JP2009229530A - Image forming device, and driving force transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a driving force required when driving a rotary member such as a gear. <P>SOLUTION: A transmission mechanism part 65 is provided with a transmitting side coupling member 651, a gear 652, a shaft 653, the first pin 654, a coil spring 655, and a bearing 656. The transmission mechanism part 65 is also provided with the second pin. The coil spring 655 is arranged in the periphery of the shaft 653 and between the gear 652 and the transmitting side coupling member 651, to energize the transmitting side coupling member 651 along a direction separated from the gear 652. An end part in a gear 652 side of the coil spring 655 is arranged in contact with the gear 652, and the coil spring 655 is brought into a state supported by the gear 652. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a driving force transmission device.

  In a so-called tandem type image forming apparatus provided with a photosensitive drum for each color, a full color image formation is not always required, and a single color (for example, black) image formation may be required. In such a case, if a photosensitive drum that is not used for image formation is rotated, abrasion of the photosensitive drum is promoted by a cleaning blade or the like. In view of this, there has been proposed a technique for switching the driven photosensitive drums by changing the arrangement state of the gears (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 7-181773

Here, in an image forming apparatus or the like, the driving force is transmitted to the driven body by urging the transmitting member provided so as to be interlocked with a rotating member such as a gear with respect to the driven body. There is a case. By the way, in such a case, the driving force required to drive the rotating member increases depending on how the member that urges the transmission member is supported.
An object of the present invention is to reduce the driving force required to drive a rotating member such as a gear.

According to the first aspect of the present invention, a drive source, a rotating member that rotates by receiving a driving force from the driving source, a driven body that is driven by receiving a driving force from the rotating member, and an interlock with the rotating member A transmission member configured to transmit the driving force from the rotating member to the driven body, and a biasing member that biases the transmission member toward the driven body. The biasing member is an image forming apparatus characterized in that it is disposed in contact with the rotating member and supported by the rotating member.
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the rotating member includes a positioning portion that positions the biasing member arranged in contact.
According to a third aspect of the present invention, the driven body is detachably attached to the transmission member, and the transmission member can be retracted from the driven body side against a biasing force from the biasing member. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided.
According to a fourth aspect of the present invention, there is provided a guide member that is inserted from the other end side of the transmission member that is formed in a cylindrical shape with one end side sealed, and the one end of the transmission member. The discharge part for discharging the air which exists in the space formed between the part side and the said guide member to the exterior of the said space is further provided, The Claim 1 thru | or 3 characterized by the above-mentioned. An image forming apparatus.
According to a fifth aspect of the present invention, the driven body and the transmission member are configured to be able to be connected / disconnected to each other, and each include a base body that can rotate around a predetermined rotation axis. And one of the transmission members includes a protrusion protruding from the one base, and the other of the driven body and the transmission member receives the protrusion on the other base. And when the driven body is connected to the transmission member, if the rotation angle of the driven body with respect to the transmission member is a predetermined angle, the receiving port is allowed to accept the protrusion. 5. The image forming apparatus according to claim 1, wherein the acceptance is prevented when the angle is not a predetermined angle.

The invention according to claim 6 is arranged between a gear that rotates by receiving a driving force, and between the gear and another arrangement member, and prevents sliding between the gear and the other arrangement member. A suppressing member that interlocks with the gear, transmits a driving force from the gear to the driven body, and a pressing member that presses the transmitting member toward the driven body. The pressing member is a driving force transmission device that is supported by the gear without contacting the suppressing member.
A seventh aspect of the present invention is the driving force transmission device according to the sixth aspect, wherein the restraining member is constituted by a sliding bearing fitted to an annular portion formed on the gear.
The invention described in claim 8 is characterized in that an inner diameter of the annularly formed restraining member is formed larger than an outer shape of the transmission member formed in a columnar shape. It is a driving force transmission device.
The invention according to claim 9 further includes a shaft that is inserted into a through-hole formed in the gear and interlocks the gear and the transmission member, and the pressing member is a coil disposed around the shaft. 9. The driving force transmission device according to claim 6, wherein the gear is provided with a groove around which the end of the coil spring is inserted around the through hole. .

According to the first aspect of the present invention, the driving force required to drive the rotating member can be reduced as compared with the case where the present invention is not adopted.
According to the second aspect of the present invention, the urging member can be stably disposed, and for example, the urging of the transmission member with respect to the driven body can be further stabilized.
According to the third aspect of the present invention, for example, the breakage of the transmission member can be suppressed.
According to the fourth aspect of the present invention, for example, compression of air by the transmission member and the guide member can be avoided, so that the slide of the transmission member can be further stabilized.
According to the fifth aspect of the present invention, for example, when the drive side driven by the driven body and the apparatus main body side where the transmission member is arranged have a predetermined arrangement relationship, this predetermined arrangement relationship It can suppress that the drive side and the apparatus main body side are arrange | positioned by relationships other than these.

According to claim 6 of the present invention, the driving force required to drive the gear can be reduced as compared with the case where the pressing member is in contact with the suppressing member.
According to the seventh aspect of the present invention, compared with a case where the suppression member is constituted by, for example, a rolling bearing, the thickness of the portion to which the suppression member is attached can be reduced, and the apparatus can be downsized. it can.
According to claim 8 of the present invention, for example, the assembly of the driving force transmission device can be further simplified as compared with the case where the present invention is not adopted.
According to the ninth aspect of the present invention, the pressing member can be stably arranged, and for example, the pressing of the transmission member can be further stabilized.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a diagram showing an overall configuration of an image forming apparatus to which the present invention is applied. An image forming apparatus 1 shown in FIG. 1 is a so-called tandem type digital color printer using an electrophotographic system, and an image forming process unit that forms an image corresponding to image data of each color inside the apparatus main body 1A. 20 is provided. Further, each unit provided in the apparatus main body 1A and a control unit 68 for controlling the operation of each apparatus are provided. Further, for example, an image processing unit 69 that performs predetermined image processing on image data received from a personal computer (PC) 3 or a scanner 4, and a hard disk (Hard Disk Drive) that stores processing programs, image data, and the like are realized. Main memory (not shown).

  In the image forming process unit 20, four image forming units 30Y, 30M, 30C, and 30K (hereinafter also collectively referred to as “image forming unit 30”) are arranged in parallel in the left-right direction at regular intervals. Each image forming unit 30 includes a photosensitive drum 31 on which an electrostatic latent image is formed while rotating in the direction of arrow A, a charging roll 32 that charges the surface of the photosensitive drum 31, and a static electricity formed on the photosensitive drum 31. A developing unit 33 for developing the electrostatic latent image with toner of each color and a drum cleaner 35 for cleaning the surface of the photosensitive drum 31 after transfer are provided. Here, each image forming unit 30 is arranged to be replaceable (detachable) with respect to the apparatus main body 1A. For example, when the photosensitive drum 31 reaches the end of its life, the image forming unit 30 is replaced in units of image forming units 30. .

The charging roll 32 is composed of a roll member in which a conductive elastic body layer and a conductive surface layer are laminated on a conductive metal core such as aluminum or stainless steel. Then, a charging bias voltage is supplied from a charging power source (not shown), and the surface of the photosensitive drum 31 is uniformly charged at a predetermined potential while being driven to rotate relative to the photosensitive drum 31.
The developing device 33 holds, in each image forming unit 30, a two-component developer composed of yellow (Y), magenta (M), cyan (C), and black (K) toners and a magnetic carrier. The electrostatic latent image formed on the body drum 31 is developed with each color toner.
The drum cleaner 35 brings a plate-like member formed of a rubber material such as urethane rubber into contact with the surface of the photosensitive drum 31 to remove toner, paper dust, and the like attached on the photosensitive drum 31.

Further, the image forming process unit 20 is provided with a laser exposure unit 26 that exposes the photosensitive drum 31 provided in each image forming unit 30. The laser exposure unit 26 acquires image data for each color from the image processing unit 69, and scans and exposes the photosensitive drum 31 of each image forming unit 30 with laser light whose lighting is controlled based on the acquired image data. To do.
Further, the image forming process unit 20 is provided with a belt unit 50. Here, the belt unit 50 can be detachably attached to the apparatus main body 1A (from the apparatus main body 1A to the front side (paper surface in the figure) in order to enable maintenance and the like and to allow the installation of a new belt unit 50. It is detachably provided on the front side). The belt unit 50 includes an intermediate transfer belt 51, primary transfer rolls 52y, 52m, 52c, and 52k, a drive roll 53, and an idle roll 54.

Here, the intermediate transfer belt 51 is an endless belt member, which is stretched by at least an idle roll 54 and a drive roll 53 and driven by a motor (not shown) having excellent constant speed. 53 is circularly moved. Each color toner image formed on each photoconductive drum 31 of each image forming unit 30 is transferred onto the intermediate transfer belt 51 in a multiple manner.
Each of the primary transfer rolls 52 y, 52 m, 52 c, 52 k is disposed inside the intermediate transfer belt 51 and at a position facing each photosensitive drum 31. Then, each of the primary transfer rolls 52y, 52m, 52c, and 52k forms a transfer electric field with each of the photosensitive drums 31 so that each color toner image of each image forming unit 30 is intermediated at the primary transfer portion T1. Transfer (primary transfer) is sequentially performed on the transfer belt 51.

The image forming process unit 20 collectively transfers (secondary transfer) the superimposed toner image transferred onto the intermediate transfer belt 51 of the belt unit 50 onto the paper P as a recording material (recording paper) at the secondary transfer unit T2. A secondary transfer roll 80 and a fixing device 81 for fixing the secondary transferred image onto the paper P.
Further, the image forming process unit 20 includes a collection container 83 that collects toner, paper dust, and the like that are removed by a drum cleaner 35 and a belt cleaner 55 (described later) and are conveyed by a conveyance path (not shown). Here, the collection container 83 is attached to the apparatus main body 1A so as to be pulled out to the front side of the apparatus main body 1A. That is, it is detachably attached to the apparatus main body 1A. For example, when the container is full due to toner or the like, the collection container 83 is pulled out by the user or the like, and a new collection container 83 is pushed into the apparatus main body 1A. The collection container 83 includes a container main body 83a for storing collected toner and the like and a conveyance member 83b. The conveying member 83b is formed in a spiral shape, receives a driving force from a driving source (not shown), rotates in the direction of arrow C in the drawing, and conveys toner or the like in the container main body 83a.

  Further, the image forming process unit 20 is provided with a first drive unit 40 that rotationally drives the photosensitive drum 31 in each image forming unit 30 on the rear side (back side) of the apparatus main body 1A. Further, the second driving unit 60 is configured not to transmit the driving force from the first driving unit 40 to some of the photosensitive drums 31 and to separate (retract) the intermediate transfer belt 51 from the part of the photosensitive drums 31. Is provided.

  In the image forming apparatus 1 of the present embodiment, the image forming process unit 20 performs an image forming operation under the control of the control unit 68. That is, the image data input from the PC 3 or the scanner 4 is subjected to predetermined image processing by the image processing unit 69 and supplied to the laser exposure unit 26. In the cyan (C) image forming unit 30 </ b> C, for example, the surface of the photosensitive drum 31 that is uniformly charged with a predetermined potential by the charging roll 32 is based on the image data from the image processing unit 69 by the laser exposure unit 26. Then, scanning exposure is performed with the laser light whose lighting is controlled, and an electrostatic latent image is formed on the photosensitive drum 31. The formed electrostatic latent image is developed by the developing device 33, and a cyan (C) toner image is formed on the photosensitive drum 31. Similarly, in the image forming units 30Y, 30M, and 30K, yellow (Y), magenta (M), and black (K) toner images are formed.

  Each color toner image formed by each image forming unit 30 is a primary image to which a predetermined primary transfer bias is applied from a transfer power source (not shown) onto an intermediate transfer belt 51 that circulates and moves in the direction of arrow B in FIG. Electrostatic transfer is sequentially performed by the transfer rolls 52y, 52m, 52c, and 52k, and a toner image superimposed on the intermediate transfer belt 51 is formed. Then, the superimposed toner image is conveyed toward the secondary transfer portion T <b> 2 in which the secondary transfer roll 80 and the drive roll 53 are disposed as the intermediate transfer belt 51 moves.

  On the other hand, the sheet P as an example of the transfer medium is taken out from the sheet holding unit 71 by a pickup roll 72 for sending out, and is transported to the position of a registration roll 74 for regulating the position of the sheet P along the transport path R1. The Then, the sheet P is conveyed from the registration roll 74 toward the secondary transfer portion T2 in synchronization with the timing at which the superimposed toner image is conveyed to the secondary transfer portion T2. In the secondary transfer portion T2, the superimposed toner images are collectively and statically formed on the paper P by the action of the transfer electric field formed between the secondary transfer roll 80 to which the secondary transfer bias voltage is applied and the drive roll 53. Electrotransfer (secondary transfer) is performed. Note that the sheet P is also transported to the secondary transfer unit T2 from the duplex transport path R2 and the transport path R3 from the manual sheet holding unit 75.

  Thereafter, the sheet P on which the superimposed toner image is electrostatically transferred is peeled off from the intermediate transfer belt 51 and conveyed to the fixing device 81. The unfixed toner image on the paper P conveyed to the fixing device 81 is fixed on the paper P by being subjected to fixing processing by heat and pressure by the fixing device 81. The paper P on which the fixed image is formed is conveyed to a paper stacking unit 91 provided in the discharge unit of the image forming apparatus 1. On the other hand, the toner (transfer residual toner) adhering to the intermediate transfer belt 51 after the secondary transfer is removed by the belt cleaner 55 arranged so as to come into contact with the intermediate transfer belt 51 to prepare for the next image forming cycle. . As described above, the toner or the like removed by the belt cleaner 55 is transported to the collection container 83 through a transport path (not shown).

Subsequently, the belt unit 50 will be described in more detail.
FIG. 2 is a diagram for explaining the belt unit 50.
Here, in the image forming apparatus 1 according to this embodiment, image formation using the image forming units 30Y, 30M, 30C, and 30K of yellow (Y), magenta (M), cyan (C), and black (K) is performed. When being performed, that is, when full-color image formation is performed, the intermediate transfer belt 51 is disposed so as to contact all the photosensitive drums 31. Further, when an image is formed using the black (K) image forming unit 30K, that is, when a monochrome image is formed, the intermediate transfer belt 51 is a photosensitive drum in the image forming units 30Y, 30M, and 30C. It is arranged so as to be separated from 31.

More specifically, as shown in FIG. 2A, the belt unit 50 according to the present embodiment includes a first support portion that rotatably supports the primary transfer roll 52k on the inner peripheral side of the intermediate transfer belt 51. 561 and a second support portion 562 that rotatably supports the primary transfer rolls 52y, 52m, and 52c. Further, the cam 563 that is disposed so as to be capable of rotating at least 180 ° and is rotationally driven (oscillated) by the second drive unit 60 and the second support portion 562 are pressed against the image forming unit 30 side. A coil spring 564 is provided.
Here, the second support portion 562 is disposed at a position facing the image forming units 30Y, 30M, and 30C with the intermediate transfer belt 51 interposed therebetween. The second support portion 562 includes a through hole 565 in the upper part of the image forming unit 33C in which the cam 563 is disposed. Further, a fulcrum 566 for rotating (swinging) the second support portion 562 relative to the first support portion 561 is provided between the first support portion 561 and the second support portion 562. ing.

  In the present embodiment, when the monochrome image formation is performed using the image forming unit 30K, the cam 563 is rotated counterclockwise in the drawing by the second drive unit 60, and the cam 563 resists the pressing force of the coil spring 564. Then, the second support portion 562 is pushed upward. As a result, the second support portion 562 rotates clockwise in the figure with the fulcrum 566 as the center of rotation. As a result, as shown in FIG. 2B, the intermediate transfer belt 51 is separated from the photosensitive drums 31 in the image forming units 30Y, 30M, and 30C.

When the intermediate transfer belt 51 is separated from the photosensitive drum 31 in each of the image forming units 30Y, 30M, and 30C, the photosensitive drum 31 (the photosensitive drum 31 in the image forming units 30Y, 30M, and 30C) is moved by the movement of the intermediate transfer belt 51. ) Is stopped. Although details will be described later, when the intermediate transfer belt 51 is separated from the photosensitive drum 31 in the image forming units 30Y, 30M, and 30C, the second driving unit 60 causes the photosensitive drums in the image forming units 30Y, 30M, and 30C to be separated. The rotational drive of 31 is also stopped.
Here, when the intermediate transfer belt 51 is brought into contact with the photosensitive drum 31 again, the cam 563 is rotated clockwise from the state shown in FIG. 5B, and the second support portion 562 is moved by the coil spring 564. Rotate counterclockwise in the figure.

  FIG. 3 is a diagram for explaining the first drive unit 40 and the second drive unit 60. Here, in the image forming apparatus 1 in the present embodiment, the first drive unit 40 and the second drive unit 60 are provided on the rear side of the apparatus main body 1A as described above. In the drawing, the side portion of the image forming unit 30C (the rear side of the image forming unit 30C) is illustrated.

As shown in the drawing, the image forming unit 30C in the present embodiment has a photosensitive member side coupling member 18c (hereinafter referred to as "photosensitive member side") that is attached to the photosensitive drum 31 and rotates in conjunction with the photosensitive drum 31 at the side portion. Coupling member 18 ").
On the other hand, the first drive unit 40 is provided corresponding to the motor M1 and the photoconductor side coupling member 18c, and is driven to rotate by the driving force generated by the motor M1. Coupling member 43 ").
In the present embodiment, the driving side coupling member 43c is coupled to the corresponding photoconductor side coupling member 18c. As a result, the photosensitive drum 31 in the image forming unit 30C receives the driving force from the motor M1 and rotates.

Here, the first drive unit 40 is provided with a gear 41c that is rotated by the motor M1, a shaft 42c that rotates in conjunction with the gear 41c, and the shaft 42c, and both end portions project from the outer peripheral surface of the shaft 42c. Pin 44. Further, the drive side coupling member 43c is provided.
The pin 44 is disposed inside the driving side coupling member 43c, and hits against the abutting surface 45 formed inside the driving side coupling member 43c when the shaft 42c is driven to rotate by the motor M1. It is arranged. As a result, the drive side coupling member 43c also rotates in conjunction with the rotation of the shaft 42c.

  The drive side coupling member 43c is slidably disposed along the axial direction of the shaft 42c. More specifically, the drive side coupling member 43c in the present embodiment has a shaft 42c disposed therein and is formed to have a larger diameter than the shaft 42c, and from the first drive unit 40 side to the image forming unit 30C side. A through-hole 46 is provided so as to penetrate therethrough. Further, the drive side coupling member 43c includes the abutting surface 45 as described above. The abutting surface 45 is formed in a flat shape and is disposed along the axial direction of the shaft 42c. The drive side coupling member 43c includes an inward protruding portion 47 that protrudes into the through hole 46 on the photosensitive member side coupling member 18c side. The inward protruding portion 47 abuts against the tip end portion of the shaft 42c when the driving side coupling member 43c slides toward the first driving unit 40 side.

  Further, the driving side coupling member 43c is formed closer to the photoconductor side coupling member 18c than the abutting surface 45, from the through hole 46 toward the outer side of the driving side coupling member 43c, and the shaft 42c. A concave groove 48 is provided so as to surround the outer peripheral surface of the first groove. When the drive side coupling member 43c slides to the first drive unit 40 side and the inward protruding portion 47 hits the tip end portion of the shaft 42c, the pin 44 is disposed in the recessed groove 48 in a rotatable state. The Further, the drive side coupling member 43c is provided with an outward projecting portion 49 projecting outward on the outer peripheral portion thereof.

  On the other hand, the second drive unit 60 in this embodiment is interlocked with the slide of a movable plate 61 (see FIG. 6), which will be described in detail later, and advances and retracts 70c (hereinafter referred to as “advance / retreat”) with respect to the photoreceptor side coupling member 18c. Member 70 "). The advance / retreat member 70 c is accommodated in a rotatable state in an accommodation portion 63 c (hereinafter also referred to as “accommodation portion 63”) formed in the housing 62 of the second drive unit 60. Here, the advancing / retreating member 70c in the present embodiment includes an inward protruding portion 70e protruding inward on the inner peripheral surface of the ring portion 70a formed in a ring shape.

  The driving side coupling member 43c in the present embodiment is disposed inside the ring portion 70a. As a result of being pressed by a coil spring (not shown), the outward projecting portion 49 is abutted against the inwardly projecting portion 70 e and the advance / retreat member 70 c is abutted against the housing 62. As a result, the drive side coupling member 43c is positioned at a predetermined position in the accommodating portion 63c. Further, the front end portion of the drive side coupling member 43c is exposed from the advance / retreat member 70c, and the front end portion is coupled to the photoconductor side coupling member 18c. Note that the drive side coupling member 43c in the present embodiment is configured by assembling two members, a connection member 19a connected to the photoconductor side coupling member 18c, and a support member 19b that supports the connection member 19a.

Here, FIG. 4 shows a state after the advance / retreat member 70c rotates. FIG. 5 shows the inside of the accommodating portion 63c.
Although the description is omitted in FIG. 3, the second drive unit 60 in the present embodiment has a protruding portion 66 (not shown in FIG. 4) that is formed in a rib shape and protrudes from the bottom of the accommodating portion 63c, as shown in FIG. Omitted). And this protrusion part 66 has the inclined surface 66a formed so that it might leave | separate gradually from the bottom part of an accommodating part. When the advance / retreat member 70c is rotated by the sliding of the movable plate 61, the advance / retreat member 70c is guided by the inclined surface 66a and moves (retreats) away from the photoconductor side coupling member 18c. When the advance / retreat member 70c moves away from the photoreceptor side coupling member 18c, the drive side coupling member 43c also moves (slides) away from the photoreceptor side coupling member 18c, as shown in FIG. As a result, as shown in the figure, the connection between the photoconductor side coupling member 18c and the drive side coupling member 43c is released. As a result, the rotation of the photosensitive drum 31 by the driving side coupling member 43c is stopped. In this state, since the pin 44 is positioned in the concave groove 48, the rotation of the drive side coupling member 43c is also stopped.

Note that the side portions in the image forming units 30Y and 30M (the rear side of the image forming units 30Y and 30M) are configured in the same manner as the side portions in the image forming unit 30C. On the other hand, the image forming unit 30K is provided with the photoconductor side coupling member 18 and the drive side coupling member 43, but is not provided with the advance / retreat member 70.
Therefore, when the movable plate 61 slides, the connection between the photoconductor side coupling member 18 and the drive side coupling member 43 provided corresponding to the image forming unit 30K is maintained, and the image forming units 30Y, 30M, The connection between the photoconductor side coupling member 18 and the driving side coupling member 43 provided corresponding to 30C is released. As a result, when the movable plate 61 slides, only the photosensitive drum 31 in the image forming unit 30K is rotationally driven, and image formation using the image forming unit 30K, that is, monochrome image formation is possible.

  In the present specification, for convenience of explanation, hereinafter, the photoreceptor side coupling member 18 provided corresponding to the image forming unit 30Y is referred to as a photoreceptor side coupling member 18y, and provided corresponding to the image forming unit 30Y. The driving side coupling member 43 is referred to as a driving side coupling member 43y. Similarly, those corresponding to the image forming unit 30M are referred to as a photoreceptor side coupling member 18m and a driving side coupling member 43m. Further, those corresponding to the image forming unit 30K are referred to as a photoconductor side coupling member 18k and a driving side coupling member 43k.

Here, FIG. 6 shows the second drive unit 60 from the rear side of the apparatus main body 1A.
As described above, the second drive unit 60 includes the movable plate 61 and the advance / retreat member 70. The second drive unit 60 includes a housing 62 that supports these members.
The housing 62 includes four accommodating portions 63y, 63m, 63c, and 63k at positions corresponding to the respective image forming units 30. Of the four accommodating portions 63y, 63m, 63c, and 63k, the advancing / retracting members 70y, 70m, and 70c provided in the accommodating portions 63y, 63m, and 63c corresponding to the image forming units 30Y, 30M, and 30C, respectively. Is stored.

Here, each of the advancing and retracting members 70y, 70m, and 70c includes, as shown in the figure, the ring portion 70a formed in a ring shape with a through hole at the center, and an arm protruding outward from the ring portion 70a. A portion 70b and a through hole 70d formed in the shape of a long hole at the tip of the arm portion 70b are provided.
On the other hand, the movable plate 61 is formed in a long shape and a thin plate shape, and is arranged so as to be slidable along the arrangement direction of the image forming unit 30. Moreover, the movable plate 61 is provided with the 1st protrusion part 611 penetrated by the through-hole 70d of the advance / retreat member 70y in the one end part. Moreover, the 2nd protrusion part 612 and the 3rd protrusion part 613 are provided in order toward this other end part from this one end part. Here, the 2nd protrusion part 612 is penetrated by the through-hole 70d of the advance / retreat member 70m, and the 3rd protrusion part 613 is penetrated by the through-hole 70d of the advance / retreat member 70c. In addition, the movable plate 61 includes a first rack gear 614 that meshes with a driving gear 1B that rotates by receiving a driving force from a motor M2 as an example of a driving source at the other end.

  When the movable plate 61 protrudes from the housing 62 as shown in this figure, each of the advance / retreat members 70y, 70m, and 70c is in a state of sliding toward the first drive unit 40 as shown in FIG. Therefore, the connection between the photoconductor side coupling members 18y, 18m, and 18c and the corresponding drive side coupling members 43y, 43m, and 43c is in a released state. As a result, it is possible to form an image using the image forming unit 30K, that is, to form an image in a single color. When the movable plate 61 is slid in the direction indicated by the arrow D in the figure, each of the advance / retreat members 70y, 70m, and 70c is pressed and rotated by the movable plate 61. As a result, the photoconductor side coupling members 18y, 18m, and 18c and the driving side coupling members 43y, 43m, and 43c are connected, and a full color image can be formed.

Here, FIG. 7 shows the back side of the movable plate 61. In other words, the movable plate 61 is viewed from the front side of the apparatus main body 1A.
As shown in the figure, the movable plate 61 in the present embodiment has a side surface opposite to the side where the first projecting portion 611 to the third projecting portion 613 are provided, and the third projecting portion 613. The 2nd rack gear 615 is provided in the back side.

Next, the second drive unit 60 will be described.
FIG. 8 shows the second drive unit 60 from the front side of the apparatus main body 1A. FIG. 9 shows a part of the transmission mechanism 65 in the second drive unit 60.
Here, as shown in FIG. 8, the second drive unit 60 has a substantially rectangular opening 621 penetrating from the rear side to the front side of the housing 62. The opening 621 is provided along the sliding direction of the movable plate 61, and the second rack gear 615 in the movable plate 61 is disposed in the opening 621. Further, the second drive unit 60 includes a transmission mechanism 65 that transmits a driving force from the movable plate 61 to a cam 563 (see FIG. 2) provided in the belt unit 50. Here, the second rack gear 615 is in mesh with a gear 652 (details will be described later) in the transmission mechanism 65.

  Here, the transmission mechanism unit 65 includes a transmission-side coupling member 651 (an example of a transmission member) that transmits a driving force to the cam 563 by rotating in conjunction with the slide of the movable plate 61. As shown in FIG. 9, the transmission side coupling member 651 is connected to a cam side coupling member 567 (an example of a driven body) provided so as to be interlocked with the cam 563, so that the driving force is increased. This is transmitted to the cam 563.

  As shown in FIG. 8, when the movable plate 61 protrudes from the housing 62, the cam 563 faces upward as shown in FIG. 2B, and the image forming units 30Y, 30M, and 30C. In this state, the intermediate transfer belt 51 is separated from each photosensitive drum 31. In the state where the movable plate 61 protrudes from the housing 62, the advancing / retracting members 70y, 70m, and 70k are slid toward the first drive unit 40 as described above (see FIG. 4), and the photoconductor side coupling. The connection between the members 18y, 18m, and 18c and the drive side coupling members 43y, 43m, and 43c is released. That is, the intermediate transfer belt 51 is separated from the photosensitive drums 31 in the image forming units 30Y, 30M, and 30C, and the driving force to the photosensitive drums 31 in the image forming units 30Y, 30M, and 30C is not transmitted. . In other words, the photosensitive drum 31 and the intermediate transfer belt 51 in the image forming unit 30K are in contact with each other, and only the photosensitive drum 31 in the image forming unit 30K can be rotationally driven. That is, a monochrome image can be formed.

  On the other hand, when the movable plate 61 is slid from the state shown in FIG. 8 in the direction of arrow F by the motor M2 (see FIG. 6) and pushed into the housing 62, the transmission side coupling member 651 is shown in the figure. Rotate 180 ° in the direction indicated by arrow G. As a result, as shown in FIG. 2A, all the photosensitive drums 31 and the intermediate transfer belt 51 come into contact with each other. The advance / retreat members 70y, 70m, and 70c also rotate and slide toward the photoconductor side coupling members 18y, 18m, and 18c. As a result, the photoreceptor side coupling members 18y, 18m, and 18c are connected to the drive side coupling members 43y, 43m, and 43c. As a result, a full color image can be formed.

Here, FIGS. 10 to 12 are diagrams for explaining the transmission mechanism unit 65.
As illustrated in FIG. 10, the transmission mechanism 65 includes a transmission side coupling member 651, a gear 652 as an example of a rotating member, a shaft 653, a first pin 654, an urging member, and an example of a pressing member. Coil spring 655 and a bearing 656. As shown in FIG. 11, the transmission mechanism 65 includes a second pin 657.
Here, as shown in FIG. 10, the transmission side coupling member 651 includes a base portion 651b having an end surface 651a formed in a cylindrical shape, and a meshing portion 651c provided on the end surface 651a and meshing with the cam side coupling member 567. (An example of a protruding portion). The base portion 651b includes a long hole 651d formed along the axial direction of the base portion 651b and penetrating from the inner peripheral surface side to the outer peripheral surface side of the base portion 651b.

  As shown in FIG. 12, the gear 652 has a predetermined thickness and is formed in a disk shape. In addition, a center hole 652a (an example of a through hole) into which the shaft 653 is inserted is provided at the center. In addition, a first protrusion 652b protruding in a cylindrical shape (annular) from the side surface of the gear 652 is provided around the center hole 652a. In addition, a second protrusion 652c (an example of an annular part) is provided around the first protrusion 652b. The second protrusion 652c protrudes in a cylindrical shape (annular) from the side surface of the gear 652. A bearing 656 that is also formed in a cylindrical shape (annular shape) is fitted to the outside of the second projecting portion 652c. The second protrusion 652c is disposed with a predetermined gap from the first protrusion 652b. Therefore, a ring-shaped groove 652d is formed between the first protrusion 652b and the second protrusion 652c. As shown in FIG. 11, the gear 652 has a concave groove 652e formed on the other side surface (back surface) so as to pass through the center hole 652a. Note that the number of teeth in the gear 652 is twice the number of teeth in the second rack gear 615. For this reason, when the 2nd rack gear 615 slides, the gear 652 (transmission mechanism part 65) rotates 180 degrees as mentioned above.

As shown in FIG. 10, the shaft 653 includes a first through hole 653 a that is provided through one end of the shaft 653 so as to be orthogonal to the axial direction. Further, as shown in FIG. 11, the other end portion is also provided with a second through-hole 653b that is also provided penetratingly in a relationship orthogonal to the axial direction. As shown in FIG. 10, one end of the shaft 653 is inserted into the base body 651 b of the transmission side coupling member 651, and the other end is inserted into the center hole 652 a in the gear 652. Then, the first pin 654 is press-fitted into the first through hole 653a through the long hole 651d in the base portion 651b, and the second pin 657 is inserted into the second through hole 653b.
Here, the first pin 654 prevents the transmission side coupling member 651 from falling off the shaft 653 and guides the sliding of the transmission side coupling member 651 with respect to the shaft 653. Further, the transmission side coupling member 651 can be interlocked with the shaft 653. Further, after the second pin 657 is inserted into the second through hole 653b, the second pin 657 is disposed in the concave groove 652e of the gear 652, and the gear 652 and the shaft 653 can be interlocked. Note that the shaft 653 in this embodiment also functions as a guide member that guides the slide (advance and retreat) of the transmission side coupling member 651.

  As shown in FIG. 10, the coil spring 655 is arranged around the shaft 653 and between the gear 652 and the transmission side coupling member 651, and biases the transmission side coupling member 651 in a direction away from the gear 652. To do. Note that the end of the coil spring 655 on the gear 652 side is disposed in a groove 652d (see FIG. 12) in the gear 652, and the position of the coil spring 655 is restricted. Here, the groove 652d can also be regarded as a positioning portion for positioning the coil spring 655. In addition, the end of the coil spring 655 on the gear 652 side is disposed in contact with the gear 652, and the coil spring 655 is supported by the gear 652. Further, since the coil spring 655 is disposed between the gear 652 and the transmission side coupling member 651, when the gear 652 is rotated by the movable plate 61, the coil spring 655 is interlocked with the gear 652 and the transmission side coupling member 651. Rotate (synchronously).

  A bearing 656 as an example of a restraining member is formed in a ring shape as shown in FIG. And this bearing 656 is arrange | positioned around the 2nd protrusion part 652c (refer FIG. 12) in the gear 652. FIG. The bearing 656 has a self-lubricating property and is configured as a so-called sliding bearing. Further, the bearing 656 has a face-grooving portion on a part of the outer peripheral surface thereof, and is in a state where a so-called D cut is made. Although not shown in the drawing, a cover (an example of another arrangement member) for holding the transmission mechanism 65 is attached to the housing 62 after the transmission mechanism 65 is installed. . When this cover is attached, the cover and the gear 652 slide, and there is a concern about the wear of the gear 652. Therefore, in the present embodiment, a bearing 656 is disposed between the cover and the gear 652, and the gear 652 and the cover are not in direct contact with each other.

Here, FIG. 13 is a view for explaining the transmission side coupling member 651.
2A is a perspective view of the transmission side coupling member 651, and FIG. 2B is a top view of the transmission side coupling member 651. FIG.
As shown in FIG. 6A and as described above, the transmission side coupling member 651 in the present embodiment has a cylindrical base portion 651b and a meshing portion 651c. In addition, the base portion 651b includes a through hole 651e penetrating in the axial direction on an end surface 651a that seals one end side.

  The meshing portion 651c is provided in a state of protruding from the end surface 651a of the base portion 651b, as shown in FIG. Further, the meshing portion 651c is formed in a shape in which a cross section in a direction orthogonal to the axial direction is a hook shape (arrow shape). In other words, the meshing portion 651c is formed in a shape whose cross section is a substantially isosceles triangle. Further, as shown in FIG. 5B, the meshing portion 651c is arranged in a state where the center in the cross section (see J in the drawing) is shifted from the rotation center (axial center) of the base portion 651b (see K in the drawing). Has been. That is, the meshing portion 651c is arranged in an eccentric state with respect to the base portion 651b.

  Further, the meshing portion 651c formed in a bowl shape has a tip portion 651f disposed so as to face the outer peripheral surface side of the base portion 651b, and an axial center than the tip portion 651f, as shown in FIG. It has the 1st top part 651g and the 2nd top part 651h arrange | positioned at the side. Moreover, it has the bottom part 651j located between the 1st top part 651g and the 2nd top part 651h, and is arrange | positioned rather than the line | wire which connects the 1st top part 651g and the 2nd top part 651h. The engaging portion 651c includes a first flat surface 651k that connects the tip portion 651f and the first top portion 651g, a second flat surface 651m that connects the tip portion 651f and the second top portion 651h, and a first top portion 651g and a bottom portion 651j. A third flat surface 651n to be connected and a fourth flat surface 651p to connect the second top portion 651h and the bottom portion 651j are provided.

  On the other hand, the through hole 651e as an example of the discharge portion is disposed on the end surface 651a of the base portion 651b as described above. The through-hole 651e is provided penetrating along the axial direction of the base portion 651b, and allows air to flow between the inside and the outside of the base portion 651b. More specifically, when the transmission-side coupling member 651 slides to the gear 652 side from the state of FIG. 10, the air existing in the space formed between the shaft 653 and the base portion 651b is transferred to the outside of the base portion 651b. Discharge.

In the above description, the air is discharged to the outside through the through hole 651e. However, for example, air can be discharged by the following configuration.
Here, FIG. 14 shows another configuration example of the transmission side coupling member 651. For example, the transmission-side coupling member 651 is provided with, for example, a semicircular cross-sectional protrusion 651s formed along the axial direction on the inner peripheral surface 651r, as shown in FIGS. it can. In addition, the figure (a2) has shown the cross section in the AA line in the figure (a1). In the case of this configuration example, air is discharged through a gap formed between the shaft 653 and the inner peripheral surface 651r. In this configuration example, the three protrusions 651s are provided at equal intervals in the circumferential direction, but it is also possible to provide three or more protrusions 651s. Further, as shown in FIG. 2A2, it is preferable to provide a tapered surface 651t whose height gradually decreases toward the insertion port at the end of the projection 651s on the insertion port side. Further, as shown in FIG. 5B, a groove 651w having a semicircular cross section, for example, formed along the axial direction can be provided on the inner peripheral surface 651r. In this configuration example, air is discharged through the groove 651w.

Here, FIG. 15 shows the relationship between the transmission side coupling member 651 and the cam side coupling member 567. In the drawing, the transmission side coupling member 651 is disposed on the back side of the paper surface, and the cam side coupling member 567 is disposed on the near side of the paper surface.
Here, the cam side coupling member 567 will be described with reference to FIG. The cam side coupling member 567 according to the present embodiment includes a meshing portion 567a (an example of a receiving port) (illustrated by a broken line) in the same manner as the transmission side coupling member 651. However, unlike the transmission side coupling member 651, the meshing portion 567a is formed so as not to protrude from the base portion 567b and to be depressed from the end surface 567c of the base portion 567b, as shown in FIG.

  The meshing portion 567a is also arranged in a state where the center in the cross section is shifted from the rotation center (axial center) of the base body portion 567b. That is, the meshing part 567a is arranged in an eccentric state with respect to the base part 567b. Further, the meshing portion 567a has an outer diameter shape corresponding to the outer diameter shape of the meshing portion 651c of the transmission side coupling member 651, and is specifically formed in a bowl shape (arrow shape). For this reason, the meshing portion 567a of the cam side coupling member 567 also includes a tip portion 567d, a first top portion 567e, a second top portion 567f, and a bottom portion 567g. Further, a first flat surface 567h, a second flat surface 567j, a third flat surface 567k, and a fourth flat surface 567m are provided. The engagement portion 567a in the cam side coupling member 567 is formed to be slightly larger than the engagement portion 651c in the transmission side coupling member 651, and the shaft center of the cam side coupling member 567 and the transmission side coupling member 651 are formed. Even if it is in a state of being out of alignment with each other, it is possible to connect the two.

  Here, both the meshing portion 651c of the transmission side coupling member 651 and the meshing portion 567a of the cam side coupling member 567 are provided in an eccentric state with respect to the base portions 651b and 567b as described above. Therefore, both of the transmission side coupling member 651 and the cam side coupling member 567 are in phase with each other and mesh with each other only at a predetermined position in the circumferential direction, as shown in FIG. . In other words, when the rotation angle of the transmission-side coupling member 651 with respect to the cam-side coupling member 567 is a predetermined angle, the meshing portion 567a is allowed to accept the meshing portion 651c and meshes with each other. If the angle is other than the predetermined angle, the acceptance is blocked as described later.

  In this state, for example, as indicated by an arrow M in FIG. 5A, when the transmission side coupling member 651 rotates, the first flat surface 651k, the second flat surface 651m, and the third flat surface in the meshing portion 651c. 651n (see FIG. 13) presses the first flat surface 567h, the second flat surface 567j, and the third flat surface 567k of the meshing portion 567a, respectively. That is, the transmission side coupling member 651 presses the cam side coupling member 567 at the three contact portions. In this case, the load from the transmission side coupling member 651 acting on the cam side coupling member 567 is not concentrated in one place but is dispersed.

When the transmission side coupling member 651 rotates in the reverse direction, the first flat surface 651k, the second flat surface 651m, and the fourth flat surface 651p in the meshing portion 651c are respectively the first flat surface 567h in the meshing portion 567a. The second flat surface 567j and the fourth flat surface 567m are pressed.
As a result, the cam side coupling member 567 rotates in conjunction with the transmission side coupling member 651, and the cam 563 (see FIG. 2) also rotates in conjunction with the transmission side coupling member 651. Therefore, the intermediate transfer belt 51 is brought into contact with or separated from the photosensitive drum 31 in the image forming units 30Y, 30M, and 30C according to the rotation of the transmission side coupling member 651 (see FIG. 2).

  When the transmission side coupling member 651 and the cam side coupling member 567 are to be connected in a state where the phase is shifted by about 45 ° in the circumferential direction, for example, as shown in FIG. The distal end portion 651f, the first top portion 651g, and the second top portion 651h of the transmission side coupling member 651 abut against the end surface 567c (see FIG. 9) of the cam side coupling member 567. As a result, the connection between the transmission side coupling member 651 and the cam side coupling member 567 is prevented. In other words, reception of the meshing portion 651c by the meshing portion 567a is prevented. At this time, the transmission side coupling member 651 retracts toward the gear 652 against the urging force of the coil spring 655 (see FIG. 10).

  Further, when the transmission side coupling member 651 and the cam side coupling member 567 are to be connected in a state where the phase is shifted by 180 ° in the circumferential direction, for example, as shown in FIG. The front end portion 651f, the first top portion 651g, and the second top portion 651h of the transmission side coupling member 651 abut against the end surface 567c of the cam side coupling member 567. As a result, also in this case, the connection between the transmission side coupling member 651 and the cam side coupling member 567 is prevented.

  The belt unit 50 in the present embodiment is detachably provided to the apparatus main body 1A as described above. Here, attachment / detachment of the belt unit 50 is performed at various timings. For example, the power is turned off in a state where the second drive unit 60 is in the monochrome mode (the state shown in FIG. 8), and then in the full color mode. A new belt unit 50 (the belt unit 50 in the state shown in FIG. 2A) may be attached. In this embodiment, the second support portion 562 is pushed up by the cam 563 and the belt unit 50 is set to the monochrome mode (the state shown in FIG. 2B), but is pushed up by the cam 563 during maintenance or the like. May be canceled and the mode may be switched to the full color mode. The belt unit 50 switched to the full color mode may be pushed into the second drive unit 60 in the monochrome mode.

By the way, if the transmission side coupling member 651 and the cam side coupling member 567 are connected to each other in a state where the modes of the second drive unit 60 and the belt unit 50 are different from each other as described above, for example, an image Although the transmission of the driving force to each photosensitive drum 31 in the forming units 30Y, 30M, and 30C is released, the intermediate transfer belt 51 comes into contact with these photosensitive drums 31.
Further, if the transmission side coupling member 651 and the cam side coupling member 567 are engaged with each other, the intended original operation becomes difficult. For example, when the second drive unit 60 is in the monochrome mode as shown in FIG. 8 and the belt unit 50 is in the full color mode as shown in FIG. 2A, the transmission side coupling member 651 and the cam side coupling are used. If the member 567 is engaged, the intended original operation becomes difficult. Specifically, even if the cam 563 is rotated by pushing the movable plate 61 in FIG. 8, the cam 563 hits the second support portion 562 and cannot be rotated. In addition, the sliding of the movable plate 61 in the pulling direction from the housing 62 is difficult because the second rack gear 615 hits the housing 62. For this reason, the movable plate 61, the cam 563 and the like are locked, and the intended original operation becomes difficult.

On the other hand, in this embodiment, when the transmission-side coupling member 651 and the cam-side coupling member 567 are engaged with each other in a state where the modes of the second drive unit 60 and the belt unit 50 are different from each other, FIG. As shown in b) and (c), the tip end portion 651f, the first top portion 651g, and the second top portion 651h of the transmission side coupling member 651 abut against the end surface 567c of the cam side coupling member 567. That is, the connection between the transmission side coupling member 651 and the cam side coupling member 567 is prevented.
In this case, in this embodiment, for example, the transmission side coupling member 651 is rotated by executing the initialization operation and sliding the movable plate 61 to connect the transmission side coupling member 651 and the cam side coupling member 567. Do. As a result, the mode of the second drive unit 60 and the mode of the belt unit 50 are synchronized with each other.

  Note that the situation where the transmission side coupling member 651 and the cam side coupling member 567 are connected in a state where the mode of the second drive unit 60 and the mode of the belt unit 50 are different from each other is caused by an assembly error in the assembly process. Can also occur. For example, when the transmission mechanism 65 is rotated 180 ° in the circumferential direction from the state shown in FIG. 8 and attached to the housing 62, the transmission side coupling member 651 and the cam side coupling member 567 are connected in different modes. Resulting in. Therefore, in this embodiment, the installation reference of each member at the time of assembly is formed at a position where the operator can visually check. Specifically, first, the engaging portion 651c of the transmission side coupling member 651 is formed in a hook shape (arrow shape) as described above. Further, as shown in FIG. 10, a gear side mark 652h is formed on the gear 652 by projecting a part of the outer peripheral surface 652g of the concave portion 652f formed in a circular shape outward and substantially in a triangular shape.

Further, as shown in FIG. 10, plate-side marks 615 a formed in a triangular shape and a concave shape are formed on the side surface of the second rack gear 615. In addition, this plate side mark 615a is arrange | positioned so that a top part may go to the tooth | gear part in the 2nd rack gear 615. FIG.
In this embodiment, the operator places the plate-side mark 615a so that the plate-side mark 615a and the front end 651f of the meshing portion 651c face each other, in other words, the plate-side mark 615a is positioned in the direction indicated by the meshing portion 651c. The movable plate 61 and the transmission mechanism 65 are assembled to the housing 62. It is also possible to assemble with reference to the gear side mark 652h. That is, the assembly can be performed so that the plate side mark 615a and the gear side mark 652h face each other.

  In this embodiment, the example in which the intermediate transfer belt 51 is contacted / separated with respect to the photosensitive drum 31 using the movable plate 61, the transmission mechanism 65, and the like has been described. By the way, these configurations are examples, and the configurations of the movable plate 61, the transmission mechanism 65, and the like are, for example, a mechanism for contacting / separating the secondary transfer roll with respect to the intermediate transfer belt in a so-called four-cycle image forming apparatus. Can also be used. Further, for example, it can be used for a mechanism for contacting / separating the cleaner with respect to the intermediate transfer belt.

Here, the transmission mechanism 65 will be further described with reference to FIG.
FIG. 16 is a perspective view showing the transmission mechanism 65 from an angle different from that in FIG.
In the transmission mechanism portion 65 in the present embodiment, the inner diameter D2 of the bearing 656 is formed larger than the outer diameter D1 of the base portion 651b in the transmission-side coupling member 651 formed in a columnar shape. And in this embodiment, the assembly of the transmission mechanism part 65 is performed as follows. First, the one end part side of the shaft 653 is inserted into the base part 651b in the transmission side coupling member 651. Then, the first pin 654 is press-fitted into the first through hole 653a (see FIG. 10) of the shaft 653 through the long hole 651d, and the transmission side coupling member 651 and the shaft 653 are integrated.

  Next, after the coil spring 655 is disposed on the outer peripheral portion of the shaft 653, the other end portion side of the shaft 653 is inserted into the center hole 652a (see FIG. 12) of the gear 652. Thereafter, the second pin 657 is inserted into the second through-hole 653b (see FIG. 11) of the shaft 653 on the back side of the gear 652, and the second pin 657 is inserted into the groove 652e ( (See FIG. 11). And the bearing 656 is arrange | positioned on the outer side of the 2nd protrusion part 652c in the gear 652. FIG. At this time, as described above, since the inner diameter D2 of the bearing 656 is larger than the outer diameter D1 of the base portion 651b in the transmission side coupling member 651, the shaft is attached to the transmission side coupling member 651. The bearing 656 can be disposed avoiding interference with the 656. Finally, a cover (not shown) is attached to the housing 62, and the assembly is completed.

By the way, the transmission mechanism 65 can be configured as shown in FIG. 17, for example. Here, FIG. 17 shows another configuration example of the transmission mechanism portion 65.
In the present embodiment, the coil spring 655 is arranged between the transmission side coupling member 651 and the gear 652 as described above. For example, as shown in FIG. A coil spring 655 may be disposed between the bearing 656 and the bearing 656. In other words, the bearing 656 and the coil spring 655 are not in contact with each other as in the present embodiment, but the bearing 656 and the coil spring 655 are in contact with each other. However, in this configuration, the bearing 656 and the gear 652 are not simply in contact with each other, and the pressing force from the coil spring 655 further acts on the gear 652. In other words, a pressing force that presses the gear 652 in the thrust direction further acts. As a result, the frictional force between the gear 652 and the bearing 656 when the gear 652 rotates increases, and the driving torque required to rotate the gear 652 increases.

On the other hand, in this embodiment, the coil spring 655 is disposed between the gear 652 and the transmission side coupling member 651, and in other words, the coil spring 655 is received by the gear 652. Further, the coil spring 655 rotates in conjunction with the gear 652 and the transmission side coupling member 651. For this reason, an increase in the driving torque is prevented.
Further, when the coil spring 655 is disposed between the transmission side coupling member 651 and the bearing 656, in other words, when the coil spring 655 is received by the bearing 656, the transmission mechanism is provided at a portion where the bearing 656 is disposed. The thickness of the part 65 will increase. On the other hand, when the configuration is such that the coil spring 655 is received by the gear 652 as in this embodiment, such an increase in thickness is suppressed. In order to avoid an increase in driving torque, a ball bearing or the like can be used for the bearing 656, but in this case, the thickness of the bearing 656 increases.

  Furthermore, in the case of the configuration shown in FIG. 6A, in order to receive the coil spring 655, the inner diameter D2 of the bearing 656 is formed smaller than the outer diameter D1 of the base portion 651b of the transmission side coupling member 651. For this reason, when assembling in this configuration, for example, first, the second pin 657 is inserted into the second through hole 653b, and the shaft 653 is inserted into the center hole 652a of the gear 652. Then, the bearing 656 and the cover 67 are installed in this order, and then the coil spring 655 is disposed around the shaft 653. Thereafter, the transmission side coupling member 651 is installed at the tip of the shaft 653, and the first pin 654 is press-fitted into the first through hole 653a through the long hole 651d.

By the way, in this assembly method, the first pin 654 is press-fitted into the first through hole 653a at the final stage of assembly, that is, at the stage where the gear 652 and the like are installed in the housing 62. As a result, the press fitting may cause damage to the gear 652 and the like. Further, the press-fit of the first pin 654 at the final stage of assembly is not good in workability.
On the other hand, in this embodiment, it is possible to avoid the press-fitting of the first pin 654 in the final stage of assembly, and the generation of scratches on the gear 652 and the like is suppressed. Moreover, workability | operativity can be made favorable.

  In order to avoid the press-fitting of the first pin 654 in the final stage, as shown in FIG. 5B, after the press-fitting of the first pin 654, the second pin 657 is inserted into the second through hole 653b. Is also possible. However, in the case of this configuration, as shown in the figure, the movement of the transmission side coupling member 651 (shaft 653) is restricted by the coil spring 655 and the bearing 656, and the projecting dimension of the shaft 653 from the gear 652 cannot be secured. Can occur. In this case, it is difficult to insert the second pin 657 into the second through hole 653b. In the present embodiment, since the bearing 656 is not disposed between the gear 652 and the coil spring 655, it is easy to ensure the protruding dimension of the shaft 653 from the gear 652.

1 is a diagram illustrating an overall configuration of an image forming apparatus to which the present invention is applied. It is a figure for demonstrating a belt unit. It is a figure for demonstrating a 1st drive unit and a 2nd drive unit. It is the figure which showed the state after the advance / retreat member rotated. It is the figure which showed the inside of the accommodating part. It is the figure which showed the 2nd drive unit from the rear side of the apparatus main body. It is the figure which showed the back surface side of the movable plate. It is the figure which showed the 2nd drive unit from the front side of the apparatus main body. It is the figure which showed a part of transmission mechanism part in a 2nd drive unit. It is a figure for demonstrating a transmission mechanism part. It is a figure for demonstrating a transmission mechanism part. It is a figure for demonstrating a transmission mechanism part. It is a figure for demonstrating a transmission side coupling member. It is the figure which showed the other structural example of the transmission side coupling member. It is the figure which showed the relationship between a transmission side coupling member and a cam side coupling member. It is the perspective view which showed the transmission mechanism part from the angle different from FIG. It is the figure which showed the other structural example of the transmission mechanism part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 567 ... Cam side coupling member, 567a ... Meshing part, 567b ... Base part, 651 ... Transmission side coupling member, 651b ... Base part, 651c ... Meshing part, 651e ... Through hole, 652 ... Gear , 652a ... center hole, 652b ... first protrusion, 652c ... second protrusion, 652d ... groove, 653 ... shaft, 655 ... coil spring, 656 ... bearing, M2 ... motor

Claims (9)

A driving source;
A rotating member that rotates in response to a driving force from the driving source;
A driven body driven by driving force from the rotating member;
A transmission member provided to be interlocked with the rotation member, and transmitting a driving force from the rotation member to the driven body;
An urging member that urges the transmission member toward the driven body,
The image forming apparatus, wherein the urging member is disposed in contact with the rotating member and supported by the rotating member.   The image forming apparatus according to claim 1, wherein the rotating member includes a positioning portion that positions the biasing member arranged in contact with the rotating member. The driven body is detachably provided to the transmission member,
The image forming apparatus according to claim 1, wherein the transmission member is provided so as to be retractable from the driven body side against an urging force from the urging member. A guide member that is inserted from the other end side of the transmission member that is sealed in a cylindrical shape at one end side, and guides the advancement and retraction of the transmission member;
A discharge part for discharging air existing in a space formed between the one end side of the transmission member and the guide member to the outside of the space;
The image forming apparatus according to claim 1, further comprising: The driven body and the transmission member are configured to be connected / disconnected to each other, and each include a base body that can rotate around a predetermined rotation axis,
One of the driven body and the transmission member includes a protruding portion protruding from the one base body, and the other of the driven body and the transmission member includes the protruding portion on the other base body. With an accepting mouth,
When the driven body is connected to the transmission member, if the rotation angle of the driven body with respect to the transmission member is a predetermined angle, the receiving port is allowed to accept the protruding portion and the predetermined angle. 5. The image forming apparatus according to claim 1, wherein the acceptance is blocked in the case of other than the above. A gear that receives a driving force to rotate,
A suppression member that is disposed between the gear and another arrangement member, and that suppresses sliding between the gear and the other arrangement member;
In conjunction with the gear, a transmission member that transmits the driving force from the gear to the driven body;
A pressing member that presses the transmission member toward the driven body,
The driving force transmitting device, wherein the pressing member is supported by the gear without contacting the suppressing member.   The driving force transmission device according to claim 6, wherein the restraining member is configured by a sliding bearing fitted to an annular portion formed in the gear.   The driving force transmission device according to claim 6 or 7, wherein an inner diameter of the annularly formed suppression member is formed larger than an outer shape of the transmission member formed in a columnar shape. A shaft that is inserted into a through-hole formed in the gear and interlocks the gear and the transmission member;
The pressing member is a coil spring disposed around the shaft,
The driving force transmission device according to any one of claims 6 to 8, wherein the gear includes a groove around which the end of the coil spring is inserted around the through hole.

Images