JP2008114990A

JP2008114990A - Image forming device

Info

Publication number: JP2008114990A
Application number: JP2006300794A
Authority: JP
Inventors: Seijun Horie; 星潤堀江
Original assignee: Funai Electric Co Ltd; Lexmark International Inc
Current assignee: Funai Electric Co Ltd; Lexmark International Inc
Priority date: 2006-11-06
Filing date: 2006-11-06
Publication date: 2008-05-22

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device with a simple and inexpensive structure capable of preventing a reverse feed of a recording paper accumulated on a paper discharge tray. <P>SOLUTION: When the recording paper P is not present between a paper feed roller and a paper discharge roller 34, a position of a reverse feed preventing member 70 is in a state of rotating in a second direction (clockwise rotation) in accordance with descent of a spindle part 74 by its one weight. Thereby, a recording paper rear end abutting part 73 rises, and a part of the recording paper conveying path between the paper discharge roller 34 and a star roller 36 is closed. Then, when the paper discharge roller 34 rotates reversely, a rear end of the recording paper P is driven in a reverse feed direction by the paper discharge roller 34, and the rear end of the recording paper P abuts on the recording paper rear end abutting part 73 and the reverse feed of the recording paper P is prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、パーソナルコンピュータ又はデジタルカメラ等と接続され、これらから出力された画像データに基いて、記録紙に画像を形成する画像形成装置に関するものである。 The present invention relates to an image forming apparatus that is connected to a personal computer, a digital camera, or the like and forms an image on a recording sheet based on image data output from the personal computer.

従来から、画像形成装置は、給紙トレイに対向する位置に設けられたピックローラ、画像形成部の上流側近傍に設けられた給紙ローラ及び画像形成部の下流側に設けられた排紙ローラによって記録紙を搬送するように構成されている。通常、ピックローラは記録紙の表面側に、給紙ローラ及び排紙ローラは裏面側に配設されているところ、これらのローラを単一のモータによって駆動しようとする場合、後述するように、給紙の初期動作において給紙ローラ及び排紙ローラを逆転させる必要がある。ところが、給紙トレイの対応枚数よりも排紙トレイの対応枚数が少なく設定されている画像形成装置においては、排紙トレイに堆積されている画像形成済みの記録紙が、排紙ローラの逆転によって逆送されてしまうという不具合が発生する虞がある。 Conventionally, an image forming apparatus includes a pick roller provided at a position facing a paper feed tray, a paper feed roller provided near the upstream side of the image forming unit, and a paper discharge roller provided downstream of the image forming unit. Is configured to convey the recording paper. Usually, the pick roller is disposed on the front side of the recording paper, and the paper feed roller and the paper discharge roller are disposed on the back side. When these rollers are driven by a single motor, as described later, In the initial feeding operation, it is necessary to reverse the feed roller and the discharge roller. However, in an image forming apparatus in which the number of paper discharge trays is set to be smaller than the number of paper feed trays, the image-formed recording paper deposited on the paper discharge tray is rotated by the reverse of the paper discharge roller. There is a possibility that a problem of reverse sending occurs.

ところで、特許文献１には、弾性部材によって原稿の逆送を防止する原稿搬送装置が示されている。また、特許文献２には、排紙ローラにバネクラッチを介して逆戻り防止レバーが設けられている自動原稿送り装置が示されている。また、特許文献３には、排紙ローラの回転軸に、テーパ面とフラット面を持つ記録紙逆送防止部材が設けられた画像形成装置が示されている。
特開２００４−２３３４５１号公報特開２００４−１７５４６０号公報特開２００１−７２２６０号公報 By the way, Japanese Patent Application Laid-Open No. H10-228561 discloses a document conveying device that prevents a document from being reversely fed by an elastic member. Patent Document 2 discloses an automatic document feeder in which a discharge roller is provided with a reverse return prevention lever via a spring clutch. Patent Document 3 discloses an image forming apparatus in which a recording paper reverse feed preventing member having a tapered surface and a flat surface is provided on a rotation shaft of a paper discharge roller.
JP 2004-233451 A JP 2004-175460 A JP 2001-72260 A

しかしながら、上記特許文献１に示された原稿搬送機構を画像形成装置に適用した場合、薄手の記録紙が使用されたとき、弾性部材によって記録紙が損傷したり、紙詰まりが発生する虞がある。また、特許文献２に示された機構を画像形成装置に適用した場合、バネクラッチ等の部品が必要となり、画像形成装置の製造コストの高騰を招来する。また、特許文献３に示された画像形成装置にあっては、フラット面よりも上方に位置する記録紙の逆送を防止することができない。 However, when the document transport mechanism disclosed in Patent Document 1 is applied to an image forming apparatus, when thin recording paper is used, the recording paper may be damaged by an elastic member or a paper jam may occur. . In addition, when the mechanism disclosed in Patent Document 2 is applied to an image forming apparatus, parts such as a spring clutch are required, resulting in an increase in manufacturing cost of the image forming apparatus. Further, in the image forming apparatus disclosed in Patent Document 3, it is not possible to prevent reverse feeding of the recording paper positioned above the flat surface.

本発明は、上記課題を解決するためになされたものであり、簡素かつ安価な構造でありながらも、薄手の記録紙が用いられた場合であっても損傷を与えることなく、排紙トレイに堆積された記録紙の逆送を効果的に防止することができる画像形成装置を提供することを目的とする。 The present invention has been made in order to solve the above-described problems. Although the structure is simple and inexpensive, the present invention can be applied to a discharge tray without damaging even when thin recording paper is used. An object of the present invention is to provide an image forming apparatus capable of effectively preventing the reverse feeding of the deposited recording paper.

上記目的を達成するために請求項１の発明は、
記録紙を保持する給紙トレイと、この給紙トレイに保持された記録紙を搬送する記録紙搬送機構と、前記記録紙搬送機構によって搬送された記録紙に画像を形成する画像形成手段と、前記記録紙搬送機構及び画像形成手段の動作を制御する制御手段と、前記画像形成手段によって画像が形成された後、前記記録紙搬送機構によって排出された記録紙が堆積される排紙トレイと、前記各部を支持する筐体とを備え、
前記記録紙搬送機構は、前記給紙トレイに対向する位置に設けられ、該給紙トレイに保持された記録紙を装置本体の内部に送出するピックローラと、前記画像形成手段の上流側に設けられ、前記ピックローラによって送出された記録紙を前記画像形成手段の方向に送出する給紙ローラと、前記画像形成手段によって画像が形成された記録紙を排紙トレイの側に排出する排紙ローラと、記録紙をその画像が形成された表面の側から前記排紙ローラに押圧するスターローラと、前記ピックローラ、給紙ローラ及び排紙ローラを駆動する単一の駆動モータとを有し、
前記給紙トレイに保持された記録紙を搬送する初期動作において、前記ピックローラは正転方向に、前記給紙ローラ及び排紙ローラは逆転方向にそれぞれ回転駆動される画像形成装置において、
前記排紙ローラが逆転方向に回転駆動されたとき、前記排紙トレイの上に堆積されている記録紙が該排紙ローラによって逆方向に搬送されないように、前記給紙ローラと前記排紙ローラとの間に逆送防止部材をさらに備え、
前記逆送防止部材は、前記筐体によって回動自在に支持される回動軸と、前記排紙ローラよりも前記画像形成部の側に設けられ、前記給紙ローラによって正方向に搬送された記録紙の裏面が接触される記録紙裏面接触部と、前記排紙ローラと前記スターローラとの接点よりも前記排紙トレイの側に設けられ、前記排紙ローラによって逆方向に搬送された記録紙の後端が当接される記録紙後端当接部と、前記回動軸を挟んで前記記録紙後端当接部とは反対側に設けられた錘部とを有し、
記録紙が前記記録紙裏面接触部の上を正方向に搬送されているとき、該記録紙裏面接触部が記録紙に押圧されることにより、前記逆送防止部材が第１方向に回動して排紙ローラとスターローラとの間の記録紙搬送経路が開かれ、
記録紙の後端が前記記録紙裏面接触部の上を通過した後には、前記錘部が自重によって下降するのに伴って、前記逆送防止部材が前記第1方向とは逆の第２方向に回動し、前記記録紙後端当接部が前記排紙ローラと前記スターローラとの間の記録紙搬送経路の一部を閉じ、それによって記録紙の逆方向への搬送を防止し得るようにしたものである。 In order to achieve the above object, the invention of claim 1
A paper feed tray for holding the recording paper, a recording paper transport mechanism for transporting the recording paper held in the paper feed tray, an image forming means for forming an image on the recording paper transported by the recording paper transport mechanism, A control means for controlling operations of the recording paper transport mechanism and the image forming means; a paper discharge tray on which the recording paper discharged by the recording paper transport mechanism is deposited after an image is formed by the image forming means; A housing for supporting each part,
The recording paper transport mechanism is provided at a position facing the paper feed tray, and is provided upstream of the image forming unit and a pick roller for feeding the recording paper held in the paper feed tray to the inside of the apparatus main body. A paper feed roller for feeding the recording paper sent by the pick roller toward the image forming means, and a paper discharge roller for discharging the recording paper on which an image has been formed by the image forming means to the side of the paper discharge tray And a star roller that presses the recording paper from the surface side on which the image is formed to the paper discharge roller, and a single drive motor that drives the pick roller, paper feed roller, and paper discharge roller,
In an image forming apparatus in which the pick roller is rotated in the forward rotation direction and the paper supply roller and the discharge roller are rotated in the reverse direction in the initial operation of conveying the recording paper held in the paper feed tray.
When the paper discharge roller is rotated in the reverse direction, the paper feed roller and the paper discharge roller are arranged so that the recording paper deposited on the paper discharge tray is not conveyed in the reverse direction by the paper discharge roller. Further comprising a reverse feed prevention member,
The reverse feed preventing member is provided on the side of the image forming unit with respect to the rotation shaft that is rotatably supported by the housing and the paper discharge roller, and is conveyed in the forward direction by the paper feed roller. A recording paper back surface contact portion that contacts the back surface of the recording paper, and a recording sheet that is provided closer to the paper discharge tray than a contact point between the paper discharge roller and the star roller, and is conveyed in the reverse direction by the paper discharge roller. A recording paper rear end abutting portion with which the rear end of the paper abuts, and a weight portion provided on the opposite side of the recording paper rear end abutting portion with the rotation shaft interposed therebetween,
When the recording paper is conveyed in the forward direction on the recording paper back surface contact portion, the recording paper back surface contact portion is pressed against the recording paper, whereby the reverse feed preventing member rotates in the first direction. The recording paper transport path between the paper discharge roller and star roller is opened,
After the trailing edge of the recording paper passes over the recording paper back surface contact portion, the reverse feed preventing member is moved in the second direction opposite to the first direction as the weight portion is lowered by its own weight. The recording paper trailing edge contact portion closes a part of the recording paper conveyance path between the paper discharge roller and the star roller, thereby preventing the recording paper from being conveyed in the reverse direction. It is what I did.

請求項２の発明は、
記録紙を搬送する記録紙搬送機構と、前記記録紙搬送機構によって搬送された記録紙に画像を形成する画像形成手段と、前記画像形成手段によって画像が形成された後、前記記録紙搬送機構によって排出された記録紙が堆積される排紙トレイと、前記各部を支持する筐体とを備え、
前記記録紙搬送機構は、記録紙を装置本体の内部に送出するピックローラと、前記画像形成手段の上流側に設けられ、前記画像形成手段によって画像が形成された記録紙を排紙トレイの側に排出する排紙ローラとを有し、
前記給紙トレイに保持された記録紙を搬送する初期動作において、前記排紙ローラが逆転方向に回転駆動される画像形成装置において、
前記排紙ローラが逆転方向に回転駆動されたとき、前記排紙トレイの上に堆積されている記録紙が該排紙ローラによって逆方向に搬送されないように、前記給紙ローラと前記排紙ローラとの間に逆送防止部材をさらに備えたものである。 The invention of claim 2
A recording paper transport mechanism for transporting the recording paper, an image forming means for forming an image on the recording paper transported by the recording paper transport mechanism, and after the image is formed by the image forming means, the recording paper transport mechanism A paper discharge tray on which the discharged recording paper is deposited, and a housing that supports each of the parts,
The recording paper transport mechanism is provided on the upstream side of the pick roller for feeding the recording paper into the apparatus main body and the image forming means, and the recording paper on which the image is formed by the image forming means is disposed on the discharge tray side. And a paper discharge roller for discharging to
In an image forming apparatus in which the paper discharge roller is rotationally driven in the reverse direction in an initial operation of conveying the recording paper held in the paper feed tray.
When the paper discharge roller is rotated in the reverse direction, the paper feed roller and the paper discharge roller are arranged so that the recording paper deposited on the paper discharge tray is not conveyed in the reverse direction by the paper discharge roller. And a reverse feed preventing member.

請求項３の発明は、請求項２に記載の画像形成装置において、
前記記録紙搬送機構は、記録紙を前記排紙ローラに押圧するスターローラを有し、
前記逆送防止部材は、前記筐体によって回動自在に支持される回動軸と、前記排紙ローラと前記スターローラとの接点よりも前記排紙トレイの側に設けられ、前記排紙ローラによって逆方向に搬送された記録紙の後端が当接される記録紙後端当接部と、前記回動軸を挟んで前記記録紙後端当接部とは反対側に設けられた錘部とを有し、
前記錘部が自重によって下降するのに伴って、前記逆送防止部材が回動し、前記記録紙後端当接部が前記排紙ローラと前記スターローラとの間の記録紙搬送経路の一部を閉じるものである。 The invention of claim 3 is the image forming apparatus according to claim 2,
The recording paper transport mechanism has a star roller that presses the recording paper against the paper discharge roller,
The reverse feed preventing member is provided on a side of the paper discharge tray with respect to a rotary shaft that is rotatably supported by the casing, and a contact point between the paper discharge roller and the star roller, and the paper discharge roller And a weight provided on the opposite side of the recording paper rear end abutting portion across the rotation shaft. And
As the weight portion is lowered by its own weight, the reverse feed preventing member rotates, and the recording paper rear end contact portion is a part of the recording paper conveyance path between the paper discharge roller and the star roller. The part is closed.

請求項１の発明によれば、給紙ローラと排紙ローラとの間に逆送防止部材を備えているので、排紙ローラが逆転方向に回転駆動された場合であっても、排紙トレイの上に堆積されている記録紙が該排紙ローラによって逆方向に搬送されることがない。従って、排紙トレイに対応枚数以上の記録紙が堆積された状態で、装置を動作させても、排紙トレイ上の既に画像が形成された記録紙が逆方向に搬送され、その上に別の画像が上書きされることがなくなる。また、記録紙裏面接触部が給紙ローラによって正方向に搬送された記録紙の裏面と接触すると、記録紙裏面接触部が記録紙に押圧されることにより、逆送防止部材が第1方向に回動して排紙ローラとスターローラとの間の記録紙搬送経路が開かれるので、薄手の記録紙が用いられた場合であっても、記録紙が損傷したり紙詰まりが発生する虞がない。一方、記録紙の後端が記録紙裏面接触部の上を通過した後には、錘部が自重によって下降するのに伴って、逆送防止部材が第２方向に回動し、記録紙後端当接部が排紙ローラとスターローラとの間の記録紙搬送経路の一部が閉じられる。このとき、記録紙後端当接部が排紙ローラとスターローラとの接点よりも排紙トレイの側に設けられているので、記録紙の後端が排紙ローラとスターローラによって挟まれることがない。従って、簡素かつ安価な構成でありながらも、記録紙の逆方向への搬送を確実に防止することができる。 According to the first aspect of the present invention, since the reverse feed preventing member is provided between the paper feed roller and the paper discharge roller, even if the paper discharge roller is driven to rotate in the reverse direction, the paper discharge tray The recording paper deposited on the paper is not conveyed in the reverse direction by the paper discharge roller. Therefore, even when the apparatus is operated with a corresponding number of sheets or more of recording paper deposited on the paper discharge tray, the recording paper on which the image has already been formed on the paper discharge tray is conveyed in the reverse direction. Images will not be overwritten. Further, when the recording paper back surface contact portion comes into contact with the back surface of the recording paper conveyed in the forward direction by the paper feed roller, the recording paper back surface contact portion is pressed against the recording paper, so that the reverse feed preventing member is moved in the first direction. Since the recording paper conveyance path between the paper discharge roller and the star roller is opened by rotating, there is a risk that the recording paper may be damaged or a paper jam may occur even if thin recording paper is used. Absent. On the other hand, after the trailing edge of the recording paper has passed over the recording paper back surface contact portion, as the weight portion descends due to its own weight, the reverse feed preventing member rotates in the second direction, and the recording paper trailing edge The contact portion closes a part of the recording paper conveyance path between the paper discharge roller and the star roller. At this time, the rear end contact portion of the recording paper is provided on the side of the discharge tray with respect to the contact point between the discharge roller and the star roller, so that the rear end of the recording paper is sandwiched between the discharge roller and the star roller. There is no. Accordingly, it is possible to reliably prevent the recording paper from being conveyed in the reverse direction while having a simple and inexpensive configuration.

請求項２の発明によれば、給紙ローラと排紙ローラとの間に逆送防止部材を備えているので、排紙ローラが逆転方向に回転駆動された場合であっても、排紙トレイの上に堆積されている記録紙が該排紙ローラによって逆方向に搬送されることがない。従って、排紙トレイに対応枚数以上の記録紙が堆積された状態で、装置を動作させても、排紙トレイ上の既に画像が形成された記録紙が逆方向に搬送され、その上に別の画像が上書きされることがなくなる。 According to the second aspect of the present invention, since the reverse feed preventing member is provided between the paper feed roller and the paper discharge roller, even if the paper discharge roller is rotationally driven in the reverse direction, the paper discharge tray The recording paper deposited on the paper is not conveyed in the reverse direction by the paper discharge roller. Therefore, even if the apparatus is operated with a corresponding number of recording sheets or more deposited on the paper discharge tray, the recording paper on which the image has already been formed on the paper discharge tray is conveyed in the reverse direction. Images will not be overwritten.

請求項３の発明によれば、録紙の後端が記録紙裏面接触部の上を通過した後には、錘部が自重によって下降するのに伴って、逆送防止部材が回動し、記録紙後端当接部が排紙ローラとスターローラとの間の記録紙搬送経路の一部が閉じられる。このとき、記録紙後端当接部が排紙ローラとスターローラとの接点よりも排紙トレイの側に設けられているので、記録紙の後端が排紙ローラとスターローラによって挟まれることがない。従って、簡素かつ安価な構成でありながらも、記録紙の逆方向への搬送を確実に防止することができる。 According to the invention of claim 3, after the rear end of the recording paper passes over the recording paper back surface contact portion, the reverse feed preventing member rotates and moves as the weight portion descends by its own weight. A part of the recording paper conveyance path between the paper discharge roller and the star roller is closed at the paper rear end contact portion. At this time, the rear end contact portion of the recording paper is provided on the side of the discharge tray with respect to the contact point between the discharge roller and the star roller, so that the rear end of the recording paper is sandwiched between the discharge roller and the star roller. There is no. Accordingly, it is possible to reliably prevent the recording paper from being conveyed in the reverse direction while having a simple and inexpensive configuration.

本発明を実施するための最良の実施形態による画像形成装置の一例としてインクジェットプリンタについて図面を参照して説明する。図１はインクジェットプリンタを示している。インクジェットプリンタ１は、記録紙Ｐを保持する給紙トレイ２と、給紙トレイ２に保持された記録紙Ｐを装置本体の内部に搬送する記録紙搬送機構３と、記録紙搬送機構３によって搬送された記録紙Ｐの先端を検知する先端センサ３９と、記録紙搬送機構３によって搬送された記録紙Ｐに画像を形成する画像形成部（画像形成手段）４と、先端センサ３９から出力された信号に基いて、記録紙搬送機構３及び画像形成部４等の動作を制御する制御回路（制御手段）５と、画像形成部４によって画像が形成された後、記録紙搬送機構３によって排出された記録紙Ｐが堆積される排紙トレイ６と、上記各部を支持するための筐体７等によって構成されている。 An ink jet printer as an example of an image forming apparatus according to the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 shows an ink jet printer. The ink jet printer 1 includes a paper feed tray 2 that holds the recording paper P, a recording paper transport mechanism 3 that transports the recording paper P held in the paper feed tray 2 to the inside of the apparatus main body, and a recording paper transport mechanism 3 that transports the recording paper P. Output from the leading edge sensor 39, the leading edge sensor 39 that detects the leading edge of the recording paper P, the image forming unit (image forming means) 4 that forms an image on the recording paper P transported by the recording paper transport mechanism 3, and the leading edge sensor 39. Based on the signal, a control circuit (control means) 5 that controls operations of the recording paper transport mechanism 3 and the image forming unit 4 and the image forming unit 4 form an image, and then the recording paper transport mechanism 3 discharges the image. The paper discharge tray 6 on which the recording paper P is deposited, and a housing 7 for supporting the above-described parts, and the like.

給紙トレイ２は、インクジェットプリンタ１の後部に設けられており、所定サイズの封筒を含む各種の記録紙Ｐを鉛直方向に対して所定の後傾角度の起立姿勢で保持する。 The paper feed tray 2 is provided at the rear part of the ink jet printer 1 and holds various recording papers P including envelopes of a predetermined size in a standing posture with a predetermined rearward tilt angle with respect to the vertical direction.

記録紙搬送機構３は、給紙トレイ２に載置された記録紙Ｐを装置本体の内部に送出するピックローラ３１と、画像形成部４の上流側に設けられ、ピックローラ３１によって送出された記録紙Ｐを画像形成部４の側に送出する給紙ローラ３２と、画像形成部４によって画像が形成された記録紙Ｐを排出するための排紙ローラ３４と、ピックローラ３１、給紙ローラ３２及び排紙ローラ３４を駆動するためのフィードモータ３５と、排紙ローラ３４に記録紙Ｐを押圧するスターローラ３６等によって構成されている。 The recording paper transport mechanism 3 is provided on the upstream side of the image forming unit 4 and the pick roller 31 that sends the recording paper P placed on the paper feed tray 2 to the inside of the apparatus main body, and is sent by the pick roller 31. A paper feed roller 32 for sending the recording paper P to the image forming unit 4 side, a paper discharge roller 34 for discharging the recording paper P on which an image has been formed by the image forming unit 4, a pick roller 31, and a paper feed roller 32, a feed motor 35 for driving the paper discharge roller 34, a star roller 36 for pressing the recording paper P against the paper discharge roller 34, and the like.

先端センサ３９は、給紙ローラ３２の上流側の近傍に配設されており、ピックローラ３１によって送出された記録紙Ｐの先端を検出し、所定の電気信号を制御回路５に出力する。画像形成部4は、インクが充填されたインクカートリッジ４０と、インクカートリッジ４０を支持しながら、記録紙Ｐの搬送方向Ａ（副走査方向）に直交する主走査方向Ｂ（図５参照）に往復移動するキャリッジ４１と、キャリッジ４１を駆動するキャリッジ駆動モータ４２等によって構成されている。インクカートリッジ４０の下面には、記録紙Ｐにインクを吐出するプリントヘッド４３が設けられている。プリントヘッド４３は、先端センサ３９によって先端が検知された後、さらに所定の距離だけ搬送された記録紙Ｐにインクを吐出して画像を形成する。キャリッジ４１は、主走査方向に平行に配設されたシャフト４４によって往復移動自在に支持され、キャリッジ駆動モータ４２に駆動されて移動する。キャリッジ駆動モータ４２の出力は、ベルト等を介してキャリッジ４１に伝達される。フィードモータ３５、キャリッジ駆動モータ４２及びプリントヘッド４３は、制御回路５によって制御される。 The leading edge sensor 39 is disposed in the vicinity of the upstream side of the paper feed roller 32, detects the leading edge of the recording paper P sent out by the pick roller 31, and outputs a predetermined electric signal to the control circuit 5. The image forming unit 4 reciprocates in the main scanning direction B (see FIG. 5) orthogonal to the transport direction A (sub-scanning direction) of the recording paper P while supporting the ink cartridge 40 filled with ink and the ink cartridge 40. A carriage 41 that moves, a carriage drive motor 42 that drives the carriage 41, and the like are included. A print head 43 that ejects ink onto the recording paper P is provided on the lower surface of the ink cartridge 40. After the leading edge is detected by the leading edge sensor 39, the print head 43 further discharges ink onto the recording paper P conveyed by a predetermined distance to form an image. The carriage 41 is reciprocally supported by a shaft 44 disposed in parallel with the main scanning direction, and is moved by being driven by a carriage drive motor 42. The output of the carriage drive motor 42 is transmitted to the carriage 41 via a belt or the like. The feed motor 35, the carriage drive motor 42 and the print head 43 are controlled by the control circuit 5.

制御回路５は、例えば、ＰＷＭ制御によってフィードモータ３５を制御する。すなわち、フィードモータ３５の駆動電圧を上げることにより、ＰＷＭデューティが増加し、フィードモータ３５の回転数が上昇する。逆に、フィードモータ３５の駆動電圧を下げることにより、ＰＷＭデューティが減少し、フィードモータ３５の回転数が下降する。 The control circuit 5 controls the feed motor 35 by, for example, PWM control. That is, by increasing the drive voltage of the feed motor 35, the PWM duty increases and the rotation speed of the feed motor 35 increases. Conversely, by lowering the drive voltage of the feed motor 35, the PWM duty is reduced and the rotation speed of the feed motor 35 is lowered.

図２及び図３は、記録紙搬送機構３におけるピックローラ３１、給紙ローラ３２及び排紙ローラ３４を回転駆動するための駆動ギア列の構成とその動作を示している。図２は、給紙トレイ２に保持された記録紙Ｐを搬送するときの記録紙搬送機構３の初期動作を、図３はその後の記録紙搬送機構３の動作を示している。ここで、上記初期動作とは、給紙トレイ２に保持された記録紙Ｐがピックローラ３１によって送出され、その先端が給紙ローラ３２に達するまでの動作をいうものとする。 2 and 3 show the configuration and operation of a drive gear train for rotationally driving the pick roller 31, the paper feed roller 32, and the paper discharge roller 34 in the recording paper transport mechanism 3. FIG. FIG. 2 shows the initial operation of the recording paper transport mechanism 3 when transporting the recording paper P held on the paper feed tray 2, and FIG. 3 shows the subsequent operation of the recording paper transport mechanism 3. Here, the initial operation refers to an operation until the recording paper P held in the paper feed tray 2 is sent out by the pick roller 31 and the leading end thereof reaches the paper feed roller 32.

ピックローラ３１、給紙ローラ３２及び排紙ローラ３４は、それぞれピックギア６１、給紙ギア（２段ギア）６２、排紙ギア６４に結合されている。給紙ギア６２は、フィードモータ３５の出力軸に嵌合されているピニオンギア６５と噛合っており、フィードモータ３５によって駆動される。また、給紙ギア６２と排紙ギア６４には、駆動力を伝達するためのベルト６３が装着されている。また、フィードモータ３５の駆動力は、ピニオンギア６５、２段ギア６６、６７、遊星ギア６８、ギア６９を介してピックギア６１に伝達される。遊星ギア６８は、２段ギア６７の回転軸６７ａに回動自在に軸支されたアーム部材６７ｂによって軸支されており、２段ギア６７の回転方向に応じてギア６９に駆動力を伝達したり、断絶したりする。また、ギア６９、ピックギア６１及びピックローラ３１は、支持アーム（図示せず）によってそれぞれ軸支されている。 The pick roller 31, the paper feed roller 32, and the paper discharge roller 34 are coupled to a pick gear 61, a paper feed gear (two-stage gear) 62, and a paper discharge gear 64, respectively. The paper feed gear 62 meshes with a pinion gear 65 fitted to the output shaft of the feed motor 35 and is driven by the feed motor 35. Further, a belt 63 for transmitting a driving force is attached to the paper feed gear 62 and the paper discharge gear 64. Further, the driving force of the feed motor 35 is transmitted to the pick gear 61 via the pinion gear 65, the second gears 66 and 67, the planetary gear 68 and the gear 69. The planetary gear 68 is pivotally supported by an arm member 67 b that is pivotally supported on a rotation shaft 67 a of the two-stage gear 67, and transmits a driving force to the gear 69 according to the rotation direction of the two-stage gear 67. Or cut off. The gear 69, the pick gear 61, and the pick roller 31 are each supported by a support arm (not shown).

給紙の初期状態においては、図２に示すように、フィードモータ３５の出力軸が反時計回りに回転し、その駆動力によってピックローラ３１は時計回りに回転し、給紙トレイ２に装填されている記録紙Ｐを送出する。このとき、給紙ローラ３２及び排紙ローラ３４も、時計回り、すなわち逆転方向に回転駆動される。 In the initial state of paper feeding, as shown in FIG. 2, the output shaft of the feed motor 35 rotates counterclockwise, and the pick roller 31 rotates clockwise by the driving force and is loaded in the paper feeding tray 2. The recording paper P being sent is sent out. At this time, the paper feed roller 32 and the paper discharge roller 34 are also driven to rotate clockwise, that is, in the reverse direction.

記録紙の先端が給紙ローラ３２に達すると、フィードモータ３５の出力軸の回転方向が時計回りに反転される。これにより、記録紙Ｐの搬送経路の下側（記録紙Ｐの裏面側）に位置する給紙ローラ３２及び排紙ローラ３４が反時計回り、すなわち正転方向に回転駆動され、記録紙Ｐが排紙トレイ６まで搬送される。なお、このときアーム部材６７ｂが矢印ｃ方向に回動されるため、遊星ギア６８とギア６９とは噛み合わず、ピックローラ３１には回転駆動力が伝達されない。 When the leading edge of the recording paper reaches the paper feed roller 32, the rotation direction of the output shaft of the feed motor 35 is reversed clockwise. As a result, the paper feed roller 32 and the paper discharge roller 34 located on the lower side of the conveyance path of the recording paper P (the back side of the recording paper P) are driven to rotate counterclockwise, that is, in the normal rotation direction. It is conveyed to the paper discharge tray 6. At this time, since the arm member 67b is rotated in the direction of the arrow c, the planetary gear 68 and the gear 69 are not engaged with each other, and the rotational driving force is not transmitted to the pick roller 31.

図４は、排紙ローラ３４の周辺部を示している。排紙ローラ３４は、筐体７によって回転自在に軸支されている。スターローラ３６は、金属製のプレート部材３７によって回転自在に軸支されている。排紙ローラ３４を挟んで排紙トレイ６とは反対側、すなわち給紙ローラ３２と排紙ローラ３４との間には、記録紙Ｐの逆送を防止するための逆送防止部材７０が設けられている。 FIG. 4 shows the periphery of the paper discharge roller 34. The paper discharge roller 34 is rotatably supported by the housing 7. The star roller 36 is rotatably supported by a metal plate member 37. A reverse feed prevention member 70 for preventing the reverse feed of the recording paper P is provided on the opposite side of the paper discharge tray 6 across the paper discharge roller 34, that is, between the paper feed roller 32 and the paper discharge roller 34. It has been.

図５は、逆送防止部材７０とその周辺の筐体７を示している。また、図６は逆送防止部材７０を、図７は筐体７における逆送防止部材７０が組み込まれる部分をそれぞれ示している。逆送防止部材７０は、排紙ローラ３４及びスターローラ３６と干渉しないように、排紙ローラ３４及びスターローラ３６に対して主走査方向Ｂに所定の距離を隔てた位置において、筐体７に形成されている開口部７ａに装着されている。逆送防止部材７０は、その本体部分から水平方向に延出された回動軸７１と、給紙ローラ３２によって正方向（矢印Ａ方向）に搬送された記録紙Ｐの裏面が接触される記録紙裏面接触部７２と、排紙ローラ３４によって逆方向（矢印Ａとは逆の方向）に搬送された記録紙Ｐの後端が当接される記録紙後端当接部７３と、図４中、逆送防止部材７０に時計回りのモーメントを付与するための錘部７４とを有している。回動軸７１は、筐体７に形成されている軸受け部７ｂに装着されている。記録紙裏面接触部７２は、排紙ローラ３４よりも画像形成部４の側において、記録紙Ｐの搬送方向Ａに対して所定の迎角をもって斜面状に形成されている。記録紙後端当接部７３は、排紙ローラ３４とスターローラ３６との接点Ｔよりも排紙トレイ６の側において、逆方向に搬送された記録紙Ｐが略垂直に当接するように形成されている。錘部７４は、回動軸７１を挟んで記録紙後端当接部７３とは反対側に設けられている。 FIG. 5 shows the reverse feed preventing member 70 and the surrounding housing 7. FIG. 6 shows a reverse feed preventing member 70, and FIG. 7 shows a portion of the housing 7 into which the reverse feed preventing member 70 is incorporated. The reverse feed preventing member 70 is attached to the housing 7 at a position spaced a predetermined distance in the main scanning direction B from the paper discharge roller 34 and the star roller 36 so as not to interfere with the paper discharge roller 34 and the star roller 36. Attached to the formed opening 7a. The reverse feed preventing member 70 is a recording in which the rotating shaft 71 extending in the horizontal direction from the main body portion and the back surface of the recording paper P conveyed in the forward direction (arrow A direction) by the paper feed roller 32 are in contact. A paper back contact portion 72, a recording paper rear end contact portion 73 with which the rear end of the recording paper P conveyed in the reverse direction (the direction opposite to the arrow A) by the paper discharge roller 34, and FIG. It has a weight portion 74 for applying a clockwise moment to the reverse feed preventing member 70. The rotating shaft 71 is attached to a bearing portion 7 b formed in the housing 7. The recording paper back surface contact portion 72 is formed in a slope shape with a predetermined angle of attack with respect to the conveyance direction A of the recording paper P on the image forming portion 4 side of the paper discharge roller 34. The recording paper rear end abutting portion 73 is formed so that the recording paper P conveyed in the opposite direction is in a substantially vertical contact with the discharge tray 6 side of the contact T between the discharge roller 34 and the star roller 36. Has been. The weight portion 74 is provided on the opposite side of the recording paper rear end contact portion 73 with the rotation shaft 71 interposed therebetween.

図８及び図９は、記録紙Ｐが正方向に搬送されるときの逆送防止部材７０の動作を示している。記録紙Ｐは、給紙ローラ３２（図１参照）によって、排紙ローラ３４まで搬送される。このとき、図８に示すように、逆送防止部材７０は、錘部７４の自重によって時計回りのモーメントを受け、記録紙裏面接触部７２及び記録紙後端当接部７３が上昇し、排紙ローラ３４とスターローラ３６との間を含む記録紙搬送経路の一部が閉じられた状態となっている。この状態からさらに記録紙Ｐが正方向に搬送されると、その先端が記録紙裏面接触部７２と接触し、記録紙裏面接触部７２を下方に押圧する。これに伴い、図９に示すように、逆送防止部材７０が第１方向（反時計回り）に回動して排紙ローラ３４とスターローラ３６との間の記録紙搬送経路が開かれ、記録紙Ｐが通過可能となる。記録紙Ｐの後端が記録紙裏面接触部７２を通過した後、逆送防止部材７０は、錘部７４の自重によって下降するのに伴って、第２方向（時計回り）に回動する。これにより、記録紙後端当接部７３が上昇し、排紙ローラ３４とスターローラ３６との間の記録紙搬送経路の一部が閉じられる。このように逆送防止部材７０の第２方向への回動は、錘部７４がその自重によって下降するのに伴ってなされる。このため、逆送防止部材７０を駆動する駆動機構を別途設ける必要がない。また、錘部７４の重さを適宜設定することにより、薄手の記録紙に対応させて少ない力で逆送防止部材７０を第１方向に回動可能とすることができ、記録紙Ｐの損傷と紙詰まりを防止できる。 8 and 9 show the operation of the reverse feed preventing member 70 when the recording paper P is conveyed in the forward direction. The recording paper P is conveyed to the paper discharge roller 34 by the paper supply roller 32 (see FIG. 1). At this time, as shown in FIG. 8, the reverse feed preventing member 70 receives a clockwise moment by the weight of the weight portion 74, and the recording paper back surface contact portion 72 and the recording paper trailing edge contact portion 73 are lifted and discharged. A part of the recording paper conveyance path including the space between the paper roller 34 and the star roller 36 is closed. When the recording paper P is further conveyed in the forward direction from this state, the leading end thereof contacts the recording paper back surface contact portion 72 and presses the recording paper back surface contact portion 72 downward. Along with this, as shown in FIG. 9, the reverse feed preventing member 70 rotates in the first direction (counterclockwise) to open the recording paper conveyance path between the paper discharge roller 34 and the star roller 36, The recording paper P can pass through. After the trailing edge of the recording paper P passes through the recording paper back surface contact portion 72, the reverse feed preventing member 70 rotates in the second direction (clockwise) as it descends due to the weight of the weight portion 74. As a result, the recording paper trailing edge abutting portion 73 is raised, and a part of the recording paper conveyance path between the paper discharge roller 34 and the star roller 36 is closed. In this way, the reverse feed preventing member 70 is rotated in the second direction as the weight 74 is lowered by its own weight. For this reason, it is not necessary to separately provide a drive mechanism for driving the reverse feed preventing member 70. Further, by appropriately setting the weight of the weight portion 74, the reverse feed preventing member 70 can be rotated in the first direction with a small force corresponding to the thin recording paper, and the recording paper P is damaged. And can prevent paper jams.

図１０は、その後、給紙トレイ２に装填されている次の記録紙に画像を形成する際に、排紙ローラ３４が逆転したときの逆送防止部材７０の動作を示している。排紙トレイ１０に１０数枚程度の記録紙Ｐが堆積されると、記録紙Ｐの後端が排紙ローラ３４に駆動されて、記録紙Ｐは排紙ローラ３４とスターローラ３６との間の記録紙搬送経路に逆送される場合がある。ところが、既に逆送防止部材７０の第２方向への回動に伴って上昇された記録紙後端当接部７３が排紙ローラ３４とスターローラ３６との間の記録紙搬送経路の一部に介在しているので、記録紙Ｐの後端は記録紙後端当接部７３と当接し、記録紙Ｐがそれ以上逆送することが防止される。 FIG. 10 shows the operation of the reverse feed preventing member 70 when the paper discharge roller 34 is reversed when an image is formed on the next recording paper loaded in the paper feed tray 2 thereafter. When about ten or more sheets of recording paper P are deposited on the paper discharge tray 10, the trailing edge of the recording paper P is driven by the paper discharge roller 34, and the recording paper P is placed between the paper discharge roller 34 and the star roller 36. May be sent back to the recording paper transport path. However, the recording paper rear end abutting portion 73 that has already been lifted as the reverse feed preventing member 70 rotates in the second direction is a part of the recording paper transport path between the paper discharge roller 34 and the star roller 36. Therefore, the trailing edge of the recording paper P abuts on the recording paper trailing edge abutting portion 73, and the recording paper P is prevented from being fed back further.

以上のように、本実施形態のインクジェットプリンタ１によれば、給紙ローラ３２と排紙ローラ３４との間に逆送防止部材７０を備えているので、排紙ローラ３４が逆転方向に回転駆動された場合であっても、排紙トレイ６の上に堆積されている記録紙Ｐが排紙ローラ３４によって逆方向に搬送されることがない。従って、排紙トレイ６に対応枚数以上の記録紙Ｐが堆積された状態で、装置を動作させても、排紙トレイ６の上の既に画像が形成された記録紙Ｐに別の画像が上書きされることがなくなる。また、記録紙裏面接触部７２が給紙ローラ３２によって正方向に搬送された記録紙Ｐの裏面と接触すると、記録紙裏面接触部７２が記録紙Ｐに押圧されることにより、逆送防止部材７０が第1方向に回動して排紙ローラ３４とスターローラ３６との間の記録紙搬送経路が開かれるので、薄手の記録紙が用いられた場合であっても、記録紙が損傷したり紙詰まが発生する虞がない。一方、記録紙Ｐの後端が記録紙裏面接触部７２の上を通過した後には、錘部７４が自重によって下降するのに伴って、逆送防止部材７０が第２方向に回動し、記録紙後端当接部７３が排紙ローラ３４とスターローラ３６との間の記録紙搬送経路の一部が閉じられる。このとき、記録紙後端当接部７３が排紙ローラ３４とスターローラ３６との接点Ｔよりも排紙トレイ６の側に設けられているので、記録紙Ｐの後端が排紙ローラ３４とスターローラ３６によって挟まれることがない。従って、簡素かつ安価な構成でありながらも、記録紙Ｐの逆方向への搬送を確実に防止することができる。 As described above, according to the inkjet printer 1 of the present embodiment, since the reverse feed preventing member 70 is provided between the paper feed roller 32 and the paper discharge roller 34, the paper discharge roller 34 is driven to rotate in the reverse direction. Even in this case, the recording paper P deposited on the paper discharge tray 6 is not conveyed in the reverse direction by the paper discharge roller 34. Therefore, even when the apparatus is operated in a state where a corresponding number of recording sheets P are accumulated on the discharge tray 6, another image is overwritten on the recording sheet P on which the image has already been formed on the discharge tray 6. It will not be done. Further, when the recording paper back surface contact portion 72 comes into contact with the back surface of the recording paper P conveyed in the forward direction by the paper feed roller 32, the recording paper back surface contact portion 72 is pressed against the recording paper P, thereby causing a reverse feed preventing member. 70 rotates in the first direction to open the recording paper conveyance path between the paper discharge roller 34 and the star roller 36, so that even when thin recording paper is used, the recording paper is damaged. There is no risk of paper jams. On the other hand, after the trailing edge of the recording paper P passes over the recording paper back surface contact portion 72, the reverse feed preventing member 70 rotates in the second direction as the weight portion 74 is lowered by its own weight. The recording paper trailing edge contact portion 73 closes a part of the recording paper conveyance path between the paper discharge roller 34 and the star roller 36. At this time, since the recording paper rear end contact portion 73 is provided on the side of the paper discharge tray 6 with respect to the contact T between the paper discharge roller 34 and the star roller 36, the rear end of the recording paper P is the paper discharge roller 34. And the star roller 36 is not pinched. Therefore, although the configuration is simple and inexpensive, it is possible to reliably prevent the recording paper P from being conveyed in the reverse direction.

なお、本発明は上記実施形態の構成に限られることなく、少なくとも給紙ローラ３２と排紙ローラ３４との間に逆送防止部材７０を備えていればよい。また、本発明は、種々の変形が可能であり、例えば、ピックローラ３１、給紙ローラ３２及び排紙ローラ３４を回転駆動するための駆動ギア列の構成や、逆送防止部材７０の形状は、図２、６に示したものに限られることはない。 Note that the present invention is not limited to the configuration of the above-described embodiment, and it is sufficient that the reverse feed preventing member 70 is provided at least between the paper feed roller 32 and the paper discharge roller 34. The present invention can be variously modified. For example, the configuration of the drive gear train for rotationally driving the pick roller 31, the paper feed roller 32, and the paper discharge roller 34, and the shape of the reverse feed preventing member 70 are as follows. These are not limited to those shown in FIGS.

本発明の一実施形態による画像形成装置の一例であるインクジェットプリンタの構成を示す図。1 is a diagram illustrating a configuration of an ink jet printer that is an example of an image forming apparatus according to an embodiment of the present invention. FIG. ピックローラ、給紙ローラ、及び排紙ローラを駆動するための駆動ギア列の構成及び排紙ローラの逆転時における回転状態を示す側面図。FIG. 4 is a side view illustrating a configuration of a drive gear train for driving a pick roller, a paper feed roller, and a paper discharge roller, and a rotation state when the paper discharge roller is reversely rotated. 排紙ローラの正転時における同駆動ギア列の回転状態を示す側面図Side view showing the rotation state of the drive gear train during normal rotation of the paper discharge roller 排紙ローラの周辺部の構成を示す側面図。FIG. 3 is a side view illustrating a configuration of a peripheral portion of a paper discharge roller. 逆送防止部材とその周辺の筐体を示す斜視図。The perspective view which shows a reverse feed prevention member and the housing | casing of the periphery. 逆送防止部材の形状を示す斜視図。The perspective view which shows the shape of a reverse feed prevention member. 筐体における逆送防止部材が組み込まれる部分を示す斜視図。The perspective view which shows the part in which the reverse feed prevention member in a housing | casing is integrated. 記録紙Ｐが正方向に搬送されるときの逆送防止部材の動作を示す側面図。FIG. 6 is a side view showing the operation of the reverse feed preventing member when the recording paper P is conveyed in the forward direction. 図８に続く逆送防止部材の動作を示す側面図。The side view which shows operation | movement of the reverse feed prevention member following FIG. 排紙ローラが逆転したときの逆送防止部材の動作を示す側面図。The side view which shows operation | movement of the reverse feed prevention member when a paper discharge roller reversely rotates.

Explanation of symbols

１インクジェットプリンタ（画像形成装置）
２給紙トレイ
３記録紙搬送機構（記録紙搬送手段）
４画像形成部（画像形成手段）
５制御回路（制御手段）
６排紙トレイ
３１ピックローラ
３２給紙ローラ
３４排紙ローラ
３６スターローラ
７０逆送防止部材
７１回動軸
７２記録紙裏面接触部
７３記録紙後端当接部
７４錘部
Ｐ記録紙 1 Inkjet printer (image forming device)
2 Paper feed tray 3 Recording paper transport mechanism (recording paper transport means)
4 Image forming unit (image forming means)
5 Control circuit (control means)
6 Paper discharge tray 31 Pick roller 32 Paper feed roller 34 Paper discharge roller 36 Star roller 70 Reverse feed prevention member 71 Rotating shaft 72 Recording paper back surface contact part 73 Recording paper rear end contact part 74 Weight part P Recording paper

Claims

A paper feed tray for holding the recording paper, a recording paper transport mechanism for transporting the recording paper held in the paper feed tray, an image forming means for forming an image on the recording paper transported by the recording paper transport mechanism, A control means for controlling operations of the recording paper transport mechanism and the image forming means; a paper discharge tray on which the recording paper discharged by the recording paper transport mechanism is deposited after an image is formed by the image forming means; A housing for supporting each part,
The recording paper transport mechanism is provided at a position facing the paper feed tray, and is provided upstream of the image forming unit and a pick roller for feeding the recording paper held in the paper feed tray to the inside of the apparatus main body. A paper feed roller for feeding the recording paper sent by the pick roller toward the image forming means, and a paper discharge roller for discharging the recording paper on which an image has been formed by the image forming means to the side of the paper discharge tray And a star roller that presses the recording paper from the surface side on which the image is formed to the paper discharge roller, and a single drive motor that drives the pick roller, paper feed roller, and paper discharge roller,
In an image forming apparatus in which the pick roller is rotated in the forward rotation direction and the paper supply roller and the discharge roller are rotated in the reverse direction in the initial operation of conveying the recording paper held in the paper feed tray.
When the paper discharge roller is rotated in the reverse direction, the paper feed roller and the paper discharge roller are arranged so that the recording paper deposited on the paper discharge tray is not conveyed in the reverse direction by the paper discharge roller. Further comprising a reverse feed prevention member,
The reverse feed preventing member is provided on the side of the image forming unit with respect to the rotation shaft that is rotatably supported by the housing and the paper discharge roller, and is conveyed in the forward direction by the paper feed roller. A recording paper back surface contact portion that contacts the back surface of the recording paper, and a recording sheet that is provided closer to the paper discharge tray than a contact point between the paper discharge roller and the star roller, and is conveyed in the reverse direction by the paper discharge roller. A recording paper rear end abutting portion with which the rear end of the paper abuts, and a weight portion provided on the opposite side of the recording paper rear end abutting portion with the rotation shaft interposed therebetween,
When the recording paper is conveyed in the forward direction on the recording paper back surface contact portion, the recording paper back surface contact portion is pressed against the recording paper, whereby the reverse feed preventing member rotates in the first direction. The recording paper transport path between the paper discharge roller and star roller is opened,
After the trailing edge of the recording paper passes over the recording paper back surface contact portion, the reverse feed preventing member is moved in the second direction opposite to the first direction as the weight portion is lowered by its own weight. The recording paper trailing edge contact portion closes a part of the recording paper conveyance path between the paper discharge roller and the star roller, thereby preventing the recording paper from being conveyed in the reverse direction. An image forming apparatus characterized by being configured as described above.

A recording paper transport mechanism for transporting the recording paper, an image forming means for forming an image on the recording paper transported by the recording paper transport mechanism, and after the image is formed by the image forming means, the recording paper transport mechanism A paper discharge tray on which the discharged recording paper is deposited, and a housing that supports each of the parts,
The recording paper transport mechanism is provided on the upstream side of the pick roller for feeding the recording paper into the apparatus main body and the image forming means, and the recording paper on which the image is formed by the image forming means is disposed on the discharge tray side. And a paper discharge roller for discharging to
In an image forming apparatus in which the paper discharge roller is rotationally driven in the reverse direction in an initial operation of conveying the recording paper held in the paper feed tray.
When the paper discharge roller is rotated in the reverse direction, the paper feed roller and the paper discharge roller are arranged so that the recording paper deposited on the paper discharge tray is not conveyed in the reverse direction by the paper discharge roller. An image forming apparatus, further comprising a reverse feed preventing member.

The recording paper transport mechanism has a star roller that presses the recording paper against the paper discharge roller,
The reverse feed preventing member is provided on a side of the paper discharge tray with respect to a rotary shaft that is rotatably supported by the casing, and a contact point between the paper discharge roller and the star roller, and the paper discharge roller And a weight provided on the opposite side of the recording paper rear end abutting portion across the rotation shaft. And
As the weight portion is lowered by its own weight, the reverse feed preventing member rotates, and the recording paper rear end contact portion is a part of the recording paper conveyance path between the paper discharge roller and the star roller. The image forming apparatus according to claim 2, wherein the part is closed.