JP2014048597A - Pressure release device and image forming apparatus - Google Patents

Pressure release device and image forming apparatus Download PDF

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JP2014048597A
JP2014048597A JP2012193666A JP2012193666A JP2014048597A JP 2014048597 A JP2014048597 A JP 2014048597A JP 2012193666 A JP2012193666 A JP 2012193666A JP 2012193666 A JP2012193666 A JP 2012193666A JP 2014048597 A JP2014048597 A JP 2014048597A
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pressure
cam
pressure release
driven
drive
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Eidai Shiozu
英大 潮津
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Canon Inc
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Canon Inc
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Abstract

PROBLEM TO BE SOLVED: To provide a pressure release device in which impact noise generated by a follower member rotated ahead is reduced.SOLUTION: A pressure release device comprises: a film holder 52 which axially supports a fixing film 18 in a rotatable manner; a pressure spring 56 which presses the film holder 52 to pressure-contact the fixing film 18 with a pressure roller 19; and pressure release means which resists the pressure force of the pressure spring 56 to release a pressure-contact state between the fixing film 18 and the pressure roller 19. The pressure release means includes: a protrusion part 54a rotationally driven by a motor 30; a pressure release cam 53 which is axially supported by a driving shaft 54 of the protrusion part 54a in a rotatable manner, and provided so as to have a prescribed play in the rotation direction with respect to the protrusion part 54a and rotate following the driving shaft 54, and which includes a cam surface 53d sliding in contact with the pressure plate 51 provided at one end part of the pressure spring 56 and resisting the pressure force of the pressure spring 56 to release the pressure-contact state between the fixing film 18 and the pressure roller 19; and a buffer member 55 which controls the prescribed play in the rotation direction between the protrusion part 54a and the pressure release cam 53.

Description

本発明は、プリンタ、複写機、ファクシミリ装置等の画像形成装置に設けられる加圧解除装置に関するものである。   The present invention relates to a pressure release device provided in an image forming apparatus such as a printer, a copying machine, or a facsimile machine.

画像形成装置における加圧解除装置は、定着装置における定着圧の解除、プロセスカートリッジに設けられる感光ドラムと現像ローラとの接離等、様々な個所で利用されている。   The pressure releasing device in the image forming apparatus is used in various places such as releasing the fixing pressure in the fixing device and contacting and separating the photosensitive drum provided in the process cartridge and the developing roller.

例えば、定着装置では、モータの正逆転を利用して、モータの駆動力を加圧ローラの回転駆動と、加圧ローラと定着ローラとの定着圧の解除と、を選択的に行うものがある。   For example, there is a fixing device that selectively performs rotation driving of a pressure roller and release of fixing pressure between the pressure roller and the fixing roller by using forward / reverse rotation of the motor. .

例えば、特許文献1に記載された定着装置では、定着加圧状態で加圧ローラを駆動するときは、モータを正回転させて加圧ローラに回転駆動力を伝達し、加圧ローラと定着フィルムとの定着圧の解除は、欠歯ギアにより圧解除カムへの駆動を解除する。   For example, in the fixing device described in Patent Document 1, when the pressure roller is driven in a fixing pressure state, the motor is rotated forward to transmit a rotational driving force to the pressure roller. To release the fixing pressure, the drive to the pressure releasing cam is released by the missing gear.

定着加圧状態から圧解除状態に移行するときは、モータを逆回転させ、加圧ローラへと繋がる駆動伝達ギア列にあるワンウェイクラッチにより加圧ローラへの駆動伝達を解除し、圧解除ギア列の振り子ギアを切り替えることにより、圧解除カムへ駆動を伝える。   When shifting from the fixing pressure state to the pressure release state, the motor is rotated in reverse, the drive transmission to the pressure roller is released by the one-way clutch in the drive transmission gear train connected to the pressure roller, and the pressure release gear train The drive is transmitted to the pressure release cam by switching the pendulum gear.

圧解除状態から定着加圧状態に移行するときは、モータを正回転させ、圧解除ギア列の振り子ギアを切り替えることにより、圧解除カムへ駆動を伝え、圧解除カムが加圧位置に来たときに欠け歯ギアにより駆動を解除する。圧解除カムの半径が最大半径(離間位置)から半径が減少する変曲点を過ぎると、圧解除カムは加圧板の加圧力により、先回しされる。このときに振り子ギアの駆動連結が保持されるように揺動アームストッパを設けることで圧解除カムの先回りによる衝突音を回避する。   When shifting from the pressure release state to the fixing pressurization state, the motor is rotated forward and the pendulum gear of the pressure release gear train is switched to transmit the drive to the pressure release cam, and the pressure release cam has come to the pressure position. Occasionally, the drive is released by a chipped gear. When the radius of the pressure release cam passes the inflection point where the radius decreases from the maximum radius (separated position), the pressure release cam is rotated by the pressure applied by the pressure plate. At this time, a rocking arm stopper is provided so that the drive connection of the pendulum gear is maintained, thereby avoiding a collision sound due to the advance of the pressure release cam.

特開2011−59260号公報JP 2011-59260 A

しかしながら、前記特許文献1では、圧解除カムが加圧板により先回りされるときに、ギア列の駆動連結を保持したとしても、ギア列に存在する回転方向のガタ分は必ず先回りされてしまう。このために、先回りによる衝突音を充分に回避することが出来ない。特に、モータから圧解除カムまでに介在する部品が多くなればなる程、そのギア列で積み上げられる回転方向のガタは大きくなる。   However, in Patent Document 1, when the pressure release cam is advanced by the pressure plate, even if the drive connection of the gear train is maintained, the backlash in the rotational direction existing in the gear train is necessarily advanced. For this reason, it is not possible to sufficiently avoid the collision sound due to the forward movement. In particular, the more parts that are interposed from the motor to the pressure release cam, the greater the play in the rotational direction that is accumulated by the gear train.

本発明は前記課題を解決するものであり、その目的とするところは、先回りさせる従動部材による衝撃音を低減した加圧解除装置を提供することである。   The present invention solves the above-mentioned problems, and an object of the present invention is to provide a pressure release device that reduces the impact noise caused by the driven member that is rotated forward.

前記目的を達成するための本発明に係る加圧解除装置の代表的な構成は、固定位置に設けられる対象部材に対して接離可能に設けられる被加圧部材と、前記被加圧部材を回転自在に軸支する揺動部材と、前記揺動部材を付勢して前記被加圧部材を前記対象部材に対して圧接させる加圧手段と、前記加圧手段の付勢力に抗して前記被加圧部材と前記対象部材との圧接状態を解除する加圧解除手段とを備え、前記加圧解除手段は、駆動手段により回転駆動する駆動部材と、前記駆動部材の回転軸に回転自在に軸支され、前記駆動部材に対して回転方向に所定の遊びを持って従動回転可能に設けられ、前記加圧手段の一端部に設けられた当接部に当接摺動して前記加圧手段の付勢力に抗して前記被加圧部材と前記対象部材との圧接状態を解除するカム面を有する従動部材と、前記駆動部材と前記従動部材との回転方向の所定の遊びを制御する緩衝部材とを有することを特徴とする。   A typical configuration of the pressure release device according to the present invention for achieving the above object includes a member to be pressed provided so as to be able to contact and separate from a target member provided at a fixed position, and the member to be pressed. A swinging member that is rotatably supported, a pressurizing unit that biases the swinging member to press the pressed member against the target member, and a biasing force of the pressurizing unit A pressure release means for releasing the pressure contact state between the member to be pressurized and the target member, the pressure release means being rotatable about a drive member that is driven to rotate by the drive means and a rotation shaft of the drive member; Supported by the drive member so as to be driven to rotate with a predetermined play with respect to the drive member, and abuts and slides on a contact portion provided at one end of the pressurizing means. A force that releases the pressure contact state between the member to be pressed and the target member against the urging force of the pressure means. And having a driven member having a surface, and a buffer member for controlling the predetermined play in the rotational direction of said driven member and the drive member.

上記構成によれば、先回りさせる従動部材のみ緩衝部材で回転速度を減速させる。これにより衝撃音を低減することが出来る。   According to the above configuration, the rotational speed is reduced only by the shock-absorbing member for the driven member to be rotated forward. Thereby, the impact sound can be reduced.

本発明に係る加圧解除装置を備えた画像形成装置の構成を示す断面説明図である。1 is a cross-sectional explanatory view illustrating a configuration of an image forming apparatus including a pressure release device according to the present invention. 本発明に係る加圧解除装置を定着装置に設けた第1実施形態の構成を示す斜視説明図である。1 is an explanatory perspective view illustrating a configuration of a first embodiment in which a pressure release device according to the present invention is provided in a fixing device. 第1実施形態における加圧解除手段の構成を説明する斜視説明図である。It is a perspective explanatory view explaining the composition of the pressure release means in the first embodiment. 第1実施形態における加圧解除手段の定着圧解除動作を説明する断面説明図である。FIG. 5 is an explanatory cross-sectional view illustrating a fixing pressure releasing operation of a pressure releasing unit in the first embodiment. 本発明に係る加圧解除装置を定着装置に設けた第2実施形態の構成を示す斜視説明図である。FIG. 6 is a perspective explanatory view showing a configuration of a second embodiment in which a pressure release device according to the present invention is provided in a fixing device. 第2実施形態における加圧解除手段の構成を説明する斜視説明図である。It is an isometric view explanatory drawing explaining the structure of the pressure release means in 2nd Embodiment. 第2実施形態における加圧解除手段の定着圧解除動作を説明する断面説明図である。FIG. 10 is a cross-sectional explanatory view for explaining a fixing pressure releasing operation of a pressure releasing unit in the second embodiment. 第2実施形態における加圧解除手段の定着圧解除動作を説明する断面説明図である。FIG. 10 is a cross-sectional explanatory view for explaining a fixing pressure releasing operation of a pressure releasing unit in the second embodiment. 本発明に係る加圧解除装置を定着装置に設けた第3実施形態の構成を示す斜視説明図である。FIG. 6 is an explanatory perspective view illustrating a configuration of a third embodiment in which a pressure release device according to the present invention is provided in a fixing device. 第3実施形態における加圧解除手段の構成を説明する斜視説明図である。It is an isometric view explanatory drawing explaining the structure of the pressure release means in 3rd Embodiment. 第3実施形態における加圧解除手段の定着圧解除動作を説明する断面説明図である。FIG. 10 is a cross-sectional explanatory diagram for explaining a fixing pressure releasing operation of a pressure releasing unit in a third embodiment. 本発明に係る加圧解除装置を定着装置に設けた第4実施形態の構成を示す斜視説明図である。FIG. 10 is a perspective explanatory view showing a configuration of a fourth embodiment in which a pressure release device according to the present invention is provided in a fixing device. 第4実施形態における加圧解除手段の構成を説明する斜視説明図である。It is a perspective explanatory view explaining the composition of the pressure release means in a 4th embodiment. 第4実施形態における加圧解除手段の定着圧解除動作を説明する断面説明図である。It is sectional explanatory drawing explaining the fixing pressure cancellation | release operation | movement of the pressure release means in 4th Embodiment. 第4実施形態における加圧解除手段の定着圧解除動作を説明する断面説明図である。It is sectional explanatory drawing explaining the fixing pressure cancellation | release operation | movement of the pressure release means in 4th Embodiment. 本発明に係る加圧解除装置をプロセスカートリッジに設けた第5実施形態の構成を示す斜視説明図である。It is a perspective explanatory view showing the composition of a 5th embodiment which provided the pressure release device concerning the present invention in the process cartridge.

図により本発明に係る加圧解除装置を備えた画像形成装置の一実施形態を具体的に説明する。   An embodiment of an image forming apparatus provided with a pressure release device according to the present invention will be specifically described with reference to the drawings.

〔第1実施形態〕
先ず、図1〜図4を用いて本発明に係る加圧解除装置を備えた画像形成装置の第1実施形態の構成について説明する。図1は本実施形態の画像形成装置101の一例としてカラーレーザプリンタを示す。
[First Embodiment]
First, the configuration of a first embodiment of an image forming apparatus provided with a pressure release device according to the present invention will be described with reference to FIGS. FIG. 1 shows a color laser printer as an example of the image forming apparatus 101 of this embodiment.

<画像形成装置>
以下、画像形成装置101の全体的構成及びその機能について説明する。
<Image forming apparatus>
Hereinafter, the overall configuration and functions of the image forming apparatus 101 will be described.

図1に示す画像形成装置101は、該画像形成装置101本体に対して着脱自在なプロセスカートリッジ5Y,5M,5C,5Kを備えている。尚、説明の都合上、プロセスカートリッジ5Y,5M,5C,5Kをプロセスカートリッジ5で代表して説明する場合もある。他の各画像形成ユニットを構成する部品も同様に説明する。   An image forming apparatus 101 shown in FIG. 1 includes process cartridges 5Y, 5M, 5C, and 5K that are detachable from the main body of the image forming apparatus 101. For convenience of explanation, the process cartridges 5Y, 5M, 5C, and 5K may be described as the process cartridge 5. The components constituting each of the other image forming units will be described in the same manner.

各プロセスカートリッジ5Y,5M,5C,5Kの下方にはレーザユニット7Y,7M,7C,7Kが配置されている。各レーザユニット7は、画像信号に基づく露光を表面に静電潜像が形成される像担持体となる感光ドラム1Y,1M,1C,1Kに対して行う。各感光ドラム1の表面は、帯電ローラ2Y,2M,2C,2Kによって所定の負極性の電位に帯電された後、レーザユニット7によってそれぞれ静電潜像が形成される。この静電潜像は現像ローラ3Y,3M,3C,3Kによって反転現像されて負極性のトナーが付着され、それぞれ、イエローY、マゼンタM、シアンC、ブラックKの各色のトナー画像が形成される。   Laser units 7Y, 7M, 7C, and 7K are disposed below the process cartridges 5Y, 5M, 5C, and 5K. Each laser unit 7 performs exposure based on the image signal to the photosensitive drums 1Y, 1M, 1C, and 1K that are image carriers on which electrostatic latent images are formed on the surface. The surface of each photosensitive drum 1 is charged to a predetermined negative potential by the charging rollers 2Y, 2M, 2C, and 2K, and then an electrostatic latent image is formed by the laser unit 7, respectively. This electrostatic latent image is reversely developed by the developing rollers 3Y, 3M, 3C, and 3K, and negative toner is attached to form toner images of yellow Y, magenta M, cyan C, and black K, respectively. .

中間転写ベルトユニット28は、中間転写ベルト8、駆動ローラ9、二次転写対向ローラ10を有して構成されている。また、各感光ドラム1に対向して、中間転写ベルト8の内側に一次転写ローラ6Y,6M,6C,6Kが配設されている。各一次転写ローラ6には図示しないバイアス印加手段により転写バイアスが印加される。   The intermediate transfer belt unit 28 includes an intermediate transfer belt 8, a drive roller 9, and a secondary transfer counter roller 10. Further, primary transfer rollers 6Y, 6M, 6C, and 6K are disposed inside the intermediate transfer belt 8 so as to face the respective photosensitive drums 1. A transfer bias is applied to each primary transfer roller 6 by a bias applying means (not shown).

各感光ドラム1は図1に示す矢印方向に回転し、中間転写ベルト8は図1の矢印a方向に回転する。そして、一次転写ローラ6に正極性のバイアスを印加することにより、各感光ドラム1の表面上に形成されたトナー画像は、感光ドラム1Yの表面上のトナー画像から順次、中間転写ベルト8の外周面上に一次転写される。そして、4色のトナー画像が重なった状態で二次転写ローラ11が対向する位置まで搬送される。   Each photosensitive drum 1 rotates in the arrow direction shown in FIG. 1, and the intermediate transfer belt 8 rotates in the arrow a direction in FIG. Then, by applying a positive bias to the primary transfer roller 6, the toner images formed on the surface of each photosensitive drum 1 are sequentially transferred from the toner image on the surface of the photosensitive drum 1 Y to the outer periphery of the intermediate transfer belt 8. Primary transfer on the surface. Then, the four color toner images are conveyed to a position where the secondary transfer roller 11 is opposed to each other.

記録材給送部29は、記録材Pを収容する給送カセット13から記録材Pを給送する給送ローラ14と、給送された記録材Pを搬送する搬送ローラ15とを有している。そして、記録材給送部29から給送された記録材Pはレジストローラ16によって二次転写ローラ11と中間転写ベルト8とのニップ部に搬送される。   The recording material feeding unit 29 includes a feeding roller 14 that feeds the recording material P from a feeding cassette 13 that houses the recording material P, and a transport roller 15 that transports the fed recording material P. Yes. Then, the recording material P fed from the recording material feeding unit 29 is conveyed to the nip portion between the secondary transfer roller 11 and the intermediate transfer belt 8 by the registration roller 16.

中間転写ベルト8から記録材Pへの転写においては、二次転写ローラ11に正極性のバイアスを印加する。これにより、二次転写ローラ11と中間転写ベルト8とのニップ部に搬送された記録材Pに中間転写ベルト8の外周面上の4色のトナー画像を二次転写する。   In transferring from the intermediate transfer belt 8 to the recording material P, a positive bias is applied to the secondary transfer roller 11. As a result, the four color toner images on the outer peripheral surface of the intermediate transfer belt 8 are secondarily transferred to the recording material P conveyed to the nip portion between the secondary transfer roller 11 and the intermediate transfer belt 8.

トナー画像を転写した後の記録材Pは、該記録材P上(記録材上)に形成されたトナー画像を定着する定着装置17に搬送される。定着装置17には、固定位置に設けられる対象部材であって加圧回転体となる加圧ローラ19と、該加圧ローラ19に対して接離可能に設けられる被加圧部材であって定着回転体となる定着フィルム18とが設けられている。そして、定着フィルム18と加圧ローラ19との定着ニップ部25を搬送される記録材Pの表面に形成された未定着トナーを加熱、加圧することで記録材Pの表面にトナー画像が定着される。   The recording material P after the toner image is transferred is conveyed to a fixing device 17 that fixes the toner image formed on the recording material P (on the recording material). The fixing device 17 includes a pressure roller 19 that is a target member that is provided at a fixed position and serves as a pressure rotator, and a pressure-receiving member that is provided so as to be able to contact with and separate from the pressure roller 19. A fixing film 18 serving as a rotating body is provided. The toner image is fixed on the surface of the recording material P by heating and pressing the unfixed toner formed on the surface of the recording material P conveyed through the fixing nip 25 between the fixing film 18 and the pressure roller 19. The

定着装置17においてトナー画像が定着された記録材Pは排出ローラ20によって排出される。中間転写ベルト8の外周面上に残留したトナーはクリーニングブレード21により掻き取られて廃トナー容器22内に収容される。また、各感光ドラム1の表面上に残留したトナーはクリーニングブレード4Y,4M,4C,4Kによりそれぞれ掻き取られて廃トナー容器24Y,24M,24C,24K内に収容される。   The recording material P on which the toner image is fixed in the fixing device 17 is discharged by the discharge roller 20. The toner remaining on the outer peripheral surface of the intermediate transfer belt 8 is scraped off by the cleaning blade 21 and stored in the waste toner container 22. The toner remaining on the surface of each photosensitive drum 1 is scraped off by the cleaning blades 4Y, 4M, 4C, and 4K and stored in the waste toner containers 24Y, 24M, 24C, and 24K.

尚、各色のトナー容器23Y,23M,23C,23K内に収容された各色のトナーは撹拌マイラ34Y,34M,34C,34Kが回転することにより撹拌され、補給ローラ12Y,12M,12C,12Kにより各現像ローラ3に供給される。   The toners of the respective colors accommodated in the toner containers 23Y, 23M, 23C, and 23K of the respective colors are stirred by the rotation of the stirring mylars 34Y, 34M, 34C, and 34K, and are respectively performed by the supply rollers 12Y, 12M, 12C, and 12K. It is supplied to the developing roller 3.

<定着装置>
次に図2を用いて定着装置17の構成について説明する。
<Fixing device>
Next, the configuration of the fixing device 17 will be described with reference to FIG.

本実施形態の定着装置17は、記録材Pを加圧搬送するために弾性層を有して回転する加圧ローラ19と、該加圧ローラ19に圧接して定着ニップ部25を形成する定着フィルム18を有する。   The fixing device 17 according to the present embodiment includes a pressure roller 19 that rotates with an elastic layer to convey the recording material P under pressure, and a fixing device that presses the pressure roller 19 to form a fixing nip portion 25. With film 18;

加圧ローラ19は定着フレーム50に回転可能に支持されている。定着フィルム18の内側には、該定着フィルム18を円筒状に保持する図示しない支持ホルダが設けられている。この支持ホルダには、定着フィルム18を介して定着ニップ部25を加熱するための加熱手段となる図示しないヒータが設けられている。定着フィルム18の両端部には、該定着フィルム18を回転自在に軸支する揺動部材となるフィルムホルダ52が配置されている。フィルムホルダ52は、定着フレーム50に設けられた切欠溝50bに摺動自在に嵌合され、該切欠溝50bに沿って移動可能に支持されている。   The pressure roller 19 is rotatably supported by the fixing frame 50. Inside the fixing film 18, a support holder (not shown) that holds the fixing film 18 in a cylindrical shape is provided. The support holder is provided with a heater (not shown) serving as a heating means for heating the fixing nip portion 25 via the fixing film 18. At both ends of the fixing film 18, film holders 52 serving as swinging members that rotatably support the fixing film 18 are disposed. The film holder 52 is slidably fitted in a notch groove 50b provided in the fixing frame 50, and is supported so as to be movable along the notch groove 50b.

一方、フィルムホルダ52が該切欠溝50bに沿って移動する方向に対して直交する方向に配置され、該フィルムホルダ52の側面に突出して設けられた加圧部26に対向する位置には当接部となる加圧板51が設けられている。加圧板51の下端部は定着フレーム50に設けられた穴50a内に挿入され、該穴50aを回動支点として回動可能に支持されている。加圧板51の上端部には、一端が定着フレーム50に保持された加圧手段となる加圧バネ56の他端が係止されている。   On the other hand, the film holder 52 is disposed in a direction orthogonal to the direction of movement along the notch groove 50b, and is in contact with a position facing the pressurizing portion 26 provided to protrude from the side surface of the film holder 52. A pressure plate 51 is provided as a part. The lower end portion of the pressure plate 51 is inserted into a hole 50a provided in the fixing frame 50, and is supported rotatably about the hole 50a as a rotation fulcrum. At the upper end of the pressure plate 51, the other end of a pressure spring 56 serving as a pressure unit having one end held by the fixing frame 50 is locked.

加圧バネ56の伸長方向の付勢力により加圧板51は穴50aを中心に図2の矢印b方向に付勢され、該加圧板51がフィルムホルダ52の加圧部26に当接して該フィルムホルダ52を切欠溝50bに沿って図2の矢印d方向に付勢する。これにより、加圧バネ56は加圧板51を介してフィルムホルダ52を切欠溝50bに沿って図2の矢印d方向に付勢して該フィルムホルダ52に回転自在に軸支された定着フィルム18を加圧ローラ19に対して圧接させる。このようにして、定着フィルム18と加圧ローラ19との間に定着ニップ部25が形成される。この定着ニップ部25を未定着トナー画像が転写された記録材Pが通過する際に、加熱、加圧されてトナー画像が記録材Pに定着される。   The pressing plate 51 is urged in the direction of arrow b in FIG. 2 by the urging force of the pressing spring 56 in the extending direction, and the pressing plate 51 comes into contact with the pressing portion 26 of the film holder 52 so that the film The holder 52 is urged in the direction of the arrow d in FIG. 2 along the notch groove 50b. As a result, the pressing spring 56 urges the film holder 52 through the pressing plate 51 in the direction of the arrow d in FIG. 2 along the notch groove 50b, and the fixing film 18 rotatably supported by the film holder 52 is supported. Is pressed against the pressure roller 19. In this way, a fixing nip portion 25 is formed between the fixing film 18 and the pressure roller 19. When the recording material P on which the unfixed toner image is transferred passes through the fixing nip portion 25, the toner image is fixed on the recording material P by being heated and pressurized.

<加圧解除手段>
次に、図2〜図4を用いて加圧解除手段の構成について説明する。
<Pressure release means>
Next, the configuration of the pressure release means will be described with reference to FIGS.

定着フィルム18と加圧ローラ19とが圧接されたままの状態で放置されると、該定着フィルム18及び加圧ローラ19の表面の弾性層が永久変形してしまう。また、定着ニップ部25に記録材Pが残った状態でユーザがジャム処理を行うと、定着フィルム18と加圧ローラ19とが圧接されている。これにより、記録材Pが破れ、破れた記録材Pの切れ端が画像形成装置101本体内に残留してしまう。   If the fixing film 18 and the pressure roller 19 are left in pressure contact with each other, the elastic layers on the surfaces of the fixing film 18 and the pressure roller 19 are permanently deformed. Further, when the user performs jam processing with the recording material P remaining in the fixing nip portion 25, the fixing film 18 and the pressure roller 19 are pressed against each other. As a result, the recording material P is torn, and a piece of the torn recording material P remains in the image forming apparatus 101 main body.

上記問題を回避するために、画像形成装置101の出荷時、指定されたジョブ後、記録材Pのジャム時等に、加圧バネ56の付勢力に抗して定着フィルム18と加圧ローラ19との圧接状態を解除して離間する加圧解除手段が設けられている。   In order to avoid the above problem, the fixing film 18 and the pressure roller 19 are resisted against the urging force of the pressure spring 56 when the image forming apparatus 101 is shipped, after a designated job, or when the recording material P is jammed. There is provided a pressure release means for releasing the pressure contact state and separating.

本実施形態の加圧解除手段は、定着フレーム50に対して回転可能に支持され、制御手段となる制御部40により制御される駆動手段となるモータ30により回転駆動する駆動部材となる駆動軸54の一端部の外周面に突出して設けられた突起部54aを有する。   The pressure release unit of the present embodiment is rotatably supported with respect to the fixing frame 50, and is a drive shaft 54 that is a drive member that is rotationally driven by a motor 30 that is a drive unit that is controlled by a control unit 40 that is a control unit. A protrusion 54a provided on the outer peripheral surface of one end of the protrusion.

更に、該突起部54aの回転軸となる駆動軸54に回転自在に軸支され、該突起部54aに対して回転方向に所定の遊びを持って従動回転可能に設けられる従動部材となる圧解除カム53を有する。圧解除カム53の外周面には加圧バネ56の一端部に設けられた加圧板51に当接摺動して該加圧バネ56の付勢力に抗して定着フィルム18と加圧ローラ19との圧接状態を解除するカム面53dを有する。またカム面53dに連続して平坦面53cが設けられている。   Further, the pressure is released as a driven member that is rotatably supported by a drive shaft 54 that serves as a rotation shaft of the protrusion 54a, and that can be driven and rotated with a predetermined play in the rotation direction with respect to the protrusion 54a. A cam 53 is provided. On the outer peripheral surface of the pressure release cam 53, the fixing film 18 and the pressure roller 19 are in contact with and slide against a pressure plate 51 provided at one end of the pressure spring 56 against the urging force of the pressure spring 56. And a cam surface 53d for releasing the pressure contact state. A flat surface 53c is provided continuously to the cam surface 53d.

更に、突起部54aと圧解除カム53との回転方向の所定の遊びを制御する緩衝部材55を有する。   Further, a buffer member 55 is provided for controlling a predetermined play in the rotational direction between the protrusion 54a and the pressure release cam 53.

本実施形態の圧解除カム53は、図4(c)に示すように、突起部54aの回転方向(図4(c)の矢印e方向)に対してカム面53dの駆動軸54からの離間距離が小さくなる変曲点53d1を有する。   As shown in FIG. 4C, the pressure release cam 53 of the present embodiment is separated from the drive shaft 54 of the cam surface 53d with respect to the rotation direction of the protrusion 54a (the direction of arrow e in FIG. 4C). It has an inflection point 53d1 where the distance becomes smaller.

また、圧解除カム53は、図3に示すように、駆動軸54が挿通される貫通穴53aに連通して突起部54aと緩衝部材55とを、それぞれの回転方向(図4の矢印e,g方向)に所定の遊びを持って収容する空隙53bを有する。圧解除カム53に設けられた空隙53bの一方の壁面53eに突起部54aが当接して該突起部54aから圧解除カム53に駆動軸54の回転駆動力が伝達される。一方、空隙53bの他方の壁面53fに緩衝部材55を介在させて突起部54aが当接して先回りする圧解除カム53に駆動軸54の回転速度に応じた制動力が伝達される。   Further, as shown in FIG. 3, the pressure release cam 53 communicates with the through hole 53a through which the drive shaft 54 is inserted, and connects the protruding portion 54a and the buffer member 55 in the respective rotation directions (arrows e, The gap 53b is accommodated with a predetermined play in the direction (g). The protrusion 54 a comes into contact with one wall surface 53 e of the gap 53 b provided in the pressure release cam 53, and the rotational driving force of the drive shaft 54 is transmitted from the protrusion 54 a to the pressure release cam 53. On the other hand, a braking force according to the rotational speed of the drive shaft 54 is transmitted to the pressure release cam 53 which is brought forward by the contact of the projection 54a with the buffer member 55 interposed in the other wall surface 53f of the gap 53b.

圧解除カム53は、定着フィルム18を加圧ローラ19から離間する。圧解除カム53は、加圧板51の長手方向(図2の上下方向)において、該加圧板51上のフィルムホルダ52の加圧部26と、加圧バネ56による加圧板51上の付勢部27との間に配設されている。   The pressure release cam 53 separates the fixing film 18 from the pressure roller 19. In the longitudinal direction of the pressure plate 51 (vertical direction in FIG. 2), the pressure release cam 53 is a pressure portion 26 of the film holder 52 on the pressure plate 51 and a biasing portion on the pressure plate 51 by the pressure spring 56. 27.

図3(a),(c)に示すように、圧解除カム53の外周面には、平坦面53cと、駆動軸54を中心とする径が異なるカム面53dとが連続して形成されている。圧解除カム53の貫通穴53aには駆動軸54が嵌挿されており、該圧解除カム53が駆動軸54に対して回転自在に支持されている。駆動軸54に固定された突起部54aは圧解除カム53の貫通穴53aに連通する該圧解除カム53の周方向に所定の長さを有する空隙53b内に該空隙53b内を回転方向に移動自在に収容されている。圧解除カム53の空隙53bの形状と、駆動軸54に設けられた突起部54aの形状とを適宜設定することにより圧解除カム53と突起部54aとの回転方向の遊び量が決定される。   As shown in FIGS. 3A and 3C, a flat surface 53 c and a cam surface 53 d having different diameters around the drive shaft 54 are continuously formed on the outer peripheral surface of the pressure release cam 53. Yes. A drive shaft 54 is fitted into the through hole 53 a of the pressure release cam 53, and the pressure release cam 53 is rotatably supported with respect to the drive shaft 54. The protrusion 54a fixed to the drive shaft 54 moves in the rotation direction in the gap 53b into the gap 53b having a predetermined length in the circumferential direction of the pressure release cam 53 communicating with the through hole 53a of the pressure release cam 53. It is freely housed. By appropriately setting the shape of the gap 53b of the pressure release cam 53 and the shape of the protrusion 54a provided on the drive shaft 54, the amount of play in the rotational direction between the pressure release cam 53 and the protrusion 54a is determined.

緩衝部材55は駆動軸54の突起部54aに隣接して圧解除カム53の空隙53b内に収容して配設される。緩衝部材55は圧解除カム53が駆動軸54に対して先回りしたときに該圧解除カム53の回転速度を減速させる役割を果たす。緩衝部材55は圧解除カム53の先回りによる回転速度を減速させるダンパとしての役割を果たす。このため、緩衝部材55の材質は、発泡ウレタン等の低反発材が望ましい。   The buffer member 55 is accommodated and disposed in the gap 53b of the pressure release cam 53 adjacent to the protrusion 54a of the drive shaft 54. The buffer member 55 serves to decelerate the rotational speed of the pressure release cam 53 when the pressure release cam 53 is advanced with respect to the drive shaft 54. The buffer member 55 serves as a damper that decelerates the rotational speed of the pressure release cam 53 in the forward direction. For this reason, the material of the buffer member 55 is preferably a low repulsion material such as urethane foam.

尚、緩衝部材55は圧解除カム53の空隙53b内から脱落しないように、圧解除カム53の空隙53bの壁面53fに該緩衝部材55の端面を両面テープ等の固定部材によって保持させる。或いは、圧解除カム53の空隙53bの表面側に壁面を設けて閉鎖空間にすることでも良い。   The end face of the buffer member 55 is held by a fixing member such as a double-sided tape on the wall surface 53f of the gap 53b of the pressure release cam 53 so that the buffer member 55 does not fall out of the gap 53b of the pressure release cam 53. Alternatively, a wall surface may be provided on the surface side of the gap 53b of the pressure release cam 53 to form a closed space.

<定着圧解除動作>
次に、図2及び図4を用いて定着装置17の定着フィルム18と加圧ローラ19との定着ニップ部25の定着圧解除動作について説明する。
<Fixing pressure release operation>
Next, the fixing pressure releasing operation of the fixing nip 25 between the fixing film 18 and the pressure roller 19 of the fixing device 17 will be described with reference to FIGS.

本実施形態では、定着離間動作と定着加圧動作とで駆動軸54の回転方向が同一方向の場合の一例について説明する。   In the present embodiment, an example in which the rotation direction of the drive shaft 54 is the same in the fixing separation operation and the fixing pressure operation will be described.

図2に示すように、圧解除カム53の平坦面53cが加圧板51と平行に配置されている状態では、加圧バネ56の付勢力により加圧板51が穴50aを中心に図2の矢印b方向に回動する。そして、フィルムホルダ52の加圧部26を押圧して該フィルムホルダ52は切欠溝50bに沿って図2の矢印d方向に押圧する。そして、該フィルムホルダ52に回転可能に軸支された定着フィルム18が加圧ローラ19に圧接されて該定着フィルム18と、加圧ローラ19とは加圧状態になっている。   As shown in FIG. 2, when the flat surface 53c of the pressure release cam 53 is arranged in parallel with the pressure plate 51, the pressure plate 51 is centered around the hole 50a by the urging force of the pressure spring 56. It rotates in the b direction. Then, the pressure part 26 of the film holder 52 is pressed, and the film holder 52 is pressed in the direction of the arrow d in FIG. 2 along the notch groove 50b. Then, the fixing film 18 rotatably supported by the film holder 52 is pressed against the pressure roller 19 so that the fixing film 18 and the pressure roller 19 are in a pressurized state.

図2に示す加圧状態から、図4(b)に示す離間状態に移行するときの動作について説明する。図2に示す制御部40がモータ30を駆動して駆動軸54を図4(a)の矢印e方向に回転する。これにより、突起部54aが圧解除カム53の空隙53bの壁面53eに当接して該圧解除カム53が駆動軸54に従動して図4(a)の矢印g方向に回転を始める。   The operation when shifting from the pressurized state shown in FIG. 2 to the separated state shown in FIG. 4B will be described. The control unit 40 shown in FIG. 2 drives the motor 30 to rotate the drive shaft 54 in the direction of arrow e in FIG. As a result, the protrusion 54a abuts against the wall surface 53e of the gap 53b of the pressure release cam 53, and the pressure release cam 53 is driven by the drive shaft 54 and starts rotating in the direction of the arrow g in FIG.

圧解除カム53の回転に伴なって加圧板51に当接していた該圧解除カム53の平坦面53cからカム面53dに移り、該カム面53dが加圧板51に当接摺動して該加圧板51を加圧バネ56の付勢力に抗して穴50aを中心に図4(a)の矢印h方向に押し戻す。このとき、加圧ローラ19の弾性力により定着フィルム18を介してフィルムホルダ52が切欠溝50bに沿って図4(a)の矢印i方向に摺動する。   As the pressure release cam 53 rotates, the pressure release cam 53 moves from the flat surface 53c of the pressure release cam 53 to the cam surface 53d, and the cam surface 53d contacts and slides on the pressure plate 51. The pressure plate 51 is pushed back in the direction of arrow h in FIG. 4A around the hole 50a against the urging force of the pressure spring 56. At this time, the film holder 52 slides in the direction of arrow i in FIG. 4A along the notch groove 50b through the fixing film 18 by the elastic force of the pressure roller 19.

このとき、駆動軸54の突起部54aは圧解除カム53の空隙53bの壁面53eに当接して直接押している。このため、該空隙53b内に収容された緩衝部材55は解放された状態である。   At this time, the protrusion 54 a of the drive shaft 54 is in direct contact with and pressed against the wall surface 53 e of the gap 53 b of the pressure release cam 53. For this reason, the buffer member 55 accommodated in the gap 53b is in a released state.

図4(b)に示すように、圧解除カム53のカム面53dが駆動軸54からの離間距離が最大となる離間位置に到達したとき、制御部40がモータ30を停止させる。これにより駆動軸54の回転が停止して圧解除カム53も停止し、定着フィルム18と加圧ローラ19との離間動作は完了する。   As shown in FIG. 4B, when the cam surface 53 d of the pressure release cam 53 reaches a separation position where the separation distance from the drive shaft 54 is maximum, the control unit 40 stops the motor 30. As a result, the rotation of the drive shaft 54 stops and the pressure release cam 53 also stops, and the separation operation between the fixing film 18 and the pressure roller 19 is completed.

このとき、図4(b)に示すように、加圧バネ56の付勢力により、加圧板51が圧解除カム53のカム面53dに当接して該圧解除カム53を図4(b)の右方向に付勢する付勢力Fは、駆動軸54の中心で受けている。このため、圧解除カム53に加圧バネ56の付勢力による回転トルクは発生しない。また、フィルムホルダ52にも加圧バネ56の付勢力が伝わらない。このため、フィルムホルダ52に軸支された定着フィルム18は安定した状態で静止し、定着フィルム18と加圧ローラ19との定着離間状態を維持する。   At this time, as shown in FIG. 4B, the pressure plate 51 abuts against the cam surface 53d of the pressure release cam 53 by the urging force of the pressure spring 56 so that the pressure release cam 53 is moved as shown in FIG. The urging force F that urges in the right direction is received at the center of the drive shaft 54. Therefore, no rotational torque is generated in the pressure release cam 53 due to the urging force of the pressure spring 56. Further, the urging force of the pressure spring 56 is not transmitted to the film holder 52 as well. For this reason, the fixing film 18 pivotally supported by the film holder 52 is stopped in a stable state, and the fixing separation state between the fixing film 18 and the pressure roller 19 is maintained.

次に、図4(b)に示す離間状態から図2に示す加圧状態に戻るときの動作について説明する。図4(c)に示すように、制御部40により制御されるモータ30により駆動軸54を図4(c)の矢印e方向に回転する。これにより、突起部54aが圧解除カム53の空隙53bの壁面53eに当接して該圧解除カム53が駆動軸54に従動して図4(c)の矢印g方向に回転を始める。   Next, the operation when returning from the separated state shown in FIG. 4B to the pressurized state shown in FIG. 2 will be described. As shown in FIG. 4 (c), the drive shaft 54 is rotated in the direction of arrow e in FIG. 4 (c) by the motor 30 controlled by the control unit 40. As a result, the protrusion 54a abuts against the wall surface 53e of the gap 53b of the pressure release cam 53, and the pressure release cam 53 is driven by the drive shaft 54 and starts rotating in the direction of arrow g in FIG.

図4(c)に示すように、圧解除カム53のカム面53dの駆動軸54からの離間距離が図4(b)に示す最大の離間距離から減少する変曲点53d1に達する。すると、加圧バネ56の付勢力により、加圧板51が圧解除カム53のカム面53dの変曲点53d1に当接して該圧解除カム53を図4(c)の右方向に付勢する付勢力Fは、圧解除カム53の回転中心となる駆動軸54の中心よりも図4(c)の上方向にずれる。   As shown in FIG. 4C, the separation distance from the drive shaft 54 of the cam surface 53d of the pressure release cam 53 reaches an inflection point 53d1 that decreases from the maximum separation distance shown in FIG. Then, due to the urging force of the pressure spring 56, the pressure plate 51 abuts against the inflection point 53d1 of the cam surface 53d of the pressure release cam 53 and urges the pressure release cam 53 in the right direction in FIG. The urging force F is shifted upward in FIG. 4C from the center of the drive shaft 54 that is the rotation center of the pressure release cam 53.

このため、圧解除カム53に図4(c)の矢印g方向の回転トルクが発生し、該圧解除カム53は駆動軸54よりも先回りする。このとき、圧解除カム53の空隙53bの壁面53fと突起部54aとの間に挟まれた緩衝部材55が自身の弾性力に抗して圧縮されてダンパとして働き、先回りする圧解除カム53の回転速度を減速させる。   For this reason, rotational torque in the direction of arrow g in FIG. 4C is generated in the pressure release cam 53, and the pressure release cam 53 is advanced ahead of the drive shaft 54. At this time, the buffer member 55 sandwiched between the wall surface 53f of the gap 53b of the pressure release cam 53 and the projection 54a is compressed against its own elastic force and acts as a damper, Reduce the rotation speed.

そして、圧縮された緩衝部材55が自身の弾性力により復元して伸長して解放される。そして、突起部54aが圧解除カム53の空隙53bの壁面53eに再び当接して直接押し始める。すると、該圧解除カム53が駆動軸54と同期して図4(c)の矢印g方向に従動回転する。そして、図2に示すように、圧解除カム53の平坦面53cが加圧板51と平行に配置された加圧位置に到達する。そのとき、制御部40はモータ30を停止させる。そして駆動軸54の回転が停止して圧解除カム53も停止し、定着フィルム18と加圧ローラ19との加圧動作は完了する。   Then, the compressed buffer member 55 is restored by its own elastic force, and is expanded and released. Then, the protrusion 54a comes into contact with the wall surface 53e of the gap 53b of the pressure release cam 53 again and starts to push directly. Then, the pressure release cam 53 is driven to rotate in the direction of the arrow g in FIG. Then, as shown in FIG. 2, the flat surface 53 c of the pressure release cam 53 reaches a pressure position where it is disposed in parallel with the pressure plate 51. At that time, the control unit 40 stops the motor 30. Then, the rotation of the drive shaft 54 stops and the pressure release cam 53 also stops, and the pressing operation of the fixing film 18 and the pressure roller 19 is completed.

上記構成によれば、圧解除カム53が駆動軸54よりも先回りするときの回転速度を緩衝部材55により減速することが出来る。これにより、駆動軸54に設けられた突起部54aと、圧解除カム53の空隙53bの壁面53e,53fとの衝突による衝撃音を低減することが出来る。   According to the above configuration, the rotational speed when the pressure release cam 53 is advanced beyond the drive shaft 54 can be reduced by the buffer member 55. Thereby, it is possible to reduce the impact sound caused by the collision between the protrusion 54a provided on the drive shaft 54 and the wall surfaces 53e and 53f of the gap 53b of the pressure release cam 53.

これにより、圧解除の負荷トルクに影響がなく、小型でより安価な構成で、衝撃音を低減出来る加圧解除装置を提供することが出来る。   As a result, it is possible to provide a pressure release device that does not affect the load torque of the pressure release, and that can reduce the impact sound with a small and inexpensive configuration.

〔第2実施形態〕
次に、図5〜図8を用いて本発明に係る加圧解除装置を備えた画像形成装置の第2実施形態の構成について説明する。尚、前記第1実施形態と同様に構成したものは同一の符号を付して説明を省略する。
[Second Embodiment]
Next, the configuration of the second embodiment of the image forming apparatus provided with the pressure release device according to the present invention will be described with reference to FIGS. In addition, what was comprised similarly to the said 1st Embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.

前記第1実施形態では、駆動軸54の一方向の回転により定着離間動作と定着加圧動作とを連続的に行う構成とした。本実施形態では、駆動軸54の回転方向が定着離間動作と定着加圧動作とで逆方向となる場合の一例について説明する。図6は本実施形態の従動部材となる圧解除カム53と駆動部材となる突起部54aと緩衝部材55の構成を示す。   In the first embodiment, the fixing separation operation and the fixing pressure operation are continuously performed by the rotation of the drive shaft 54 in one direction. In the present embodiment, an example in which the rotation direction of the drive shaft 54 is opposite between the fixing separation operation and the fixing pressure operation will be described. FIG. 6 shows a configuration of a pressure release cam 53 as a driven member, a protrusion 54a as a driving member, and a buffer member 55 according to this embodiment.

<定着圧解除動作>
図5に示すように、圧解除カム53の平坦面53cが加圧板51と平行に配置されている状態では、前記第1実施形態と同様に定着フィルム18と加圧ローラ19とは加圧状態になっている。
<Fixing pressure release operation>
As shown in FIG. 5, in the state where the flat surface 53c of the pressure release cam 53 is arranged in parallel with the pressure plate 51, the fixing film 18 and the pressure roller 19 are in a pressurized state as in the first embodiment. It has become.

先ず、図5に示す加圧状態から、図7(b)に示す離間状態に移行するときの動作について説明する。図5に示す制御部40により制御されるモータ30により駆動軸54を図7(a)の矢印e方向に回転する。これにより、突起部54aが圧解除カム53の空隙53b内に収容された緩衝部材55を介在して壁面53eを押圧し、該圧解除カム53が駆動軸54に従動して図7(a)の矢印g方向に回転を始める。   First, the operation when shifting from the pressurized state shown in FIG. 5 to the separated state shown in FIG. 7B will be described. The drive shaft 54 is rotated in the direction of arrow e in FIG. 7A by the motor 30 controlled by the control unit 40 shown in FIG. As a result, the protruding portion 54a presses the wall surface 53e via the buffer member 55 accommodated in the gap 53b of the pressure releasing cam 53, and the pressure releasing cam 53 is driven by the drive shaft 54, and FIG. The rotation starts in the direction of arrow g.

図7(a)に示すように、加圧板51に当接した圧解除カム53の平坦面53cからカム面53dに移ると、加圧板51からの付勢力Fにより圧解除カム53の回転は一旦止められる。その後、更に回転する駆動軸54の突起部54aにより緩衝部材55が押圧されて弾性変形して圧縮される。   As shown in FIG. 7A, when the pressure release cam 53 abutted against the pressure plate 51 moves from the flat surface 53c to the cam surface 53d, the pressure release cam 53 is temporarily rotated by the urging force F from the pressure plate 51. It can be stopped. Thereafter, the buffer member 55 is pressed and elastically deformed and compressed by the protruding portion 54a of the rotating drive shaft 54.

緩衝部材55が圧縮されて駆動軸54の突起部54aが圧縮された緩衝部材55を介して圧解除カム53の空隙53bの壁面53eを押圧する。そして、該圧解除カム53は加圧板51から受ける付勢力Fに抗して緩衝部材55を圧縮した状態で駆動軸54に従動して回転を再開する。   The wall surface 53e of the gap 53b of the pressure release cam 53 is pressed through the buffer member 55 in which the buffer member 55 is compressed and the protrusion 54a of the drive shaft 54 is compressed. The pressure release cam 53 resumes rotation by being driven by the drive shaft 54 in a state where the buffer member 55 is compressed against the urging force F received from the pressure plate 51.

図7(b)に示すように、圧解除カム53のカム面53dが駆動軸54からの離間距離が最大となる離間位置に到達したとき、制御部40はモータ30を停止する。これにより駆動軸54の回転が停止して圧解除カム53の回転が停止し、定着フィルム18と加圧ローラ19との離間動作は完了する。このとき、加圧バネ56により付勢された加圧板51から圧解除カム53のカム面53dが受ける付勢力Fは駆動軸54の中心で受けている。   As shown in FIG. 7B, when the cam surface 53 d of the pressure release cam 53 reaches a separation position where the separation distance from the drive shaft 54 is maximum, the control unit 40 stops the motor 30. As a result, the rotation of the drive shaft 54 stops and the rotation of the pressure release cam 53 stops, and the separation operation between the fixing film 18 and the pressure roller 19 is completed. At this time, the urging force F received by the cam surface 53 d of the pressure release cam 53 from the pressure plate 51 urged by the pressure spring 56 is received at the center of the drive shaft 54.

このため、圧解除カム53に加圧バネ56の付勢力による回転トルクは発生しない。また、フィルムホルダ52にも加圧バネ56の付勢力が伝わらない。このため、フィルムホルダ52に軸支された定着フィルム18は安定した状態で静止し、定着フィルム18と加圧ローラ19との定着離間状態を維持する。   Therefore, no rotational torque is generated in the pressure release cam 53 due to the urging force of the pressure spring 56. Further, the urging force of the pressure spring 56 is not transmitted to the film holder 52 as well. For this reason, the fixing film 18 pivotally supported by the film holder 52 is stopped in a stable state, and the fixing separation state between the fixing film 18 and the pressure roller 19 is maintained.

次に、図7(b)に示す離間状態から図5に示す加圧状態に戻るときの動作について説明する。本実施形態では、図8(a)に示すように、加圧状態に戻るときの駆動軸54の回転方向は、図8(a)の矢印j方向で示すように、離間状態に移行するときとは逆方向に回転する。   Next, the operation when returning from the separated state shown in FIG. 7B to the pressurized state shown in FIG. 5 will be described. In the present embodiment, as shown in FIG. 8A, the rotation direction of the drive shaft 54 when returning to the pressurized state is when shifting to the separated state as shown by the arrow j direction in FIG. 8A. Rotates in the opposite direction.

図7(b)に示す離間状態において、圧解除カム53は、カム面53dと加圧板51との間の摩擦力Rにより保持されている。このため、駆動軸54が図8(a)の矢印j方向に回転しても突起部54aが圧解除カム53の空隙53bの壁面53fに当接するまでは圧解除カム53は静止したままで該駆動軸54のみが図8(a)に示す矢印j方向に回転を始める。   In the separated state shown in FIG. 7B, the pressure release cam 53 is held by the frictional force R between the cam surface 53d and the pressure plate 51. For this reason, even if the drive shaft 54 rotates in the direction of arrow j in FIG. 8A, the pressure release cam 53 remains stationary until the projection 54a contacts the wall surface 53f of the gap 53b of the pressure release cam 53. Only the drive shaft 54 starts to rotate in the direction of the arrow j shown in FIG.

このとき、突起部54aに押圧されて弾性変形して圧縮されていた緩衝部材55は突起部54aによる押圧から解放されて自身の弾性力により復元して伸長する。更に、駆動軸54が図8(a)の矢印j方向に回転して突起部54aが圧解除カム53の空隙53bの壁面53fを押圧し、該圧解除カム53は、カム面53dと加圧板51との間の摩擦力Rに抗して該駆動軸54に従動回転する。   At this time, the buffer member 55 that has been pressed and elastically deformed and compressed by the protruding portion 54a is released from the pressing by the protruding portion 54a and is restored and stretched by its own elastic force. Further, the drive shaft 54 rotates in the direction of the arrow j in FIG. 8A, and the projection 54a presses the wall surface 53f of the gap 53b of the pressure release cam 53. The pressure release cam 53 includes the cam surface 53d and the pressure plate. The drive shaft 54 is driven to rotate against the frictional force R between the drive shaft 51 and the shaft 51.

図8(b)に示すように、圧解除カム53のカム面53dの駆動軸54からの離間距離が図7(b)に示す最大の離間距離から減少する変曲点53d1に達する。すると、加圧バネ56の付勢力により、加圧板51が圧解除カム53のカム面53dの変曲点53d1に当接して該圧解除カム53を図8(b)の右方向に付勢する付勢力Fは、圧解除カム53の回転中心となる駆動軸54の中心よりも図8(b)の下方向にずれる。   As shown in FIG. 8B, the separation distance from the drive shaft 54 of the cam surface 53d of the pressure release cam 53 reaches an inflection point 53d1 where the separation distance decreases from the maximum separation distance shown in FIG. Then, due to the urging force of the pressure spring 56, the pressure plate 51 abuts on the inflection point 53d1 of the cam surface 53d of the pressure release cam 53 and urges the pressure release cam 53 in the right direction in FIG. The biasing force F is shifted downward in FIG. 8B from the center of the drive shaft 54 that is the rotation center of the pressure release cam 53.

このため、圧解除カム53に図8(b)の矢印k方向の回転トルクが発生し、該圧解除カム53は駆動軸54より先回りする。このとき、圧解除カム53の空隙53bの壁面53eと突起部54aとの間に挟まれた緩衝部材55が自身の弾性力に抗して圧縮されてダンパとして働き、先回りする圧解除カム53の回転速度を減速させる。   For this reason, a rotational torque in the direction of arrow k in FIG. 8B is generated in the pressure release cam 53, and the pressure release cam 53 moves forward from the drive shaft 54. At this time, the buffer member 55 sandwiched between the wall surface 53e of the gap 53b of the pressure release cam 53 and the protrusion 54a is compressed against its own elastic force to act as a damper, and the pressure release cam 53 of the preceding pressure release cam 53 Reduce the rotation speed.

そして、圧縮された緩衝部材55が自身の弾性力により復元して伸長して解放され、突起部54aが圧解除カム53の空隙53bの壁面53fに再び当接して直接押し始める。すると、該圧解除カム53が駆動軸54と同期して図8(b)の矢印k方向に従動回転する。そして、図5に示すように、圧解除カム53の平坦面53cが加圧板51と平行に配置された加圧位置に到達する。そのとき、制御部40はモータ30を停止させる。そして駆動軸54の回転が停止して圧解除カム53の回転が停止し、定着フィルム18と加圧ローラ19との加圧動作は完了する。   Then, the compressed buffer member 55 is restored by its own elastic force and extended and released, and the projection 54a comes into contact with the wall surface 53f of the gap 53b of the pressure release cam 53 again and starts to push directly. Then, the pressure release cam 53 is driven to rotate in the direction of the arrow k in FIG. Then, as shown in FIG. 5, the flat surface 53 c of the pressure release cam 53 reaches the pressurization position arranged in parallel with the pressurization plate 51. At that time, the control unit 40 stops the motor 30. Then, the rotation of the drive shaft 54 stops and the rotation of the pressure release cam 53 stops, and the pressing operation of the fixing film 18 and the pressure roller 19 is completed.

上記構成によれば、圧解除カム53が駆動軸54よりも先回りするときの回転速度を緩衝部材55により減速することが出来る。これにより、駆動軸54に設けられた突起部54aと、圧解除カム53の空隙53bの壁面53e,53fとの衝突による衝撃音を低減することが出来る。他の構成は前記第1実施形態と同様に構成され、同様の効果を得ることが出来る。   According to the above configuration, the rotational speed when the pressure release cam 53 is advanced beyond the drive shaft 54 can be reduced by the buffer member 55. Thereby, it is possible to reduce the impact sound caused by the collision between the protrusion 54a provided on the drive shaft 54 and the wall surfaces 53e and 53f of the gap 53b of the pressure release cam 53. Other configurations are the same as those in the first embodiment, and the same effects can be obtained.

〔第3実施形態〕
次に、図9〜図11を用いて本発明に係る加圧解除装置を備えた画像形成装置の第3実施形態について説明する。尚、前記各実施形態と同様に構成したものは同一の符号を付して説明を省略する。
[Third Embodiment]
Next, a third embodiment of the image forming apparatus provided with the pressure release device according to the present invention will be described with reference to FIGS. In addition, what was comprised similarly to each said embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.

前記各実施形態では、加圧板51に当接摺動する圧解除カム53を一部材により構成した場合の一例を示した。本実施形態では、加圧板51に当接摺動する二分割された駆動カム70と従動カム71とを有する。   In each of the above-described embodiments, an example in which the pressure release cam 53 that contacts and slides on the pressure plate 51 is constituted by one member is shown. In the present embodiment, a drive cam 70 and a driven cam 71 that are divided into two parts that come into contact with and slide on the pressure plate 51 are provided.

<加圧解除手段>
本実施形態の加圧解除手段は、駆動軸54に駆動カム70の貫通穴70aが挿通され、駆動軸54の外周面に突出した突起部54aが駆動カム70の貫通穴70aに連通して形成された溝部70fに嵌入されている。本実施形態の駆動カム70は図9に示す制御部40により制御されるモータ30により回転駆動する駆動部材として構成される。
<Pressure release means>
The pressurizing release means of the present embodiment is formed by inserting a through hole 70a of the drive cam 70 into the drive shaft 54, and a protrusion 54a protruding from the outer peripheral surface of the drive shaft 54 communicating with the through hole 70a of the drive cam 70. The groove portion 70f is inserted. The drive cam 70 of this embodiment is configured as a drive member that is rotationally driven by a motor 30 that is controlled by the control unit 40 shown in FIG.

更に、駆動カム70の回転軸となる駆動軸54に従動部材となる従動カム71の貫通穴71aが回転自在に軸支される。従動カム71は駆動カム70に対して回転方向に所定の遊びを持って従動回転可能に設けられる。従動カム71の外周面には加圧バネ56の一端部に設けられた当接部となる加圧板51に当接摺動して該加圧バネ56の付勢力に抗して定着フィルム18と加圧ローラ19との圧接状態を解除するカム面71dが形成されている。   Further, a through hole 71a of a driven cam 71 that is a driven member of a drive shaft 54 that is a rotation shaft of the drive cam 70 is rotatably supported. The driven cam 71 is provided so as to be driven to rotate with a predetermined play in the rotation direction with respect to the drive cam 70. On the outer peripheral surface of the driven cam 71, the fixing film 18 and the pressing film 51 are slid against and slid against a pressing plate 51 serving as a contacting portion provided at one end of the pressing spring 56. A cam surface 71d for releasing the pressure contact state with the pressure roller 19 is formed.

一方、駆動カム70の外周面には、加圧バネ56の一端部に設けられた当接部となる加圧板51に当接摺動して該加圧バネ56の付勢力に抗して定着フィルム18と加圧ローラ19との圧接状態を解除する第二のカム面70dが形成されている。   On the other hand, on the outer peripheral surface of the drive cam 70, the contact is slid against a pressure plate 51 which is a contact portion provided at one end of the pressure spring 56, and is fixed against the urging force of the pressure spring 56. A second cam surface 70d for releasing the pressure contact state between the film 18 and the pressure roller 19 is formed.

従動カム71は、図11(c)に示すように、駆動カム70の回転方向に対してカム面71dの駆動軸54からの離間距離が小さくなる変曲点71d1を有する。一方、駆動カム70は該駆動カム70の回転方向に対して第二のカム面70dの駆動軸54からの離間距離が小さくなる変曲点を有さない。   As shown in FIG. 11C, the driven cam 71 has an inflection point 71d1 in which the distance of the cam surface 71d from the drive shaft 54 becomes small with respect to the rotational direction of the drive cam 70. On the other hand, the drive cam 70 does not have an inflection point at which the distance from the drive shaft 54 of the second cam surface 70d becomes small with respect to the rotation direction of the drive cam 70.

即ち、駆動カム70が図11(a)の矢印g方向に回転する間は第二のカム面70dの駆動軸54からの離間距離は徐々に大きくなるように構成される。そして、第二のカム面70dの駆動軸54からの離間距離が該駆動カム70の回転方向に対して小さくなる変曲点は存在しない。   That is, while the drive cam 70 rotates in the direction of the arrow g in FIG. 11A, the separation distance of the second cam surface 70d from the drive shaft 54 is gradually increased. There is no inflection point at which the separation distance of the second cam surface 70d from the drive shaft 54 becomes smaller with respect to the rotation direction of the drive cam 70.

図11に示すように、従動カム71のカム面71dと、駆動カム70の第2のカム面70dとは連続的に繋がっている。駆動カム70と従動カム71との間には、該駆動カム70と従動カム71との回転方向の所定の遊びを制御する緩衝部材55が設けられている。駆動カム70または従動カム71の少なくとも一方に緩衝部材55を回転方向に所定の遊びを持って収容する空隙72が設けられている。   As shown in FIG. 11, the cam surface 71d of the driven cam 71 and the second cam surface 70d of the drive cam 70 are continuously connected. A buffer member 55 is provided between the drive cam 70 and the driven cam 71 to control a predetermined play in the rotational direction between the drive cam 70 and the driven cam 71. At least one of the driving cam 70 and the driven cam 71 is provided with a gap 72 for accommodating the buffer member 55 with a predetermined play in the rotational direction.

本実施形態では、前記第1実施形態の圧解除カム53のカム面53dを、従動カム71のカム面71dと、駆動カム70の第2のカム面70dとにより二分割して構成した一例である。   In this embodiment, the cam surface 53d of the pressure release cam 53 of the first embodiment is divided into two parts by the cam surface 71d of the driven cam 71 and the second cam surface 70d of the drive cam 70. is there.

本実施形態では、定着離間動作と定着加圧動作とで駆動軸54の回転方向が同一方向の場合の一例について説明する。   In the present embodiment, an example in which the rotation direction of the drive shaft 54 is the same in the fixing separation operation and the fixing pressure operation will be described.

図9及び図11に示すように、定着フィルム18を加圧ローラ19から離間するための加圧解除手段は駆動カム70と従動カム71とを有して構成される。そして、該駆動カム70と従動カム71とは、加圧板51の長手方向(図9の上下方向)において、該加圧板51上のフィルムホルダ52の加圧部26と、加圧バネ56による加圧板51上の付勢部27との間に配設されている。   As shown in FIGS. 9 and 11, the pressure release means for separating the fixing film 18 from the pressure roller 19 includes a drive cam 70 and a driven cam 71. The driving cam 70 and the driven cam 71 are applied by a pressing portion 26 of the film holder 52 on the pressing plate 51 and a pressing spring 56 in the longitudinal direction of the pressing plate 51 (vertical direction in FIG. 9). It is disposed between the urging portion 27 on the pressure plate 51.

図10に示すように、駆動カム70と従動カム71とは略半月形状で構成され、駆動カム70に設けられた駆動軸54を中心とする円弧状の軸受凹部70gに従動カム71に設けられた円弧状の軸受凸部71gが摺動自在に嵌合されている。駆動カム70と従動カム71には駆動軸54を中心とする扇型形状の側壁70h,71hが設けられており、両者の側壁70h,71hの間に緩衝部材55が収容される空隙72が形成される。   As shown in FIG. 10, the drive cam 70 and the driven cam 71 are formed in a substantially half-moon shape, and are provided in the driven cam 71 with an arc-shaped bearing recess 70 g centering on the drive shaft 54 provided in the drive cam 70. An arc-shaped bearing convex portion 71g is slidably fitted. The drive cam 70 and the driven cam 71 are provided with fan-shaped side walls 70h, 71h centering on the drive shaft 54, and a gap 72 for accommodating the buffer member 55 is formed between the side walls 70h, 71h. Is done.

図10に示すように、駆動カム70は駆動軸54に貫通穴70aが挿通されて支持され、該駆動軸54の外周面に設けられた突起部54aが駆動カム70の溝部70fに嵌入されて固定されることにより、駆動カム70が駆動軸54と一体的に回転する。   As shown in FIG. 10, the drive cam 70 is supported by inserting a through hole 70 a through the drive shaft 54, and a projection 54 a provided on the outer peripheral surface of the drive shaft 54 is fitted into a groove 70 f of the drive cam 70. By being fixed, the drive cam 70 rotates integrally with the drive shaft 54.

一方、従動カム71は駆動軸54に貫通穴71aが挿通されると共に、駆動カム70の軸受凹部70gに従動カム71の軸受凸部71gが摺動自在に嵌合されて従動カム71は駆動軸54に対して回転自在に軸支される。   On the other hand, the driven cam 71 has a through hole 71a inserted through the drive shaft 54, and a bearing convex portion 71g of the driven cam 71 is slidably fitted into the bearing cam 70g of the drive cam 70 so that the driven cam 71 It is pivotally supported with respect to 54.

駆動カム70には従動カム71の側壁71hの外周端部に設けられた突当面71eに対向する突当面70eが設けられている。そして、該駆動カム70及び従動カム71の駆動軸54を中心にして該突当面70e,71eの反対側には互いに対向する突当面70b,71bが設けられている。   The driving cam 70 is provided with an abutting surface 70e facing the abutting surface 71e provided at the outer peripheral end of the side wall 71h of the driven cam 71. Further, abutting surfaces 70b, 71b facing each other are provided on the opposite side of the abutting surfaces 70e, 71e around the drive shaft 54 of the drive cam 70 and the driven cam 71.

そして、従動カム71が駆動軸54を中心に回転する。そして図10(c)及び図11(a)に示すように、突当面70b,71bが当接する姿勢位置から、図11(c)に示すように、突当面70e,71eが当接する姿勢位置までの間が駆動カム70と従動カム71との回転方向の所定の遊びとなる。   Then, the driven cam 71 rotates around the drive shaft 54. Then, as shown in FIGS. 10 (c) and 11 (a), from the posture position where the abutting surfaces 70b and 71b abut, as shown in FIG. 11 (c), the posture position where the abutting surfaces 70e and 71e abut. A predetermined play in the rotational direction of the drive cam 70 and the driven cam 71 is between the two.

尚、図示しないが、駆動カム70の軸受凹部70gと、従動カム71の軸受凸部71gとの嵌合が外れないように、従動カム71の軸受凸部71gと駆動軸54との間にスラスト止めが設けられている。   Although not shown, a thrust is provided between the bearing convex portion 71g of the driven cam 71 and the drive shaft 54 so that the bearing concave portion 70g of the driving cam 70 and the bearing convex portion 71g of the driven cam 71 are not disengaged. A stop is provided.

緩衝部材55は、駆動カム70の側壁70hと、従動カム71の側壁71hとで形成される空隙72内に配設される。図10(c)に示すように、駆動カム70の突当面70bに対して従動カム71の突当面71bが当接するところまで開いた状態では、緩衝部材55が解放された状態である。このとき、駆動カム70の第二のカム面70dと従動カム71のカム面71dとは連続的に繋がるようにオーバラップしている。   The buffer member 55 is disposed in a gap 72 formed by the side wall 70 h of the drive cam 70 and the side wall 71 h of the driven cam 71. As shown in FIG. 10C, when the contact surface 71b of the driven cam 71 is in contact with the contact surface 70b of the drive cam 70, the buffer member 55 is released. At this time, the second cam surface 70d of the drive cam 70 and the cam surface 71d of the driven cam 71 overlap so as to be continuously connected.

一方、図11(c)に示すように、駆動カム70の突当面70eに対して従動カム71の突当面71eが当接するところまで閉じた状態では、緩衝部材55が自身の弾性力に抗して弾性変形して圧縮された状態である。   On the other hand, as shown in FIG. 11C, in a state where the abutting surface 71e of the driven cam 71 is in contact with the abutting surface 70e of the drive cam 70, the buffer member 55 resists its own elastic force. It is in a state of being elastically deformed and compressed.

緩衝部材55は、従動カム71が駆動カム70に対して先回りしたときに、従動カム71の回転速度を減速させる役割を果たす。緩衝部材55の材質は、従動カム71の先回りによる回転速度を減速させるダンパの役割を果たす。このため、発泡ウレタン等の低反発材が望ましい。緩衝部材55は、駆動カム70と従動カム71との間の空隙72内から脱落しないように、駆動カム70或いは従動カム71の少なくとも一方の端面に両面テープ等の固定手段により保持させることが出来る。或いは、駆動カム70と従動カム71との間の空隙72の表面側に壁面を設けて閉鎖空間にすることでも良い。   The buffer member 55 plays a role of decelerating the rotational speed of the driven cam 71 when the driven cam 71 moves forward with respect to the drive cam 70. The material of the buffer member 55 serves as a damper that reduces the rotational speed of the driven cam 71 in the forward direction. For this reason, a low resilience material such as urethane foam is desirable. The buffer member 55 can be held by a fixing means such as double-sided tape on at least one end face of the drive cam 70 or the driven cam 71 so as not to drop out of the gap 72 between the drive cam 70 and the driven cam 71. . Alternatively, a wall surface may be provided on the surface side of the gap 72 between the drive cam 70 and the driven cam 71 to form a closed space.

<定着圧解除動作>
次に、図9及び図11を用いて定着装置17の定着フィルム18と加圧ローラ19との定着ニップ部25の定着圧解除動作について説明する。
<Fixing pressure release operation>
Next, the fixing pressure releasing operation of the fixing nip portion 25 between the fixing film 18 and the pressure roller 19 of the fixing device 17 will be described with reference to FIGS. 9 and 11.

本実施形態では、定着離間動作と定着加圧動作とで駆動軸54の回転方向が同一方向の場合の一例について説明する。   In the present embodiment, an example in which the rotation direction of the drive shaft 54 is the same in the fixing separation operation and the fixing pressure operation will be described.

図9に示すように、駆動カム70の平坦面70cが加圧板51と平行に配置されている状態では、加圧バネ56の付勢力により加圧板51が穴50aを中心に図9の矢印b方向に回動する。そして、フィルムホルダ52の加圧部26を押圧して該フィルムホルダ52は切欠溝50bに沿って図9の矢印d方向に押圧する。そして、該フィルムホルダ52に回転可能に軸支された定着フィルム18が加圧ローラ19に圧接されて該定着フィルム18と加圧ローラ19とは加圧状態になっている。   As shown in FIG. 9, when the flat surface 70c of the drive cam 70 is arranged in parallel with the pressure plate 51, the pressure plate 51 is centered around the hole 50a by the urging force of the pressure spring 56, and the arrow b in FIG. Rotate in the direction. Then, the pressure part 26 of the film holder 52 is pressed, and the film holder 52 is pressed in the direction of the arrow d in FIG. 9 along the notch groove 50b. Then, the fixing film 18 rotatably supported by the film holder 52 is pressed against the pressure roller 19 so that the fixing film 18 and the pressure roller 19 are in a pressurized state.

先ず、図9に示す加圧状態から、図11(b)に示す離間状態に移行するときの動作について説明する。図9に示す制御部40により制御されるモータ30により駆動軸54に固定された駆動カム70を図11(a)の矢印g方向に回転する。   First, the operation when shifting from the pressurized state shown in FIG. 9 to the separated state shown in FIG. 11B will be described. The drive cam 70 fixed to the drive shaft 54 is rotated in the direction of arrow g in FIG. 11A by the motor 30 controlled by the control unit 40 shown in FIG.

そして、駆動カム70の突当面70bが従動カム71の突当面71bに当接し、従動カム71が駆動カム70に従動して図11(a)の矢印g方向に回転を始める。このとき、空隙72内に収容された緩衝部材55は解放された状態である。   Then, the abutting surface 70b of the driving cam 70 comes into contact with the abutting surface 71b of the driven cam 71, and the driven cam 71 is driven by the driving cam 70 and starts to rotate in the direction of the arrow g in FIG. At this time, the buffer member 55 accommodated in the gap 72 is in a released state.

駆動カム70の回転に伴なって加圧板51に当接していた該駆動カム70の平坦面70cから第二のカム面70dに移る。そして、該第二のカム面70dが加圧板51に当接摺動して該加圧板51を加圧バネ56の付勢力に抗して穴50aを中心に図11(a)の矢印h方向に押し戻す。このとき、加圧ローラ19の弾性力により定着フィルム18を介してフィルムホルダ52が切欠溝50bに沿って図11(a)の矢印i方向に摺動する。   As the drive cam 70 rotates, the flat surface 70c of the drive cam 70 that has been in contact with the pressure plate 51 moves to the second cam surface 70d. Then, the second cam surface 70d comes into contact with and slides against the pressure plate 51, and the pressure plate 51 resists the urging force of the pressure spring 56, and the direction of the arrow h in FIG. Push back to. At this time, the film holder 52 slides in the direction of the arrow i in FIG. 11A along the notch groove 50b through the fixing film 18 by the elastic force of the pressure roller 19.

図11(b)に示すように、駆動カム70のカム面70dが駆動軸54からの離間距離が最大となる離間位置に到達したとき、制御部40はモータ30を停止する。これにより駆動軸54の回転が停止して駆動カム70も停止し、定着フィルム18と加圧ローラ19との離間動作は完了する。   As shown in FIG. 11B, when the cam surface 70d of the drive cam 70 reaches the separation position where the separation distance from the drive shaft 54 is maximum, the control unit 40 stops the motor 30. As a result, the rotation of the drive shaft 54 stops and the drive cam 70 also stops, and the separation operation between the fixing film 18 and the pressure roller 19 is completed.

このとき、図11(b)に示すように、加圧バネ56の付勢力により、加圧板51が駆動カム70のカム面70dに当接して該駆動カム70を図11(b)の右方向に付勢する付勢力Fは、駆動軸54の中心で受けている。このため、駆動カム70に加圧バネ56の付勢力による回転トルクは発生しない。また、フィルムホルダ52にも加圧バネ56の付勢力が伝わらない。このため、フィルムホルダ52に軸支された定着フィルム18は安定した状態で静止し、定着フィルム18と加圧ローラ19との定着離間状態を維持する。   At this time, as shown in FIG. 11 (b), the urging force of the pressure spring 56 causes the pressure plate 51 to abut against the cam surface 70d of the drive cam 70 so that the drive cam 70 is moved to the right in FIG. 11 (b). The urging force F for urging is received at the center of the drive shaft 54. For this reason, rotational torque due to the urging force of the pressure spring 56 is not generated in the drive cam 70. Further, the urging force of the pressure spring 56 is not transmitted to the film holder 52 as well. For this reason, the fixing film 18 pivotally supported by the film holder 52 is stopped in a stable state, and the fixing separation state between the fixing film 18 and the pressure roller 19 is maintained.

次に、図11(b)に示す離間状態から図9に示す加圧状態に戻るときの動作について説明する。図11(c)に示すように、モータ30により駆動軸54に固定された駆動カム70を図11(c)の矢印g方向に回転する。これにより、駆動カム70の突当面70bが従動カム71の突当面71bに当接して従動カム71が駆動カム70に従動して図11(c)の矢印g方向に回転する。   Next, the operation when returning from the separated state shown in FIG. 11B to the pressurized state shown in FIG. 9 will be described. As shown in FIG. 11C, the drive cam 70 fixed to the drive shaft 54 by the motor 30 is rotated in the direction of the arrow g in FIG. As a result, the abutting surface 70b of the drive cam 70 contacts the abutting surface 71b of the driven cam 71, and the driven cam 71 is driven by the drive cam 70 and rotates in the direction of the arrow g in FIG.

図11(c)に示すように、従動カム71のカム面71dの駆動軸54からの離間距離が図11(b)に示す最大の離間距離から減少する変曲点71d1に達する。すると、加圧バネ56の付勢力により、加圧板51が従動カム71のカム面71dの変曲点71d1に当接して該従動カム71を図11(c)の右方向に付勢する付勢力Fは、該従動カム71の回転中心となる駆動軸54の中心よりも図11(c)の上方向にずれる。   As shown in FIG. 11C, the inflection point 71d1 where the separation distance from the drive shaft 54 of the cam surface 71d of the driven cam 71 decreases from the maximum separation distance shown in FIG. Then, due to the biasing force of the pressure spring 56, the pressure plate 51 abuts against the inflection point 71d1 of the cam surface 71d of the driven cam 71 and biases the driven cam 71 in the right direction in FIG. F deviates upward in FIG. 11C from the center of the drive shaft 54, which is the rotation center of the driven cam 71.

このため、従動カム71に図11(c)の矢印g方向の回転トルクが発生し、該従動カム71は駆動カム70よりも先回りする。このとき、従動カム71の当接面71iと駆動カム70の当接面70iとの間に挟まれた緩衝部材55が自身の弾性力に抗して圧縮されてダンパとして働き、先回りする従動カム71の回転速度を減速させる。   For this reason, rotational torque in the direction indicated by the arrow g in FIG. 11C is generated in the driven cam 71, and the driven cam 71 is ahead of the drive cam 70. At this time, the shock absorbing member 55 sandwiched between the contact surface 71i of the driven cam 71 and the contact surface 70i of the drive cam 70 is compressed against its own elastic force to act as a damper, and the driven cam that moves forward. Reduce the speed of 71.

その後、圧縮された緩衝部材55が自身の弾性力により復元して伸長して解放される。そして、駆動カム70の突当面70bと、従動カム71の突当面71bとが再び当接して直接押し始める。すると、該従動カム71は駆動カム70と同期して図11(c)の矢印g方向に従動回転し、図9に示すように、駆動カム70の平坦面70cが加圧板51と平行に配置された加圧位置に到達する。そのとき、制御部40はモータ30を停止する。そして、駆動軸54の回転が停止して駆動カム70も停止し、定着フィルム18と加圧ローラ19との加圧動作は完了する。   Thereafter, the compressed buffer member 55 is restored by its own elastic force, and is expanded and released. Then, the abutting surface 70b of the drive cam 70 and the abutting surface 71b of the driven cam 71 come into contact again and start to push directly. Then, the driven cam 71 is driven to rotate in the direction of arrow g in FIG. 11C in synchronization with the drive cam 70, and the flat surface 70 c of the drive cam 70 is arranged in parallel with the pressure plate 51 as shown in FIG. The pressed position is reached. At that time, the control unit 40 stops the motor 30. Then, the rotation of the drive shaft 54 stops and the drive cam 70 also stops, and the pressing operation of the fixing film 18 and the pressure roller 19 is completed.

上記構成によれば、従動カム71を駆動カム70から分離し、従動カム71を先回りさせ、その回転速度を緩衝部材55によって減速させる。これにより、従動カム71と駆動カム70との衝突による衝撃音を低減することが出来る。   According to the above configuration, the driven cam 71 is separated from the drive cam 70, the driven cam 71 is advanced, and the rotation speed is reduced by the buffer member 55. Thereby, it is possible to reduce the impact sound caused by the collision between the driven cam 71 and the drive cam 70.

また、加圧バネ56の付勢力に抗して加圧板51を付勢するカムを従動カム71と駆動カム70とに二分割することで、緩衝部材55を収容する空隙72のスペースを前記各実施形態の空隙53bのスペースよりも大きくとることが出来る。   Further, by dividing the cam for urging the pressure plate 51 against the urging force of the pressure spring 56 into a driven cam 71 and a drive cam 70, the space 72 for accommodating the buffer member 55 is made into the spaces described above. It can be made larger than the space of the gap 53b in the embodiment.

これにより、空隙72のスペースに応じた大きな体積を有する緩衝部材55を取り付けることが出来、緩衝効果も向上して先回りする従動カム71の回転速度の減速効果を向上することが出来、更なる衝撃音の低減に繋がる。他の構成は前記各実施形態と同様に構成され、同様の効果を得ることが出来る。   As a result, the buffer member 55 having a large volume corresponding to the space of the gap 72 can be attached, the buffering effect can be improved, and the effect of reducing the rotational speed of the follower cam 71 can be improved. This leads to sound reduction. Other configurations are the same as those in the above embodiments, and the same effects can be obtained.

〔第4実施形態〕
次に、図12〜図15を用いて本発明に係る加圧解除装置を備えた画像形成装置の第4実施形態の構成について説明する。尚、前記各実施形態と同様に構成したものは同一の符号を付して説明を省略する。
[Fourth Embodiment]
Next, the configuration of the fourth embodiment of the image forming apparatus provided with the pressure release device according to the present invention will be described with reference to FIGS. In addition, what was comprised similarly to each said embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.

前記第3実施形態では、駆動軸54の一方向の回転により定着離間動作と定着加圧動作とを連続的に行う構成とした。本実施形態では、駆動軸54の回転方向が定着離間動作と定着加圧動作とで逆方向となる場合の一例について説明する。   In the third embodiment, the fixing separation operation and the fixing pressure operation are continuously performed by the rotation of the drive shaft 54 in one direction. In the present embodiment, an example in which the rotation direction of the drive shaft 54 is opposite between the fixing separation operation and the fixing pressure operation will be described.

本実施形態では、図13に示すように、図10に示して前述した第3実施形態の駆動カム70と従動カム71との取り付けが上下逆である。その他の構成は前記第3実施形態と同様であるため詳細な説明を省略する。   In this embodiment, as shown in FIG. 13, the mounting of the drive cam 70 and the driven cam 71 of the third embodiment described above with reference to FIG. 10 is upside down. Since other configurations are the same as those of the third embodiment, detailed description thereof is omitted.

<定着圧解除動作>
図12〜図15を用いて定着圧解除動作について説明する。本実施形態では、駆動軸54の回転方向が定着離間動作と定着加圧動作で逆方向に回転する。
<Fixing pressure release operation>
The fixing pressure releasing operation will be described with reference to FIGS. In the present embodiment, the rotation direction of the drive shaft 54 rotates in the opposite direction between the fixing separation operation and the fixing pressure operation.

図12に示すように、駆動カム70の平坦面70cが加圧板51と平行に配置されている。この状態では、加圧バネ56の付勢力により加圧板51が穴50aを中心に図12の矢印b方向に回動する。そして、フィルムホルダ52の加圧部26を押圧して該フィルムホルダ52は切欠溝50bに沿って図12の矢印d方向に押圧される。そして、該フィルムホルダ52に回転可能に軸支された定着フィルム18が加圧ローラ19に圧接されて該定着フィルム18と加圧ローラ19とは加圧状態になっている。   As shown in FIG. 12, the flat surface 70 c of the drive cam 70 is arranged in parallel with the pressure plate 51. In this state, the pressing plate 51 is rotated about the hole 50a in the direction of arrow b in FIG. Then, by pressing the pressure part 26 of the film holder 52, the film holder 52 is pressed in the direction of the arrow d in FIG. 12 along the notch groove 50b. Then, the fixing film 18 rotatably supported by the film holder 52 is pressed against the pressure roller 19 so that the fixing film 18 and the pressure roller 19 are in a pressurized state.

図12に示す加圧状態から、図14(b)に示す離間状態に移行するときの動作について説明する。図14(a)に示すように、制御部40により制御されるモータ30により駆動軸54に固定された駆動カム70を図14(a)の矢印g方向に回転する。   The operation when shifting from the pressurized state shown in FIG. 12 to the separated state shown in FIG. 14B will be described. As shown in FIG. 14 (a), the drive cam 70 fixed to the drive shaft 54 by the motor 30 controlled by the control unit 40 is rotated in the direction of arrow g in FIG. 14 (a).

そして、緩衝部材55を介して従動カム71が従動回転する。従動カム71の回転に伴なって加圧板51に当接していた該従動カム71の平坦面71cからカム面71dに移ると、加圧板51からの付勢力Fにより従動カム71の回転は一旦止められる。更に回転する駆動カム70により緩衝部材55は自身の弾性力に抗して圧縮される。   Then, the driven cam 71 rotates following the buffer member 55. When the driven cam 71 moves from the flat surface 71c of the driven cam 71 that has been in contact with the pressure plate 51 to the cam surface 71d, the rotation of the driven cam 71 is temporarily stopped by the urging force F from the pressure plate 51. It is done. Further, the buffer member 55 is compressed against its own elastic force by the rotating drive cam 70.

緩衝部材55が圧縮されると、図14(a)に示すように、駆動カム70の突当面70eが従動カム71の突当面71eに当接する。そして、従動カム71は加圧板51からの付勢力Fに抗して緩衝部材55を圧縮した状態で回転を再開する。従動カム71の回転に伴なってカム面71dが加圧板51に当接摺動して加圧板51を加圧バネ56の付勢力に抗して穴50aを中心に図14(a)の矢印h方向に押し戻す。このとき、加圧ローラ19の弾性力により定着フィルム18を介してフィルムホルダ52が切欠溝50bに沿って図14(a)の矢印i方向に摺動する。   When the buffer member 55 is compressed, the abutting surface 70e of the drive cam 70 comes into contact with the abutting surface 71e of the driven cam 71 as shown in FIG. Then, the driven cam 71 resumes rotation in a state where the buffer member 55 is compressed against the urging force F from the pressure plate 51. As the driven cam 71 rotates, the cam surface 71d comes into contact with and slides against the pressure plate 51, and the pressure plate 51 resists the urging force of the pressure spring 56, and the arrow in FIG. Push back in the h direction. At this time, the film holder 52 slides in the direction of the arrow i in FIG. 14A along the notch groove 50b through the fixing film 18 by the elastic force of the pressure roller 19.

図14(b)に示すように、駆動カム70のカム面70dが駆動軸54からの離間距離が最大となる離間位置に到達したとき、制御部40はモータ30を停止する。これにより駆動軸54の回転が停止して駆動カム70も停止し、定着フィルム18と加圧ローラ19との離間動作は完了する。   As shown in FIG. 14B, when the cam surface 70d of the drive cam 70 reaches the separation position where the separation distance from the drive shaft 54 is maximum, the control unit 40 stops the motor 30. As a result, the rotation of the drive shaft 54 stops and the drive cam 70 also stops, and the separation operation between the fixing film 18 and the pressure roller 19 is completed.

このとき、図14(b)に示すように、加圧バネ56の付勢力により、加圧板51が駆動カム70のカム面70dに当接して該駆動カム70を図14(b)の右方向に付勢する付勢力Fは、駆動軸54の中心で受けている。このため、駆動カム70に加圧バネ56の付勢力による回転トルクは発生しない。また、フィルムホルダ52にも加圧バネ56の付勢力が伝わらない。このため、フィルムホルダ52に軸支された定着フィルム18は安定した状態で静止し、定着フィルム18と加圧ローラ19との定着離間状態を維持する。   At this time, as shown in FIG. 14 (b), the pressing plate 51 abuts against the cam surface 70d of the driving cam 70 by the urging force of the pressing spring 56 so that the driving cam 70 is moved to the right in FIG. 14 (b). The urging force F for urging is received at the center of the drive shaft 54. For this reason, rotational torque due to the urging force of the pressure spring 56 is not generated in the drive cam 70. Further, the urging force of the pressure spring 56 is not transmitted to the film holder 52 as well. For this reason, the fixing film 18 pivotally supported by the film holder 52 is stopped in a stable state, and the fixing separation state between the fixing film 18 and the pressure roller 19 is maintained.

次に、図14(b)に示す離間状態から図12に示す加圧状態に戻るときの動作について説明する。本実施形態では、加圧状態に戻るときの駆動軸54の回転方向は、離間状態に移行するときとは逆方向に回転する。図15(a)に示すように、従動カム71のカム面71dは加圧板51との間の摩擦力Rにより保持されている。   Next, the operation for returning from the separated state shown in FIG. 14B to the pressurized state shown in FIG. 12 will be described. In the present embodiment, the rotation direction of the drive shaft 54 when returning to the pressurized state rotates in the opposite direction to that when shifting to the separated state. As shown in FIG. 15 (a), the cam surface 71 d of the driven cam 71 is held by the frictional force R with the pressure plate 51.

このため、モータ30により駆動軸54に固定された駆動カム70を図15(a)の矢印k方向に回転すると、駆動カム70のみが図15(a)の矢印k方向に回転を始める。このとき、駆動カム70の当接面70iと従動カム71の当接面71iとの間で圧縮されていた緩衝部材55が自身の弾性力により伸長して復元して解放される。そして、駆動カム70の突当面70bが従動カム71の突当面71bに当接して、従動カム71は摩擦力Rに抗して駆動カム70に従動して図15(a)の矢印k方向に回転する。   Therefore, when the drive cam 70 fixed to the drive shaft 54 by the motor 30 is rotated in the direction of the arrow k in FIG. 15A, only the drive cam 70 starts to rotate in the direction of the arrow k in FIG. At this time, the buffer member 55 compressed between the contact surface 70i of the drive cam 70 and the contact surface 71i of the driven cam 71 is expanded and restored by its own elastic force and released. Then, the abutting surface 70b of the driving cam 70 comes into contact with the abutting surface 71b of the driven cam 71, and the driven cam 71 is driven by the driving cam 70 against the friction force R in the direction of the arrow k in FIG. Rotate.

図15(b)に示すように、従動カム71のカム面71dの駆動軸54からの離間距離が図14(b)に示す最大の離間距離から減少する変曲点71d1に達する。すると、加圧バネ56の付勢力により、加圧板51が従動カム71のカム面71dの変曲点71d1に当接して該従動カム71を図15(b)の右方向に付勢する付勢力Fは、該従動カム71の回転中心となる駆動軸54の中心よりも図15(b)の下方向にずれる。   As shown in FIG. 15B, the separation distance from the drive shaft 54 of the cam surface 71d of the driven cam 71 reaches an inflection point 71d1 where the separation distance decreases from the maximum separation distance shown in FIG. Then, due to the biasing force of the pressure spring 56, the pressure plate 51 abuts against the inflection point 71d1 of the cam surface 71d of the driven cam 71 and biases the driven cam 71 in the right direction in FIG. F is shifted downward in FIG. 15B from the center of the drive shaft 54 which is the rotation center of the driven cam 71.

このため、従動カム71に図15(b)の矢印k方向の回転トルクが発生し、該従動カム71は駆動カム70よりも先回りする。このとき、従動カム71の当接面71iと駆動カム70の当接面70iとの間に挟まれた緩衝部材55が自身の弾性力に抗して圧縮されてダンパとして働き、先回りする従動カム71の回転速度を減速させる。   For this reason, rotational torque in the direction of arrow k in FIG. 15B is generated in the driven cam 71, and the driven cam 71 is advanced ahead of the drive cam 70. At this time, the shock absorbing member 55 sandwiched between the contact surface 71i of the driven cam 71 and the contact surface 70i of the drive cam 70 is compressed against its own elastic force to act as a damper, and the driven cam that moves forward. Reduce the speed of 71.

その後、圧縮された緩衝部材55が自身の弾性力により復元して伸長して解放される。そして、駆動カム70の突当面70bと、従動カム71の突当面71bとが再び当接して直接押し始める。すると、該従動カム71は駆動カム70と同期して図15(b)の矢印k方向に従動回転する。   Thereafter, the compressed buffer member 55 is restored by its own elastic force, and is expanded and released. Then, the abutting surface 70b of the drive cam 70 and the abutting surface 71b of the driven cam 71 come into contact again and start to push directly. Then, the driven cam 71 is driven to rotate in the direction of the arrow k in FIG.

そして、図12に示すように、駆動カム70の平坦面70cが加圧板51と平行に配置された加圧位置に到達する。そのとき、制御部40がモータ30を停止させる。そして、駆動軸54の回転が停止して駆動カム70と従動カム71も停止し、定着フィルム18と加圧ローラ19との加圧動作は完了する。   Then, as shown in FIG. 12, the flat surface 70 c of the drive cam 70 reaches the pressure position where it is arranged in parallel with the pressure plate 51. At that time, the control unit 40 stops the motor 30. Then, the rotation of the drive shaft 54 stops, the drive cam 70 and the driven cam 71 also stop, and the pressing operation of the fixing film 18 and the pressure roller 19 is completed.

上記構成によれば、従動カム71を駆動カム70から分離し、従動カム71を先回りさせ、その回転速度を緩衝部材55によって減速させる。これにより、従動カム71と駆動カム70との衝突による衝撃音を低減することが出来る。   According to the above configuration, the driven cam 71 is separated from the drive cam 70, the driven cam 71 is advanced, and the rotation speed is reduced by the buffer member 55. Thereby, it is possible to reduce the impact sound caused by the collision between the driven cam 71 and the drive cam 70.

また、加圧バネ56の付勢力に抗して加圧板51を付勢するカムを従動カム71と駆動カム70とに二分割することで、緩衝部材55を収容する空隙72のスペースを前記第1、第2実施形態の空隙53bのスペースよりも大きくとることが出来る。   Further, the cam for urging the pressure plate 51 against the urging force of the pressure spring 56 is divided into a driven cam 71 and a drive cam 70, so that the space of the gap 72 for accommodating the buffer member 55 can be increased. It can be made larger than the space of the gap 53b in the first and second embodiments.

これにより、空隙72のスペースに応じた大きな体積を有する緩衝部材55を取り付けることが出来、緩衝効果も向上して先回りする従動カム71の回転速度の減速効果を向上することが出来、更なる衝撃音の低減に繋がる。他の構成は前記各実施形態と同様に構成され、同様の効果を得ることが出来る。   As a result, the buffer member 55 having a large volume corresponding to the space of the gap 72 can be attached, the buffering effect can be improved, and the effect of reducing the rotational speed of the follower cam 71 can be improved. This leads to sound reduction. Other configurations are the same as those in the above embodiments, and the same effects can be obtained.

〔第5実施形態〕
次に、図16を用いて本発明に係る加圧解除装置を備えた画像形成装置の第5実施形態の構成について説明する。尚、前記各実施形態と同様に構成したものは同一の符号を付して説明を省略する。
[Fifth Embodiment]
Next, the configuration of the fifth embodiment of the image forming apparatus including the pressure release device according to the present invention will be described with reference to FIG. In addition, what was comprised similarly to each said embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.

前記各実施形態では、加圧解除装置を定着装置17の定着フィルム18と加圧ローラ19との加圧を解除する装置として構成した。本実施形態では、固定位置に設けられる対象部材を表面に静電潜像が形成される像担持体となる感光ドラム1とした。また、該感光ドラム1に対して接離可能に設けられる被加圧部材を該感光ドラム1に対向してトナーを供給する現像回転体となる現像ローラ3として構成したものである。   In each of the embodiments described above, the pressure release device is configured as a device that releases the pressurization between the fixing film 18 and the pressure roller 19 of the fixing device 17. In the present embodiment, the target member provided at the fixed position is the photosensitive drum 1 serving as an image carrier on which an electrostatic latent image is formed. Further, a member to be pressed provided so as to be able to come into contact with and separate from the photosensitive drum 1 is configured as a developing roller 3 serving as a developing rotary member that supplies toner facing the photosensitive drum 1.

以下に、プロセスカートリッジ5の現像ローラ3を感光ドラム1に対して当接、離間する構成について説明する。前述した各実施形態の加圧解除装置を適用可能である。本実施形態では、駆動軸54の回転方向が現像ローラ3の離間動作と当接動作とで同一方向に構成される場合の一例について説明する。   Hereinafter, a configuration in which the developing roller 3 of the process cartridge 5 is brought into contact with and separated from the photosensitive drum 1 will be described. The pressure release device of each embodiment described above can be applied. In the present embodiment, an example in which the rotation direction of the drive shaft 54 is configured in the same direction by the separation operation and the contact operation of the developing roller 3 will be described.

<プロセスカートリッジの現像ローラ当接離間動作>
図16に示すように、プロセスカートリッジ5は、画像形成装置101本体に対して固定位置に位置決めされたドラムユニット86と、該ドラムユニット86に対して回動中心83を中心に揺動可能に配設された現像ユニット81を有して構成されている。現像ユニット81は現像ローラ3を回転自在に軸支する揺動部材として構成される。
<Processing Cartridge Developing Roller Contact / Separation>
As shown in FIG. 16, the process cartridge 5 is disposed so as to be swingable around a rotation center 83 with respect to the drum unit 86 positioned at a fixed position with respect to the main body of the image forming apparatus 101. The developing unit 81 is configured. The developing unit 81 is configured as a swinging member that rotatably supports the developing roller 3.

ドラムユニット86と現像ユニット81には引張バネ85の端部がそれぞれ係止されており、現像ユニット81に回転可能に軸支された現像ローラ3は引張バネ85の引っ張り力によりドラムユニット80に回転可能に軸支された感光ドラム1に加圧当接されている。引張バネ85は現像ユニット81を付勢して現像ローラ3を感光ドラム1に対して圧接させる加圧手段として構成される。   The end of the tension spring 85 is locked to the drum unit 86 and the developing unit 81, respectively, and the developing roller 3 rotatably supported by the developing unit 81 can be rotated to the drum unit 80 by the pulling force of the tension spring 85. It is in pressure contact with the shaft-supported photosensitive drum 1. The tension spring 85 is configured as a pressing unit that urges the developing unit 81 to press the developing roller 3 against the photosensitive drum 1.

画像形成装置101本体には圧解除アーム82が回動中心84を中心に揺動可能に設けられている。圧解除アーム82の一方の端面82aは現像ユニット81の回動中心83よりも図16の下方に配置された当接面81aに当接し、該圧解除アーム82の他方の端面82bは圧解除カム53のカム面53dに当接するように構成されている。圧解除アーム82には圧解除カム53側の端面82bが常に該圧解除カム53のカム面53dに当接するように付勢手段となる図示しない捩じりコイルバネが備えられている。   A pressure release arm 82 is provided in the main body of the image forming apparatus 101 so as to be swingable about a rotation center 84. One end surface 82a of the pressure releasing arm 82 contacts an abutting surface 81a disposed below the rotation center 83 of the developing unit 81 in FIG. 16, and the other end surface 82b of the pressure releasing arm 82 is a pressure releasing cam. It is comprised so that it may contact | abut to 53d cam surface 53d. The pressure release arm 82 is provided with a torsion coil spring (not shown) serving as a biasing means so that the end surface 82b on the pressure release cam 53 side always abuts against the cam surface 53d of the pressure release cam 53.

本実施形態において、引張バネ85の付勢力に抗して現像ローラ3と感光ドラム1との圧接状態を解除する加圧解除手段は、制御部40により制御されるモータ30により回転駆動する駆動軸54の外周面に突設された突起部54aを有する。   In this embodiment, the pressure releasing means for releasing the pressure contact state between the developing roller 3 and the photosensitive drum 1 against the urging force of the tension spring 85 is a drive shaft that is rotationally driven by the motor 30 controlled by the control unit 40. A protrusion 54 a is provided on the outer peripheral surface of the protrusion 54.

更に、突起部54aの回転軸となる駆動軸54に回転自在に軸支され、該突起部54aに対して回転方向に所定の遊びを持って従動回転可能に設けられた従動部材となる圧解除カム53を有する。   Further, the pressure release becomes a driven member that is rotatably supported by a drive shaft 54 that serves as a rotation shaft of the protrusion 54a, and that is driven to rotate with a predetermined play in the rotation direction with respect to the protrusion 54a. A cam 53 is provided.

圧解除カム53のカム面53dは引張バネ85の一端部に設けられた現像ユニット81を介して圧解除アーム82の端面82bからなる当接部に当接摺動する。そして、該圧解除アーム82を介して引張バネ85の付勢力に抗して現像ローラ3と感光ドラム1との圧接状態を解除する。   The cam surface 53d of the pressure release cam 53 abuts and slides on the contact portion formed by the end surface 82b of the pressure release arm 82 via the developing unit 81 provided at one end of the tension spring 85. Then, the pressure contact state between the developing roller 3 and the photosensitive drum 1 is released against the biasing force of the tension spring 85 via the pressure release arm 82.

更に、突起部54aと圧解除カム53との回転方向の所定の遊びを制御する緩衝部材55を有する。圧解除カム53は、突起部54aと緩衝部材55とを回転方向に所定の遊びを持って収容する空隙53bを有する。   Further, a buffer member 55 is provided for controlling a predetermined play in the rotational direction between the protrusion 54a and the pressure release cam 53. The pressure release cam 53 has a gap 53b that accommodates the protrusion 54a and the buffer member 55 with a predetermined play in the rotation direction.

また、圧解除カム53は、突起部54aの回転方向に対してカム面53dの駆動軸54からの離間距離が小さくなる変曲点53d1を有する。   Further, the pressure release cam 53 has an inflection point 53d1 in which the distance of the cam surface 53d from the drive shaft 54 becomes small with respect to the rotation direction of the protrusion 54a.

現像ローラ3を感光ドラム1から離間するための圧解除カム53は、画像形成装置101本体に配設され、制御部40により制御されてモータ30により回転駆動される駆動軸54に回転自在に軸支されている。圧解除カム53の外周面には駆動軸54を中心とする径(駆動軸54からの離間距離)が連続的に異なるカム面53dが形成されている。   A pressure release cam 53 for separating the developing roller 3 from the photosensitive drum 1 is disposed in the main body of the image forming apparatus 101, and is rotatable about a drive shaft 54 controlled by the control unit 40 and driven to rotate by the motor 30. It is supported. On the outer peripheral surface of the pressure release cam 53, a cam surface 53d having continuously different diameters (a distance from the drive shaft 54) around the drive shaft 54 is formed.

圧解除カム53の貫通穴53aには駆動軸54が嵌挿されており、該圧解除カム53が駆動軸54に対して回転自在に支持されている。駆動軸54に固定された突起部54aは圧解除カム53の貫通穴53aに連通する該圧解除カム53の周方向に所定の長さを有する空隙53b内に該空隙53b内を回転方向に移動自在に収容されている。圧解除カム53の空隙53bの形状と、駆動軸54に設けられた突起部54aの形状とを適宜設定することにより圧解除カム53と突起部54aとの回転方向の遊び量が決定される。   A drive shaft 54 is fitted into the through hole 53 a of the pressure release cam 53, and the pressure release cam 53 is rotatably supported with respect to the drive shaft 54. The protrusion 54a fixed to the drive shaft 54 moves in the rotation direction in the gap 53b into the gap 53b having a predetermined length in the circumferential direction of the pressure release cam 53 communicating with the through hole 53a of the pressure release cam 53. It is freely housed. By appropriately setting the shape of the gap 53b of the pressure release cam 53 and the shape of the protrusion 54a provided on the drive shaft 54, the amount of play in the rotational direction between the pressure release cam 53 and the protrusion 54a is determined.

駆動軸54は、画像形成装置101本体に対して、回転可能に支持されている。駆動軸54は、モータ30により回転駆動される。駆動軸54には、駆動を圧解除カム53に伝えるための突起部54aを有している。   The drive shaft 54 is rotatably supported with respect to the image forming apparatus 101 main body. The drive shaft 54 is rotationally driven by the motor 30. The drive shaft 54 has a protrusion 54 a for transmitting the drive to the pressure release cam 53.

緩衝部材55は駆動軸54の突起部54aに隣接して圧解除カム53の空隙53b内に収容して配設される。緩衝部材55は圧解除カム53が駆動軸54に対して先回りしたときに該圧解除カム53の回転速度を減速させる役割を果たす。緩衝部材55は圧解除カム53の先回りによる回転速度を減速させるダンパとしての役割を果たす。このため、緩衝部材55の材質は、発泡ウレタン等の低反発材が望ましい。   The buffer member 55 is accommodated and disposed in the gap 53b of the pressure release cam 53 adjacent to the protrusion 54a of the drive shaft 54. The buffer member 55 serves to decelerate the rotational speed of the pressure release cam 53 when the pressure release cam 53 is advanced with respect to the drive shaft 54. The buffer member 55 serves as a damper that decelerates the rotational speed of the pressure release cam 53 in the forward direction. For this reason, the material of the buffer member 55 is preferably a low repulsion material such as urethane foam.

尚、緩衝部材55は圧解除カム53の空隙53b内から脱落しないように、圧解除カム53の空隙53bの壁面53fに該緩衝部材55の端面を両面テープ等の固定部材によって保持させる。或いは、圧解除カム53の空隙53bの表面側に壁面を設けて閉鎖空間にすることでも良い。   The end face of the buffer member 55 is held by a fixing member such as a double-sided tape on the wall surface 53f of the gap 53b of the pressure release cam 53 so that the buffer member 55 does not fall out of the gap 53b of the pressure release cam 53. Alternatively, a wall surface may be provided on the surface side of the gap 53b of the pressure release cam 53 to form a closed space.

次に、図16を用いてプロセスカートリッジ5の現像ローラ3と感光ドラム1との当接、離間動作について説明する。   Next, the contact and separation operations of the developing roller 3 of the process cartridge 5 and the photosensitive drum 1 will be described with reference to FIG.

本実施形態では、感光ドラム1に対する現像ローラ3の当接動作と、現像ローラ3の離間動作とで駆動軸54の回転方向が同一方向の場合の一例について説明する。   In the present embodiment, an example in which the rotation direction of the drive shaft 54 is the same in the contact operation of the developing roller 3 with respect to the photosensitive drum 1 and the separation operation of the developing roller 3 will be described.

図16(a)に示すように、圧解除カム53のカム面53dで駆動軸54からの離間距離が最小となる当接位置に圧解除アーム82の端面82bが当接している。この状態では、引張バネ85の引っ張り力により現像ユニット81が回動中心83を中心に図16(a)の反時計回り方向に付勢されて現像ローラ3が感光ドラム1に対して加圧状態になっている。   As shown in FIG. 16A, the end surface 82b of the pressure release arm 82 is in contact with the contact position where the separation distance from the drive shaft 54 is minimum on the cam surface 53d of the pressure release cam 53. In this state, the developing unit 81 is urged counterclockwise in FIG. 16A around the rotation center 83 by the pulling force of the tension spring 85, and the developing roller 3 is pressed against the photosensitive drum 1. It has become.

先ず、現像ローラ3が、図16(a)に示す加圧状態から、図16(b)に示す離間状態に移行するときの動作について説明する。図16(a)に示すように、制御部40によりモータ30を制御して駆動軸54を図16(a)の矢印e方向に回転する。これにより、突起部54aが圧解除カム53の空隙53bの壁面53eに当接して該圧解除カム53が駆動軸54に従動して図16(a)の矢印g方向に回転を始める。   First, the operation when the developing roller 3 shifts from the pressurized state shown in FIG. 16A to the separated state shown in FIG. 16B will be described. As shown in FIG. 16 (a), the control unit 40 controls the motor 30 to rotate the drive shaft 54 in the direction of arrow e in FIG. 16 (a). As a result, the protrusion 54a abuts against the wall surface 53e of the gap 53b of the pressure release cam 53, and the pressure release cam 53 is driven by the drive shaft 54 and starts rotating in the direction of the arrow g in FIG.

圧解除カム53のカム面53dに端面82bが当接摺動する圧解除アーム82が図示しない捩じりコイルバネの付勢力に抗して回動中心84を中心に図16(a)の矢印m方向に回動する。そして、該圧解除アーム82の端面82aが現像ユニット81の当接面81aを押圧して現像ユニット81が引張バネ85の引っ張り力に抗して回動中心83を中心に図16(a)の矢印n方向に回転し、現像ローラ3を感光ドラム1から離間する動作を開始する。   The pressure release arm 82 in which the end face 82b comes into contact with and slides on the cam surface 53d of the pressure release cam 53 is opposed to the biasing force of a torsion coil spring (not shown), and the arrow m in FIG. Rotate in the direction. Then, the end surface 82a of the pressure release arm 82 presses against the contact surface 81a of the developing unit 81, and the developing unit 81 resists the pulling force of the tension spring 85, and the center of rotation 83 is shown in FIG. Rotating in the direction of arrow n, the operation of separating the developing roller 3 from the photosensitive drum 1 is started.

このとき、駆動軸54の突起部54aは圧解除カム53の空隙53bの壁面53eに当接して直接押している。このため、該空隙53b内に収容された緩衝部材55は解放された状態である。   At this time, the protrusion 54 a of the drive shaft 54 is in direct contact with and pressed against the wall surface 53 e of the gap 53 b of the pressure release cam 53. For this reason, the buffer member 55 accommodated in the gap 53b is in a released state.

図16(b)に示すように、圧解除カム53のカム面53dが駆動軸54からの離間距離が最大となる離間位置に到達したとき、制御部40はモータ30を停止する。これにより駆動軸54の回転が停止して圧解除カム53も停止し、現像ローラ3を感光ドラム1から離間する動作は完了する。   As shown in FIG. 16B, when the cam surface 53d of the pressure release cam 53 reaches the separation position where the separation distance from the drive shaft 54 is maximum, the control unit 40 stops the motor 30. As a result, the rotation of the drive shaft 54 stops and the pressure release cam 53 also stops, and the operation of separating the developing roller 3 from the photosensitive drum 1 is completed.

このとき、図16(b)に示すように、引張バネ85の引っ張り力と、図示しない捩じりコイルバネの付勢力とにより、解除アーム82の端面82bが圧解除カム53のカム面53dに当接して該圧解除カム53を図16(b)の左方向に付勢する。その付勢力Fは、駆動軸54の中心で受けている。このため、圧解除カム53に引張バネ85の引っ張り力と、図示しない捩じりコイルバネの付勢力とによる回転トルクは発生しない。このため、現像ユニット81に軸支された現像ローラ3は安定した状態で静止し、現像ローラ3と感光ドラム1との離間状態を維持する。   At this time, as shown in FIG. 16B, the end surface 82b of the release arm 82 abuts against the cam surface 53d of the pressure release cam 53 by the pulling force of the tension spring 85 and the biasing force of the torsion coil spring (not shown). In contact therewith, the pressure release cam 53 is urged to the left in FIG. The biasing force F is received at the center of the drive shaft 54. For this reason, no rotational torque is generated in the pressure release cam 53 due to the pulling force of the tension spring 85 and the biasing force of a torsion coil spring (not shown). For this reason, the developing roller 3 pivotally supported by the developing unit 81 stops in a stable state, and maintains a separated state between the developing roller 3 and the photosensitive drum 1.

次に、現像ローラ3が図16(b)に示す離間状態から図16(a)に示す加圧状態に戻るときの動作について説明する。図16(c)に示すように、制御部40により制御されるモータ30により駆動軸54を図16(c)の矢印e方向に回転する。これにより、突起部54aが圧解除カム53の空隙53bの壁面53eに当接して該圧解除カム53が駆動軸54に従動して図16(c)の矢印g方向に回転を始める。   Next, the operation when the developing roller 3 returns from the separated state shown in FIG. 16B to the pressure state shown in FIG. As shown in FIG. 16 (c), the drive shaft 54 is rotated in the direction of arrow e in FIG. 16 (c) by the motor 30 controlled by the control unit 40. As a result, the protrusion 54a abuts against the wall surface 53e of the gap 53b of the pressure release cam 53, and the pressure release cam 53 is driven by the drive shaft 54 and starts rotating in the direction of arrow g in FIG.

図16(c)に示すように、圧解除カム53のカム面53dの駆動軸54からの離間距離が図16(b)に示す最大の離間距離から減少する変曲点53d1に達する。すると、圧解除カム53に引張バネ85の引っ張り力と、図示しない捩じりコイルバネの付勢力とにより、圧解除アーム82の端面82bが圧解除カム53のカム面53dの変曲点53d1に当接して該圧解除カム53を図16(c)の左方向に付勢する。その付勢力Fは、圧解除カム53の回転中心となる駆動軸54の中心よりも図16(c)の下方向にずれる。   As shown in FIG. 16C, the separation distance from the drive shaft 54 of the cam surface 53d of the pressure release cam 53 reaches an inflection point 53d1 where the separation distance decreases from the maximum separation distance shown in FIG. Then, the end surface 82b of the pressure release arm 82 contacts the inflection point 53d1 of the cam surface 53d of the pressure release cam 53 by the pulling force of the tension spring 85 and the biasing force of the torsion coil spring (not shown) on the pressure release cam 53. In contact therewith, the pressure release cam 53 is urged to the left in FIG. The biasing force F is shifted downward in FIG. 16C from the center of the drive shaft 54 that is the rotation center of the pressure release cam 53.

このため、圧解除カム53に図16(c)の矢印g方向の回転トルクが発生し、該圧解除カム53は駆動軸54よりも先回りする。このとき、圧解除カム53の空隙53bの壁面53fと突起部54aとの間に挟まれた緩衝部材55が自身の弾性力に抗して圧縮されてダンパとして働き、先回りする圧解除カム53の回転速度を減速させる。   For this reason, rotational torque in the direction of arrow g in FIG. 16C is generated in the pressure release cam 53, and the pressure release cam 53 is advanced ahead of the drive shaft 54. At this time, the buffer member 55 sandwiched between the wall surface 53f of the gap 53b of the pressure release cam 53 and the projection 54a is compressed against its own elastic force and acts as a damper, Reduce the rotation speed.

そして、圧縮された緩衝部材55が自身の弾性力により復元して伸長して解放され、突起部54aが圧解除カム53の空隙53bの壁面53eに再び当接して直接押し始める。すると、該圧解除カム53が駆動軸54と同期して図16(c)の矢印g方向に従動回転する。   Then, the compressed cushioning member 55 is restored by its own elastic force, is expanded and released, and the projection 54a comes into contact with the wall surface 53e of the gap 53b of the pressure release cam 53 again and starts to push directly. Then, the pressure release cam 53 is driven to rotate in the direction of the arrow g in FIG.

そして、図16(a)に示すように、圧解除カム53のカム面53dで駆動軸54からの離間距離が最小となる当接位置に圧解除アーム82の端面82bが当接する加圧位置に到達する。そのとき、制御部40がモータ30を停止させる。そして、駆動軸54の回転が停止して圧解除カム53も停止し、現像ローラ3と感光ドラム1との加圧動作は完了する。   Then, as shown in FIG. 16 (a), the cam surface 53d of the pressure release cam 53 is in a pressure position where the end surface 82b of the pressure release arm 82 comes into contact with the contact position where the separation distance from the drive shaft 54 is minimized. To reach. At that time, the control unit 40 stops the motor 30. Then, the rotation of the drive shaft 54 stops and the pressure release cam 53 also stops, and the pressurizing operation between the developing roller 3 and the photosensitive drum 1 is completed.

上記構成によれば、圧解除カム53が駆動軸54よりも先回りするときの回転速度を緩衝部材55により減速することが出来る。これにより、駆動軸54に設けられた突起部54aと、圧解除カム53の空隙53bの壁面53e,53fとの衝突による衝撃音を低減することが出来る。他の構成は前記各実施形態と同様に構成され、同様の効果を得ることが出来る。   According to the above configuration, the rotational speed when the pressure release cam 53 is advanced beyond the drive shaft 54 can be reduced by the buffer member 55. Thereby, it is possible to reduce the impact sound caused by the collision between the protrusion 54a provided on the drive shaft 54 and the wall surfaces 53e and 53f of the gap 53b of the pressure release cam 53. Other configurations are the same as those in the above embodiments, and the same effects can be obtained.

18 …定着フィルム(被加圧部材;定着回転体)
19 …加圧ローラ(対象部材;加圧回転体)
30 …モータ(駆動手段)
51 …加圧板(当接部)
52 …フィルムホルダ(揺動部材)
53 …圧解除カム(従動部材)
53d …カム面
54 …駆動軸(回転軸)
54a …突起部(駆動部材)
55 …緩衝部材
56 …加圧バネ(加圧手段)
18: Fixing film (pressurized member; fixing rotating body)
19… Pressure roller (target member; pressure rotator)
30 ... Motor (drive means)
51… Pressure plate (contact part)
52 ... Film holder (rocking member)
53… Pressure release cam (driven member)
53d ... cam surface
54… Drive shaft (rotary shaft)
54a ... Projection (drive member)
55… Cushioning member
56… Pressure spring (Pressure means)

Claims (8)

固定位置に設けられる対象部材に対して接離可能に設けられる被加圧部材と、
前記被加圧部材を回転自在に軸支する揺動部材と、
前記揺動部材を付勢して前記被加圧部材を前記対象部材に対して圧接させる加圧手段と、
前記加圧手段の付勢力に抗して前記被加圧部材と前記対象部材との圧接状態を解除する加圧解除手段と、
を備え、
前記加圧解除手段は、
駆動手段により回転駆動する駆動部材と、
前記駆動部材の回転軸に回転自在に軸支され、前記駆動部材に対して回転方向に所定の遊びを持って従動回転可能に設けられ、前記加圧手段の一端部に設けられた当接部に当接摺動して前記加圧手段の付勢力に抗して前記被加圧部材と前記対象部材との圧接状態を解除するカム面を有する従動部材と、
前記駆動部材と前記従動部材との回転方向の所定の遊びを制御する緩衝部材と、
を有することを特徴とする加圧解除装置。
A member to be pressed provided so as to be able to contact and separate from a target member provided at a fixed position;
A rocking member that rotatably supports the member to be pressed, and
Pressurizing means for urging the swinging member to press the pressed member against the target member;
Pressure release means for releasing the pressure contact state between the member to be pressurized and the target member against the urging force of the pressure means;
With
The pressure release means is
A drive member that is rotationally driven by a drive means;
An abutting portion that is rotatably supported by a rotation shaft of the driving member, is rotatably driven with a predetermined play in the rotation direction with respect to the driving member, and is provided at one end of the pressurizing means A driven member having a cam surface that abuts and slides to release the pressure contact state between the member to be pressed and the target member against the urging force of the pressing means;
A buffer member for controlling a predetermined play in the rotational direction of the drive member and the driven member;
A pressure release device.
前記従動部材は、前記駆動部材の回転方向に対して前記カム面の前記回転軸からの離間距離が小さくなる変曲点を有することを特徴とする請求項1に記載の加圧解除装置。   2. The pressure release device according to claim 1, wherein the driven member has an inflection point at which a separation distance of the cam surface from the rotation shaft becomes small with respect to a rotation direction of the drive member. 前記従動部材は、前記駆動部材と前記緩衝部材とを回転方向に所定の遊びを持って収容する空隙を有することを特徴とする請求項1または請求項2に記載の加圧解除装置。   3. The pressure release device according to claim 1, wherein the driven member includes a gap that accommodates the driving member and the buffer member with a predetermined play in a rotation direction. 4. 前記駆動部材は、前記加圧手段の一端部に設けられた当接部に当接摺動して前記加圧手段の付勢力に抗して前記被加圧部材と前記対象部材との圧接状態を解除する第二のカム面を有し、前記駆動部材の回転方向に対して前記第二のカム面の前記回転軸からの離間距離が小さくなる変曲点を有さないことを特徴とする請求項2に記載の加圧解除装置。   The driving member abuts and slides on a contact portion provided at one end of the pressurizing unit, and pressurizes the pressed member and the target member against the urging force of the pressurizing unit. And a second cam surface for releasing the rotation of the drive member, and the second cam surface does not have an inflection point at which the distance from the rotation shaft of the second cam surface is small. The pressure release device according to claim 2. 前記駆動部材または前記従動部材の少なくとも一方に前記緩衝部材を回転方向に所定の遊びを持って収容する空隙を有することを特徴とする請求項1、2、4のいずれか1項に記載の加圧解除装置。   5. The additive according to claim 1, wherein at least one of the driving member and the driven member has a gap for accommodating the buffer member with a predetermined play in a rotation direction. Pressure release device. 前記従動部材のカム面と、前記駆動部材の第2のカム面とは連続的に繋がっていることを特徴とする請求項4または請求項5に記載の加圧解除装置。   The pressure release device according to claim 4 or 5, wherein the cam surface of the driven member and the second cam surface of the drive member are continuously connected. 請求項1〜6のいずれか1項に記載の加圧解除装置を有し、
前記対象部材は、記録材上に形成されたトナー画像を定着する定着装置の加圧回転体であり、前記被加圧部材は前記加圧回転体に対向する定着回転体であることを特徴とする画像形成装置。
The pressure release device according to any one of claims 1 to 6,
The target member is a pressure rotator of a fixing device that fixes a toner image formed on a recording material, and the member to be pressed is a fixing rotator facing the pressure rotator. Image forming apparatus.
請求項1〜6のいずれか1項に記載の加圧解除装置を有し、
前記対象部材は、表面に静電潜像が形成される像担持体であり、前記被加圧部材は前記像担持体に対向してトナーを供給する現像回転体であることを特徴とする画像形成装置。
The pressure release device according to any one of claims 1 to 6,
The target member is an image carrier on which an electrostatic latent image is formed on a surface, and the pressed member is a developing rotary member that supplies toner to the image carrier. Forming equipment.
JP2012193666A 2012-09-04 2012-09-04 Pressure release device and image forming apparatus Pending JP2014048597A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9388000B2 (en) 2014-01-31 2016-07-12 Canon Kabushiki Kaisha Spacing mechanism for spacing two members, and a fixing device sheet feeding-conveying device and image forming apparatus incorporating same
JP2018092103A (en) * 2016-12-07 2018-06-14 京セラドキュメントソリューションズ株式会社 Fixation device and image formation apparatus
US10114320B2 (en) 2016-11-28 2018-10-30 Kyocera Document Solutions Inc. Fixing device and image forming apparatus
CN109581841A (en) * 2017-09-28 2019-04-05 兄弟工业株式会社 Image forming apparatus
JP2020024355A (en) * 2018-07-27 2020-02-13 株式会社リコー Image forming apparatus

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9388000B2 (en) 2014-01-31 2016-07-12 Canon Kabushiki Kaisha Spacing mechanism for spacing two members, and a fixing device sheet feeding-conveying device and image forming apparatus incorporating same
US10114320B2 (en) 2016-11-28 2018-10-30 Kyocera Document Solutions Inc. Fixing device and image forming apparatus
JP2018092103A (en) * 2016-12-07 2018-06-14 京セラドキュメントソリューションズ株式会社 Fixation device and image formation apparatus
CN108170013A (en) * 2016-12-07 2018-06-15 京瓷办公信息系统株式会社 Fixing device and image forming apparatus
US10222728B2 (en) 2016-12-07 2019-03-05 Kyocera Document Solutions Inc. Fixing device and image forming apparatus
CN108170013B (en) * 2016-12-07 2020-11-10 京瓷办公信息系统株式会社 Fixing device and image forming apparatus
CN109581841A (en) * 2017-09-28 2019-04-05 兄弟工业株式会社 Image forming apparatus
CN109581841B (en) * 2017-09-28 2022-11-11 兄弟工业株式会社 Image forming apparatus with a toner supply unit
JP2020024355A (en) * 2018-07-27 2020-02-13 株式会社リコー Image forming apparatus
JP7169540B2 (en) 2018-07-27 2022-11-11 株式会社リコー image forming device

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