JP2012162343A - Image forming apparatus - Google Patents

Image forming apparatus Download PDF

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JP2012162343A
JP2012162343A JP2011022600A JP2011022600A JP2012162343A JP 2012162343 A JP2012162343 A JP 2012162343A JP 2011022600 A JP2011022600 A JP 2011022600A JP 2011022600 A JP2011022600 A JP 2011022600A JP 2012162343 A JP2012162343 A JP 2012162343A
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recording medium
skew
belt
unit
image
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Yasuyuki Sekino
恭行 関野
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Ricoh Co Ltd
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Ricoh Co Ltd
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  • Registering Or Overturning Sheets (AREA)
  • Paper Feeding For Electrophotography (AREA)
  • Controlling Sheets Or Webs (AREA)
  • Feeding Of Articles By Means Other Than Belts Or Rollers (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that corrects skew without damaging a recording medium by using a suction belt conveyance mechanism that rotates in a direction parallel to a surface of the recording medium and corrects the skew regardless of the thickness and type of a sheet by varying a suction force by the belt.SOLUTION: The image forming apparatus includes: a sheet feeding unit 2 for storing a plurality of recording media M and feeding each one; a conveyance mechanism 10 for conveying the recording medium fed by the feeding unit along a conveyance path P; and an image formation unit 20 with an image recording part 26 that records images on the recording medium fed by the conveyance path. A skew correction conveyance mechanism 40 with a suction conveyance belt 55 for sucking the conveyed recording medium and rotating the medium in its surface direction, is disposed in an upstream of the image recording part.

Description

本発明は画像記録部に向けて搬送される記録媒体がスキューを起こした場合に、記録媒体を損傷したり、画像記録部への到達タイミングにズレを発生させることなくスキューを補正することができる画像形成装置に関する。   The present invention can correct the skew when the recording medium conveyed toward the image recording unit is skewed without damaging the recording medium or causing a deviation in the arrival timing to the image recording unit. The present invention relates to an image forming apparatus.

電子写真式の画像形成装置(複写機、プリンタ)にあっては、給紙部から給紙された記録媒体を記録媒体搬送機構により転写部(画像記録部)に搬送し、転写部にて像担持体(感光体)上に形成された画像を記録媒体上に転写し、その後定着部にて画像を定着する。
また、インクジェットプリンタ等にあっては、給紙部から給紙された記録媒体を記録媒体搬送機構により印字部(画像記録部)に搬送し、印字部にて記録媒体上に画像を形成する。
上記画像形成プロセスの一連の流れの中で、給紙もしくは搬送時に記録媒体が正規の搬送方向に対して斜めになった(スキューしている)場合にそのまま画像記録部にて画像記録が行われると、記録媒体面に対して傾いて記録されたスキュー画像が形成される。
スキュー状態での画像記録を防止する対策としては、画像記録部の直前位置に配置されたレジストローラ対を停止させた状態でそのニップ部に記録媒体先端縁を突き当て、搬送手段により記録媒体を押し込むことによりスキュー補正を行う方法が知られている。
しかし、この方法では、記録媒体の先端縁に傷が発生したり、超厚の記録媒体、コート系の記録媒体においては搬送手段でのスリップによる押し込み量不足が発生しスキュー補正不足となる。
また、特許文献1のように、搬送方向に対して鉛直方向に設けられたゲートに記録媒体先端縁を突き当ててスキュー補正を行う方法等が提案されている。
しかし、このスキュー補正方法でも記録媒体の先端縁に傷が発生し易くなるという不具合がある。
In an electrophotographic image forming apparatus (copier, printer), a recording medium fed from a paper feeding unit is transported to a transfer unit (image recording unit) by a recording medium transporting mechanism, and an image is transferred from the transfer unit. The image formed on the carrier (photosensitive member) is transferred onto a recording medium, and then the image is fixed by a fixing unit.
In an inkjet printer or the like, a recording medium fed from a paper feeding unit is conveyed to a printing unit (image recording unit) by a recording medium conveyance mechanism, and an image is formed on the recording medium by the printing unit.
In the above-described flow of the image forming process, when the recording medium is inclined (skewed) with respect to the normal conveyance direction during paper feeding or conveyance, image recording is performed as it is. As a result, a skew image recorded with an inclination to the recording medium surface is formed.
As a measure to prevent image recording in the skew state, the recording medium leading edge is abutted against the nip portion in a state where the registration roller pair disposed immediately before the image recording portion is stopped, and the recording medium is moved by the conveying means. A method for correcting skew by pushing in is known.
However, in this method, scratches occur at the leading edge of the recording medium, and in an ultra-thick recording medium or a coating-type recording medium, the amount of pushing in due to slip in the conveying means occurs, resulting in insufficient skew correction.
Further, as disclosed in Patent Document 1, a method of correcting skew by abutting the leading edge of a recording medium against a gate provided in a direction perpendicular to the conveyance direction has been proposed.
However, even with this skew correction method, there is a problem that scratches are likely to occur at the leading edge of the recording medium.

従来のスキュー補正のための方法では、レジストローラ対のニップ部に記録媒体先端を当接させた状態で記録媒体を押し込んだり、ゲートに記録媒体先端縁を突き当ててスキュー補正を行っていたため、記録媒体の先端縁に傷が発生したり、超厚の記録媒体、コート系の記録媒体をスキュー補正する際に搬送手段がスリップして押し込み量不足が発生しスキュー補正不足となっていた。
本発明は、記録媒体の面と並行な面方向へ回動可能な吸着式のベルト搬送機構を用いることにより、記録媒体にダメージを与えることなくスキュー補正を行うと共に、ベルトによる吸着力を可変とすることで用紙厚・用紙種によらずスキュー補正が可能となる画像形成装置を提供することを目的としている。
In the conventional method for skew correction, the recording medium is pushed with the front end of the recording medium in contact with the nip portion of the registration roller pair, or the front end edge of the recording medium is abutted against the gate to perform skew correction. When the leading edge of the recording medium is scratched, or when skew correction is performed on an ultra-thick recording medium or a coating-type recording medium, the conveying means slips and the pushing amount is insufficient, resulting in insufficient skew correction.
The present invention makes it possible to perform skew correction without damaging the recording medium and to make the adsorption force by the belt variable by using an adsorption-type belt conveyance mechanism that can rotate in a plane direction parallel to the surface of the recording medium. Accordingly, an object of the present invention is to provide an image forming apparatus capable of correcting skew regardless of the sheet thickness and the sheet type.

上記目的を達成するため、請求項1の発明は、複数枚の記録媒体を収容して一枚ずつ給紙する給紙部と、給紙部から給紙された記録媒体を搬送経路に沿って搬送する搬送機構と、該搬送経路を搬送される該記録媒体上に画像を記録する画像記録部を備えた画像形成ユニットと、を有する画像形成装置において、前記画像記録部の上流に、搬送される前記記録媒体を吸着してその面方向に回転させる吸着搬送ベルトを備えたスキュー補正搬送機構を配置したことを特徴とする。
スキュー状態にある記録媒体を吸着搬送ベルトにより吸着して搬送経路から持ち上げた状態とし、吸着搬送ベルトを面方向へ回動させて搬送方向を補正してから、画像記録部に搬送するようにしたので、記録媒体にダメージを与えることなく、スキュー補正を行うことができる。
請求項2の発明は、前記スキュー補正搬送機構の上流に配置されて前記記録媒体のスキューの有無、及びスキュー角度を検出するスキュー検出部と、制御手段と、を備え、前記制御手段は、前記スキュー検出部がスキューを検出した場合に、その検出結果に基づいて前記スキュー補正搬送機構を制御して、前記吸着搬送ベルトがスキュー状態にある前記記録媒体と同一方向になるように回転させてから該記録媒体を吸着させ、その後正規搬送方向となるように前記吸着搬送ベルトを回転させてから搬送することを特徴とする。
スキュー検出部がスキューを検出した場合に、その検出結果に基づいてスキュー補正搬送機構を制御して、吸着搬送ベルトによって記録媒体を吸着させて所定方向へ所定角度回転させる。このため、スキュー状態にあった記録媒体を正規搬送方向に補正した上で搬送することができる。この際、記録媒体にダメージを与えることが防止される。
In order to achieve the above object, a first aspect of the present invention is a paper feeding unit that accommodates a plurality of recording media and feeds them one by one, and a recording medium fed from the paper feeding unit along a transport path. In an image forming apparatus having a transport mechanism that transports and an image forming unit that includes an image recording unit that records an image on the recording medium transported through the transport path, the image transport unit is transported upstream of the image recording unit. A skew correction transport mechanism including a suction transport belt that sucks and rotates the recording medium in the surface direction is arranged.
The recording medium in the skew state is sucked by the suction transport belt and lifted from the transport path, and the suction transport belt is rotated in the surface direction to correct the transport direction, and then transported to the image recording unit. Therefore, skew correction can be performed without damaging the recording medium.
According to a second aspect of the present invention, there is provided a skew detection unit that is disposed upstream of the skew correction transport mechanism and detects the skew of the recording medium and a skew angle, and a control unit, and the control unit includes the control unit, When the skew detection unit detects skew, the skew correction conveyance mechanism is controlled based on the detection result, and the suction conveyance belt is rotated so as to be in the same direction as the recording medium in the skew state. The recording medium is adsorbed, and then the adsorbing and conveying belt is rotated so as to be in the normal conveying direction and then conveyed.
When the skew detection unit detects the skew, the skew correction conveyance mechanism is controlled based on the detection result, and the recording medium is adsorbed by the adsorption conveyance belt and rotated by a predetermined angle in a predetermined direction. For this reason, the recording medium in the skew state can be transported after being corrected in the regular transport direction. At this time, damage to the recording medium is prevented.

請求項3の発明は、前記スキュー補正搬送機構が前記スキュー補正動作を行ったことによって前記画像記録部への到達タイミングが変動する場合に、前記制御手段は前記吸着搬送ベルトによる前記記録媒体の搬送速度を変更して前記到達タイミングを適正に修正することを特徴とする。
スキュー補正搬送機構がスキュー補正動作を行ったことによって画像記録部への到達タイミングが変動する場合に、制御手段は吸着搬送ベルトによる記録媒体の搬送速度を変更、調整して到達タイミングを適正に修正する。このように吸着搬送ベルトによる搬送時に搬送速度を可変とすることにより、転写時(画像記録時)の書き出し位置合わせが可能となる。
請求項4の発明は、前記吸着搬送ベルトによる吸着力を調整可能に構成したことを特徴とする。
吸着搬送ベルトによる記録媒体の吸着時に、吸着力を可変とすることにより、各種の記録媒体に対応することが可能となる。
請求項5の発明は、前記吸着搬送ベルトは、静電吸着式であることを特徴とする。
According to a third aspect of the present invention, when the arrival timing to the image recording unit varies due to the skew correction transport mechanism performing the skew correction operation, the control means transports the recording medium by the suction transport belt. The arrival timing is appropriately corrected by changing the speed.
When the arrival timing to the image recording unit fluctuates due to the skew correction transport mechanism performing the skew correction operation, the control means changes and adjusts the transport speed of the recording medium by the suction transport belt to correct the arrival timing appropriately. To do. Thus, by changing the conveyance speed during conveyance by the adsorption conveyance belt, it is possible to align the writing position at the time of transfer (image recording).
According to a fourth aspect of the present invention, the suction force by the suction conveyance belt can be adjusted.
By making the adsorption force variable when the recording medium is adsorbed by the adsorbing and conveying belt, it is possible to cope with various recording media.
The invention according to claim 5 is characterized in that the adsorption transport belt is of an electrostatic adsorption type.

本発明によれば、スキュー補正搬送機構の上流に記録媒体のスキューの有無、及びスキュー状態(スキュー角度)を検出するスキュー検出部を配置し、スキュー検出部がスキューを検出した場合に、その検出結果に基づいてスキュー補正搬送機構を制御して、吸着搬送ベルトによって記録媒体を吸着させて所定方向へ所定角度回転させる。このため、スキュー状態にあった記録媒体を正規搬送方向に補正した上で搬送することができる。この際、記録媒体にダメージを与えることが防止される。
また、吸着搬送ベルトによる記録媒体の吸着時に、吸着力を可変とすることにより、各種の記録媒体に対応することが可能となる。
スキュー補正搬送機構がスキュー補正動作を行ったことによって画像記録部への到達タイミングが変動する場合に、制御手段は吸着搬送ベルトによる記録媒体の搬送速度を変更、調整して到達タイミングを適正に修正する。このように吸着搬送ベルトによる搬送時に搬送速度を可変とすることにより、転写時(画像記録時)の書き出し位置合わせが可能となる。
According to the present invention, a skew detection unit that detects the presence / absence of skew of a recording medium and a skew state (skew angle) is arranged upstream of the skew correction transport mechanism, and when the skew detection unit detects skew, the detection is performed. The skew correction transport mechanism is controlled based on the result, and the recording medium is sucked by the suction transport belt and rotated by a predetermined angle in a predetermined direction. For this reason, the recording medium in the skew state can be transported after being corrected in the regular transport direction. At this time, damage to the recording medium is prevented.
In addition, when the recording medium is adsorbed by the adsorbing and conveying belt, it is possible to cope with various recording media by changing the adsorbing force.
When the arrival timing to the image recording unit fluctuates due to the skew correction transport mechanism performing the skew correction operation, the control means changes and adjusts the transport speed of the recording medium by the suction transport belt to correct the arrival timing appropriately. To do. Thus, by changing the conveyance speed during conveyance by the adsorption conveyance belt, it is possible to align the writing position at the time of transfer (image recording).

本発明の画像形成装置の一例としての電子写真式画像形成装置の概略構成説明図である。1 is a schematic configuration explanatory diagram of an electrophotographic image forming apparatus as an example of an image forming apparatus of the present invention. スキュー補正搬送機構の具体例を示す外観斜視図である。It is an external appearance perspective view which shows the specific example of a skew correction conveyance mechanism. (a)及び(b)は吸着搬送ベルトの断面図である。(A) And (b) is sectional drawing of an adsorption conveyance belt. スキュー検出部による検出動作を説明するための平面図である。It is a top view for demonstrating the detection operation by a skew detection part. (a)乃至(d)は本発明によるスキュー補正方法を説明する平面図である。(A) thru | or (d) is a top view explaining the skew correction method by this invention. (a)乃至(d)は本発明によるスキュー補正方法を説明する正面図である。(A) thru | or (d) is a front view explaining the skew correction method by this invention. スキュー補正動作を示すフローチャートである。It is a flowchart which shows skew correction operation | movement.

以下、添付図面に基づいて本発明の実施形態を説明する。
図1は本発明の画像形成装置の一例としての電子写真式画像形成装置の概略構成説明図である。
画像形成装置1は、カラー画像形成装置であり、給紙部2と、記録媒体搬送機構10と、画像形成ユニット20と、これらを制御する図示しない制御手段と、を概略備えている。
本発明の実施形態に係る画像形成装置1の特徴的な構成は、複数枚の記録媒体Mを収容して一枚ずつ給紙する給紙部2と、給紙部2から給紙された記録媒体Mを搬送経路Pに沿って搬送する記録媒体搬送機構10と、搬送経路Pを搬送される記録媒体M上にトナー画像を記録する画像記録部26を備えた画像形成ユニット20と、を有する画像形成装置において、画像記録部26の搬送方向上流位置に、搬送される記録媒体を吸着してその面方向に回転させて方向転換させる吸着搬送ベルト55を備えたスキュー補正搬送機構40を配置した点にある。
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic configuration explanatory diagram of an electrophotographic image forming apparatus as an example of the image forming apparatus of the present invention.
The image forming apparatus 1 is a color image forming apparatus, and generally includes a paper feeding unit 2, a recording medium transport mechanism 10, an image forming unit 20, and a control unit (not shown) that controls these units.
A characteristic configuration of the image forming apparatus 1 according to the embodiment of the present invention includes a sheet feeding unit 2 that houses a plurality of recording media M and feeds the sheets one by one, and a recording fed from the sheet feeding unit 2. A recording medium transport mechanism 10 that transports the medium M along the transport path P; and an image forming unit 20 that includes an image recording unit 26 that records a toner image on the recording medium M transported along the transport path P. In the image forming apparatus, the skew correction transport mechanism 40 including the suction transport belt 55 that sucks the recording medium to be transported and rotates it in the surface direction to change the direction is disposed at the upstream position in the transport direction of the image recording unit 26. In the point.

また、スキュー補正搬送機構40の上流には、記録媒体のスキュー(正規搬送方向に対する傾き)の有無、及びスキュー状態(スキュー角度)を検出するスキュー検出部70が配置されている。
給紙部2は、記録媒体Mを積層した状態で収容する記録媒体収容部3と、記録媒体収容部3内の最上部の記録媒体に接してこれを搬送経路Pに送り出す給紙ローラ4等、を備えている。
搬送経路Pは、給紙部2から画像形成ユニット20を経て機外、或いは両面搬送路P1へ繋がっている。
搬送機構10は、搬送経路Pに沿って配置された搬送用のローラ対11等から構成されている。
Further, upstream of the skew correction transport mechanism 40, a skew detection unit 70 for detecting the presence / absence of skew of the recording medium (tilt with respect to the normal transport direction) and a skew state (skew angle) is disposed.
The sheet feeding unit 2 includes a recording medium accommodating unit 3 that accommodates the recording media M in a stacked state, a sheet feeding roller 4 that contacts the uppermost recording medium in the recording medium accommodating unit 3 and sends the recording medium to the conveyance path P, and the like. It is equipped with.
The conveyance path P is connected from the paper feed unit 2 to the outside of the apparatus via the image forming unit 20 or the double-sided conveyance path P1.
The transport mechanism 10 includes a pair of transport rollers 11 and the like disposed along the transport path P.

画像形成ユニット20は、一列に配列された複数個の感光体ドラム(イエロー、マゼンタ、シアン、黒)21と、各感光体ドラムの外周に沿って順次配置された画像情報書込み部22、現像部23、及び一次転写部24と、一部の走行面を各感光体ドラム21に沿って配設された中間転写ベルト25と、感光体ドラム列の下流側に配置された二次転写部(画像記録部)26と、二次転写部26よりも搬送経路Pの下流側に配置された定着部27と、を概略備えている。二次転写部26には、搬送経路Pを搬送されてきた記録媒体Pの面上に中間転写ベルト25上のトナー像を転写するための二次転写手段(転写ローラ、転写コロトロン等)26aが設けられている。
中間転写ベルト25は、複数個の支持ローラ25aによってエンドレスに調整されており、矢印方向へ駆動される。
The image forming unit 20 includes a plurality of photosensitive drums (yellow, magenta, cyan, black) 21 arranged in a row, an image information writing unit 22 arranged sequentially along the outer periphery of each photosensitive drum, and a developing unit. 23, a primary transfer unit 24, an intermediate transfer belt 25 having a part of the running surface disposed along each photosensitive drum 21, and a secondary transfer unit (image) disposed downstream of the photosensitive drum row. A recording unit) 26 and a fixing unit 27 disposed on the downstream side of the transport path P from the secondary transfer unit 26. The secondary transfer unit 26 includes secondary transfer means (transfer roller, transfer corotron, etc.) 26a for transferring the toner image on the intermediate transfer belt 25 onto the surface of the recording medium P that has been transported along the transport path P. Is provided.
The intermediate transfer belt 25 is adjusted endlessly by a plurality of support rollers 25a and is driven in the direction of the arrow.

各画像情報書込み部22では、図示しない原稿読取り部から得られた光学的な画像情報を、予め一様に帯電された各感光体ドラム21上に照射して静電潜像を形成し、各現像部23では各感光体ドラム上の静電潜像を各色のトナーで現像する。各一次転写部24では各感光体ドラム上のトナー像を中間転写ベルト25の面上に順次重ね転写してゆき、重ねトナー像を形成する。
二次転写部26では、記録媒体搬送機構10によって搬送経路を二次転写部26に向けて搬送されてきた記録媒体M上に所定のタイミングにて中間転写ベルト25上の重ねトナー像を転写する。
二次転写部26を通過した記録媒体は、定着部27において加熱、加圧を受けて重ねトナー像が定着される。
この一連の流れにおいて、搬送経路Pを搬送される記録媒体に傾き(スキュー)が発生すると、二次転写部26上で画像記録される際に記録媒体とトナー画像の夫々の向きが平行とならず、画像ズレが生じる。
本発明では、スキュー補正搬送機構40、スキュー検出部70等を用いてこのようなスキューを修正するための補正作業を実施する。
Each image information writing unit 22 irradiates optical image information obtained from a document reading unit (not shown) onto each photosensitive drum 21 that is uniformly charged in advance to form an electrostatic latent image. The developing unit 23 develops the electrostatic latent image on each photosensitive drum with toner of each color. Each primary transfer unit 24 sequentially superimposes and transfers the toner image on each photosensitive drum onto the surface of the intermediate transfer belt 25 to form a superimposed toner image.
In the secondary transfer unit 26, the superimposed toner image on the intermediate transfer belt 25 is transferred at a predetermined timing onto the recording medium M that has been conveyed toward the secondary transfer unit 26 through the conveyance path by the recording medium conveyance mechanism 10. .
The recording medium that has passed through the secondary transfer unit 26 is heated and pressed by the fixing unit 27 to fix the superimposed toner image.
In this series of flows, if an inclination (skew) occurs in the recording medium conveyed along the conveyance path P, when the image is recorded on the secondary transfer unit 26, the directions of the recording medium and the toner image are parallel to each other. Therefore, image shift occurs.
In the present invention, a correction operation for correcting such skew is performed using the skew correction transport mechanism 40, the skew detection unit 70, and the like.

次に本発明の特徴的な構成について更に詳細に説明する。
図2はスキュー補正搬送機構40の具体例を示す外観斜視図である。
スキュー補正搬送機構40は、固定側の駆動部41と、可動部(ベルト搬送部)50とから概略構成されている。
駆動部41は、画像形成装置の固定部材に固定されたベルト搬送部回転駆動用のモータ42と、モータ42の出力軸と一体化された出力プーリ43と、可動部50側に回転自在に設けた従動プーリ44と、出力プーリ43と従動プーリ44との間に張設されてモータからの回転駆動力を可動部50に伝達する伝達ベルト45と、を備えている。
Next, the characteristic configuration of the present invention will be described in more detail.
FIG. 2 is an external perspective view showing a specific example of the skew correction transport mechanism 40.
The skew correction transport mechanism 40 is generally configured by a fixed drive unit 41 and a movable unit (belt transport unit) 50.
The drive unit 41 is rotatably provided on the side of the movable unit 50 and a motor 42 for driving the rotation of the belt conveyance unit fixed to the fixing member of the image forming apparatus, an output pulley 43 integrated with the output shaft of the motor 42. And a transmission belt 45 that is stretched between the output pulley 43 and the driven pulley 44 and transmits the rotational driving force from the motor to the movable unit 50.

可動部(ベルト搬送部)50は、従動プーリ44を回転自在に軸支するプーリ軸支部52を上部に有したケーシング51と、ケーシング51の2つの側壁51aに設けた軸受部51bによって夫々回転自在に軸支された前後2つの回転軸部53、54と、各回転軸部53、54と一体のローラによってエンドレスに張設された吸着式の吸着搬送ベルト55と、ケーシング51の後部に固定された搬送ベルト駆動用のモータ57と、モータ57の出力プーリ57aと回転軸部54と一体の従動プーリ58との間に張設された伝達ベルト59と、を備えている。
駆動部41は、ケーシング51上部の一つの角隅部に配置されている。
The movable portion (belt transport portion) 50 is rotatable by a casing 51 having a pulley shaft support portion 52 that rotatably supports a driven pulley 44 at an upper portion and bearing portions 51b provided on two side walls 51a of the casing 51, respectively. Fixed to the rear part of the casing 51 and the suction-type suction conveyance belt 55 stretched endlessly by rollers integral with the rotary shaft parts 53, 54. And a transmission belt 59 stretched between an output pulley 57a of the motor 57 and a driven pulley 58 integral with the rotating shaft portion 54.
The drive unit 41 is disposed at one corner at the top of the casing 51.

図示しない制御手段による制御によってモータ42を正逆回転させることによって伝達ベルト45を介して従動プーリ44を正逆回転させると、可動部50はモータ42の出力軸を中心として水平面内で(記録媒体の面方向に)揺動(回動)する。モータ42の回転角度を高精度に制御することにより、搬送経路P上における可動部50の水平方向傾斜角度を微調整することができる。
搬送経路P上における記録媒体Mの正規搬送方向に対する可動部50の水平方向傾斜角度を所定に設定してから、モータ57を駆動して吸着搬送ベルト55を記録媒体搬送方向へ回転させることにより、記録媒体を吸着搬送ベルトによって吸着しつつ任意の方向に軌道修正することができる。即ち、上流側に位置するスキュー検出部70によって記録媒体の搬送姿勢にスキューがあることが判明した場合、制御手段は、スキュー検出部70から得た記録媒体のスキュー方向、スキュー角度に関する情報に基づいてモータ42を駆動して可動部50を所定方向へ所定角度回動させることにより、吸着搬送ベルト55によって吸着した状態の当該記録媒体の姿勢を正規搬送方向と合致させることができる。この際、搬送経路の幅方向に対する記録媒体の幅方向位置も正規に修正される。この状態でモータ57を駆動することにより記録媒体を転写部26に正規の姿勢で送り出すことができる。吸着搬送ベルト55による記録媒体の吸着は、スキューの補正が完了し、且つ下流側への送出が完了した時点で解除すればよい。
When the driven pulley 44 is rotated forward / reversely via the transmission belt 45 by rotating the motor 42 forward / reversely under the control of a control means (not shown), the movable portion 50 moves in the horizontal plane around the output shaft of the motor 42 (recording medium). Oscillate (turn) in the direction of the surface. By controlling the rotation angle of the motor 42 with high accuracy, the horizontal inclination angle of the movable portion 50 on the transport path P can be finely adjusted.
By setting the horizontal inclination angle of the movable portion 50 with respect to the normal conveyance direction of the recording medium M on the conveyance path P to a predetermined value, the motor 57 is driven to rotate the suction conveyance belt 55 in the recording medium conveyance direction. The track can be corrected in an arbitrary direction while adsorbing the recording medium by the adsorbing and conveying belt. That is, when the skew detection unit 70 located on the upstream side finds that there is a skew in the transport posture of the recording medium, the control unit is based on information on the skew direction and skew angle of the recording medium obtained from the skew detection unit 70. By driving the motor 42 and rotating the movable part 50 in a predetermined direction by a predetermined angle, the posture of the recording medium attracted by the suction conveyance belt 55 can be matched with the normal conveyance direction. At this time, the position in the width direction of the recording medium with respect to the width direction of the transport path is also properly corrected. By driving the motor 57 in this state, the recording medium can be sent to the transfer unit 26 in a normal posture. The adsorption of the recording medium by the adsorption conveyance belt 55 may be canceled when the skew correction is completed and the delivery to the downstream side is completed.

本実施例においては、吸着式の吸着搬送ベルト55として静電吸着ベルトを用いた例を説明するが、可動部50を回動させる過程で記録媒体を吸着保持し続け、その後吸着を解除できる手段であれば、負圧吸引式等々、どのような吸着搬送ベルトであってもよい。
本実施例の静電式の吸着搬送ベルト55は、図3の断面図に示すように、複数の電極60を所定の間隔を隔てて長手方向(搬送方向)に配置すると共に、これらを絶縁層62内に埋設一体化したシート状の媒体をベルト状に構成したものである。隣接する各電極60の向きは、プラス電極60Aとマイナス電極60Bが交互に異なるように配列されている。これら電極60へ静電吸着ベルト電源部64によって電圧を印加すると誘電分極が発生し、記録媒体Mの吸着面が分極するため、静電吸着ベルト55との間に静電吸着力(クーロン力)が発生する。この静電吸着力により記録媒体Mを静電吸着ベルトに吸着することができる。
また、印加する電圧を可変とすることにより静電吸着力が可変となり、任意の紙種、紙厚に対応することが可能となる。
In this embodiment, an example in which an electrostatic attraction belt is used as the attraction-type adsorption conveyance belt 55 will be described. If so, any suction conveyance belt such as a negative pressure suction type may be used.
As shown in the cross-sectional view of FIG. 3, the electrostatic adsorption / conveyance belt 55 of this embodiment has a plurality of electrodes 60 arranged in the longitudinal direction (conveyance direction) at a predetermined interval, and these are also provided as insulating layers. A sheet-like medium embedded and integrated in 62 is configured in a belt shape. The adjacent electrodes 60 are arranged so that the plus electrodes 60A and the minus electrodes 60B are alternately different. When a voltage is applied to these electrodes 60 by the electrostatic attraction belt power supply unit 64, dielectric polarization occurs, and the attraction surface of the recording medium M is polarized. Therefore, an electrostatic attraction force (Coulomb force) between the electrode 60 and the electrostatic attraction belt 55 is obtained. Occurs. The recording medium M can be attracted to the electrostatic attraction belt by this electrostatic attraction force.
Further, by making the applied voltage variable, the electrostatic attraction force becomes variable, and it becomes possible to cope with any paper type and paper thickness.

次に、本実施例におけるスキュー検出部70としては、CIS(Contact Image Sensor:密着型撮像素子)を用いており、図4に示すように、記録媒体Mが搬送経路Pに沿って搬送されてきてCISに前端部M1が進入した時点で前端部を読み取り、その後規定距離記録媒体を搬送させて前端部M1が破線で示した記録媒体M`の位置に前進したときの前端部M1の位置を読み取る。また、CISは同様に記録媒体の側端部M2の位置の変化を読取る。
CISは、周知のようにイメージスキャナ等に用いられる素子であり、原稿からの反射光をCCDやCMOS撮像素子などのイメージセンサを使って検出してから画像データとして取り込むデバイスである。
Next, a CIS (Contact Image Sensor) is used as the skew detection unit 70 in this embodiment, and the recording medium M is conveyed along the conveyance path P as shown in FIG. When the front end M1 enters the CIS, the front end is read, and then the recording medium M is conveyed to the specified distance, and the position of the front end M1 when the front end M1 advances to the position of the recording medium M ` indicated by the broken line. read. Similarly, the CIS reads a change in the position of the side end M2 of the recording medium.
As is well known, the CIS is an element used for an image scanner or the like, and is a device that detects reflected light from a document using an image sensor such as a CCD or a CMOS image sensor and then captures the image data as image data.

次に、図5、及び図6は本発明によるスキュー補正方法を説明する平面図、及び正面図であり、図7はスキュー補正動作を示すフローチャートである。
本発明に係るスキュー補正搬送機構、及びスキュー検出部を用いたスキュー補正方法について説明する。
まず、図5(a)、図6(a)に示すように記録媒体Mが転写部26に搬送されてくる直前に、スキュー検出部70により記録媒体の前端部M1、側端部M2を複数回検出し、記録媒体のスキューの有無、スキューがある場合の傾きを算出する(図7、S1、S2、S3)。
記録媒体Mの傾きの有無、傾き方向、傾き角度は、図4に示したように、搬送される記録媒体の前端縁M1が実線位置から破線位置までに移動した搬送距離Xと、搬送距離Xを移動する過程でCISよって読取られた側端部M2の各位置間の差yの比から算出する。
Next, FIGS. 5 and 6 are a plan view and a front view for explaining a skew correction method according to the present invention, and FIG. 7 is a flowchart showing a skew correction operation.
A skew correction transport mechanism and a skew correction method using the skew detector according to the present invention will be described.
First, as shown in FIGS. 5A and 6A, a plurality of front end portions M1 and side end portions M2 of the recording medium are formed by the skew detection unit 70 immediately before the recording medium M is conveyed to the transfer unit 26. The number of times of detection is detected, and the presence or absence of skew of the recording medium and the inclination when there is skew are calculated (FIG. 7, S1, S2, S3).
As shown in FIG. 4, the presence / absence, tilt direction, and tilt angle of the recording medium M are determined by the transport distance X and the transport distance X where the front edge M1 of the transported recording medium moves from the solid line position to the broken line position. Is calculated from the ratio of the difference y between each position of the side end M2 read by the CIS in the process of moving.

次に記録媒体Mに傾きがあることが判明した場合には(S3、Y)、制御手段は検出された傾きを修正するために算出した角度分だけ可動部50を回転させ、可動部50(吸着搬送ベルト55)を記録媒体Mに対して平行にする(S7)。
可動部50の回転後に、図5、図6の(b)(c)に示すように、吸着搬送ベルト55に含まれる各電極60へ静電吸着ベルト電源部64から電圧を印加することにより吸着搬送ベルトに記録媒体Mを吸着させて持ち上げ(S8)、その後に可動部50をステップ7での回転方向とは逆方向へ同じ角度だけ回転させて吸着搬送ベルト55を元の位置に戻して記録媒体を正規の搬送方向、搬送位置に戻す(S10)。
なお、図6に示すように可動部50の回転時には搬送ローラ11の従動ローラ11b側を上昇させて両搬送ローラ11a、11bを離間させてニップを解除する。
Next, when it is found that the recording medium M has an inclination (S3, Y), the control unit rotates the movable part 50 by an angle calculated to correct the detected inclination, and the movable part 50 ( The suction conveyance belt 55) is made parallel to the recording medium M (S7).
After rotation of the movable unit 50, as shown in FIGS. 5 and 6B and 6C, the electrostatic chucking belt power supply unit 64 applies a voltage to each electrode 60 included in the chucking conveyance belt 55 so that the chucking is performed. The recording medium M is attracted to the transport belt and lifted (S8), and then the movable portion 50 is rotated by the same angle in the direction opposite to the rotation direction in Step 7 to return the suction transport belt 55 to the original position and perform recording. The medium is returned to the normal transport direction and transport position (S10).
As shown in FIG. 6, when the movable portion 50 rotates, the driven roller 11b side of the conveying roller 11 is raised to separate the conveying rollers 11a and 11b to release the nip.

最後に図5(d)、図6(d)に示すように、モータ57を駆動して吸着搬送ベルト55を駆動させ、吸着搬送ベルト55により吸着した記録媒体Mの搬送を行う。ある程度記録媒体を送り出した時点で吸着搬送ベルト55による吸着を解除する。
この時、記録媒体がスキュー検出部70に到達した時間から記録媒体の進み量、もしくは遅れ量を算出することにより、吸着搬送ベルト55の搬送速度を変化させて転写部26への記録媒体到達時間を調節し、画像の書出し位置を合わせる(S5、6)。
ステップ3において、スキューが検出されない場合には吸着搬送ベルトによる吸着を行わないでそのまま転写部26へ搬送してもよいし、或いは吸着搬送ベルトによって吸着した上で到達時間の進みと遅延を判定した上で、搬送するようにしてもよい(S4、5、6)。
Finally, as shown in FIGS. 5D and 6D, the motor 57 is driven to drive the suction conveyance belt 55, and the recording medium M sucked by the suction conveyance belt 55 is conveyed. When the recording medium is delivered to some extent, the suction by the suction conveyance belt 55 is released.
At this time, by calculating the advance amount or delay amount of the recording medium from the time when the recording medium reaches the skew detection unit 70, the conveyance speed of the suction conveyance belt 55 is changed to change the recording medium arrival time to the transfer unit 26. To adjust the image writing position (S5, 6).
In step 3, if no skew is detected, it may be conveyed directly to the transfer unit 26 without being suctioned by the suction conveyance belt, or the advance and delay of the arrival time are determined after suction by the suction conveyance belt. It may be transported above (S4, 5, 6).

このように本発明によれば、スキュー補正搬送機構40の上流に記録媒体のスキューの有無、及びスキュー状態(スキュー角度)を検出するスキュー検出部70を配置し、スキュー検出部がスキューを検出した場合に、その検出結果に基づいてスキュー補正搬送機構を制御して、吸着搬送ベルト55によって記録媒体を吸着させて所定方向へ所定角度回転させる。
より具体的には、スキュー検出部の検出結果に基づいてスキュー補正搬送機構を制御して、吸着搬送ベルトがスキュー状態にある記録媒体と同一方向になるように回転させてから該記録媒体を吸着させ、その後正規搬送方向となるように吸着搬送ベルトを逆回転させてから搬送する。
このため、スキュー状態にあった記録媒体を正規搬送方向に補正した上で搬送することができる。この際、記録媒体にダメージを与えることが防止される。
As described above, according to the present invention, the skew detection unit 70 for detecting the presence / absence of skew of the recording medium and the skew state (skew angle) is arranged upstream of the skew correction transport mechanism 40, and the skew detection unit detects the skew. In this case, the skew correction conveyance mechanism is controlled based on the detection result, and the recording medium is adsorbed by the adsorption conveyance belt 55 and rotated by a predetermined angle in a predetermined direction.
More specifically, the skew correction conveyance mechanism is controlled based on the detection result of the skew detection unit, and the adsorption conveyance belt is rotated in the same direction as the recording medium in the skew state, and then the recording medium is adsorbed. After that, the suction conveyance belt is reversely rotated so as to be in the normal conveyance direction, and then conveyed.
For this reason, the recording medium in the skew state can be transported after being corrected in the regular transport direction. At this time, damage to the recording medium is prevented.

また、吸着搬送ベルトによる記録媒体の吸着時に、吸着力を可変とすることにより、各種の記録媒体に対応することが可能となる。
スキュー補正搬送機構がスキュー補正動作を行ったことによって画像記録部への到達タイミングが変動する場合に、制御手段は吸着搬送ベルトによる記録媒体の搬送速度を変更、調整して到達タイミングを適正に修正する。このように吸着搬送ベルトによる搬送時に搬送速度を可変とすることにより、転写時(画像記録時)の書き出し位置合わせが可能となる。
なお、本発明は電子写真式画像形成装置一般に適用できるばかりでなく、インクジェットプリンタ、その他の記録媒体搬送経路、画像記録部を備えた画像形成装置一般に適用することができる。
In addition, when the recording medium is adsorbed by the adsorbing and conveying belt, it is possible to cope with various recording media by changing the adsorbing force.
When the arrival timing to the image recording unit fluctuates due to the skew correction transport mechanism performing the skew correction operation, the control means changes and adjusts the transport speed of the recording medium by the suction transport belt to correct the arrival timing appropriately. To do. Thus, by changing the conveyance speed during conveyance by the adsorption conveyance belt, it is possible to align the writing position at the time of transfer (image recording).
The present invention can be applied not only to an electrophotographic image forming apparatus in general, but also to an image forming apparatus generally provided with an inkjet printer, other recording medium conveyance path, and an image recording unit.

1…画像形成装置、2…給紙部、3…記録媒体収容部、4…給紙ローラ、10…記録媒体搬送機構、11…搬送ローラ、11a…搬送ローラ、11b…従動ローラ、20…画像形成ユニット、21…各感光体ドラム、23…現像部、24…一次転写部、25…中間転写ベルト、26…画像記録部(二次転写部)、26a…二次転写手段、27…定着部、40…スキュー補正搬送機構、41…駆動部、42…モータ、43…出力プーリ、44…従動プーリ、45…伝達ベルト、50…可動部、51…ケーシング、51a…側壁、51b…軸受部、52…プーリ軸支部、53、54…回転軸部、55…吸着搬送ベルト(静電吸着ベルト)、57…モータ、57a…出力プーリ、58…従動プーリ、59…伝達ベルト、60…電極、60A…プラス電極、60B…マイナス電極、62…絶縁層、64…静電吸着ベルト電源部、70…スキュー検出部 DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Paper feed part, 3 ... Recording medium accommodating part, 4 ... Paper feed roller, 10 ... Recording medium conveyance mechanism, 11 ... Conveyance roller, 11a ... Conveyance roller, 11b ... Follower roller, 20 ... Image Forming unit, 21 ... each photosensitive drum, 23 ... developing part, 24 ... primary transfer part, 25 ... intermediate transfer belt, 26 ... image recording part (secondary transfer part), 26a ... secondary transfer means, 27 ... fixing part , 40 ... skew correction transport mechanism, 41 ... drive unit, 42 ... motor, 43 ... output pulley, 44 ... driven pulley, 45 ... transmission belt, 50 ... movable part, 51 ... casing, 51a ... side wall, 51b ... bearing part, 52 ... Pulley shaft support part, 53, 54 ... Rotating shaft part, 55 ... Adsorption conveyance belt (electrostatic adsorption belt), 57 ... Motor, 57a ... Output pulley, 58 ... Driven pulley, 59 ... Transmission belt, 60 ... Electrode, 60A …plus Electrode, 60B ... negative electrode, 62: insulating layer, 64 ... electrostatic attraction belt power unit, 70 ... skew detector

特開2007−106572公報JP 2007-106572 A

Claims (5)

記録媒体を一枚ずつ給紙する給紙部と、給紙部から給紙された記録媒体を搬送経路に沿って搬送する搬送機構と、該搬送経路を搬送される該記録媒体上に画像を記録する画像記録部を備えた画像形成ユニットと、を有する画像形成装置において、
前記画像記録部の上流に、搬送される前記記録媒体を吸着してその面方向に回転させる吸着搬送ベルトを備えたスキュー補正搬送機構を配置したことを特徴とする画像形成装置。
A paper feeding unit that feeds the recording medium one by one; a transport mechanism that transports the recording medium fed from the paper feeding unit along the transport path; and an image on the recording medium transported through the transport path. In an image forming apparatus having an image forming unit including an image recording unit for recording,
An image forming apparatus comprising: a skew correction transport mechanism provided with a suction transport belt that sucks and rotates the transported recording medium in the surface direction upstream of the image recording section.
前記スキュー補正搬送機構の上流に配置されて前記記録媒体のスキューの有無、及びスキュー角度を検出するスキュー検出部と、制御手段と、を備え、
前記制御手段は、前記スキュー検出部がスキューを検出した場合に、その検出結果に基づいて前記スキュー補正搬送機構を制御して、前記吸着搬送ベルトがスキュー状態にある前記記録媒体と同一方向になるように回転させてから該記録媒体を吸着させ、その後正規搬送方向となるように前記吸着搬送ベルトを回転させてから搬送することを特徴とする請求項1に記載の画像形成装置。
A skew detector disposed upstream of the skew correction transport mechanism to detect the skew of the recording medium and a skew angle; and a control unit,
When the skew detection unit detects skew, the control unit controls the skew correction transport mechanism based on the detection result, so that the suction transport belt is in the same direction as the recording medium in a skew state. The image forming apparatus according to claim 1, wherein the recording medium is adsorbed after being rotated in this manner, and then the adsorbing and conveying belt is rotated so as to be in a normal conveying direction and then conveyed.
前記スキュー補正搬送機構が前記スキュー補正動作を行ったことによって前記画像記録部への到達タイミングが変動する場合に、前記制御手段は前記吸着搬送ベルトによる前記記録媒体の搬送速度を変更して前記到達タイミングを適正に修正することを特徴とする請求項1又は2に記載の画像形成装置。   When the arrival timing to the image recording unit fluctuates due to the skew correction transport mechanism performing the skew correction operation, the control unit changes the transport speed of the recording medium by the suction transport belt and performs the arrival. The image forming apparatus according to claim 1, wherein the timing is corrected appropriately. 前記吸着搬送ベルトによる吸着力を調整可能に構成したことを特徴とする請求項1乃至3の何れか一項に記載の画像形成装置。   The image forming apparatus according to claim 1, wherein the suction force by the suction conveyance belt is adjustable. 前記吸着搬送ベルトは、静電吸着式であることを特徴とする請求項1乃至4の何れか一項に記載の画像形成装置。   The image forming apparatus according to claim 1, wherein the suction conveyance belt is of an electrostatic suction type.
JP2011022600A 2011-02-04 2011-02-04 Image forming apparatus Withdrawn JP2012162343A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9731923B2 (en) 2014-09-04 2017-08-15 Seiko Epson Corporation Medium transport method, medium transport device, and image recording device
US9776819B2 (en) 2014-12-09 2017-10-03 Ricoh Company, Ltd. Sheet conveying device and image forming apparatus incorporating the sheet conveying device
US11066263B2 (en) 2014-12-09 2021-07-20 Ricoh Company, Ltd. Sheet conveying device and image forming apparatus incorporating the sheet conveying device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9731923B2 (en) 2014-09-04 2017-08-15 Seiko Epson Corporation Medium transport method, medium transport device, and image recording device
US9776819B2 (en) 2014-12-09 2017-10-03 Ricoh Company, Ltd. Sheet conveying device and image forming apparatus incorporating the sheet conveying device
US10358311B2 (en) 2014-12-09 2019-07-23 Ricoh Company, Ltd. Sheet conveying device and image forming apparatus incorporating the sheet conveying device
US11066263B2 (en) 2014-12-09 2021-07-20 Ricoh Company, Ltd. Sheet conveying device and image forming apparatus incorporating the sheet conveying device

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