JP5817254B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including a pair of rollers for conveying a recording sheet.

  Image forming apparatuses such as laser printers are provided with a pair of rollers (roller-like members) for transporting a recording sheet, such as a photosensitive drum and a transfer roller, a pair of registration rollers, and a pair of transport rollers. Yes. In such a roller, one roller is biased by the other roller in order to generate a conveying force.

  By the way, if the image forming apparatus is placed in a high temperature environment for a long time before the shipped image forming apparatus reaches the user, indentations such as dents are formed on the surfaces of the pair of rollers that are in pressure contact. It can happen.

  Therefore, for example, in Patent Document 1, when a ring member having a protrusion provided on the outer peripheral surface is loosely fitted to the shaft of one roller in a rotatable state, and the apparatus is not operated for a long time, the protrusion is connected to the other roller. A configuration is disclosed in which the pair of rollers are spaced apart from each other by being brought into contact with each other. According to this, it can prevent that an indentation arises on the surface of a roller.

  In the image forming apparatus disclosed in Patent Document 1, when the other roller starts to rotate during use, the ring member rotates and the protrusion of the ring member separates from the other roller, so that one roller is pressed against the other roller. It has come to be.

JP 2000-320537 A

  However, in the above-described prior art, the position of the ring member whose protrusion is separated from the other roller is not particularly restricted, and therefore can freely rotate, and the protrusion may interfere with the other roller again. . Also, when separating one roller from the other roller, the ring member is rotated while separating one roller, and the protrusion is disposed between the shaft of one roller and the end of the other roller. Since it is necessary, there is a problem that it is not easy to assemble one roller and the other roller in a separated state.

  The present invention has been made in view of the above background, and in a configuration including a separation member that separates one roller from the other roller, the separation member that is retracted from between one roller and the other roller is in a retracted position. It is an object of the present invention to provide an image forming apparatus that can be maintained at the same time. Another object of the present invention is to provide an image forming apparatus that can be easily assembled in a state where one roller and the other roller are separated from each other.

In order to achieve the above object, an image forming apparatus according to the present invention includes a pair of rollers for conveying a recording sheet between one roller and the other roller, a first urging member, a separation member, and a release member. And a maintenance member.
The pair of rollers is supported so as to be movable in a direction in which one roller approaches and separates from the other roller.
The first urging member urges one roller toward the other roller.
The separation member has a separation position where one roller is separated from the other roller against the urging force of the first urging member, and one roller can contact the other roller by the urging force of the first urging member. It is supported so that it can rotate between the retracted position.
The release member rotates the separation member from the separation position to the retracted position by the rotation of the pair of rollers.
The maintaining member maintains the spacing member at a predetermined position. The maintaining member includes a rotating body that rotates integrally with the separating member, and a second urging member having a pressing portion that is pressed by the rotating body.
The rotating body has a retracted position maintaining engagement portion that maintains the separating member in the retracted position by engaging the pressing portion when the separating member is in the retracted position.

  According to this, since the rotating body of the maintaining member has the retracted position maintaining engagement portion that maintains the separating member at the retracted position by engaging the pressing portion when the separating member is at the retracted position, the pair of rollers The separating member retracted from between (one roller and the other roller) can be maintained at the retracted position.

In the image forming apparatus described above, the rotary member may be configured to have a separated position maintaining engagement portion pressing portion when the spacer member is in the separated position is maintained in spaced position spaced member by engaging .

  According to this, since the separation member can be maintained also in the separation position, the separation member is detached during transportation of the image forming apparatus and the pair of rollers (one roller and the other roller) are in pressure contact with each other. This can be prevented.

  In each of the image forming apparatuses described above, it is preferable that the separation member is formed integrally with the bearing of one of the rollers.

  According to this, the separation member can be rotatably supported with respect to the shaft of one roller, and the number of parts can be reduced and the axial direction can be reduced as compared with the configuration in which the separation member and the bearing are provided as separate parts. The apparatus can be downsized.

In images forming apparatus described above, the second biasing member can be configured to serve as the first urging member.

  According to this, the separation member can be maintained in the retracted position while urging one roller toward the other roller with the same component. In addition, the number of parts can be reduced.

In order to achieve the above object, an image forming apparatus according to the present invention includes a first frame, a second frame that is detachably attached to the first frame, one roller, and the other roller. A pair of rollers for conveying the recording sheet between them, a release member provided on the first frame, and a first urging member, a separation member and a maintaining member provided on the second frame are provided.
The pair of rollers is movable in a direction in which one roller supported by the second frame approaches and separates from the other roller supported by the first frame.
The first urging member urges one roller toward the other roller.
The separation member includes a separation position in which one roller is moved in a direction away from the other roller against the urging force of the first urging member, and the other roller is urged by the urging force of the first urging member. It is supported so as to be movable between a retracted position where it can come into contact.
The release member moves the separation member from the separation position to the retracted position by the rotation of the pair of rollers.
The maintenance member maintains the separation member in the separation position when the second frame is attached to the first frame.

According to this, since the spacer member is maintained in spaced position by the maintenance member, the one roller is maintained in a position not in contact with the other roller, mounting the second frame to the first frame Thus, one roller and the other roller can be easily assembled in a separated state.

In the above-described image forming apparatus, the separating member is rotatably supported, and the maintaining member is a rotating body that rotates integrally with the separating member, and a second urging member having a pressing portion that is pressed by the rotating body. It can be set as the structure which has these.
And a rotary body can be set as the structure which has a separation position maintenance engagement part which maintains a separation member in a separation position by a press part engaging.

According to this, when the pressing portion of the second urging member is engaged with the separation position maintaining engagement portion of the rotator, the separation member that can be rotated together with the rotator is maintained at the separation position firmly to some extent. Can do. Thus, the spacer member when mounting the second frame to the first frame can be suppressed to be rotated, mounting the second frame while maintaining the spacer member in spaced positions on the first frame It becomes possible.

  In the above-described image forming apparatus, it is preferable that the second urging member also serves as the first urging member.

  According to this, the separation member can be maintained at the separation position while urging one roller toward the other roller with the same component. In addition, the number of parts can be reduced.

In the image forming apparatus comprising a first frame and a second frame, the spacer member is rotatably supported, retaining member, when mounting the second frame to at least a first frame, spaced It can be set as the structure which has the fixed stopper which regulates rotation of a separation member and maintains it in a separation position by contacting the separation member in a position.

According to this, by the stopper, the second frame because the rotation of the spacer member when mounting the first frame is suppressed, the second while maintaining the spacer member to the separating position frame first It can be attached to the frame.

In the image forming apparatus comprising a first frame and a second frame, the spacer member is rotatably supported with respect to the rotation axis of one of the rollers, the release member, the other roller and so as to rotate integrally The separation member and the release member are in contact with each other when the separation member is in the separation position so that the rotational driving force of the other roller can be transmitted, and are separated when the separation member is in the retracted position. The rotational driving force can be configured so as not to be transmitted.

  According to this, since the separation member can be moved from the separation position to the retracted position by the rotation of the pair of rollers, the pair of rollers can be easily brought into contact with each other. Further, when the separating member is in the retracted position, the rotational driving force of the other roller is not transmitted to the separating member, so that the rotation of the separating member can be suppressed.

  In the above-described image forming apparatus, the separating member is preferably formed integrally with the bearing of one roller.

  According to this, the separation member can be rotatably supported with respect to the shaft of one roller, and the number of parts can be reduced and the axial direction can be reduced as compared with the configuration in which the separation member and the bearing are provided as separate parts. The apparatus can be downsized.

In the image forming apparatus having the rotating body described above, the rotating body is provided on the peripheral surface separately from the separated position maintaining engagement portion, and is separated by engaging the pressing portion when the separating member is in the retracted position. It can be set as the structure which has a retracted position maintenance engagement part which maintains a member in a retracted position.
In this case, it is preferable that the rotating body is configured to rotate the separation member to the retracted position when the end of the retracted position maintaining engagement portion is pressed by the pressing portion.

  According to this, when the pressing portion engages with the retracted position maintaining engagement portion of the rotating body, the separation member that can rotate together with the rotating body can be maintained in the retracted position firmly to some extent, and the pair of rollers Interference between the separating member after contact and the other roller can be suppressed. In addition, since the rotating body rotates when the end of the retracted position maintaining engagement portion is pressed by the pressing portion, the separating member can be reliably rotated to the retracted position.

  According to the present invention, the separating member retracted from between the pair of rollers (one roller and the other roller) can be maintained at the retracted position. Further, it is possible to easily assemble one roller and the other roller in a separated state.

1 is a diagram illustrating a schematic configuration of a laser printer as an example of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows a state when attaching or detaching a process cartridge. FIG. 2 is a cross-sectional view taken along the line XX in FIG. 1 showing a configuration around a registration roller. It is a figure which shows the support structure of a driven roller seen from the Y direction of FIG. FIG. 6 is a side view showing a configuration around a registration roller when a separation gear portion is in a separation position. FIG. 6 is a side view showing a configuration around a registration roller while the separation gear portion is rotating from the separation position to the retracted position. FIG. 6 is a side view showing a configuration around a registration roller when a separation gear is in a retracted position.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, first, a schematic configuration of the laser printer 1 as an example of the image forming apparatus according to the embodiment will be described, and then a detailed configuration of the laser printer 1 according to the characteristic part of the present invention will be described. .

  In the following description, the direction will be described with reference to the user who uses the laser printer 1. That is, the right side in FIG. 1 is “front”, the left side is “rear”, the front side is “left”, and the back side is “right”. Also, the vertical direction in FIG.

<Schematic configuration of laser printer>
As shown in FIG. 1, the laser printer 1 includes a main body housing 2 as an example of a first frame, a paper feeding unit 3 that supplies paper S as an example of a recording sheet, an exposure device 4, and a paper S. A process cartridge 5 for transferring a toner image (developer image) thereon and a fixing device 8 for thermally fixing the toner image on the paper S are mainly provided.

  The paper feed unit 3 is provided in the lower part of the main body housing 2 and mainly includes a paper feed tray 31, a paper pressing plate 32, a paper feed mechanism 33, and a registration roller 90. The paper S stored in the paper feed tray 31 is moved upward by the paper pressing plate 32, supplied toward the process cartridge 5 by the paper feed mechanism 33, passes through the registration roller 90, and the photosensitive drum 61 and the transfer roller 63. It is conveyed between.

  The exposure apparatus 4 is disposed in the upper part of the main body housing 2 and includes a laser light emitting unit (not shown), a polygon mirror, a lens, a reflecting mirror, and the like that are not shown. In this exposure device 4, the surface of the photosensitive drum 61 is exposed by scanning the surface of the photosensitive drum 61 at high speed with laser light (see the chain line) based on the image data emitted from the laser light emitting unit.

  The process cartridge 5 is disposed below the exposure apparatus 4 and is detachably mounted on the main body housing 2 through an opening formed when the front cover 21 provided on the main body housing 2 is opened. (See FIG. 2). The process cartridge 5 includes a drum unit 6 and a developing unit 7.

  The drum unit 6 mainly includes a photosensitive drum 61, a charger 62, and a transfer roller 63 in a drum frame 60 as an example of a second frame. The developing unit 7 is detachably attached to the drum frame 60. Within the developing frame 70, a developing roller 71, a supply roller 72, a layer thickness regulating blade 73, toner ( And a toner containing portion 74 for containing a developer.

  In the process cartridge 5, the surface of the photosensitive drum 61 is uniformly charged by the charger 62 and then exposed by high-speed scanning of the laser light from the exposure device 4, whereby an image is formed on the photosensitive drum 61. An electrostatic latent image based on the data is formed. Further, the toner in the toner container 74 is supplied to the developing roller 71 via the supply roller 72 and enters between the developing roller 71 and the layer thickness regulating blade 73 to form a thin layer of a certain thickness on the developing roller 71. It is carried on.

  The toner carried on the developing roller 71 is supplied from the developing roller 71 to the electrostatic latent image formed on the photosensitive drum 61. As a result, the electrostatic latent image is visualized and a toner image is formed on the photosensitive drum 61. Thereafter, the sheet S is conveyed between the photosensitive drum 61 and the transfer roller 63 so that the toner image on the photosensitive drum 61 is transferred onto the sheet S.

  The fixing device 8 is disposed behind the process cartridge 5, and mainly includes a heating roller 81 and a pressure roller 82 disposed so as to face the heating roller 81 and press the heating roller 81. In the fixing device 8, the toner image transferred onto the paper S is thermally fixed while the paper S passes between the heating roller 81 and the pressure roller 82. The paper S on which the toner image has been thermally fixed is discharged onto the paper discharge tray 22 by the transport rollers 23 and 24.

<Detailed configuration of laser printer>
As shown in FIGS. 2 and 3, the laser printer 1 includes a registration roller 90 as an example of a pair of rollers, a bearing member 100, a first urging member, and a second member as a configuration related to the characteristic part of the present invention. A torsion spring 65 as an example of an urging member and a release gear 93 as an example of a release member are provided.

  In the drawing to be referred to, only the configuration on the left end side of the registration roller 90 is shown, but in the present embodiment, the configuration on the right end side of the registration roller 90 is the same as that on the left end side, that is, The bearing member 100, the torsion spring 65, and the release gear 93 are provided so as to be symmetrical.

  The registration roller 90 includes a driven roller 92 as an example of one roller disposed on the upper side and a driving roller 91 as an example of the other roller disposed on the lower side. The registration roller 90 corrects the skew of the sheet S by restricting the movement of the leading end of the sheet S conveyed from the sheet feeding tray 31, and then removes the sheet S between the driving roller 91 and the driven roller 92. The sheet is conveyed between the photosensitive drum 61 and the transfer roller 63.

  The driving roller 91 is rotatably supported by the main body housing 2 and is configured to be rotationally driven by a driving force transmitted from a motor (not shown) provided in the main body housing 2.

  The driven roller 92 is rotatably supported by a drum frame 60 of the process cartridge 5 via a bearing member 100 described later, and is driven to rotate when in contact with the drive roller 91 (see FIGS. 1 and 7). It is provided to rotate following the drive roller 91.

  As shown in FIG. 4, the drum frame 60 is formed with a recessed support portion 60 </ b> A that is long in the vertical direction and whose lower portion is narrower than the diameter of the bearing member 100 (bearing portion 110). The member 100 is supported so as to be movable up and down with respect to the drum frame 60 by being inserted into the support portion 60A. With such a configuration, the driven roller 92 approaches or moves away from the driving roller 91 disposed below when the drum frame 60 (process cartridge 5) is attached to the main body housing 2 (vertical direction). ) Can be moved.

  As shown in FIGS. 3 and 5, the bearing member 100 mainly includes a bearing portion 110, a cam portion 120 as an example of a rotating body, and a separation gear portion 130 as an example of a separation member. That is, in the present embodiment, the bearing (bearing portion 110), the rotating body, and the separation member of the driven roller 92 are formed as an integral member.

  The bearing portion 110 is a bearing that rotatably supports the rotating shaft 92A of the driven roller 92, and a cam portion 120 and a separation gear portion 130 are formed around the bearing portion 110. A portion of the bearing portion 110 located on the inner side in the left-right direction than the cam portion 120 is supported so as to be movable up and down with respect to the drum frame 60 by being inserted into the support portion 60A.

  Further, the portion of the bearing portion 110 located on the outer side in the left-right direction with respect to the cam portion 120 is a guide groove provided on the inner surfaces of the left and right side walls of the main body housing 2 when the process cartridge 5 is mounted on the main body housing 2. 25 (see also FIG. 2). The process cartridge 5 reaches the mounting position (see FIG. 1) while the bearing 110 is guided by the guide groove 25.

  The cam portion 120 is a substantially plate-like portion that protrudes radially outward from the outer peripheral surface of the bearing portion 110, and a separation position maintaining member that extends along the front-rear direction in the posture shown in FIG. 5 on the outer peripheral surface. It has a joint portion 121 and a retracted position maintaining engagement portion 122 extending substantially along the vertical direction from the rear end portion of the separated position maintaining engagement portion 121. In the present embodiment, the separation position maintaining engagement portion 121 and the retracted position maintaining engagement portion 122 are formed in a substantially planar shape that can be engaged (contacted) with the rod-shaped pressing arm 65A of the torsion spring 65. The connecting portion 123 that connects the separated position maintaining engagement portion 121 and the retracted position maintaining engagement portion 122 has a curved shape in which an obtuse angle when viewed from the side is chamfered.

  In the posture shown in FIG. 5, the separation gear portion 130 has a plurality of gear teeth provided so as to protrude radially outward from the lower portion of the outer peripheral surface of the cam portion 120, and the rotation shaft 92 </ b> A (rotation center) of the driven roller 92. ) Are arranged so as to be arranged in a circular arc shape centering on). Since the separation gear portion 130 (that is, the separation member) is formed integrally with the bearing portion 110, it is supported so as to be rotatable with respect to the rotation shaft 92 </ b> A of the driving roller 91 and the drum frame 60. As a matter of course, the separation gear portion 130 rotates integrally with the cam portion 120 (rotating body).

  Such a separation gear portion 130 is provided so as to be able to mesh with a gear tooth of a release gear 93 described later. As shown in FIG. 5, when the separation gear portion 130 is engaged with the release gear 93, the driven roller 92 is connected to the torsion spring 65. When the bearing member 100 is rotated away from the drive roller 91 against the biasing force and the meshing with the release gear 93 is released as shown in FIG. 7, the driven roller 92 is biased by the torsion spring 65. Thus, the drive roller 91 can be contacted.

  That is, the separation gear unit 130 is separated from the drum frame 60 at a separation position (see FIG. 5) where the driven roller 92 is separated from the driving roller 91, and a retracted position where the driven roller 92 can contact the driving roller 91 (FIG. 7). Reference) is supported so as to be rotatable.

  In the present embodiment, when the process cartridge 5 (drum unit 6) and the laser printer 1 are shipped from the factory, the bearing member 100 is in a posture in which the separation gear portion 130 is in the separation position shown in FIG. ing. Then, as will be described later, the bearing member 100 rotates when the drive roller 91 is rotationally driven during use, and the separation gear portion 130 is displaced to the retracted position shown in FIG.

  As shown in FIG. 5, the torsion spring 65 is a member that urges the driven roller 92 toward the drive roller 91 (downward) via the bearing member 100, and is provided on the outer surfaces of the left and right side walls of the drum frame 60. Is provided. The torsion spring 65 presses the separated position maintaining engagement portion 121 or the retracted position maintaining engagement portion 122 (see FIG. 7) of the cam portion 120 (in other words, pressed against the cam portion 120). A pressing arm 65A as an example is provided.

  As described above, when the process cartridge 5 and the laser printer 1 are shipped from the factory, the separation gear portion 130 is in the separation position shown in FIG. At this time, the pressing arm 65 </ b> A is engaged (contacted) with the separated position maintaining engagement portion 121 of the cam portion 120. Thereby, since rotation of the bearing member 100 provided with the cam portion 120 and the separation gear portion 130 is restricted, the separation gear portion 130 is maintained at the separation position.

  As shown in FIGS. 3 and 5, the release gear 93 is a spur gear fixed to the end of the rotation shaft 91 </ b> A of the drive roller 91 provided in the main body housing 2 so as to rotate integrally with the drive roller 91. Is provided. The release gear 93 is disposed so as to be positioned below the cam portion 120 when the process cartridge 5 is attached to the main body housing 2, and can be engaged with the separation gear portion 130 as described above. ing.

  The release gear 93 and the separation gear portion 130 are engaged (contacted) when the separation gear portion 130 is in the separation position (see FIG. 5), so that the rotational driving force of the driving roller 91 can be transmitted to the bearing member 100. When the gear portion 130 is in the retracted position (see FIG. 7), the separation gear portion 130 is separated from the release gear 93 so that the rotational driving force of the drive roller 91 cannot be transmitted to the bearing member 100. .

  That is, the release gear 93 and the separation gear portion 130 are configured such that when the separation gear portion 130 is in the separation position (see FIG. 5), the bearing member 100 is rotated by the rotation of the release gear 93 and the separation gear portion 130 is in the retracted position (FIG. 7). When the release gear 93 is rotated, the bearing member 100 is configured not to rotate.

  In the present embodiment, one of the left and right release gears 93 is a gear for inputting driving force from a motor (not shown) provided in the main body housing 2 to the rotating shaft 91A of the driving roller 91. It may function. The release gear 93 may be provided separately from the gear for inputting the driving force from the motor to the rotation shaft 91A of the driving roller 91.

As shown in FIG. 5, the laser printer 1 further includes a stopper 66.
The stopper 66 is a substantially columnar protrusion that protrudes outward in the left-right direction from the outer surface of the left and right side walls of the drum frame 60, and is provided integrally with the drum frame 60.

  This stopper 66 is provided on the front side of the support portion 60A of the drum frame 60 so that the front portion of the separation gear portion 130 at the separation position (the frontmost gear teeth in the posture shown in FIG. 5) can contact. It has become. As a result, the rotation of the separating gear portion 130 (bearing member 100) in the separating position in the counterclockwise direction shown in the figure is restricted.

  By providing such a stopper 66, the bearing member is particularly suitable when the process cartridge 5 is mounted on the main body housing 2, in which a force for rotating the bearing member 100 in the counterclockwise direction shown in the figure is likely to act. The rotation of 100 is effectively restricted. As a result, the separation gear 130 can be more reliably maintained at the separation position.

  In the present embodiment described above, the cam member 120, the torsion spring 65, and the stopper 66 maintain the separation gear 130 at a predetermined position, specifically, the retracted position and the separation position. Will function as.

<Assembly of registration rollers>
Next, the assembly of the registration roller 90 (the drive roller 91 and the driven roller 92) to the main body housing 2 in the assembly process of the laser printer 1 will be briefly described.
The drive roller 91 is assembled to the main body casing 2 during the process of assembling the main body casing 2 (the apparatus main body of the laser printer 1).

  On the other hand, the driven roller 92 is first assembled to the drum frame 60. More specifically, the driven roller 92 is assembled to the drum frame 60 by inserting the rotating shaft 92 </ b> A into the support portion 60 </ b> A of the drum frame 60 via the bearing member 100. At this time, as shown in FIG. 5, the bearing member 100 is in a posture in which the pressing arm 65 </ b> A of the torsion spring 65 is engaged (contacted) with the separation position maintaining engagement portion 121 of the cam portion 120, that is, in the separation position. Be placed.

  Thereafter, as shown in FIG. 2, the driven roller 92 is assembled to the main body casing 2 by mounting the drum frame 60 (process cartridge 5) on the main body casing 2 to which the driving roller 91 is assembled. As shown in FIG. 5, at this time, the bearing member 100 (the separation gear portion 130) is separated due to the engagement between the separation position maintaining engagement portion 121 and the pressing arm 65 </ b> A or the rotation restriction by the contact with the stopper 66. By maintaining the position, the driven roller 92 is assembled to the main body housing 2 in a state of being separated from the driving roller 91.

<Operation of laser printer>
Next, the operation of the laser printer 1, specifically, the operation around the registration roller 90 when using the laser printer 1 in a state where the driving roller 91 and the driven roller 92 are separated from each other will be described.

  When the operation of the laser printer 1 is started, a driving force is input to the driving roller 91, so that the release gear 93 is rotated in the counterclockwise direction in the drawing integrally with the driving roller 91. As a result, as shown in FIG. 6, the bearing member 100 is rotated in the clockwise direction in the drawing via the separation gear portion 130 that meshes with the gear teeth of the release gear 93. The bearing member 100 continues to rotate until the meshing between the separation gear portion 130 and the release gear 93 is released.

  When the meshing between the separation gear portion 130 and the release gear 93 is released, the cam portion 120 gets over the position where the connection portion 123 (the end portion of the retracted position maintaining engagement portion 122) most flexes the pressing arm 65A, and the pressing arm 65A will be in the state which presses the connection part 123 toward the downward direction. Then, due to the urging force of the pressing arm 65A (torsion spring 65), the cam portion 120 (bearing member 100) further rotates in the clockwise direction in the figure, and the pressing arm 65A engages with the retracted position as shown in FIG. The portion 122 is engaged (contacted).

  In this process, the pressing arm 65A presses the retracted position maintaining engagement portion 122 downward, so that the driven roller 92 supported by the bearing member 100 moves downward. Will contact (pressure contact). Accordingly, the driven roller 92 is driven and rotated by the rotational driving of the driving roller 91, and the sheet S can be conveyed between the driving roller 91 and the driven roller 92.

  When the separation gear portion 130 is in the retracted position shown in FIG. 7, the separation gear portion 130 is maintained at the retracted position by the engagement of the retracting position maintaining engagement portion 122 and the pressing arm 65A. The rotation is restricted. Further, even if the bearing member 100 attempts to rotate from the retracted position in the clockwise direction in the drawing, the lower end portion of the separated position maintaining engagement portion 121 of the cam portion 120 comes into contact with the stopper 66. Is regulated. Thus, the separation gear portion 130 (separation member) displaced to the retracted position is prevented from interfering with the release gear 93 (drive roller 91) again.

According to the above, the following effects can be obtained in the present embodiment.
Since the cam portion 120 has the retraction position maintaining engagement portion 122 that the pressing arm 65A engages when the separation gear portion 130 is in the retraction position, the separation gear portion 130 retreated from between the driven roller 92 and the driving roller 91. Can be maintained in the retracted position.

  Further, since the cam portion 120 has the separation position maintaining engagement portion 121 with which the pressing arm 65A is engaged when the separation gear portion 130 is in the separation position, the separation gear portion 130 can be maintained also in the separation position. . As a result, it is possible to prevent the driven gear 92 and the driving roller 91 from being in pressure contact due to the separation gear 130 being displaced (the bearing member 100 is rotated) while the laser printer 1 or the process cartridge 5 is being transported. .

  Since the separation gear portion 130 is formed integrally with the bearing portion 110, the separation gear portion 130 can be rotatably supported with respect to the rotation shaft 92 </ b> A of the driven roller 92. In addition, the number of parts can be reduced and the size of the apparatus in the left-right direction (axial direction) can be reduced compared to a configuration in which a separation member that separates the driven roller 92 from the drive roller 91 and a bearing of the driven roller 92 are provided as separate parts. Can be planned.

  Further, the torsion spring 65 (second urging member) for maintaining the separation gear portion 130 at a predetermined position also serves as a spring (first urging member) that urges the driven roller 92 toward the driving roller 91. Therefore, the number of parts can be reduced also by this.

  The position where the driven roller 92 does not come into contact with the driving roller 91 by the separation gear portion 130 being maintained at the separation position by the engagement between the separation position maintaining engagement portion 121 and the pressing arm 65A or the contact with the stopper 66. Therefore, by attaching the process cartridge 5 (drum frame 60) to the main body housing 2, the driven roller 92 and the driving roller 91 can be easily assembled in a separated state.

  More specifically, the engagement between the separation position maintaining engagement portion 121 and the pressing arm 65A allows the separation gear portion 130 that can be rotated together with the cam portion 120 to be maintained at a certain separation position, so that the process cartridge 5 can be mounted. The rotation of the separation gear portion 130 can be suppressed. In the present embodiment, the rotation of the separation gear 130 can also be suppressed by the stopper 66. As a result, the process cartridge 5 can be mounted while the separation gear portion 130 is maintained at the separation position.

  In the present embodiment, during the process of assembling the process cartridge 5, in other words, the separation gear portion 130 can be disposed at the separation position outside the main body housing 2 (before being assembled to the main body housing 2). Compared with the case where the separation gear portion 130 assembled to the housing 2 is displaced to the separation position, the operation of arranging the separation gear portion 130 at the separation position is facilitated.

  The separation gear portion 130 and the release gear 93 are configured to rotate the separation gear portion 130 from the separation position to the retracted position by the rotation of the release gear 93 when the separation gear portion 130 is in the separation position. The roller 92 and the driving roller 91 can be easily brought into contact with each other. Further, when the separation gear portion 130 is in the retracted position, the separation gear portion 130 does not rotate even if the release gear 93 rotates. The displacement of the gear part 130 can be suppressed.

  Since the pressing arm 65A engages with the retracted position maintaining engagement part 122, the separating gear part 130 can be maintained at the retracting position firmly to some extent, so that the separating gear part 130 after the driven roller 92 and the driving roller 91 are in contact with each other Interference with the drive roller 91 can be suppressed. Moreover, since the cam part 120 rotates when the connection part 123 is pressed by the pressing arm 65A, the separation gear part 130 can be reliably rotated to the retracted position.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. About a concrete structure, it can change suitably in the range which does not deviate from the meaning of this invention.

  In the above embodiment, the stopper 66 as the maintenance member is provided integrally with the drum frame 60 (second frame), but the present invention is not limited to this. For example, the stopper may be manufactured as a separate part from the second frame and fixed to the second frame.

  In the embodiment, both the cam portion 120 (rotating body) and the torsion spring 65 (second urging member) and the stopper 66 are used as the maintaining member for maintaining the separating gear portion 130 (separating member) in the separating position. However, the present invention is not limited to this. For example, the maintenance member for maintaining the separation member in the separation position may be only one of the rotating body, the second urging member, and the stopper.

  In the said embodiment, although the separation position maintenance engagement part 121 and the retracted position maintenance engagement part 122 were formed in planar shape, this invention is not limited to this. For example, when the pressing portion that engages with the separation position maintenance engagement portion or the retraction position maintenance engagement portion has a convex portion, the separation position maintenance engagement portion or the retraction position maintenance engagement portion is You may form in the shape which has a recessed part which can be engaged.

  In the above-described embodiment, the separation gear portion 130 (the separation member) is formed integrally with the bearing portion 110 (the bearing of one roller), but the present invention is not limited to this. That is, in the present invention, the spacing member and the bearing of one roller may be formed separately. For example, the separating member may be a chipped gear or the like that is formed separately from the bearing portion 110 of the driven roller 92 and has gear teeth that can mesh with the gear teeth of the release gear 93 on a part of the outer peripheral surface.

  In the embodiment, the torsion spring 65 is exemplified as the first urging member and the second urging member. However, the present invention is not limited to this, and may be a coil spring, a leaf spring, or the like. In addition, in this invention, the press part which a 2nd biasing member has refers to the site | part which contacts a rotary body and is pressed by a rotary body (pressing a rotary body). And this press part may be a part of member itself which provides urging | biasing force like the torsion spring 65 of the said embodiment, and is arrange | positioned between the rotary body and the member which provides urging | biasing force. Another member may be used.

  In the embodiment, the second urging member also serves as the first urging member. However, the present invention is not limited to this, and the first urging member and the second urging member are separate parts. Also good. In this case, the first urging member and the second urging member may be the same type of parts (for example, both are torsion springs or the like), or different parts (for example, one is a torsion spring and the other is a coil spring or the like). ).

  In the embodiment, the registration roller 90 is exemplified as the pair of rollers, but the present invention is not limited to this. In other words, in the present invention, the pair of rollers may be a pair of roller-shaped members that are urged toward the other for conveying the recording sheet. For example, FIG. It may be a pair of conveying rollers 23, a photosensitive drum 61 and a transfer roller 63, or a photosensitive drum 61 and a developing roller 71.

  In the embodiment, the main body housing 2 is illustrated as the first frame and the drum frame 60 is illustrated as the second frame, but the present invention is not limited to this. For example, when the pair of rollers is the photosensitive drum 61 and the developing roller 71 of the above-described embodiment, the drum frame 60 may be adopted as the first frame and the developing frame 70 may be adopted as the second frame. Further, when the first frame is the main body housing 2 (apparatus main body), the second frame is a frame of a process cartridge in which the drum unit 6 and the developing unit 7 of the above-described embodiment are integrally formed (cannot be attached / detached). Housing).

  In the above-described embodiment, the release gear 93 (release member) and the separation gear portion 130 (separation member) are configured such that the rotational driving force can be transmitted by meshing the gear teeth with each other, but the present invention is limited to this. It is not something. For example, the release member and the separation member (the separation member at the separation position) may be configured such that at least one of them does not have gear teeth and the rotational driving force can be transmitted by a frictional force.

  In the embodiment, the laser printer 1 that exposes the photosensitive drum 61 (photosensitive member) with laser light is exemplified as the image forming apparatus, but the present invention is not limited to this. For example, an electrophotographic printer that exposes a photoreceptor with LED light, an ink jet printer, or a thermal printer may be used. The image forming apparatus is not limited to a printer, and may be, for example, a copier or a multi-function machine including a document reading apparatus such as a flat bed scanner. Furthermore, the image forming apparatus may be capable of forming not only a monochrome image but also a color image.

  In the embodiment, the paper S such as plain paper or postcard is exemplified as the recording sheet. However, the present invention is not limited to this, and may be, for example, an OHP sheet.

DESCRIPTION OF SYMBOLS 1 Laser printer 2 Main body housing | casing 5 Process cartridge 60 Drum frame 65 Torsion spring 65A Press arm 66 Stopper 90 Registration roller 91 Driving roller 91A Rotating shaft 92 Driven roller 92A Rotating shaft 93 Release gear 100 Bearing member 110 Bearing portion 120 Cam portion 121 Separation Position maintenance engagement part 122 Retraction position maintenance engagement part 123 Connection part 130 Separation gear part S Paper

Claims (10)

A pair of rollers that are supported so as to be movable in a direction in which one of the rollers approaches and separates from the other roller, and that conveys a recording sheet between the one roller and the other roller;
A first biasing member that biases the one roller toward the other roller;
A separation position that separates the one roller from the other roller against the biasing force of the first biasing member, and the one roller contacts the other roller by the biasing force of the first biasing member A separation member supported so as to be pivotable between the retracted position, and
A release member that rotates the separation member from the separation position to the retracted position by rotation of the pair of rollers;
A maintaining member for maintaining the spacing member in a predetermined position,
The maintaining member includes a rotating body that rotates integrally with the separation member, and a second urging member having a pressing portion that is pressed against the rotating body,
The rotating body has a retracted position maintaining engagement portion that maintains the separating member in the retracted position by engaging the pressing portion when the separating member is in the retracted position, and the separating member is in the separated position. An image forming apparatus comprising: a separation position maintaining engagement portion that maintains the separation member at the separation position by the engagement of the pressing portion . A pair of rollers that are supported so as to be movable in a direction in which one of the rollers approaches and separates from the other roller, and conveys a recording sheet between the one roller and the other roller;
A first biasing member that biases the one roller toward the other roller;
A separation position that separates the one roller from the other roller against the biasing force of the first biasing member, and the one roller contacts the other roller by the biasing force of the first biasing member A separation member supported so as to be pivotable between the retracted position, and
A release member that rotates the separation member from the separation position to the retracted position by rotation of the pair of rollers;
A maintaining member for maintaining the spacing member in a predetermined position,
The maintaining member includes a rotating body that rotates integrally with the separation member, and a second urging member having a pressing portion that is pressed against the rotating body,
The rotating body is to have a retracted position holding engagement portion in which the spacer member to maintain the spacing member in the retracted position by the pressing portion is engaged when in the retracted position,
The image forming apparatus , wherein the second urging member also serves as the first urging member . The rotating body, according to claim 2, characterized in that it has a separated position maintaining engagement portion into which the pressing portion when the spacer member is in the separate position to maintain the separation member by engaging with the said separated position The image forming apparatus described in 1. The image forming apparatus according to claim 1 , wherein the separation member is formed integrally with a bearing of the one roller. A first frame;
A second frame detachably attached to the first frame;
One roller supported by the second frame is movable in a direction approaching and separating from the other roller supported by the first frame, and between the one roller and the other roller. A pair of rollers that convey the recording sheet at
A first biasing member that is provided on the second frame and biases the one roller toward the other roller;
A separation position that is provided on the second frame and moves the one roller in a direction away from the other roller against the urging force of the first urging member; and the one roller is the first roller. A separation member that is supported so as to be movable between a retreat position that enables contact with the other roller by the urging force of the urging member;
A release member that is provided on the first frame and moves the separation member from the separation position to the retracted position by rotation of the pair of rollers;
A maintaining member that is provided on the second frame and maintains the spacing member at the spacing position when the second frame is attached to the first frame ;
The spacing member is rotatably supported,
The maintaining member includes a rotating body that rotates integrally with the separation member, and a second urging member having a pressing portion that is pressed against the rotating body,
The image forming apparatus according to claim 1, wherein the rotating body includes a separation position maintaining engagement portion that maintains the separation member at the separation position by engaging the pressing portion . The image forming apparatus according to claim 5 , wherein the second urging member also serves as the first urging member. A first frame;
A second frame detachably attached to the first frame;
One roller supported by the second frame is movable in a direction approaching and separating from the other roller supported by the first frame, and between the one roller and the other roller. A pair of rollers that convey the recording sheet at
A first biasing member that is provided on the second frame and biases the one roller toward the other roller;
A separation position that is provided on the second frame and moves the one roller in a direction away from the other roller against the urging force of the first urging member; and the one roller is the first roller. A separation member that is supported so as to be movable between a retreat position that enables contact with the other roller by the urging force of the urging member;
A release member that is provided on the first frame and moves the separation member from the separation position to the retracted position by rotation of the pair of rollers;
A maintaining member that is provided on the second frame and maintains the spacing member at the spacing position when the second frame is attached to the first frame ;
The spacing member is rotatably supported,
When the second frame is mounted on at least the first frame, the maintaining member is brought into contact with the spacing member at the spacing position, thereby restricting the rotation of the spacing member to the spacing position. An image forming apparatus having a fixed stopper to be maintained . A first frame;
A second frame detachably attached to the first frame;
One roller supported by the second frame is movable in a direction approaching and separating from the other roller supported by the first frame, and between the one roller and the other roller. A pair of rollers that convey the recording sheet at
A first biasing member that is provided on the second frame and biases the one roller toward the other roller;
A separation position that is provided on the second frame and moves the one roller in a direction away from the other roller against the urging force of the first urging member; and the one roller is the first roller. A separation member that is supported so as to be movable between a retreat position that enables contact with the other roller by the urging force of the urging member;
A release member that is provided on the first frame and moves the separation member from the separation position to the retracted position by rotation of the pair of rollers;
A maintaining member that is provided on the second frame and maintains the spacing member at the spacing position when the second frame is attached to the first frame ;
The separation member is supported so as to be rotatable with respect to the rotation shaft of the one roller,
The release member is provided to rotate integrally with the other roller,
The separation member and the release member are in contact with each other when the separation member is in the separation position so that the rotational driving force of the other roller can be transmitted, and are separated when the separation member is in the retracted position. An image forming apparatus configured to be unable to transmit the rotational driving force of the other roller . The image forming apparatus according to claim 8 , wherein the spacing member is formed integrally with a bearing of the one roller. The rotating body is
A retracted position maintenance is provided on a peripheral surface separately from the separated position maintaining engagement portion, and the spaced apart member is maintained at the retracted position by engaging the pressing portion when the spaced member is in the retracted position. Having an engaging portion,
The image according to claim 5 , wherein the separation member is configured to rotate to the retracted position by pressing an end portion of the retracted position maintaining engagement portion by the pressing portion. Forming equipment.

Images