JP5783417B2 - Image forming apparatus - Google Patents
Image forming apparatus Download PDFInfo
- Publication number
- JP5783417B2 JP5783417B2 JP2011254486A JP2011254486A JP5783417B2 JP 5783417 B2 JP5783417 B2 JP 5783417B2 JP 2011254486 A JP2011254486 A JP 2011254486A JP 2011254486 A JP2011254486 A JP 2011254486A JP 5783417 B2 JP5783417 B2 JP 5783417B2
- Authority
- JP
- Japan
- Prior art keywords
- paper
- paper feed
- feed roller
- roller
- gear
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 230000002093 peripheral effect Effects 0.000 claims description 25
- 238000000926 separation method Methods 0.000 claims description 13
- 230000006835 compression Effects 0.000 description 17
- 238000007906 compression Methods 0.000 description 17
- 230000003028 elevating effect Effects 0.000 description 16
- 108091008695 photoreceptors Proteins 0.000 description 8
- 238000011144 upstream manufacturing Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Landscapes
- Paper Feeding For Electrophotography (AREA)
- Electrophotography Configuration And Component (AREA)
- Electrostatic Charge, Transfer And Separation In Electrography (AREA)
- Sheets, Magazines, And Separation Thereof (AREA)
Description
本発明は画像形成装置に関し、より詳細には、給紙ローラの周速度よりも転写ローラの周速度が速い電子写真方式の画像形成装置に関するものである。 The present invention relates to an image forming apparatus, and more particularly to an electrophotographic image forming apparatus in which a peripheral speed of a transfer roller is higher than a peripheral speed of a paper feed roller.
従来の電子写真方式の画像形成装置では、用紙トレイから給紙ローラによって用紙を１枚ずつ搬送路へ引き出し、複数の搬送ローラ対によって転写ローラへ搬送していた。ここで、用紙搬送方向下流側（以下、単に「下流側」と記すことがある）の搬送ローラ対によって用紙の先端が挟持され、且つ用紙搬送方向上流側（以下、単に「上流側」と記すことがある）の搬送ローラ対によって用紙の後端も挟持されている時がある。この時、上流側と下流側のローラ対の周速度に差があると、用紙に弛み又は張力が生じる。 In a conventional electrophotographic image forming apparatus, sheets are pulled out one by one from a sheet tray by a sheet feeding roller to a conveying path and conveyed to a transfer roller by a plurality of conveying roller pairs. Here, the leading edge of the sheet is sandwiched by a pair of conveyance rollers on the downstream side in the sheet conveyance direction (hereinafter sometimes simply referred to as “downstream side”), and the upstream side in the sheet conveyance direction (hereinafter simply referred to as “upstream side”). In some cases, the trailing edge of the sheet is also held by the pair of conveying rollers. At this time, if there is a difference in the peripheral speed between the upstream and downstream roller pairs, the paper is slackened or tensioned.
そこで、特許文献１では、下流側の搬送ローラ対の周速度を上流側の搬送ローラ対の周速度よりも速くすると共に、上流側の搬送ローラ対の回転軸とローラとの間にワンウェイクラッチを設けて、上流側の搬送ローラ対から用紙を容易に引き抜けるようにして、下流側の搬送ローラ対の駆動負荷上昇を抑えることが提案されている。 Therefore, in Patent Document 1, the peripheral speed of the downstream transport roller pair is made faster than the peripheral speed of the upstream transport roller pair, and a one-way clutch is installed between the rotation shaft of the upstream transport roller pair and the roller. It has been proposed to suppress the increase in the driving load of the downstream conveying roller pair by providing the sheet so that the sheet can be easily pulled out from the upstream conveying roller pair.
また、特許文献２では、給紙ローラにワンウェイクラッチを設けて、給紙ローラから用紙を容易に引き抜けるようにすると共に、給紙ローラのローラ軸と駆動軸との間に一定の角度範囲で相対的に回転可能とし、先行する用紙が下流側の搬送ローラ対による挟持・搬送によって給紙ローラから引き抜かれた後、所定の遅れを経て後続の用紙が搬送されるようにし、用紙間に所望の間隔を形成することが提案されている。 Further, in Patent Document 2, a one-way clutch is provided on the paper feed roller so that the paper can be easily pulled out from the paper feed roller, and a relative angle is fixed between the roller shaft of the paper feed roller and the drive shaft. After the preceding paper is pulled out from the paper feed roller by nipping / conveying by a pair of downstream conveying rollers, the subsequent paper is conveyed after a predetermined delay, and the desired paper is conveyed between the papers. It has been proposed to form intervals.
近年、画像形成装置においても装置の小型・軽量化が市場から強く求められている。そこで、給紙ローラから転写ローラまでの搬送経路を短くするとともに、給紙ローラから転写ローラまでの搬送ローラ対をすべてなくし、給紙ローラから転写ローラに用紙を直接搬送する構成が開発検討されている。 In recent years, there has been a strong demand from the market to reduce the size and weight of image forming apparatuses. In view of this, a configuration has been developed in which the transport path from the paper feed roller to the transfer roller is shortened, the transport roller pair from the paper feed roller to the transfer roller is eliminated, and the paper is transported directly from the paper feed roller to the transfer roller. Yes.
かかる構成においても、転写ローラの周速度を給紙ローラの周速度より速くした場合には、給紙ローラから用紙を引き抜くための転写ローラの駆動負荷上昇を抑えると同時に、用紙の安定搬送を図るために給紙ローラ側にワンウェイクラッチを設ける必要がある。 Even in such a configuration, when the peripheral speed of the transfer roller is higher than the peripheral speed of the paper feed roller, an increase in the driving load of the transfer roller for pulling out the paper from the paper feed roller is suppressed, and at the same time, the paper is stably conveyed. Therefore, it is necessary to provide a one-way clutch on the paper feed roller side.
しかしながら、ワンウェイクラッチを設けことは部品点数の増加につながり、装置の小型・軽量化に沿わなくなる。 However, the provision of the one-way clutch leads to an increase in the number of parts, and the device is not reduced in size and weight.
そこで、本発明の目的は、給紙ローラから転写ローラに用紙を直接搬送する画像形成装置において、部品点数を増加させることなく、しかも転写ローラでの用紙搬送を安定して行えるようにすることにある。 SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to make it possible to stably convey a sheet with a transfer roller without increasing the number of parts in an image forming apparatus that directly conveys a sheet from a sheet feeding roller to a transfer roller. is there.
前記目的を達成する本発明に係る画像形成装置は、給紙ローラから送り出された用紙を、像担持体と転写ローラとによって挟持し搬送しながら像担持体から用紙にトナー像を転写し、給紙ローラの周速度よりも転写ローラの周速度が速い電子写真方式の画像形成装置であって、用紙を積載し昇降自在な昇降板と、給紙ローラに対して接触位置と離間位置とに移動可能な用紙分離部材とを備え、昇降板上に積載された用紙を１枚給紙する度に給紙ローラと用紙分離部材とが離接し、給紙ローラは空転可能機構を介して駆動軸に取り付けられ、給紙ローラから送り出された用紙の先端が像担持体と転写ローラとによって挟持されてから、給紙ローラと用紙分離部材とが離間するまでの間、空転可能機構によって給紙ローラが空転することを特徴とする。 The image forming apparatus according to the present invention that achieves the above object transfers the toner image from the image carrier to the paper while nipping and transporting the paper fed from the paper feed roller between the image carrier and the transfer roller, and feeding the paper. An electrophotographic image forming apparatus in which the peripheral speed of the transfer roller is faster than the peripheral speed of the paper roller. Each time a sheet stacked on the lifting plate is fed, the sheet feeding roller and the sheet separating member come into contact with each other, and the sheet feeding roller is connected to the drive shaft via the idle mechanism. The paper feed roller is moved by the idling mechanism until the paper feed roller and the paper separation member are separated after the leading edge of the paper attached and fed from the paper feed roller is sandwiched between the image carrier and the transfer roller. Characterized by idling That.
そして、前記の空転可能機構は、前記駆動軸に設けられた半径方向外方に突出した凸部と、給紙ローラに形成された凹部又は切り欠き部とを有し、凹部又は切り欠き部の周方向の長さが、凸部の周方向の長さよりも長く、凹部又は切り欠き部の側壁と凸部とが当接するまで給紙ローラが空転する機構である。 The idle possible mechanism of the, said has a convex portion protruding radially outwardly provided on the drive shaft, and a recess or cutout portion which is formed on the paper feed roller, recess or cut-out of length in the circumferential direction is longer than the circumferential length of the convex portion, the sidewall and the convex portion of the recess or cutout portion is Ru mechanism der sheet feeding roller idles until abutment.
また、用紙分離部材は、昇降板の昇降に連動して、給紙ローラに対して離接するようにするのが好ましい。 Further, it is preferable that the sheet separating member is separated from and in contact with the sheet feeding roller in conjunction with the lifting and lowering of the lifting plate.
本発明の画像形成装置では、給紙ローラから転写ローラに用紙を直接搬送するので、用紙搬送路を短くでき、装置の小型・軽量化を図ることができる。また、用紙分離部材を給紙ローラに対して接触位置と離間位置とに移動可能とし、且つ給紙ローラを空転可能機構を介して駆動軸に取り付けたので、ワンウェイクラッチを取り付けることなく、像担持体と転写ローラとによる用紙の搬送における給紙ローラによる負荷を軽減・消滅させることができ、用紙の安定搬送が可能となる。これにより、用紙に転写される画像の位置ズレなどが防止でき高画質化が図れる。 In the image forming apparatus of the present invention, since the sheet is directly conveyed from the sheet feeding roller to the transfer roller, the sheet conveying path can be shortened, and the apparatus can be reduced in size and weight. In addition, since the paper separating member can be moved to the contact position and the separation position with respect to the paper feed roller, and the paper feed roller is attached to the drive shaft via the idling mechanism, it is possible to carry an image without attaching a one-way clutch. It is possible to reduce or eliminate the load caused by the paper feed roller in the conveyance of the sheet by the body and the transfer roller, and it is possible to stably convey the sheet. As a result, it is possible to prevent misalignment of the image transferred to the paper and to improve the image quality.
以下、本発明を実施例によりさらに詳しく説明するが本発明はこれらの例に何ら限定されるものではない。 EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these examples at all.
図１は、本発明に係る画像形成装置の一例を示すプリンターＤの概略構成図である。図１に示すプリンターＤは、トナー画像を担持し、反時計回りに回転駆動する円筒状の感光体（像担持体）１の周囲に、感光体１の表面を一様に帯電させる帯電ローラ２と、感光体１表面に光を照射して静電潜像を形成する露光装置３と、感光体１にトナーを供給し感光体１上の静電潜像を現像してトナー画像を形成する現像装置４と、現像装置４によって形成された感光体１上のトナー画像を用紙Ｐに転写する転写ローラ６とを備えている。 FIG. 1 is a schematic configuration diagram of a printer D showing an example of an image forming apparatus according to the present invention. A printer D shown in FIG. 1 carries a toner image, and a charging roller 2 that uniformly charges the surface of the photoconductor 1 around a cylindrical photoconductor (image carrier) 1 that rotates counterclockwise. And an exposure device 3 for irradiating the surface of the photoconductor 1 to form an electrostatic latent image, and supplying toner to the photoconductor 1 and developing the electrostatic latent image on the photoconductor 1 to form a toner image. A developing device 4 and a transfer roller 6 for transferring the toner image on the photoreceptor 1 formed by the developing device 4 to the paper P are provided.
また、装置下部には給紙部１０を備えている。給紙部１０は、用紙Ｐを積載する用紙トレイ１１と、用紙Ｐの搬送方向先端部を昇降させる昇降板１２と、給紙ローラ１３と、給紙ローラ１３に対して接触位置と離間位置とに移動する用紙分離部材１４と、用紙分離部材１４を給紙ローラ１３の方向に付勢する圧縮コイルばね１５とを有する。昇降板１２が上昇すると共に、用紙分離部材１４が給紙ローラ１３と接触位置になると、給紙ローラ１３によって最上の用紙から順に１枚ずつ搬送路に引き出される。 In addition, a sheet feeding unit 10 is provided at the lower part of the apparatus. The paper feed unit 10 includes a paper tray 11 on which the paper P is stacked, a lifting plate 12 that raises and lowers the front end of the paper P in the transport direction, a paper feed roller 13, and a contact position and a separation position with respect to the paper feed roller 13. And a compression coil spring 15 that urges the sheet separating member 14 in the direction of the paper feed roller 13. When the elevating plate 12 is raised and the sheet separating member 14 comes into contact with the sheet feeding roller 13, the sheet feeding roller 13 sequentially pulls out the sheets one by one from the uppermost sheet.
画像形成動作について説明する。まず、所定の周速度で回転する感光体１の外周面が帯電ローラ２によって一様に帯電される。次に、帯電された感光体１の表面に、例えばパーソナルコンピュータなどの外部装置から入力される画像データに基づいて露光装置３から光が照射されて感光体１に静電潜像が形成される。続いて、この静電潜像は、現像装置４から供給されるトナーによって可視像化される。このようにして感光体１の表面に形成されたトナー画像は感光体１の回転によって、感光体１と転写ローラ６とのニップ部（転写領域）に搬送される。転写ローラ６は、不図示の駆動モータによって回転すると共に、圧縮コイルばね（不図示）によって感光体１に圧接している。また、転写ローラ６には、不図示の電圧印加手段によって転写バイアス電圧が印加される。 An image forming operation will be described. First, the outer peripheral surface of the photoreceptor 1 rotating at a predetermined peripheral speed is uniformly charged by the charging roller 2. Next, the surface of the charged photoconductor 1 is irradiated with light from the exposure device 3 based on image data input from an external device such as a personal computer to form an electrostatic latent image on the photoconductor 1. . Subsequently, the electrostatic latent image is visualized with toner supplied from the developing device 4. The toner image formed on the surface of the photoreceptor 1 in this way is conveyed to the nip portion (transfer area) between the photoreceptor 1 and the transfer roller 6 by the rotation of the photoreceptor 1. The transfer roller 6 is rotated by a drive motor (not shown) and pressed against the photosensitive member 1 by a compression coil spring (not shown). Further, a transfer bias voltage is applied to the transfer roller 6 by a voltage applying unit (not shown).
一方、用紙トレイ１１に積載された用紙Ｐは、給紙ローラ１３によって最上の用紙から順に搬送路に引き出される。そして、タイミングセンサー１６によって用紙Ｐの先端位置が検知され、感光体１の回転タイミングに合わせて転写領域に搬送される。感光体１と転写ローラ６とのニップ部を用紙Ｐが通過する際に、転写ローラ６に転写バイアス電圧が印加され、感光体１に形成されたトナー画像が用紙Ｐに転写される。トナー画像が転写された用紙Ｐは定着装置７に搬送される。定着装置７において用紙Ｐは加熱・加圧されて用紙Ｐ上のトナー画像は用紙Ｐに溶融定着する。トナー画像が定着した用紙Ｐは排紙ローラ対８によって排紙トレイ９に排出される。 On the other hand, the sheets P stacked on the sheet tray 11 are sequentially drawn out from the uppermost sheet to the conveyance path by the sheet feeding roller 13. Then, the leading end position of the paper P is detected by the timing sensor 16 and conveyed to the transfer area in accordance with the rotation timing of the photosensitive member 1. When the paper P passes through the nip portion between the photoconductor 1 and the transfer roller 6, a transfer bias voltage is applied to the transfer roller 6, and the toner image formed on the photoconductor 1 is transferred to the paper P. The sheet P on which the toner image is transferred is conveyed to the fixing device 7. In the fixing device 7, the paper P is heated and pressurized, and the toner image on the paper P is melted and fixed on the paper P. The paper P on which the toner image is fixed is discharged to the paper discharge tray 9 by the paper discharge roller pair 8.
プリンターＤでは、給紙ローラ１３から、感光体１と転写ローラ６とのニップ部までの間の搬送路には搬送ローラ対を設けていない。これにより搬送路を短くし装置の小型化を図っている。また、プリンターＤでは、転写ローラ６の周速度を給紙ローラ１３の周速度よりも速くしている。これにより、搬送路において用紙Ｐが弛んでループ状になるのを防ぎ、搬送路を最小限の容積に抑えて装置のさらなる小型化を図っている。 In the printer D, no conveyance roller pair is provided in the conveyance path from the paper feed roller 13 to the nip portion between the photosensitive member 1 and the transfer roller 6. This shortens the transport path and reduces the size of the apparatus. In the printer D, the peripheral speed of the transfer roller 6 is set higher than the peripheral speed of the paper feed roller 13. As a result, the paper P is prevented from being loosened and looped in the transport path, and the transport path is kept to a minimum volume, thereby further miniaturizing the apparatus.
一方で、用紙Ｐが、給紙ローラ１３と用紙分離部材１４との間と、感光体１と転写ローラ６との間の両方に挟持された状態が生じる。そして、用紙Ｐは、周速度の速い感光体１と転写ローラ６との搬送力によって、給紙ローラ１３と用紙分離部材１４との間から引き抜かれる。このとき感光体１と転写ローラ６との回動駆動負荷が上昇し、用紙Ｐの搬送速度が変化すると、用紙Ｐに転写されるトナー画像が乱れる。そこで、本発明では、用紙Ｐの先端が感光体１と転写ローラ６とのニップ部に挟持されると、用紙分離部材１４を接触位置から離隔位置に移動させるとともに、給紙ローラ１３を空転させて、感光体１と転写ローラ６との回動駆動負荷の上昇を抑え、用紙Ｐが安定して搬送されるようにした。以下、用紙分離部材１４を接触位置から離隔位置に移動させる機構及び給紙ローラ１３を駆動と空転させる機構について詳述する。 On the other hand, a state in which the paper P is sandwiched between the paper feed roller 13 and the paper separation member 14 and between the photoreceptor 1 and the transfer roller 6 occurs. Then, the paper P is pulled out from between the paper feed roller 13 and the paper separation member 14 by the conveying force between the photosensitive member 1 and the transfer roller 6 having a high peripheral speed. At this time, when the rotational driving load between the photosensitive member 1 and the transfer roller 6 increases and the conveyance speed of the paper P changes, the toner image transferred to the paper P is disturbed. Therefore, in the present invention, when the leading edge of the paper P is nipped by the nip portion between the photosensitive member 1 and the transfer roller 6, the paper separation member 14 is moved from the contact position to the separation position, and the paper feed roller 13 is idled. Thus, an increase in rotational driving load between the photosensitive member 1 and the transfer roller 6 is suppressed, and the paper P is stably conveyed. Hereinafter, a mechanism for moving the paper separation member 14 from the contact position to the separation position and a mechanism for driving and idling the paper feed roller 13 will be described in detail.
図２及び図３に、給紙部１０の部分斜視図を示す。用紙Ｐの搬送方向先端部を積載する昇降板１２は、図２の矢印Ａ方向から見て左右両側にある軸１２１ａ及び軸１２１ｂによって給紙ローラ側が昇降自在に支持されている。また、昇降板１２は、図３で示すように、圧縮コイルばね１２４によって給紙ローラ１３の方向へ常に付勢されている。 2 and 3 are partial perspective views of the paper feeding unit 10. The lifting plate 12 on which the front end of the sheet P in the transport direction is stacked is supported by the shaft 121a and the shaft 121b on the left and right sides as viewed from the direction of arrow A in FIG. Further, as shown in FIG. 3, the elevating plate 12 is always urged toward the paper feed roller 13 by a compression coil spring 124.
また、昇降板１２の左右側部には突出部１２２ａ，１２２ｂが形成されている。そして、ハウジングに回転自在に設けられたカムギア２４ａ，２４ｂのそれぞれの内側面にはカム突起２４１ａ，２４１ｂが形成されている。カムギア２４ａ，２４ｂが回転して、カム突起２４１ａ，２４１ｂが昇降板１２の突出部１２２ａ，１２２ｂに当接し、突出部１２２ａ，１２２ｂを押し下げることによって、昇降板１２は、圧縮コイルばね１２４の付勢力に抗して押し下げられる。図４に、このときの状態を示す垂直断面図を示す。そして、カムギア２４ａ，２４ｂが回転してカム突起２４１ａ，２４１ｂと突出部１２２ａ，１２２ｂとの係合状態が解消されると、昇降板１２は、圧縮コイルばね１２４の付勢力によって上方に移動し、給紙ローラ１３と圧接した状態となる。図５に、このときの状態を示す垂直断面図を示す。 In addition, protrusions 122 a and 122 b are formed on the left and right sides of the elevating plate 12. Cam protrusions 241a and 241b are formed on the inner surfaces of the cam gears 24a and 24b that are rotatably provided on the housing. The cam gears 24a and 24b rotate, the cam protrusions 241a and 241b come into contact with the projecting portions 122a and 122b of the elevating plate 12, and the projecting portions 122a and 122b are pushed down, so that the elevating plate 12 biases the compression coil spring 124. Pushed down against. FIG. 4 is a vertical sectional view showing the state at this time. When the cam gears 24a and 24b rotate and the engagement state between the cam protrusions 241a and 241b and the protrusions 122a and 122b is released, the elevating plate 12 moves upward by the urging force of the compression coil spring 124, The state is in pressure contact with the paper feed roller 13. FIG. 5 is a vertical sectional view showing the state at this time.
図６に示すように、給紙ローラ１３に圧接し、用紙Ｐを一枚ずつ搬送路に送り出す用紙分離部材１４は、給紙ローラ１３と接触して用紙Ｐを挟み込むフリクションパッド１４１とそれを保持するホルダー１４２とを有し、圧縮コイルばね１５によって給紙ローラ１３の方向に常に付勢されている。そして、ホルダー１４２に形成された突起１４２ａが、レバー保持部１８ａを支点として揺動する略Ｌ字状のレバー１８に当接している。また、レバー１８の自由端側は、昇降板１２の先端位置にあるレバー当接部１２３（図５に図示）の下方に位置している。 As shown in FIG. 6, the paper separating member 14 that presses the paper feed roller 13 and feeds the paper P one by one to the transport path contacts the paper feed roller 13 and holds the friction pad 141 that sandwiches the paper P. And is always urged in the direction of the paper feed roller 13 by the compression coil spring 15. The protrusion 142a formed on the holder 142 is in contact with the substantially L-shaped lever 18 that swings with the lever holding portion 18a as a fulcrum. Further, the free end side of the lever 18 is located below a lever contact portion 123 (shown in FIG. 5) at the tip position of the elevating plate 12.
図４に示したように、昇降板１２が、圧縮コイルばね１２４の付勢力に抗して押し下げられると、レバー１８の自由端側が昇降板１２のレバー当接部１２３によって押し下げられて、レバー１８はレバー保持部１８ａを支点として下方向へ移動する。レバー１８が下方に移動することによって、レバー１８に当接しているホルダー１４２の突起１４２ａが下方に押し下げられ、用紙分離部材１４は下方に移動する。これによって、用紙分離部材１４は、給紙ローラ１３から離れた離間位置となる。一方、図５に示したように、昇降板１２が、圧縮コイルばね１２４の付勢力によって上方に移動すると、レバー１８は通常状態に戻り、用紙分離部材１４は圧縮コイルばね１５によって給紙ローラ１３に圧接する。このように、用紙分離部材１４は、昇降板の昇降に連動して給紙ローラ１３に対して接触位置と離間位置とに移動する。 As shown in FIG. 4, when the lifting plate 12 is pushed down against the urging force of the compression coil spring 124, the free end side of the lever 18 is pushed down by the lever contact portion 123 of the lifting plate 12, and the lever 18 Moves downward with the lever holding portion 18a as a fulcrum. As the lever 18 moves downward, the projection 142a of the holder 142 that is in contact with the lever 18 is pushed downward, and the sheet separating member 14 moves downward. As a result, the sheet separating member 14 is separated from the sheet feeding roller 13. On the other hand, as shown in FIG. 5, when the elevating plate 12 moves upward by the urging force of the compression coil spring 124, the lever 18 returns to the normal state, and the sheet separating member 14 is fed by the compression coil spring 15 to the paper feed roller 13. Press contact. As described above, the sheet separating member 14 moves to the contact position and the separation position with respect to the sheet feeding roller 13 in conjunction with the lifting and lowering of the lifting plate.
次ぎに、カムギア２４ａ，２４ｂ及び給紙ローラ１３の回転駆動機構について説明する。図２及び図３に示すように、給紙ローラ１３は駆動軸１７に取り付けられており、駆動軸１７の両端に取り付けられた連結ギア２５ａ，２５ｂは、カムギア２４ａ，２４ｂと歯合している。図７に、図２の矢印Ｂ方向から見た斜視図を示す。なお、図７ではギア列を保持する本体の基板を省略している。 Next, the rotational drive mechanism of the cam gears 24a and 24b and the paper feed roller 13 will be described. As shown in FIGS. 2 and 3, the paper feed roller 13 is attached to the drive shaft 17, and the connecting gears 25a and 25b attached to both ends of the drive shaft 17 mesh with the cam gears 24a and 24b. . FIG. 7 is a perspective view seen from the direction of arrow B in FIG. In FIG. 7, the substrate of the main body that holds the gear train is omitted.
図７に示すように、ラチェット欠歯ギア２２と欠歯ギア２３、カムギア２４ａとが同軸上に取り付けられている。そして、ラチェット欠歯ギア２２と欠歯ギア２３とは、モータからの回転駆動を伝達する駆動ギア２１と歯合し、カムギア２４ａは、連結ギア２５ａと歯合している。ラチェット欠歯ギア２２の側面には、回転方向に向かって段差を設けた段部２２２が形成されている。段部２２２には、ソレノイド４０によって軸３１を中心として揺動するレバー３０の係止部３２が係合する。 As shown in FIG. 7, the ratchet toothless gear 22, the toothless gear 23, and the cam gear 24a are coaxially attached. The ratchet toothless gear 22 and the toothless gear 23 mesh with the drive gear 21 that transmits the rotational drive from the motor, and the cam gear 24a meshes with the connecting gear 25a. On the side surface of the ratchet toothless gear 22, a step portion 222 having a step in the rotational direction is formed. An engaging portion 32 of the lever 30 that swings about the shaft 31 is engaged with the step portion 222 by the solenoid 40.
図８に、図７に示すギア列の正面図を示す。軸３１を中心として揺動可能なレバー３０は、係止部３２と作用部３３とを有する。作用部３３は、ソレノイド４０の作動桿４１と連結している。ソレノイド４０に通電がなされると、圧縮コイルばね４２の付勢力に抗して作動桿４１が上方に移動し、レバー３０は軸３１を中心として反時計回りに回転する。これにより、段部２２２と係止部３２との係合が解除され、ラチェット欠歯ギア２２は回転可能状態となる。その後、ソレノイド４０が非通電状態になると、圧縮コイルばね４２の付勢力によって作動桿４１が下方に移動し、レバー３０は軸３１を中心として時計回りに回転し、係止部３２がラチェット欠歯ギア２２の軸部に摺接する。そして、ラチェット欠歯ギア２２が１回転したところで係止部３２と段部２２２とが再び係合し、ラチェット欠歯ギア２２の回転が止められる。なお、係止部３２と段部２２２とが係合している状態のとき、ラチェット欠歯ギア２２の欠歯部２２１が駆動ギア２１との噛み合い位置にあり、駆動ギア２１から回転駆動力はラチェット欠歯ギア２２には伝達されない。 FIG. 8 shows a front view of the gear train shown in FIG. The lever 30 that can swing around the shaft 31 includes a locking portion 32 and an action portion 33. The action portion 33 is connected to the operating rod 41 of the solenoid 40. When the solenoid 40 is energized, the operating rod 41 moves upward against the urging force of the compression coil spring 42, and the lever 30 rotates counterclockwise about the shaft 31. Thereby, engagement with the step part 222 and the latching | locking part 32 is cancelled | released, and the ratchet missing gear 22 will be in a rotatable state. Thereafter, when the solenoid 40 is de-energized, the operating rod 41 is moved downward by the urging force of the compression coil spring 42, the lever 30 is rotated clockwise around the shaft 31, and the locking portion 32 is ratchet toothless. The shaft 22 of the gear 22 is in sliding contact. Then, when the ratchet missing gear 22 makes one rotation, the locking portion 32 and the stepped portion 222 are engaged again, and the rotation of the ratchet missing gear 22 is stopped. When the locking portion 32 and the stepped portion 222 are engaged, the missing tooth portion 221 of the ratchet missing gear 22 is in the meshing position with the driving gear 21, and the rotational driving force from the driving gear 21 is It is not transmitted to the ratchet missing gear 22.
図９に、ラチェット欠歯ギア２２、欠歯ギア２３、カムギア２４ａの組立斜視図を示す。カムギア２４ａは、第１連結軸２４２によって欠歯ギア２３と連結され、欠歯ギア２３と一体で回転する。欠歯ギア２３には欠歯部２３１が形成されており、この部分では駆動ギア２１からの回転駆動力は伝達されない。ラチェット欠歯ギア２２は、第２連結軸２３４によって欠歯ギア２３と連結されているが、欠歯ギア２３に対して一定の角度範囲で自由に回動することができる。すなわち、欠歯ギア２３の側面に周方向に所定長さ形成された溝部２３３（図１０に図示）に、ラチェット欠歯ギア２２の側面に形成された突起２２３が係入し、溝部２３３（図１０に図示）の端部壁と突起２２３との間には圧縮コイルばね２６が介装されている。ラチェット欠歯ギア２２にも欠歯部２２１が形成されており、この部分では駆動ギア２１からの回転駆動力は伝達されない。 FIG. 9 shows an assembled perspective view of the ratchet toothless gear 22, the toothless gear 23, and the cam gear 24a. The cam gear 24 a is connected to the toothless gear 23 by the first connecting shaft 242 and rotates integrally with the toothless gear 23. A toothless portion 231 is formed in the toothless gear 23, and the rotational driving force from the drive gear 21 is not transmitted in this portion. Although the ratchet toothless gear 22 is connected to the toothless gear 23 by the second connecting shaft 234, the ratchet toothless gear 22 can freely rotate with respect to the toothless gear 23 within a certain angular range. That is, the protrusion 223 formed on the side surface of the ratchet toothless gear 22 is engaged with the groove portion 233 (shown in FIG. 10) formed in the circumferential direction on the side surface of the toothless gear 23, and the groove portion 233 (FIG. A compression coil spring 26 is interposed between the end wall of FIG. The ratchet missing gear 22 is also formed with a missing tooth portion 221, and the rotational driving force from the drive gear 21 is not transmitted in this portion.
図１０〜図１５によって、このような構造のギア駆動機構の動作説明をする。なお、これらの図（ａ），（ｂ），（ｃ）は、ラチェット欠歯ギア２２、欠歯ギア２３、カムギア２４ｂの同時期の動きを示している。 The operation of the gear drive mechanism having such a structure will be described with reference to FIGS. These drawings (a), (b), and (c) show the simultaneous movements of the ratchet missing gear 22, the missing gear 23, and the cam gear 24b.
図１０は、ギア駆動機構が待機状態のときの図である。同図（ａ）に示すように、ラチェット欠歯ギア２２は、レバー３０の係止部３２と段部２２２とが係合して回転が止められている。また、ラチェット欠歯ギア２２は、欠歯部２２１が駆動ギア２１と対向する位置にあり、駆動ギア２１からの回転駆動は伝達されていない。同図（ｂ）に示すように、欠歯ギア２３も、欠歯部２３１が駆動ギア２１と対向する位置にあり、駆動ギア２１から回転駆動は欠歯ギア２３にも伝達されない。この状態のとき、圧縮コイルばね２６は、溝部２３３の端部壁と突起２２３との間で圧縮された状態にある。同図（ｃ）に示すように、カムギア２４ｂは、カム突起２４１ｂが昇降板１２の突出部１２２ｂと係合した位置にあり、昇降板１２は下方に押し下げられた状態にある。この状態のとき、図４に示したように、用紙分離部材１４は給紙ローラ１３から離間した位置にある。 FIG. 10 is a diagram when the gear drive mechanism is in a standby state. As shown in FIG. 5A, the ratchet toothless gear 22 is stopped from rotating by the engaging portion 32 and the step portion 222 of the lever 30 engaging with each other. Further, the ratchet toothless gear 22 is in a position where the toothless portion 221 faces the drive gear 21, and the rotational drive from the drive gear 21 is not transmitted. As shown in FIG. 2B, the missing gear 23 is also in a position where the missing tooth portion 231 faces the drive gear 21, and the rotational drive is not transmitted from the drive gear 21 to the missing gear 23. In this state, the compression coil spring 26 is compressed between the end wall of the groove 233 and the protrusion 223. As shown in FIG. 5C, the cam gear 24b is in a position where the cam projection 241b is engaged with the protruding portion 122b of the elevating plate 12, and the elevating plate 12 is pushed downward. In this state, as shown in FIG. 4, the sheet separating member 14 is at a position separated from the sheet feeding roller 13.
次ぎに、図１１（ａ）に示すように、ソレノイド４０に通電されてレバー３０の係止部３２と段部２２２との係合が解除されると、ラチェット欠歯ギア２２は回転可能となる。一方、同図（ｂ）に示すように、欠歯ギア２３は未だ回転できない状態にあるので、圧縮コイルばね２６によって、ラチェット欠歯ギア２３は反時計回りに回転し、ラチェット欠歯バネ２３の歯部が駆動ギア２１と歯合するようになる。このとき、欠歯ギア２３及びカムギア２４ｂは、図１０（ｂ）、（ｃ）に示す待機状態のままである。 Next, as shown in FIG. 11A, when the solenoid 40 is energized and the engagement between the locking portion 32 and the step portion 222 of the lever 30 is released, the ratchet missing gear 22 becomes rotatable. . On the other hand, as shown in FIG. 4B, the toothless gear 23 is still in a state of being unable to rotate. Therefore, the ratchet toothless gear 23 is rotated counterclockwise by the compression coil spring 26, and the ratchet toothless spring 23 is rotated. The tooth portion comes into mesh with the drive gear 21. At this time, the missing gear 23 and the cam gear 24b remain in the standby state shown in FIGS. 10 (b) and 10 (c).
図１２（ａ）に示すように、駆動ギア２１からの回転駆動がラチェット欠歯ギア２２に伝達され、ラチェット欠歯ギア２２が回転して、突起２２３が欠歯ギア２３の側面突起２３２と当接すると、同図（ｂ）に示すように欠歯ギア２３も回転を始める。また、欠歯ギア２３の回転によってカムギア２４ａも回転する。そして、カムギア２４ａと歯合する連結ギア２５ａが回転し、これにより、連結ギア２５ａが取り付けられた駆動軸１７と、連結軸１７の他方端に取り付けられた連結ギア２５ｂが回転し、同図（ｃ）に示すように、連結ギア２５ｂと歯合するカムギア２４ｂが回転する。このとき、駆動軸１７に取り付けられている給紙ローラ１３も回転を始める。 As shown in FIG. 12 (a), the rotational drive from the drive gear 21 is transmitted to the ratchet missing gear 22, the ratchet missing gear 22 rotates, and the projection 223 contacts the side projection 232 of the missing gear 23. Upon contact, the missing gear 23 also starts rotating as shown in FIG. Further, the cam gear 24 a is also rotated by the rotation of the toothless gear 23. Then, the connecting gear 25a meshing with the cam gear 24a rotates, whereby the drive shaft 17 to which the connecting gear 25a is attached and the connecting gear 25b attached to the other end of the connecting shaft 17 are rotated. As shown in c), the cam gear 24b meshing with the connecting gear 25b rotates. At this time, the paper feed roller 13 attached to the drive shaft 17 also starts to rotate.
これにより、図１３（ｃ）に示すように、カムギア２４ａ，２４ｂのカム突起２４１ａ，２４１ｂと、昇降板１２の突出部１２２ａ，１２２ｂとの係合が解除されるので、昇降板１２は圧縮コイルばね１２４の付勢力によって上方に移動し、昇降板１２上に積載されている用紙Ｐが給紙ローラ１３に圧接するようになる。また同時に、レバー１８によって押し下げられていた用紙分離部材１４も、圧縮コイルばね１５の付勢力によって給紙ローラ１３と圧接する接触位置となる（図５を参照）。そして、給紙ローラ１３の回転によって用紙Ｐの給紙が始まる。なお、ソレノイド４０は、レバー３０の係止部３２と段部２２２との係合が解除された後、非通電状態に戻り、図１３（ａ）に示すように、レバー３０の係止部３２はラチェット欠歯ギア２２の軸と摺接する位置に戻る。 As a result, as shown in FIG. 13C, the engagement between the cam protrusions 241a and 241b of the cam gears 24a and 24b and the protrusions 122a and 122b of the lift plate 12 is released. The paper P is moved upward by the urging force of the spring 124, and the paper P loaded on the elevating plate 12 comes into pressure contact with the paper feed roller 13. At the same time, the sheet separating member 14 pushed down by the lever 18 is also brought into a contact position where it is brought into pressure contact with the sheet feeding roller 13 by the urging force of the compression coil spring 15 (see FIG. 5). Then, the paper P starts to be fed by the rotation of the paper feed roller 13. The solenoid 40 returns to the non-energized state after the engagement between the locking portion 32 of the lever 30 and the stepped portion 222 is released, and the locking portion 32 of the lever 30 as shown in FIG. Returns to the position in sliding contact with the axis of the ratchet toothless gear 22.
図１４（ａ）に示すように、ラチェット欠歯ギア２２がさらに回転し、ラチェット欠歯ギア２２の欠歯部２２１が駆動ギア２１と対向する位置に至ると、ラチェット欠歯ギア２２は駆動ギア２１からの回転駆動力を伝達されなくなる。このとき、同図（ｂ）に示すように、欠歯ギア２３は駆動ギア２１とまだ歯合しており回転を続けているため、圧縮コイルばね２６の弾性力でラチェット欠歯ギア２２はさらに少し回転し、レバー３０の係止部３２と段部２２２との係合し、ラチェット欠歯ギア２２の回転が完全に停止する。また、同図（ｃ）に示すように、カムギア２４ａ，２４ｂのカム突起２４１ａ，２４１ｂは、昇降板１２の突出部１２２ａ，１２２ｂの傾斜面と接触し、昇降板１２は徐々に下方に押し下げられる。また同時に、昇降板が下方に押し下げられると、図４に示したように、用紙分離部材１４もレバー１８によって給紙ローラ１３から離れる方向（下方）に押し下げられられる。これにより、給紙ローラ１３の回転による用紙Ｐの給紙は停止する。 As shown in FIG. 14A, when the ratchet missing gear 22 further rotates and the missing tooth portion 221 of the ratchet missing gear 22 reaches a position facing the drive gear 21, the ratchet missing gear 22 is driven. The rotational driving force from 21 is not transmitted. At this time, as shown in FIG. 5B, the toothless gear 23 is still in mesh with the drive gear 21 and continues to rotate, so that the ratchet toothless gear 22 is further rotated by the elastic force of the compression coil spring 26. The lever 30 is slightly rotated, and the engaging portion 32 and the step portion 222 of the lever 30 are engaged, and the rotation of the ratchet missing gear 22 is completely stopped. Further, as shown in FIG. 5C, the cam protrusions 241a and 241b of the cam gears 24a and 24b are in contact with the inclined surfaces of the protrusions 122a and 122b of the elevating plate 12, and the elevating plate 12 is gradually pushed down. . At the same time, when the elevating plate is pushed down, the paper separating member 14 is also pushed down (downward) from the paper feed roller 13 by the lever 18 as shown in FIG. As a result, the feeding of the paper P by the rotation of the paper feed roller 13 is stopped.
次いで、図１５（ｂ）に示すように、欠歯ギア２３の欠歯部２３１が駆動ギア２１と対向する位置になると、欠歯ギア２３は駆動ギアから回転駆動力を伝達されなくなる。そして、同図（ｃ）に示すように、カムギア２４ａ，２４ｂのカム突起２４１ａ，２４１ｂが突出部１２２ａ，１２２ｂと係合して、昇降板１２は押し下げられた状態となり、図４に示したように、用紙分離部材１４はレバー１８によって給紙ローラ１３から離れた離隔位置となる。このとき、圧縮コイルばね１２４の弾性力が、突出部１２２ａ、１２２ｂを介してカム突起２４１ａ、２４１ｂが伝わり、カムギア２４ａ、２４ｂが若干回転してカム突起２４１ａ，２４１ｂと突出部１２２ａ，１２２ｂとは定位置で係合し、図１０に示す待機状態に戻る。 Next, as shown in FIG. 15B, when the missing tooth portion 231 of the missing gear 23 is in a position facing the drive gear 21, the missing gear 23 can no longer transmit the rotational driving force from the drive gear. As shown in FIG. 4C, the cam protrusions 241a and 241b of the cam gears 24a and 24b engage with the protrusions 122a and 122b, so that the lift plate 12 is pushed down, as shown in FIG. In addition, the sheet separating member 14 is separated from the sheet feeding roller 13 by the lever 18. At this time, the elastic force of the compression coil spring 124 is transmitted to the cam protrusions 241a and 241b via the protrusions 122a and 122b, and the cam gears 24a and 24b are slightly rotated to define the cam protrusions 241a and 241b and the protrusions 122a and 122b. Engage in a fixed position and return to the standby state shown in FIG.
以上のようにラチェット欠歯ギア２２、欠歯ギア２３、カムギア２４ａ，２４ｂが１回転するごとに、用紙Ｐが用紙トレイ１１から引き出され、感光体１と転写ローラ６とのニップ部に搬送される。搬送された用紙Ｐの先端が感光体１と転写ローラ６とのニップ部で挟持された時、昇降板１２が押し下げられた状態となり、用紙分離部材１４が給紙ローラ１３から離れた離隔位置になれば、転写ローラ６の周速度を給紙ローラ１３の周速度よりも速くした場合であっても、給紙ローラ１３が転写ローラ６の回転駆動の負荷となることが回避される。 As described above, every time the ratchet toothless gear 22, the toothless gear 23, and the cam gears 24 a and 24 b make one rotation, the paper P is pulled out from the paper tray 11 and conveyed to the nip portion between the photosensitive member 1 and the transfer roller 6. The When the leading edge of the conveyed paper P is nipped by the nip portion between the photoreceptor 1 and the transfer roller 6, the elevating plate 12 is pushed down, and the paper separating member 14 is at a separation position away from the paper feeding roller 13. In this case, even when the peripheral speed of the transfer roller 6 is higher than the peripheral speed of the paper feed roller 13, it is possible to avoid the paper feed roller 13 from being a rotational driving load for the transfer roller 6.
しかしながら、給紙ローラ１３による用紙Ｐの搬送距離は、給紙のときのスリップや給紙ローラ外形のバラツキや用紙Ｐの積載束の厚みの変化などの影響を考慮して、給紙ローラ１３から転写ローラ６までの距離よりも長くする必要がある。この結果、給紙ローラ１２と用紙分離部材１４との間および感光体１と転写ローラ６との間の両方で用紙Ｐが挟持される時間が短いながら不可避的に生じる。このときは、給紙ローラ１３が転写ローラ６の回転駆動の負荷となり、用紙Ｐに転写される画像の位置ズレなどが生じるおそれがある。 However, the transport distance of the paper P by the paper feed roller 13 is determined from the paper feed roller 13 in consideration of effects such as slips during paper feed, variations in the outer shape of the paper feed roller, and changes in the thickness of the stack of paper P. It is necessary to make the distance longer than the distance to the transfer roller 6. As a result, the time for which the paper P is sandwiched between the paper feeding roller 12 and the paper separating member 14 and between the photosensitive member 1 and the transfer roller 6 is unavoidably short. At this time, the paper feed roller 13 becomes a load for rotational driving of the transfer roller 6, and there is a possibility that the image transferred onto the paper P is misaligned.
そこで本発明では、駆動軸１７と給紙ローラ１３の間に空転可能機構５０を介在させ、給紙ローラ１２と用紙分離部材１４との間および感光体１と転写ローラ６との間の両方で用紙Ｐが挟持され、転写ローラ６と用紙分離部材１４との間から用紙Ｐを引き抜く力が作用したときに、給紙ローラ１３を空転するようにして、給紙ローラ１３が転写ローラ６の回転駆動の負荷にならないようにした。図１６に、空転可能機構の一例を示す斜視図を示す。 Therefore, in the present invention, the idling mechanism 50 is interposed between the drive shaft 17 and the paper feed roller 13, and both between the paper feed roller 12 and the paper separating member 14 and between the photoreceptor 1 and the transfer roller 6. When the sheet P is sandwiched and a force for pulling out the sheet P from between the transfer roller 6 and the sheet separating member 14 is applied, the sheet feed roller 13 rotates idly so that the sheet feed roller 13 rotates. It was made not to become a driving load. FIG. 16 is a perspective view showing an example of the idling mechanism.
円筒状で、内周面に軸方向と平行な複数本の突条５１ａが形成され、外周面の軸方向端部に周方向長さｄ１の凸部５１ｂが形成された固定具５１が、断面が略コ字状の駆動軸１７に固定される。そして、この固定具５１に給紙ローラ１３が回転自在に外嵌されている。給紙ローラ１３は、円筒状の基部１３１と、基部１３１の外周に形成された弾性層１３２とを有する。基部１３１の軸方向端部には、周方向の長さＬの切り欠き部１３１ａが形成されている。この切り欠き部１３１ａの周方向長さＬは、凸部５１ｂの周方向長さｄ１よりも長く、固定具５１の凸部５１ｂが切り欠き部１３１ａ内に位置するように、給紙ローラ１３は固定具５１に取り付けられる。切り欠き部１３１ａの周方向長さＬと、凸部５１ｂの周方向長さｄ１との差が給紙ローラ１３が空転可能な長さｄ２となる。すなわち、切り欠き部１３１ａの側壁１３１ｃが凸部５１ｂと当接するまで、給紙ローラ１３は空転する。 Cylindrical, axially parallel to a plurality of protrusions 51a are formed on the inner peripheral surface, the fixture 51 the projections 51b are formed in the axial end portion of the outer peripheral surface circumferential length d 1 is, The cross section is fixed to the drive shaft 17 having a substantially U shape. The paper feed roller 13 is rotatably fitted on the fixture 51. The paper feed roller 13 includes a cylindrical base 131 and an elastic layer 132 formed on the outer periphery of the base 131. A notch 131 a having a circumferential length L is formed at the axial end of the base 131. Circumferential length L of the notch portion 131a is longer than the circumferential length d 1 of the convex portion 51b, so as to be positioned on the convex portion 51b is notched portion 131a of the fixture 51, the paper feed roller 13 Is attached to the fixture 51. The circumferential length L of the notch 131a, the difference between the circumferential length d 1 of the convex portion 51b is a paper feed roller 13 is possible length idle d 2. That is, the paper feed roller 13 rotates idly until the side wall 131c of the notch 131a contacts the convex 51b.
給紙ローラ１３は、図１６の矢印方向に回転して用紙Ｐを送り出す。駆動軸１７からの回転駆動力は、駆動軸１７と共に回転する固定具５１の凸部５１ｂが、基部１３１の切り欠き部１３１ａの回転方向下流側の側面１３１ｂに当接することによって給紙ローラ１３に伝達される。 The paper feed roller 13 rotates in the direction of the arrow in FIG. The rotational driving force from the drive shaft 17 is applied to the paper feed roller 13 by the convex portion 51b of the fixture 51 rotating together with the drive shaft 17 coming into contact with the side surface 131b on the downstream side in the rotational direction of the notch 131a of the base 131. Communicated.
転写ローラ６の周速度が給紙ローラ１３の周速度よりも速く設定されているので、用紙Ｐの先端が感光体１と転写ローラ６との間で挟持されると、用紙Ｐには転写ローラ６側に引っ張られる力が生じる。前述のように、給紙ローラ１３には、長さｄ２だけ空転可能であるので、このとき、給紙ローラ１３は駆動軸１７の回転速度よりも速く回転し、転写ローラ６の回転駆動の負荷上昇を回避する。 Since the peripheral speed of the transfer roller 6 is set faster than the peripheral speed of the paper feed roller 13, when the leading edge of the paper P is sandwiched between the photosensitive member 1 and the transfer roller 6, the transfer roller A force to be pulled to the 6 side is generated. As described above, since the paper feed roller 13 can idle by the length d 2 , the paper feed roller 13 rotates faster than the rotational speed of the drive shaft 17 at this time, and the transfer roller 6 rotates. Avoid increasing load.
給紙ローラ１３が空転可能な長さｄ２は、給紙ローラ１３による用紙Ｐの搬送距離と、給紙ローラ１３から転写ローラ６までの距離との差及び給紙ローラ１３と転写ローラ６との周速度差等を考慮し適宜決定すればよい。なお、通常、給紙ローラ１３の周速度は転写ローラ６のそれよりも２〜３％遅く設定される。 Sheet feeding roller 13 the length d 2 capable idle rotation has a transport distance of the sheet P by the paper feed roller 13, the difference and the sheet feeding roller 13 and the distance from the sheet feeding roller 13 to the transfer roller 6 and the transfer roller 6 What is necessary is just to determine suitably considering the peripheral speed difference of these. Normally, the peripheral speed of the paper feed roller 13 is set to be 2 to 3% slower than that of the transfer roller 6.
なお、空転可能機構５０における、固定具５１の凸部５１ｂと給紙ローラ１３の切り欠き部１３１ａと係合構造は、図１６に例示した構成の他に、例えば、固定具５１の外周面に軸方向に平行な凸部を設けると共に、給紙ローラ１３の基部１３１の内周面に、軸方向に平行な凹部を設け、凹部の周方向の長さを凸部の周方向の長さよりも長くした係合構造としてもよい。また、前記実施形態では、昇降板１２及び用紙分離部材１４の昇降を３枚のギアとカム機構を用いて１つの駆動源によって行っていたが、昇降板１２と用紙分離部材１４の昇降をそれぞれ別の駆動源によって行うようにしてもよい。 In the idling mechanism 50, the protrusion 51b of the fixture 51 and the notch 131a of the paper feed roller 13 and the engagement structure are, for example, on the outer peripheral surface of the fixture 51 in addition to the configuration illustrated in FIG. A convex portion parallel to the axial direction is provided, and a concave portion parallel to the axial direction is provided on the inner peripheral surface of the base 131 of the paper feed roller 13 so that the circumferential length of the concave portion is larger than the circumferential length of the convex portion. A long engagement structure may be used. In the above embodiment, the lifting plate 12 and the sheet separating member 14 are moved up and down by one drive source using three gears and a cam mechanism. However, the lifting plate 12 and the sheet separating member 14 are moved up and down, respectively. You may make it carry out by another drive source.
本発明の画像形成装置では、装置の小型・軽量化を図ることができると共に、ワンウェイクラッチを取り付けることなく、感光体と転写ローラとによる用紙の搬送における給紙ローラによる負荷を軽減・消滅させることができ、用紙の安定搬送が可能となる。これにより、用紙に転写される画像の位置ズレなどが防止でき高画質化が図れ有用である。 In the image forming apparatus of the present invention, it is possible to reduce the size and weight of the apparatus, and to reduce or eliminate the load caused by the sheet feeding roller in the conveyance of the sheet by the photosensitive member and the transfer roller without attaching a one-way clutch. The paper can be stably conveyed. Thereby, it is possible to prevent the positional deviation of the image transferred to the paper and to improve the image quality, which is useful.
１ 感光体（像担持体）
６ 転写ローラ
Ｄ プリンター（画像形成装置）
Ｐ 用紙
１２ 昇降板
１３ 給紙ローラ
１４ 用紙分離部材
１７ 駆動軸
５０ 空転可能機構
５１ｂ 凸部
１３１ａ 切り欠き部
1 Photoconductor (image carrier)
6 Transfer roller D Printer (image forming device)
P paper 12 elevating plate 13 paper feed roller 14 paper separating member 17 drive shaft 50 idling mechanism 51b convex 131a notch
Claims (2)
用紙を積載し昇降自在の昇降板と、給紙ローラに対して接触位置と離間位置とに移動可能な用紙分離部材とを備え、昇降板上に積載された用紙を１枚給紙する度に給紙ローラと用紙分離部材とが離接し、給紙ローラは空転可能機構を介して駆動軸に取り付けられ、
給紙ローラから送り出された用紙の先端が像担持体と転写ローラとによって挟持されてから、給紙ローラと用紙分離部材とが離間するまでの間、空転可能機構によって給紙ローラが空転し、
前記空転可能機構が、前記駆動軸に設けられた半径方向外方に突出した凸部と、給紙ローラに形成された凹部又は切り欠き部とを有し、凹部又は切り欠き部の周方向の長さが、突部の周方向の長さよりも長く、凹部又は切り欠き部の側壁と凸部とが当接するまで給紙ローラが空転する機構である
ことを特徴とする画像形成装置。 The toner image is transferred from the image carrier to the paper while the paper fed from the paper feed roller is nipped and conveyed by the image carrier and the transfer roller, and the transfer roller has a higher peripheral speed than the paper feed roller. An electrophotographic image forming apparatus,
Each time a sheet stacked on the lifting plate is fed, the sheet includes a lifting plate that can be stacked and moved up and down, and a sheet separating member that can move to a contact position and a separation position with respect to the sheet feeding roller. The paper feed roller and the paper separation member are separated from each other, and the paper feed roller is attached to the drive shaft via an idle rotation mechanism
From the time when the leading edge of the paper fed from the paper feeding roller is sandwiched between the image carrier and the transfer roller until the paper feeding roller and the paper separating member are separated, the paper feeding roller idles by the idling mechanism ,
The idling mechanism has a convex portion that protrudes outward in the radial direction provided on the drive shaft, and a concave portion or a notch portion formed in the paper feed roller, and the circumferential direction of the concave portion or the notch portion is An image forming system characterized in that the length is longer than the circumferential length of the protrusion, and the paper feed roller idles until the side wall of the recess or notch and the protrusion come into contact with each other. apparatus.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2011254486A JP5783417B2 (en) | 2011-11-22 | 2011-11-22 | Image forming apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2011254486A JP5783417B2 (en) | 2011-11-22 | 2011-11-22 | Image forming apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2013107743A JP2013107743A (en) | 2013-06-06 |
| JP5783417B2 true JP5783417B2 (en) | 2015-09-24 |
Family
ID=48704929
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2011254486A Expired - Fee Related JP5783417B2 (en) | 2011-11-22 | 2011-11-22 | Image forming apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP5783417B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015117102A (en) * | 2013-12-18 | 2015-06-25 | コニカミノルタ株式会社 | Image formation device |
| JP6565313B2 (en) * | 2015-05-13 | 2019-08-28 | ブラザー工業株式会社 | Sheet supply apparatus and image forming apparatus |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3242168B2 (en) * | 1992-11-24 | 2001-12-25 | ブラザー工業株式会社 | Paper feeder |
| JPH07187416A (en) * | 1993-12-28 | 1995-07-25 | Matsushita Graphic Commun Syst Inc | Paper feeder |
| JPH08225168A (en) * | 1995-02-21 | 1996-09-03 | Canon Inc | Sheet material feeding device and image forming apparatus |
| JP2001225977A (en) * | 2000-02-17 | 2001-08-21 | Canon Inc | Paper feeder and image forming apparatus |
| JP3843730B2 (en) * | 2000-11-13 | 2006-11-08 | ブラザー工業株式会社 | Image forming apparatus and recording medium supply apparatus |
| JP4821133B2 (en) * | 2005-02-25 | 2011-11-24 | 富士ゼロックス株式会社 | Image forming apparatus |
| JP2007070064A (en) * | 2005-09-07 | 2007-03-22 | Canon Inc | Image forming apparatus and recording material conveyance control method |
-
2011
- 2011-11-22 JP JP2011254486A patent/JP5783417B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2013107743A (en) | 2013-06-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8387975B2 (en) | Sheet conveying apparatus and image forming apparatus | |
| JP5979922B2 (en) | Sheet feeding apparatus and image forming apparatus | |
| CN103373615B (en) | Sheet material conveyer, paper feed, image processing system | |
| JP6575749B2 (en) | Sheet feeding apparatus and image forming apparatus | |
| CN103838099B (en) | Image forming apparatus | |
| JP4006432B2 (en) | Sheet feeding apparatus and image forming apparatus | |
| JP5783417B2 (en) | Image forming apparatus | |
| JP2012201446A (en) | Sheet feeding apparatus, and image forming apparatus | |
| JP2001171859A (en) | Sheet feeding apparatus, image forming apparatus provided with the apparatus, and image reading apparatus | |
| JP5870055B2 (en) | Paper feeding device and image forming apparatus having the same | |
| US9738468B2 (en) | Sheet feeding apparatus and image forming apparatus | |
| JP5979389B2 (en) | Image forming apparatus | |
| JP2006315775A (en) | Image forming device | |
| JP2013112428A (en) | Paper feeding device and image forming device | |
| JP2015117102A (en) | Image formation device | |
| JP6045324B2 (en) | Sheet feeding apparatus and image forming apparatus | |
| JP2006103818A (en) | Recording medium supply apparatus and image forming apparatus | |
| JP7685359B2 (en) | Sheet conveying device | |
| JP5959931B2 (en) | Sheet feeding apparatus and image forming apparatus | |
| JP5925031B2 (en) | Sheet feeding apparatus and image forming apparatus | |
| JP2025082465A (en) | Sheet conveyance device | |
| JP2007091451A (en) | Image forming apparatus | |
| JP4689537B2 (en) | Image forming apparatus | |
| JP2022181486A (en) | Sheet feeding device and image forming device | |
| JP2010247929A (en) | Paper transport mechanism and image forming apparatus having the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A711 | Notification of change in applicant |
Free format text: JAPANESE INTERMEDIATE CODE: A712 Effective date: 20130418 |
|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20140625 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20150316 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20150326 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20150518 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20150625 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20150708 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 5783417 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| LAPS | Cancellation because of no payment of annual fees |