JP2008304596A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily take out a transfer device from an image forming apparatus. <P>SOLUTION: The image forming apparatus is equipped with an external frame, a photoreceptor drum, a developing device, an intermediate transfer belt 71, a transfer unit 76, a secondary transfer member moving mechanism, a movement regulating mechanism and a releasing mechanism. The transfer unit 76 has a secondary transfer roller 761 arranged to freely come close to/separate from the intermediate transfer belt 71 so as to transfer an image transferred to the intermediate transfer belt 71 to paper. The secondary transfer member moving mechanism moves the second transfer roller 761 to a transfer position where the second transfer roller 761 comes into contact with the intermediate transfer belt 71, and a retreat position where it is separated from the intermediate transfer belt 71. The movement regulating mechanism regulates the movement of the transfer unit 76 relative to the external frame. The releasing mechanism moves the second transfer roller 761 from the transfer position to the retreat position and also releases the regulation of the movement of the transfer unit 76 by the movement regulating mechanism. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus including a transfer unit that transfers an image from an image carrier to a sheet.

  An image forming apparatus includes an image forming unit capable of forming an image on a sheet based on image information, a sheet conveying unit that conveys the sheet to the image forming unit, a sheet storing unit that stores the sheet, and a sheet on which an image is formed. And a discharge part capable of discharging the gas. In this image forming apparatus, the paper is transported from the paper storage unit to the image forming unit by the paper transport unit. Then, an image is formed on the sheet based on the image information, and the sheet on which the image is formed is discharged from the discharge unit.

  The image forming unit includes an electrostatic image carrier on which an electrostatic latent image is formed on the surface based on image information, a developing device that supplies a developer to the electrostatic image carrier, an electrostatic latent image carrier, An intermediate transfer belt to which an image of an electrostatic latent image carrier is transferred in order to transfer the image formed on the sheet to a sheet, and a transfer device to transfer the image on the intermediate transfer belt to the sheet. In this image forming unit, an electrostatic latent image is formed on the electrostatic image carrier on the basis of image information, and a developer is supplied from the developing device to the electrostatic latent image carrier. After the developer image is formed on the electrostatic latent image carrier in this way, the developer image is transferred to the intermediate transfer belt. The developer image on the intermediate transfer belt is transferred onto a sheet by a transfer device (see Patent Document 1).

Some image forming apparatuses change the posture of the transfer apparatus between a transferable state (transfer position) and an untransferable state (retraction position). In some cases, the transfer device can be taken out by releasing the lock for jamming or the like. Here, the transferable state is a state where the transfer device is close to or in contact with the intermediate transfer belt, and the untransferable state is a state where the transfer device is separated from the intermediate transfer belt.
JP 2005-62642 A

  In a conventional image forming apparatus, when a transfer device is taken out for jam processing or maintenance, first, the posture of the transfer device is changed from a transferable state to an untransferable state, and then the lock is released and the transfer device is taken out. There is a need. For this reason, when the transfer device is taken out, two operations of changing the posture of the transfer device and releasing the lock are necessary, making it difficult to take out the transfer device from the image forming apparatus.

  An object of the present invention is to facilitate removal of a transfer device from an image forming apparatus.

  An image forming apparatus according to a first aspect includes an apparatus main body, an electrostatic latent image carrier, a developing device, an intermediate transfer member, a transfer unit, a secondary transfer member moving mechanism, a movement restricting mechanism, and a releasing mechanism. And. The electrostatic latent image carrier is a member capable of carrying an electrostatic latent image formed based on image information. The developing device supplies a developer to the electrostatic latent image carrier. The intermediate transfer member is a member to which an image formed on the electrostatic latent image carrier is transferred. The transfer unit includes a secondary transfer member that is disposed so as to be close to and away from the intermediate transfer member and transfers an image transferred to the intermediate transfer member onto a sheet. The secondary transfer member moving mechanism moves the secondary transfer member to a transfer position in contact with the intermediate transfer member and a retracted position away from the intermediate transfer member. The movement restricting mechanism restricts the movement of the transfer unit relative to the apparatus main body. The release mechanism moves the secondary transfer member from the transfer position to the retracted position and releases the transfer unit movement restriction by the movement restriction mechanism.

  In this image forming apparatus, at the time of image formation, an electrostatic latent image is formed on the electrostatic latent image carrier based on image information, and a developer is supplied from the developing device. Then, the developer image formed on the electrostatic latent image carrier is transferred to the intermediate transfer member, and the image is transferred from the intermediate transfer member to the sheet by the secondary transfer member. When the transfer device is taken out of the image forming apparatus for jamming or the like, the secondary transfer member is moved from the transfer position to the retracted position by the release mechanism and the movement restriction by the movement restriction mechanism is released.

  Here, since the transfer device is moved from the transfer position to the retracted position by the release mechanism and the movement restriction is released, it is not necessary to separately perform the separation operation and the movement restriction release operation of the transfer device. It can be easily removed from the forming apparatus.

  An image forming apparatus according to a second aspect is the image forming apparatus according to the first aspect, wherein the secondary transfer member moving mechanism includes a biasing member that biases the secondary transfer member toward the intermediate transfer member, and 2 And a cam for moving the next transfer member so as to be separated from the intermediate transfer member against the biasing force of the biasing member.

  Here, a biasing force that applies the secondary transfer member to the intermediate transfer member by the biasing member is applied to the secondary transfer member, and the secondary transfer member is moved away from the intermediate transfer member by the cam. it can.

  An image forming apparatus according to a third aspect is the image forming apparatus according to the second aspect, wherein the transfer unit further includes a support frame capable of rotatably supporting the secondary transfer member and contacting the cam. Yes. The secondary transfer member moving mechanism further includes a rotation shaft that rotatably supports the support frame with respect to the apparatus main body, and the urging member and the cam are disposed on the opposite side of the secondary transfer member with the rotation shaft interposed therebetween. Is provided.

  In this image forming apparatus, the secondary transfer member can be moved closer to or away from the intermediate transfer member by rotating the support frame by the biasing member and the cam.

  An image forming apparatus according to a fourth aspect is the image forming apparatus according to the second or third aspect, wherein the movement restricting mechanism has a locking portion that can be locked to the apparatus main body.

  Here, the movement of the transfer device can be restricted by the locking portion being locked to the apparatus main body.

  An image forming apparatus according to a fifth aspect is the image forming apparatus according to the fourth aspect, wherein the release mechanism rotates the shaft having a locking portion, a lever attached to one end of the shaft, and the cam. And a rotating body. The locking portion is locked and released from the apparatus main body as the shaft is rotated by the lever.

  Here, by rotating the lever and rotating the cam and rotating the cam, the movement restriction can be released simultaneously with separating the secondary transfer member from the intermediate transfer member.

  An image forming apparatus according to a sixth aspect is the image forming apparatus according to the fifth aspect, wherein the cam is rotated by 180 ° when the lever is rotated by an angle of not less than 75 ° and not more than 105 °, whereby the secondary transfer member. Moves between the transfer position and the retracted position.

  Here, since the lever is rotated by an angle of 75 ° or more and 105 ° or less, the secondary transfer member is separated from the intermediate transfer member and the cam is rotated, so that the operation is facilitated.

  Here, a 180 ° cam is preferable as the basic shape of the cam. That is, it is preferable that the top dead center and the bottom dead center are set at an interval of 180 ° so as to face each other. With such a cam shape, it is possible to secure a wider portion of the same radius at each of the top dead center and the bottom dead center, and also to secure an appropriate time from the top dead center to the bottom dead center. is there. If the same radius portion can be secured widely at the top dead center and the bottom dead center, the posture of the support frame as the cam follower can be kept constant even if the cam angle is deviated. Further, since an appropriate time can be secured from the top dead center to the bottom dead center, the impact on the cam follower (support frame) side accompanying the rotation of the cam is reduced.

  On the other hand, the lever operating angle is preferably about 90 °. In particular, if the operating angle of the lever is smaller than 75 °, the movement of the member operated by the lever becomes abrupt, and if it exceeds 105 °, the operating angle is too large and there is a high possibility of interference with other members. Difficult to operate.

  Therefore, in the present invention, the operation angle of the lever is set to 75 ° or more and 105 ° or less, and the cam is rotated by 180 ° with respect to the operation angle of the lever. It moves between the transfer position and the retracted position.

  An image forming apparatus according to a seventh aspect is the image forming apparatus according to the fifth or sixth aspect, wherein the release mechanism is engaged with the first gear fixed to the shaft and the first gear fixed to the shaft of the cam. And a possible second gear.

  In this image forming apparatus, when the lever is rotated, the shaft rotates with the rotation of the lever. The first gear rotates with the rotation of the shaft, and the second gear rotates due to the rotation of the first gear. The cam rotates with the rotation of the second gear.

  Here, when the lever is rotated, the locking portion provided at one end of the lever is rotated to release the locking, and when the cam rotates, the support frame moves the second transfer member to the intermediate transfer member. It can be made to turn away from.

  In the present invention, the transfer device can be easily taken out from the image forming apparatus.

1. Configuration FIG. 1 shows a color printer 1 which is an image forming apparatus according to an embodiment of the present invention. FIG. 1 is a schematic diagram for showing the arrangement of each component, and details of each part are omitted. Note that an arrow A in FIG. 1 indicates the circulation direction of the intermediate transfer belt 71.

  The color printer 1 is connected to a computer (not shown) or the like, and is a device that can print a color image on paper based on image information transmitted from an external computer or the like.

  The color printer 1 includes an image forming unit 2 that forms an image based on image information, a paper transport unit 3 that transports a paper, a fixing unit 4 that fixes an image formed by the image forming unit 2 to the paper, A paper storage unit 5 that stores paper, a discharge unit 6 that discharges the paper to the top of the color printer 1, a transfer device 7 that transfers an image to the paper, and an outer frame 8 (device main body) are provided.

  The image forming unit 2 includes four toner image forming units 2a, 2b, 2c, and 2d for forming toner images of different colors. The four toner image forming units 2a to 2d are arranged in a row in the horizontal direction. As shown in FIGS. 1 and 2, the photosensitive drum 21, the developing device 22, the charging device 24, and the exposure are respectively provided. A device 25, a cleaning device 26, and a toner container 27 are included. Here, the toner image forming portion 2a is a portion that forms a black image, the toner image forming portion 2b is a portion that forms a yellow image, and the toner image forming portion 2c is a portion that forms a cyan image. The toner image forming unit 2d is a part for forming a magenta image.

  The photosensitive drum 21 is a member capable of carrying an electrostatic latent image formed based on image information. The rotation axis of each photosensitive drum 21 extends in a direction perpendicular to the paper surface of FIG.

  The developing device 22 is a device for supplying toner to the photosensitive drum 21 and is disposed adjacent to the photosensitive drum 21. The developing device 22 has a developer storage space 221 for storing the developer therein, and includes a developing roller 222, a mag roller 223, and two diffusion members 224. The developing roller 222 is disposed to face the photosensitive drum 21 and is a member for supplying the toner in the developer storage space 221 to the photosensitive drum 21. The mag roller 223 is a roller for supplying toner in the developer storage space 221 to the developing roller 222. The diffusion member 224 is a member for diffusing the toner in the developer storage space 221.

  The charging device 24 is a device for charging the surface of the photosensitive drum 21, and is disposed below the photosensitive drum 21 and adjacent to the photosensitive drum 21.

  The exposure device 25 is a portion that irradiates the photosensitive drum 21 with light based on the image information, and is disposed above the photosensitive drum 21 and at a position where light can be irradiated between the charging device 24 and the developing device 22. Has been. Specifically, it is disposed above the developing device 22 and the toner container 27.

  The cleaning device 26 is a device for cleaning toner remaining without being transferred to the photosensitive drum 21, and includes a cleaning roller 261 and a cleaning blade 262. Further, the cleaning device 26 is disposed on the side of the photosensitive drum 21 in the vicinity of the photosensitive drum 21. The cleaning roller 261 is a member that removes transfer residual toner on the surface of the photosensitive drum 21 to the inside of the apparatus, and is disposed in parallel with the rotation axis of the photosensitive drum 21. The cleaning blade 262 is close to the photosensitive drum 21. The cleaning blade 262 is a member for scraping the residual toner that has not been removed by the cleaning roller 261 from the photosensitive drum 21 and collecting it in the apparatus.

  The toner container 27 is a member that stores toner that can be supplied to the developing device 22 and is arranged in a line. Specifically, magenta, cyan, yellow, black, and black toner are stored from the left side of FIG. When the toner in the developing device 22 decreases, the toner is supplied from the toner container 27 to the developing device 22. The toner container has two stirring members 271 for stirring the toner. Here, two toner containers 27 containing black toner are connected to the developing device 22 as shown by a one-dot chain line in FIG. The two toner containers 27 for storing the black toner are arranged because the black toner is used for both the single-color image forming operation and the color image forming operation, and is consumed most.

  The paper transport unit 3 is a part that transports the paper in the paper storage unit 5 in the order of the image forming unit 2, the fixing unit 4, and the discharge unit 6, and includes a transport belt 31.

  The fixing unit 4 is a part for fixing the image formed on the sheet by the image forming unit 2, and includes a pressure roller 41 and a heating roller 42.

  The paper storage unit 5 includes a plurality of paper feed cassettes 51 that can store various types of paper. The paper storage unit 5 is disposed at the lower part of the color printer 1.

  The discharge unit 6 is a part for discharging a sheet having an image fixed on the surface thereof to the outside of the color printer 1 and is provided on a side part.

  The outer frame 8 is a member in which the image forming unit 2, the fixing unit 4, the transfer device 7, and the like can be arranged, and has a locking plate 81 shown in FIGS. 5 and 6.

2. As shown in FIG. 1, the transfer device 7 is a device for transferring a toner image formed on the photosensitive drum 21 onto a sheet, and includes an intermediate transfer belt 71 (intermediate transfer member), a drive roller, and the like. 72, a tension roller 73, a first transfer roller 74, a support roller 75, a transfer unit 76 (see FIGS. 2 and 3), and an intermediate transfer belt cleaning device 78.

  The intermediate transfer belt 71 is a member disposed below each of the toner image forming units 2 a to 2 d and is disposed so as to be close to each photosensitive drum 21. The intermediate transfer belt 71 is an endless belt, and is stretched around a driving roller 72, a tension roller 73, and a first transfer roller 74. Further, the intermediate transfer belt 71 is a member to which a toner image carried on the photosensitive drum 21 is transferred.

  The driving roller 72 is a roller for circulating the intermediate transfer belt 71 in one direction, that is, in the direction of the arrow A in FIG. 1, and is disposed in the vicinity of the toner image forming unit 2a. The drive roller 72 is connected to a motor (not shown) and is driven by this motor.

  The tension roller 73 is a roller that is rotated by the power of the driving roller 72 being transmitted through the intermediate transfer belt 71, and is disposed in the vicinity of the toner image forming unit 2d. The tension roller 73 is urged away from the drive roller 72 by a spring 73a, thereby applying tension to the intermediate transfer belt 71. Therefore, the intermediate transfer belt 71 is stretched. Maintained. Specifically, a pair of bearings (not shown) that support the shaft of the tension roller 73 are supported so as to be movable with respect to the frame, and the pair of bearings are biased in the above-described direction by a spring 73a. ing.

  The first transfer roller 74 is a roller for transferring an image on the intermediate transfer belt 71 to a sheet, and is disposed below the toner image forming unit 2b. The first transfer roller 74 is disposed on the inner peripheral side of the intermediate transfer belt 71.

  The support roller 75 is a roller for supporting the intermediate transfer belt 71 and is disposed so as to face each photosensitive drum 21 with the intermediate transfer belt 71 interposed therebetween. Therefore, the intermediate transfer belt 71 is arranged in a direction in which the photosensitive drums 21 are arranged from a portion close to the photosensitive drum 21 arranged at one end to a portion close to the photosensitive drum 21 arranged at the other end. It is parallel.

  2 and 3, the transfer unit 76 is a unit for transferring an image transferred to the intermediate transfer belt 71 to a sheet, and is disposed below the intermediate transfer belt 71. The transfer unit 76 includes a second transfer roller 761 (secondary transfer member), a support frame 762, a rotating shaft 763, a coil spring 764, a first gear 765, a second gear 766, and a cam 767. , A rotation shaft 768, a lever 769 (see FIG. 4), and a locking pin 770 (see FIGS. 5 and 6).

  The second transfer roller 761 is disposed so as to face the first transfer roller 74 with the intermediate transfer belt 71 interposed therebetween, and sandwiches the sheet with the intermediate transfer belt 71 at a position closest to the intermediate transfer belt 71 side. It is a possible member. Here, the second transfer roller 761 can be located at the transfer position closest to the intermediate transfer belt 71 (position in FIG. 2) and the separation position farthest from the intermediate transfer belt 71 (position in FIG. 3).

  The support frame 762 is a member for rotatably supporting the second transfer roller 761 and is a plate-like member extending in one direction. Further, the support frame 762 has a hole for supporting the second transfer roller 761 at the upper part of one end, and a coil spring 764 is attached to the upper part of the other end. Further, the support frame 762 has a contact portion 762b for making contact with the cam 767 at the other end, and a through hole 762c for rotatably supporting the rotation shaft 763 is provided at an approximately upper portion in the longitudinal direction. Is provided. The support frame 762 is disposed to face both ends of the second transfer roller 761 in the axial direction.

  The rotation shaft 763 is a shaft for rotating the support frame 762, and is disposed so as to penetrate through the through hole 762 c of the support frame 762. The rotating shaft 763 is rotatably attached to a frame (not shown) of the transfer unit 76.

  The coil spring 764 is a member that applies a biasing force to the second transfer roller so that the second transfer roller 761 is brought close to the intermediate transfer belt 71. Specifically, the other end portion (the right end portion in FIGS. 2 and 3) of the support frame 762 is urged downward in FIG. Here, when the other end portion of the support frame 762 is urged downward, the urging force rotates about the rotation shaft 763 of the support frame 762 and the one end portion is moved upward. That is, the second transfer roller 761 moves to the intermediate transfer belt 71 side.

  The first gear 765 is a member attached to the rotation shaft 768 and meshes with the second gear 766. The first gear 765 is disposed on the outer side in the axial direction of the rotation shaft 763 of the support frame 762, and the uppermost outer peripheral end is located above the lower end of the support frame 762. Further, the first gear 765 rotates with the rotation of the rotation shaft 768.

  The second gear 766 is a member that is arranged side by side with the first gear 765 and rotates as the first gear 765 rotates. The second gear 766 is a disk-shaped member having a small diameter that is half the diameter of the first gear 765. For this reason, the gear ratio of the first gear 765: second gear 766 is 2: 1.

  The cam 767 is a member for moving the second transfer roller 761 away from the intermediate transfer belt 71 by pushing up the support frame 762 upward, and is disposed so as to be able to contact the contact portion 762b of the support frame 762. ing. The cam 767 is a member attached to the rotation shaft 768 of the second gear 766 and is a member that can rotate as the second gear 766 rotates. Further, the cam 767 is an elliptical member, and the first portion 767a (top dead center) farthest from the rotation shaft 768 and the second portion 767b (bottom dead center) closest to the rotation shaft 768. The position is changed every time the rotation of 180 is rotated by 180 °.

  The rotation shaft 768 is a member that rotates the first gear 765 and the locking pin 770 and extends in a direction substantially orthogonal to the support frame 762.

  As shown in FIG. 4, the lever 769 is attached to one end of the rotating shaft 768 and is a member for rotating the rotating shaft 768. The lever 769 is arranged so as to extend in a direction orthogonal to the axial direction of the rotation shaft 768 and can rotate about 90 °. Further, the lever 769 extends vertically upward from the rotating shaft 768 (the state shown in FIG. 4), and the second portion 767b of the cam 767 is in contact with the contact portion 762b of the support frame 762 (FIG. 2). In other words, the second transfer roller 761 is close to the intermediate transfer belt 71, and the first portion 767a of the cam 767 is in contact with the contact portion 762b while extending in the horizontal direction from the rotation shaft 768. In other words, the second transfer roller 761 is separated from the intermediate transfer belt 71 (the state shown in FIG. 3).

  As shown in FIGS. 5 and 6, the locking pin 770 is attached to the other end of the rotating shaft 768 and extends in a direction substantially orthogonal to the axial direction of the rotating shaft 768. Specifically, it extends in the same direction as the lever 769 extends. The locking pin 770 is a portion that can be locked to the locking plate 81 of the outer frame 8 in a state of extending in the vertical direction from the rotation shaft 768, and is horizontal from the rotation shaft 768 as the lever 769 rotates. The locking between the outer frame 8 and the locking plate 81 is released by being rotated to a state where the outer frame 8 extends.

  The intermediate transfer belt cleaning device 78 is a device for cleaning the surface of the intermediate transfer belt 71 and has a pair of belt cleaning rollers 781.

  Here, the support frame 762, the rotation shaft 763, the coil spring 764, and the cam 767 constitute a second transfer roller moving mechanism, and the locking pin 770 and the outer frame 8 constitute the transfer unit 76. A movement restricting mechanism is configured, and the rotating shaft 768, the lever 769, the first gear 765, and the second gear 766 configure a release mechanism.

3. Operation An image forming operation will be described.

  When image information is transmitted from an external computer or the like, an electrostatic latent image is formed on the photosensitive drum 21 based on the image information. Specifically, the surface of the photosensitive drum 21 is charged by the charging device 24, and light is irradiated by the exposure device 25 based on the image information, whereby an electrostatic latent image is formed on the photosensitive drum 21. . When an electrostatic latent image is formed on the photosensitive drum 21, toner is supplied from the developing device 22 onto the photosensitive drum 21. The toner image formed on the photosensitive drum 21 is transferred onto the intermediate transfer belt 71, and the second transfer roller 761 and the intermediate transfer belt 71 come close to each other as the intermediate transfer belt 71 circulates. Transported to position. At this time, the sheet in the sheet storage unit 5 is conveyed by the sheet conveying unit 3 between the intermediate transfer belt 71 and the second transfer roller 761. The toner image on the intermediate transfer belt 71 is transferred to a sheet by the first transfer roller 74 and the second transfer roller 761, and the sheet is conveyed to the fixing unit 4 by the sheet conveying unit 3. The toner image is fixed on the sheet by the fixing unit 4, and the sheet is discharged from the discharge unit 6.

  Next, an operation of pulling out the transfer unit 76 to the outside of the outer frame 8 for jam processing and maintenance will be described.

  In an image forming operation enabled state, the second transfer roller 761 is close to the intermediate transfer belt 71, that is, the lever 769 extends from the rotation shaft 768 upward in the vertical direction. Specifically, the second portion 767b of the cam 767 is in contact with the contact portion 762b, and the locking pin 770 is locked to the outer frame 8. From this state, the lever 769 is rotated 90 degrees so as to extend from the rotating shaft 768 in the horizontal direction. As the lever 769 rotates, the rotation shaft 768 rotates and the first gear 765 rotates. When the first gear 765 rotates, the second gear 766 that meshes with the first gear 765 rotates. At this time, since the gear ratio of the first gear 765: second gear 766 is 2: 1, the second gear 766 is rotated 180 degrees when the first gear 765 rotates 90 degrees. As the second gear 766 rotates, the cam 767 rotates 180 degrees, and the first portion 767a comes into contact with the contact portion 762b. That is, the other end portion of the support frame 762 is pushed upward, and the second rotating roller 761 is separated from the intermediate transfer belt 71. At the same time, the locking pin 770 rotates 90 degrees by the rotation of the rotating shaft 768. When the locking pin 770 rotates 90 degrees, the locking between the locking pin 770 and the outer frame 8 is released. In this state, the lever 769 is pulled out to the front side of the sheet of FIG. At this time, the support frame 762 is pulled out by the first gear 765, and the entire transfer unit 76 can be pulled out.

  Here, by rotating the lever 769, the second transfer roller 761 can be separated from the intermediate transfer belt 71 and the movement restriction to the outer frame 8 can be released. It becomes easy to pull out. This facilitates jam handling and maintenance. Moreover, since the rotation angle of the lever 769 is 90 degrees, it is easy to rotate. Further, since the cam 767 is a 180-degree cam (a cam in which the portion closest to the rotation center and the portion farthest from the rotation center are 180 degrees apart), the second transfer roller 761 is subjected to intermediate transfer. When separating from the belt 71, the second transfer roller 761 can be smoothly separated from the intermediate transfer belt 71.

4). Other Embodiments (a) In the above embodiment, a 180-degree cam (a cam in which a portion closest to the rotation center and a portion farthest from the rotation center are 180 degrees apart) is used. The invention is not limited to this, and may be a cam of 150 degrees or the like.

  (B) In the above embodiment, the color printer 1 has been described. However, the present invention is not limited to this, and may be a copying machine, a multifunction machine, or the like.

  (C) Further, in the above embodiment, the separation / movement restriction releasing mechanism is operated by rotating the lever 769 by 90 degrees. However, the present invention is not limited to this, and the rotation angle of the lever is from 75 degrees to 105 degrees. It may be between. In this case, it becomes easier to operate the lever as in the case of 90 degrees.

1 is an overall schematic diagram of a color printer 1 when forming a color image. FIG. FIG. 4 is a schematic diagram illustrating a state in which a second transfer roller is close to an intermediate transfer belt. Schematic which shows the state which the 2nd transfer roller is spaced apart from the intermediate transfer belt. The perspective view which shows a transfer unit etc. FIG. The figure which shows the state of the latching pin in the state of FIG. The figure which shows the state of the latching pin at the time of rotating a lever 90 degree | times from the state of FIG.

Explanation of symbols

1 Color printer (image forming device)
8 Outer frame (device main body)
21 Photosensitive drum (electrostatic latent image carrier)
22 Developing device 71 Intermediate transfer belt (intermediate transfer member)
74 First transfer roller 76 Transfer unit 761 Second transfer roller (secondary transfer member)
762 Support frame 762b Contact portion 763 Rotating shaft 764 Coil spring (biasing member)
765 First gear 766 Second gear 767 Cam 768 Rotating shaft (axis)
769 Lever 770 Locking pin (Locking part)

Claims (7)

The device body;
An electrostatic latent image carrier capable of carrying an electrostatic latent image formed based on image information;
A developing device for supplying a developer to the electrostatic latent image carrier;
An intermediate transfer member to which an image formed on the electrostatic latent image carrier is transferred;
A transfer unit which is disposed so as to be close to and away from the intermediate transfer member, and which is used for transferring an image transferred to the intermediate transfer member onto a sheet; ,
A secondary transfer member moving mechanism for moving the secondary transfer member to a transfer position in contact with the intermediate transfer member and a retracted position away from the intermediate transfer member;
A movement restricting mechanism for restricting movement of the transfer unit relative to the apparatus main body;
A release mechanism that moves the secondary transfer member from the transfer position to the retracted position and releases the movement restriction of the transfer unit by the movement restriction mechanism;
An image forming apparatus. The secondary transfer member moving mechanism is
A biasing member that biases the secondary transfer member toward the intermediate transfer member;
A cam that moves the secondary transfer member away from the intermediate transfer member against the urging force of the urging member;
The image forming apparatus according to claim 1. The transfer unit further includes a support frame that can rotatably support the secondary transfer member and abuts the cam.
The secondary transfer member moving mechanism further includes a rotation shaft that rotatably supports the support frame with respect to the apparatus main body, and the urging member and the cam sandwich the rotation shaft between the second transfer member and the cam. Provided on the opposite side of the next transfer member,
The image forming apparatus according to claim 2. The movement restriction mechanism has a locking portion that can be locked to the apparatus main body.
The image forming measure according to claim 2 or 3. The release mechanism includes a shaft having the locking portion, a lever attached to one end of the shaft, and a rotating body for rotating the cam.
The locking portion is locked and unlocked to the apparatus main body with the rotation of the shaft by the lever.
The image forming apparatus according to claim 4.   The cam is rotated by 180 ° when the lever is rotated by an angle of 75 ° or more and 105 ° or less, and the secondary transfer member moves between the transfer position and the retracted position. Image forming apparatus. The image according to claim 5, wherein the release mechanism includes a first gear fixed to the shaft and a second gear fixed to the cam shaft and meshable with the first gear. Forming equipment.

Images