１は前記図３に示したような蛇行防止プーリ６２を備えた従動ローラ、１１ａは補助ローラ、１２は給紙装置、１３は記録紙搬送路、１３ａはレジストローラ対、１３ｂは記録紙搬送ローラ対、１５は記録紙搬送路、１６は排出部、２０Ｍ、２０Ｃ、２０Ｙ、２０Ｂはクリーニング装置、３０Ｍ、３０Ｃ、３０Ｙ、３０Ｂは電子写真プロセス部材、４０は駆動ローラ１０から記録紙搬送ベルト８に作用する力のベクトル、４１は転写ローラ９Ｍ、９Ｃ、９Ｙ、９Ｂから記録紙搬送ベルト８に作用する力のベクトル、４２は記録紙搬送ベルト８に作用する駆動ローラ１０から受ける力とは作用方向が垂直な方向の力の成分のベクトル、５０は定着装置である。なお、以下の説明では、本発明を、記録紙搬送ベルト８を用いたタンデム型画像形成装置を例に説明するが、無端ベルトとしての中間転写ベルトを用いたタンデム型画像形成装置であってもよい。   In the figure, 1 is an image forming apparatus, 2 is a housing (housing) of the image forming apparatus, 3M, 3C, 3Y, and 3B are magenta (M), cyan (C), yellow (Y), and black (B), respectively. Corresponding developing devices, 4M, 4C, 4Y, and 4B are magenta (M), cyan (C), yellow (Y), and black (B) photosensitive drums that are provided correspondingly, and 5M. 5C, 5Y and 5B are also main chargers, 6M, 6C, 6Y and 6B are LED print head units, 7M, 7C, 7Y and 7B are toner supply containers, and 8 is one end surface shown in FIG. A recording paper conveying belt as an endless belt provided with such a meandering prevention belt 61, 9M, 9C, 9Y and 9B are transfer rollers, 10 is a driving roller provided with a meandering prevention pulley, and 11 is as shown in FIG. Snake A driven roller having a prevention pulley 62, 11a is an auxiliary roller, 12 is a paper feeder, 13 is a recording paper conveyance path, 13a is a registration roller pair, 13b is a recording paper conveyance roller pair, 15 is a recording paper conveyance path, and 16 is The discharge unit, 20M, 20C, 20Y and 20B are cleaning devices, 30M, 30C, 30Y and 30B are electrophotographic process members, 40 is a force vector acting on the recording paper transport belt 8 from the driving roller 10, and 41 is a transfer roller 9M. , 9C, 9Y, 9B, a vector of force acting on the recording paper conveyance belt 8, 42 is a vector of force components in a direction perpendicular to the direction of the force received from the driving roller 10 acting on the recording paper conveyance belt 8, Reference numeral 50 denotes a fixing device. In the following description, the present invention will be described by taking a tandem type image forming apparatus using the recording paper conveying belt 8 as an example. However, even in a tandem type image forming apparatus using an intermediate transfer belt as an endless belt. Good.

図１は、本発明になるタンデム型カラー画像形成装置の一例を概略的に示す断面図である。図示の画像形成装置１は、この画像形成装置１のハウジング（筐体）２に収容され、使用する複数色のトナー、例えばマゼンタ（Ｍ）、シアン（Ｃ）、イエロー（Ｙ）、ブラック（Ｂ）のそれぞれに対応して設けられた、現像装置３Ｍ、３Ｃ、３Ｙ、３Ｂ、感光体ドラム（像担持体）４Ｍ、４Ｃ、４Ｙ、４Ｂ、主帯電器５Ｍ、５Ｃ、５Ｙ、５Ｂ、ＬＥＤプリントヘッドユニット６Ｍ、６Ｃ、６Ｙ、６Ｂ、トナー供給容器７Ｍ、７Ｃ、７Ｙ、７Ｂなどで構成される電子写真プロセス部材３０Ｍ、３０Ｃ、３０Ｙ、３０Ｂが、図示の例では、上流側から順に、マゼンタ用電子写真プロセス部材３０Ｍ、シアン用電子写真プロセス部材３０Ｃ、イエロー用電子写真プロセス部材３０Ｙ、及びブラック用電子写真プロセス部材３０Ｂの順に記録紙搬送ベルト８による記録紙搬送方向に配列されている。   FIG. 1 is a sectional view schematically showing an example of a tandem color image forming apparatus according to the present invention. The illustrated image forming apparatus 1 is accommodated in a housing (housing) 2 of the image forming apparatus 1 and uses a plurality of color toners such as magenta (M), cyan (C), yellow (Y), and black (B ) Provided corresponding to each of the developing devices 3M, 3C, 3Y, 3B, photosensitive drums (image carriers) 4M, 4C, 4Y, 4B, main chargers 5M, 5C, 5Y, 5B, LED prints In the illustrated example, the electrophotographic process members 30M, 30C, 30Y, and 30B including the head units 6M, 6C, 6Y, and 6B, the toner supply containers 7M, 7C, 7Y, and 7B are arranged for magenta in order from the upstream side. The recording paper is conveyed in the order of the electrophotographic process member 30M, the cyan electrophotographic process member 30C, the yellow electrophotographic process member 30Y, and the black electrophotographic process member 30B. It is arranged in the recording sheet conveying direction by the belt 8.

そして記録紙搬送ベルト８は、一端面に設けられた図３に示したように蛇行防止ベルト６１をガイドし、記録紙搬送ベルト８の蛇行を制限する蛇行防止プーリ６２を設けた駆動ローラ１０、及び従動ローラ１１、テンション用の補助ローラ１１ａに懸架されて駆動され、各感光体ドラム（像担持体）４Ｍ、４Ｃ、４Ｙ、４Ｂの位置には、記録紙搬送ベルト８を挟んで相対して設置されて形成されたトナー像を記録紙に転写させるための転写ローラ９Ｍ、９Ｃ、９Ｙ、９Ｂが設けられている。また、この記録紙搬送ベルト８の搬送方向上流には、給紙装置１２から記録紙搬送路１３を経由して送られてくる記録紙の姿勢を正し、各電子写真プロセス部材におけるトナー像の形成タイミングに合わせて記録紙搬送ベルト８に送り出すレジストローラ対１３ａが設けられ、レジストローラ対１３ａから供給された記録紙は、記録紙搬送ベルト８によって搬送される。   As shown in FIG. 3, the recording paper transport belt 8 guides the meandering prevention belt 61 as shown in FIG. 3, and the drive roller 10 is provided with a meandering prevention pulley 62 that restricts the meandering of the recording paper transport belt 8. The driven roller 11 and the tension auxiliary roller 11a are suspended and driven. The photosensitive drums (image carriers) 4M, 4C, 4Y, and 4B are opposed to each other with the recording paper conveyance belt 8 interposed therebetween. Transfer rollers 9M, 9C, 9Y, and 9B are provided for transferring the toner images formed and installed onto the recording paper. Further, upstream of the recording paper conveying belt 8 in the conveying direction, the posture of the recording paper sent from the paper feeding device 12 via the recording paper conveying path 13 is corrected, and the toner image on each electrophotographic process member is corrected. A registration roller pair 13 a that is fed to the recording paper conveyance belt 8 in accordance with the formation timing is provided, and the recording paper supplied from the registration roller pair 13 a is conveyed by the recording paper conveyance belt 8.

画像形成を行う際には、電子写真プロセス部材３０Ｃ、３０Ｙ、及び３０Ｂにおける感光体ドラム４Ｍ、４Ｃ、４Ｙ、４Ｂの表面は主帯電器５Ｍ、５Ｃ、５Ｙ、５Ｂによって一様に＋４００Ｖに帯電され、画像データが入力されるとＬＥＤプリントヘッド６Ｍ、６Ｃ、６Ｙ、６Ｂが画像データに対応するＬＥＤ光を感光体ドラム４Ｍ、４Ｃ、４Ｙ、４Ｂの表面に照射する。これによって感光体ドラム４Ｍ、４Ｃ、４Ｙ、４Ｂの表面は、ＬＥＤ光の照射された露光部分の電圧が＋２５Ｖにまで減衰して、非露光部分と露光部分とによって感光体ドラム４Ｍ、４Ｃ、４Ｙ、４Ｂ上に静電潜像が形成される。そして、現像装置３Ｍ、３Ｃ、３Ｙ、３Ｂによって現像剤中の正帯電トナーが感光体ドラム４Ｍ、４Ｃ、４Ｙ、４Ｂ上の露光部に付着し、静電潜像が現像されて感光体ドラム４Ｍ、４Ｃ、４Ｙ、４Ｂ上にトナー像が形成される。   When forming an image, the surfaces of the photosensitive drums 4M, 4C, 4Y, and 4B in the electrophotographic process members 30C, 30Y, and 30B are uniformly charged to +400 V by the main chargers 5M, 5C, 5Y, and 5B. When the image data is input, the LED print heads 6M, 6C, 6Y, and 6B irradiate the surface of the photosensitive drums 4M, 4C, 4Y, and 4B with the LED light corresponding to the image data. As a result, the surface of the photosensitive drums 4M, 4C, 4Y, and 4B attenuates the voltage of the exposed portion irradiated with the LED light to + 25V, and the photosensitive drums 4M, 4C, and 4Y are formed by the non-exposed portion and the exposed portion. 4B, an electrostatic latent image is formed. Then, positively charged toner in the developer adheres to the exposed portions on the photosensitive drums 4M, 4C, 4Y, and 4B by the developing devices 3M, 3C, 3Y, and 3B, and the electrostatic latent image is developed to develop the photosensitive drum 4M. A toner image is formed on 4C, 4Y, and 4B.

感光体ドラム４Ｍ、４Ｃ、４Ｙ、及び４Ｂは、記録紙搬送ベルト８を挟んで転写ローラ９Ｍ、９Ｃ、９Ｙ、及び９Ｂと対向しており、これら転写ローラ９Ｍ〜９Ｂは、記録紙搬送ベルト８を支持するとともに、感光体ドラム４Ｍ〜４Ｂに記録紙搬送ベルト８を当接させる役割を担っており、後述するように、記録紙搬送ベルト８上の記録紙に感光体ドラム４Ｍ〜４Ｂ上のトナー像が転写される。なお、これら転写ローラ９Ｍ〜９Ｂには−１．５ｋＶの電圧が印加されている。   The photosensitive drums 4M, 4C, 4Y, and 4B are opposed to the transfer rollers 9M, 9C, 9Y, and 9B with the recording paper conveyance belt 8 interposed therebetween. The transfer rollers 9M to 9B are connected to the recording paper conveyance belt 8. The recording paper transport belt 8 is in contact with the photosensitive drums 4M to 4B. As will be described later, the recording paper on the recording paper transport belt 8 is placed on the photosensitive drums 4M to 4B. The toner image is transferred. A voltage of −1.5 kV is applied to these transfer rollers 9M to 9B.

現像によって、現像装置３Ｍ、３Ｃ、３Ｙ、及び３Ｂの中の現像剤が消費されると、それぞれトナー供給容器７Ｍ、７Ｃ、７Ｙ、及び７Ｂからトナーが現像装置３Ｍ、３Ｃ、３Ｙ、及び３Ｂ中に搬送されてトナーの補給が行われ、現像装置３Ｍ、３Ｃ、３Ｙ、及び３Ｂ内には常に適量の現像剤が収容されることになる。   When the developer in the developing devices 3M, 3C, 3Y, and 3B is consumed by the development, toner is supplied from the toner supply containers 7M, 7C, 7Y, and 7B to the developing devices 3M, 3C, 3Y, and 3B, respectively. Thus, the toner is replenished, and an appropriate amount of developer is always stored in the developing devices 3M, 3C, 3Y, and 3B.

記録紙搬送ベルト８上の記録紙が感光体ドラム４Ｍの下を通過する際、転写ローラ９Ｍに印加された−１．５ＫＶの電圧により、感光体ドラム４Ｍに付着したトナー像が記録紙に引きつけられてトナー像が記録紙に転写される。このようにして、電子写真プロセス部材３０Ｍでマゼンタトナー像が記録紙に転写された後、順次電子写真プロセス部材３０Ｃ、３０Ｙ、及び３０Ｂでシアン、イエロー、及びブラックの各色のトナー像が記録紙に転写されて、各色トナー像が重ね合わされ、カラー画像が記録紙に転写されることになる。その後、記録紙は定着装置５０に搬送されて、ここでカラー画像が定着されて、記録紙搬送路１５を経て排出部１６に排出される。   When the recording paper on the recording paper conveyance belt 8 passes under the photosensitive drum 4M, the toner image attached to the photosensitive drum 4M is attracted to the recording paper by the voltage of −1.5 KV applied to the transfer roller 9M. Then, the toner image is transferred to the recording paper. In this way, after the magenta toner image is transferred to the recording paper by the electrophotographic process member 30M, the toner images of cyan, yellow, and black are sequentially transferred to the recording paper by the electrophotographic process members 30C, 30Y, and 30B. After being transferred, the color toner images are superimposed, and the color image is transferred to the recording paper. Thereafter, the recording paper is conveyed to the fixing device 50, where the color image is fixed, and is discharged to the discharge portion 16 through the recording paper conveyance path 15.

このように構成した画像形成装置において本発明では、図２に示したように、各転写ローラ９Ｍ、９Ｃ、９Ｙ、９Ｂを感光体ドラム（像担持体）４Ｍ、４Ｃ、４Ｙ、４Ｂの軸方向に対し、所定角度θを持たせ、記録紙搬送ベルト８が一側に寄せられるよう配置した。   In the image forming apparatus configured as described above, in the present invention, as shown in FIG. 2, the transfer rollers 9M, 9C, 9Y, and 9B are arranged in the axial direction of the photosensitive drums (image carriers) 4M, 4C, 4Y, and 4B. On the other hand, the recording paper transport belt 8 is arranged so as to be brought to one side with a predetermined angle θ.

すなわち記録紙搬送ベルト８は、記録紙搬送ベルト８の蛇行を制限する蛇行防止プーリ６２を設けた駆動ローラ１０、及び従動ローラ１１、テンション用の補助ローラ１１ａに懸架されて駆動され、かつ、感光体ドラム（像担持体）４Ｍ、４Ｃ、４Ｙ、４Ｂのそれぞれに相対して設置された転写ローラ９Ｍ、９Ｃ、９Ｙ、９Ｂに挟まれているが、この各転写ローラ９Ｍ、９Ｃ、９Ｙ、９Ｂを感光体ドラム（像担持体）４Ｍ、４Ｃ、４Ｙ、４Ｂの軸方向に対し、所定角度θを持たせて配置することにより、記録紙搬送ベルト８を一側に寄せることができ、しかもその寄せ量を、前記図３に示した蛇行防止プーリ６２と蛇行防止ベルト６１によって前記無担ベルトが異常走行しないような値とすることで、無理なく蛇行を防止できる画像形成装置を提供することができる。   That is, the recording paper conveyance belt 8 is suspended and driven by the driving roller 10 provided with the meandering prevention pulley 62 that restricts the meandering of the recording paper conveyance belt 8, the driven roller 11, and the auxiliary roller 11 a for tension. Each of the transfer rollers 9M, 9C, 9Y, and 9B is sandwiched between transfer rollers 9M, 9C, 9Y, and 9B that are installed to face each of the body drums (image carriers) 4M, 4C, 4Y, and 4B. Is disposed at a predetermined angle θ with respect to the axial direction of the photosensitive drums (image carriers) 4M, 4C, 4Y, and 4B, so that the recording paper transport belt 8 can be brought to one side, and An image forming apparatus that can prevent the meandering effortlessly by setting the shifting amount to a value that prevents the unsupported belt from running abnormally by the meandering prevention pulley 62 and the meandering prevention belt 61 shown in FIG. It is possible to provide.

なお、所定角度θとしては、２度前後の角度であることが好ましく、この角度が小さ過ぎると充分な効果が得られず、また５度を超えるとベルトの材質にもよるが記録紙搬送ベルト８に加わる力が大きくなりすぎて記録紙搬送ベルト８の耐久性を損ねる恐れがあると共に、感光体ドラム（像担持体）４Ｍ、４Ｃ、４Ｙ、４Ｂの径にもよるが、感光体ドラム（像担持体）４Ｍ、４Ｃ、４Ｙ、４Ｂの端部で充分な転写ニップが得られない恐れがある。
また本実施例では記録紙搬送ベルト８に加わる力を分散させるため、すべての転写ローラを傾斜させて配置する場合を示したが、この限りではなく実施形態に応じて転写ローラ９Ｍ、９Ｃ、９Ｙ、９Ｂのうちの少なくとも一つに対応する感光体ドラム（像担持体）４Ｍ、４Ｃ、４Ｙ、４Ｂの軸方向に対して傾斜させて配置してもよい。 The predetermined angle θ is preferably about 2 degrees, and if this angle is too small, a sufficient effect cannot be obtained. If the angle exceeds 5 degrees, the recording paper conveying belt depends on the material of the belt. There is a possibility that the force applied to 8 becomes too large and the durability of the recording paper transport belt 8 may be impaired, and depending on the diameters of the photosensitive drums (image carriers) 4M, 4C, 4Y, and 4B, the photosensitive drum ( Image carrier) There is a possibility that a sufficient transfer nip may not be obtained at the ends of 4M, 4C, 4Y, and 4B.
In this embodiment, in order to disperse the force applied to the recording paper conveyance belt 8, the case where all the transfer rollers are inclined is shown. However, the present invention is not limited to this, and the transfer rollers 9M, 9C, 9Y are not limited thereto. , 9B, the photosensitive drums (image carriers) 4M, 4C, 4Y, and 4B may be inclined with respect to the axial direction.

このように、前記少なくとも一つの転写ローラを前記像担持体の軸方向に対して所定角度を持たせ、前記無端ベルトが一側に寄せられるよう配置することにより、転写ローラという画像形成装置に用いられ、かつ、駆動ローラとベルトへの力の作用位置が異なる転写ローラを用いて無端ベルトの蛇行を防止できるから、無端ベルトの耐久性を損ねることがなく、無端ベルトにスプロケットを設けたり両側縁周長を異ならせる、テーパローラを用いるなどの、無端ベルトの下流側に進むにつれて速度差分、主走査方向で斜めになってしまうような方法を取る必要が無く、また、特別な斜めローラというコストを上げる方法も必要ないから、簡単、安価な方法で、中間転写ベルトや記録紙搬送ベルトなどの無端ベルトの蛇行を防止して色ズレを防止した画像形成装置を提供することができる。   In this way, the at least one transfer roller has a predetermined angle with respect to the axial direction of the image carrier, and is arranged so that the endless belt is brought close to one side, thereby being used for an image forming apparatus called a transfer roller. In addition, the endless belt can be prevented from meandering by using a transfer roller with a different position of the force applied to the drive roller and the belt, so that the endless belt is not impaired and sprockets are provided on the endless belt. There is no need to adopt a method that makes the circumference different, or uses a tapered roller, etc., so that the speed difference becomes oblique in the main scanning direction as it goes downstream of the endless belt, and the cost of a special oblique roller is reduced. Since there is no need for a lifting method, a simple and inexpensive method prevents meandering of endless belts such as intermediate transfer belts and recording paper transport belts to prevent color misregistration. It is possible to provide an image forming apparatus.

また、前記転写ローラに持たせた所定角度による前記無端ベルトの寄せ量を、前記蛇行防止プーリと蛇行防止ベルトによって前記無担ベルト６０が寄り止めガイドを乗り越えてしまうような異常走行をしないような値としたことにより、無理なく蛇行を防止できる画像形成装置を提供することができる。   Further, the amount of the endless belt brought about by a predetermined angle given to the transfer roller is not caused to run abnormally such that the unsupported belt 60 gets over the detent guide by the meandering prevention pulley and the meandering prevention belt. By setting the value, it is possible to provide an image forming apparatus that can prevent meandering without difficulty.

本発明によれば、簡単、安価な構成で中間転写ベルトや記録紙搬送ベルトなどのベルトの蛇行を防止し、色ズレのない画像を形成できる画像形成装置が提供できる。   According to the present invention, it is possible to provide an image forming apparatus that can prevent the meandering of belts such as an intermediate transfer belt and a recording paper transport belt with a simple and inexpensive configuration and can form an image without color misregistration.

本発明になる画像形成装置の一例を概略的に示す断面図である。1 is a cross-sectional view schematically illustrating an example of an image forming apparatus according to the present invention. 本発明になる画像形成装置における転写材搬送ベルトの蛇行防止機構の概略図である。It is the schematic of the meandering prevention mechanism of the transfer material conveyance belt in the image forming apparatus which becomes this invention. 従来の画像形成装置における蛇行防止ベルトとプーリを示した図である。FIG. 6 is a view showing a meandering prevention belt and a pulley in a conventional image forming apparatus.

符号の説明Explanation of symbols

４Ｍ、４Ｃ、４Ｙ、４Ｂ 感光体ドラム（像担持体）
８ 記録紙搬送ベルト
９Ｍ、９Ｃ、９Ｙ、９Ｂ 転写ローラ
４０ ベルト懸架によるベルトの進行方向
４１ 転写ローラによるベルト進行方向
４２ 転写ローラによるベルトの偏り力 4M, 4C, 4Y, 4B Photosensitive drum (image carrier)
8 Recording Paper Conveying Belts 9M, 9C, 9Y, 9B Transfer Roller 40 Belt Travel Direction 41 by Belt Suspension 41 Belt Travel Direction 42 by Transfer Roller Belt Biasing Force by Transfer Roller

Claims (2)

使用する複数色のトナーのそれぞれに対応させて設けられ、電子写真プロセスによりトナー像を担持する像担持体と、該像担持体の配列方向を搬送方向とし、各像担持体上に形成されたトナー像を転写する中間転写ベルト、または記録紙を搬送してトナー像を転写させる搬送ベルトなどの無端ベルトと、該無端ベルトを挟んで前記各像担持体のそれぞれに相対して設置された転写ローラと、前記無端ベルトを張架して駆動すると共に、前記無端ベルトの端面に設けられた蛇行防止ベルトをガイドし、前記無端ベルトの蛇行を制限する蛇行防止プーリとを設けた駆動ローラまたは／及び従動ローラとを備えた画像形成装置において、
前記少なくとも一つの転写ローラを前記像担持体の軸方向に対して所定角度を持たせ、前記無端ベルトが一側に寄せられるよう配置したことを特徴とする画像形成装置。 An image carrier that is provided corresponding to each of a plurality of color toners to be used and carries a toner image by an electrophotographic process, and an arrangement direction of the image carrier is a transport direction, and is formed on each image carrier. An endless belt such as an intermediate transfer belt for transferring a toner image or a conveying belt for transferring a recording paper by transferring a recording paper, and a transfer disposed opposite to each of the image carriers with the endless belt interposed therebetween. A driving roller provided with a roller and a meander-preventing pulley that drives the endless belt in a stretched manner, guides a meandering-preventing belt provided on an end surface of the endless belt, and restricts the meandering of the endless belt; And an image forming apparatus provided with a driven roller,
An image forming apparatus, wherein the at least one transfer roller is disposed at a predetermined angle with respect to an axial direction of the image carrier so that the endless belt is brought close to one side. 前記転写ローラに持たせた所定角度による前記無端ベルトの寄せ量を、前記蛇行防止プーリと蛇行防止ベルトによって前記無担ベルトが異常走行しないような値としたことを特徴とする請求項１に記載した画像形成装置。   2. The approaching amount of the endless belt at a predetermined angle given to the transfer roller is set to a value that prevents the unsupported belt from running abnormally by the meandering prevention pulley and the meandering prevention belt. Image forming apparatus.
JP2004053659A 2004-02-27 2004-02-27 Image forming apparatus Pending JP2005242121A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007156173A (en) * 2005-12-06 2007-06-21 Canon Inc Image forming apparatus
JP2009186754A (en) * 2008-02-06 2009-08-20 Konica Minolta Business Technologies Inc Image forming device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007156173A (en) * 2005-12-06 2007-06-21 Canon Inc Image forming apparatus
JP2009186754A (en) * 2008-02-06 2009-08-20 Konica Minolta Business Technologies Inc Image forming device

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