JP4419604B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a printer or a copier. More specifically, the present invention relates to an image forming apparatus in which an image forming unit including a photoconductor is detachable.

  2. Description of the Related Art Conventionally, in some image forming apparatuses, a consumable part such as a photoconductor is unitized to be detachable so that it can be replaced by a user. For example, a tandem type image forming apparatus having image forming units for four colors of yellow, magenta, cyan, and black includes a total of four image forming units for each color. When such an image forming unit is mounted on the image forming apparatus main body, at least the photosensitive drum needs to be driven to rotate. Therefore, the photosensitive drum is connected to a drive source provided in the image forming apparatus main body so that power can be transmitted.

Various configurations of the connecting portion have been conventionally proposed (see, for example, Patent Document 1 and Patent Document 2). In the image forming apparatus described in Patent Document 1, each of the drive gear and the photosensitive drum has a separate coupling shaft, and a twisted polygonal column hole and a twisted polygonal column protrusion are connected to each of the connecting portions. Is formed. When the holes and the protrusions are fitted to each other and driven to rotate, a force to be screwed into each other works and alignment is performed. Moreover, in the coupling structure described in Patent Document 2, a plurality of convex portions are provided at the end portions of the universal joint incorporated in the gear, and are fitted by the convex portions.
JP 2000-214646 A USP 6397029

  However, in the conventional image forming apparatus described above, both the positioning of the entire image forming unit and the rotation axis alignment of the photosensitive member and the drive unit are performed at the joint portion. For this reason, there is a risk that stress is applied to the casing and the photosensitive unit due to the installation conditions of the casing. There is also a method of positioning the image forming unit with respect to the housing, but in this case, it is difficult to align the drive shaft and the photosensitive member shaft, which may cause uneven rotation or wear of the photosensitive member. was there. Further, in a connecting portion using a universal joint as described in Patent Document 2, the direction of the joint tip when the image forming unit is not attached is restricted in order to improve workability during attachment / detachment. There was also a problem that it was necessary to take measures such as.

  The present invention has been made to solve the problems of the conventional image forming apparatus described above. That is, an object of the present invention is to provide an image forming apparatus in which an image forming unit can be easily attached and detached, positioning to an apparatus main body is reliable, and drive transmission to a mounted photoreceptor is reliably performed. There is.

An image forming apparatus of the present invention, which has been made for the purpose of solving this problem, is an image forming apparatus that forms an image by mounting a detachable photosensitive unit, and is provided with respect to a first bearing member and a first bearing member. It is rotatably supported Te, a first drive transmission member for receiving a rotational driving force to the photosensitive member of the photosensitive member unit, with provided fixed relative to the first bearing member, fixed to one end of the photosensitive member unit to the first fitting member to be fitted, and a second drive transmission member you position between the photosensitive member unit and the first drive transmission member, a second drive transmission member, spaced from the first drive transmission member have a biasing member for biasing the direction of the second drive transmission member is in the state where the photosensitive unit is mounted, the rotary drive to the photoreceptor of the photoreceptor unit rotates together with the first drive transmission member The photoconductor unit is loaded. In the state of not being a shall be spaced from the first drive transmission member.

  According to the image forming apparatus of the present invention, the rotational driving force to the photosensitive unit is received by the first drive transmission member. On the other hand, the first fitting member is fixed to the first bearing member that rotatably supports the first drive transmission member. Therefore, the first fitting member is not affected by the rotational driving force of the first drive transmission member, and its arrangement is fixed. Further, since the first fitting member is fitted to one end of the photosensitive unit, the photosensitive unit is positioned by the first fitting member, and stress due to the rotational driving force is applied to those fitting portions. There is nothing. Thereby, the positioning to the apparatus main body is reliable. Further, since the second drive transmission member is disposed between the first drive transmission member and the photosensitive unit and is rotated together with the first drive transmission member, the first drive transmission member is interposed via the second drive transmission member. Is transmitted to the photosensitive unit. Therefore, transmission of drive to the mounted photoconductor is reliably performed.

Further, according to the present invention, the side protrusions provided at at least three positions on the side of the second drive transmission member are fixed to the first bearing member, and the side protrusions are biasing members. It is desirable to have a retaining portion that abuts from the side.
In this case, since the biasing member is provided, the second drive transmission member is separated from the first drive transmission member and can freely rotate when the photosensitive unit is not attached. Therefore, the photosensitive unit can be easily attached and detached. Further, when the second drive transmission member is urged by the urging member, the side projection comes into contact with the retaining portion. Therefore, the second drive transmission member does not fall off from the first bearing member.

Furthermore, in the present invention, it is desirable that the retaining portion and the first fitting member are integral with the first bearing member, and the retaining portion side of the side projection is inclined.
In this way, since the retaining portion and the first fitting member are integral with the first bearing member, the number of parts is small. In addition, since the side protrusion portion of the side protrusion portion is inclined, the inclined portion and the stopper portion are in contact with each other, and the axial direction of the second drive transmission member is substantially perpendicular to the stopper portion. Stop facing. Therefore, it is easy to mount the photosensitive unit.
Further, the second drive transmission member has a twisted triangular prism shape, and the first drive transmission member is formed with an untwisted triangular prism-shaped hole into which the second drive transmission member is inserted . the contact between the ridge and the triangular prism hole in the wall of the drive transmission member, the better the rotation from the first drive transmission member to the second drive transmission member is an der Rukoto shall be transmitted.

The image forming apparatus of the present invention further includes a main body and a photosensitive unit that can be attached to and detached from the main body. The image forming apparatus performs image formation by attaching the photosensitive unit to the main body. A first bearing member, a first drive transmission member that is rotatably supported with respect to the first bearing member, receives a rotational driving force to the photosensitive member of the photosensitive unit , and is fixed to the first bearing member. And a first fitting member fixedly fitted to one end of the photosensitive unit, and the photosensitive unit is rotatably supported with respect to the second bearing member and the second bearing member. with a flange that rotates together with the photosensitive member, with provided fixed relative to the second bearing member, and a second fitting member fixedly fitted to the first fitting member, the body and the photosensitive member while the first drive transmission between the units Possess a second drive transmission member you position between the wood and the flange, a second drive transmission member, and a biasing member for biasing a direction away from the first drive transmission member or flange, the second The drive transmission member rotates together with the first drive transmission member and the flange in a state where the photoconductor unit is mounted on the main body, transmits the rotational drive from the first drive transmission member to the flange, and the photoconductor unit is mounted on the main body. in the state of not being, to be a shall spaced from the first drive transmission member or flange.

  In this case, in the main body of the image forming apparatus, the first fitting member fitted to one end of the photosensitive unit is not affected by the rotational driving force, and the arrangement thereof is fixed. Yes. On the other hand, in the photoconductor unit, the second fitting member fitted to the first fitting member is fixed to the second bearing member, so that the arrangement is fixed regardless of the rotation of the photoconductor. Thereby, the positioning of the photosensitive unit and the apparatus main body is reliable. Further, since the second drive transmission member is disposed between the first drive transmission member and the flange of the photosensitive unit and is rotated together with the first drive transmission member and the flange, the second drive transmission member is interposed via the second drive transmission member. The rotational driving force of one drive transmission member is transmitted to the photoreceptor unit. Therefore, transmission of drive to the mounted photoconductor is reliably performed.

Further, in the present invention, the second drive transmission member has side projections at least at three positions on the side portion thereof, and is fixed to the first bearing member or the second bearing member. It is desirable that the protrusion has a retaining portion that comes into contact with the biasing member.
In this case, since the biasing member is provided, the second drive transmission member is separated from the first drive transmission member or the flange and can freely rotate when the photosensitive unit is not attached. Therefore, the photosensitive unit can be easily attached and detached. Further, when the second drive transmission member is urged by the urging member, the side projection comes into contact with the retaining portion. Therefore, the second drive transmission member does not fall off from the first bearing member or the second bearing member.

Further, in the present invention, it is desirable that the first fitting member is coaxial with the first drive transmission member, and the second fitting member is coaxial with the photosensitive member.
If it does in this way, it can position so that a 1st drive transmission member and a photoreceptor may become coaxial by fitting with the 1st fitting member and the 2nd fitting member. Furthermore, if both the first fitting member and the second fitting member are cylindrical, these fittings are easy.
Further, the second drive transmission member has a twisted triangular prism shape, and the first drive transmission member is formed with an untwisted triangular prism-shaped hole into which the second drive transmission member is inserted . the contact between the ridge and the triangular prism hole in the wall of the drive transmission member, the rotation from the first drive transmission member to the second drive transmission member is transmitted, further rotated in the flange to der Rukoto shall be transmitted Better.

  According to the image forming apparatus of the present invention, the image forming unit can be easily attached and detached, the positioning to the apparatus main body is reliable, and the drive transmission to the mounted photoconductor is reliably performed.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to a tandem type color printer.

  In the color printer 1 of the present invention, as shown in FIG. 1, the image forming units 10Y, 10M, 10C, and 10K for each color are arranged along the intermediate transfer belt 11. A paper cassette 12 is attached to the lower part of the color printer 1, and the paper in the paper cassette 12 is conveyed to the paper feeding / conveying section 14 by the paper feeding roller 13. The images formed by being superimposed on the intermediate transfer belt 11 by the image forming units 10Y, 10M, 10C, and 10K for the respective colors are transferred to a sheet by the secondary transfer unit 15 and fixed by the fixing unit 16. The sheet on which the image is formed in this manner is discharged by the discharge roller 17. All of these configurations are housed in the housing 20.

  The image forming units 10Y, 10M, 10C, and 10K for the respective colors have the same configuration, and each includes a photoreceptor 21, a developing unit 22, an exposure unit 23, a charging unit 24, a cleaner unit 25, and a transfer unit 26. ing. Since the configuration and operation of each part of the image forming units 10Y, 10M, 10C, and 10K are general, a description thereof is omitted here. Among the image forming units 10Y, 10M, 10C, and 10K, a predetermined portion including at least the photosensitive member 21 is unitized to form an image forming unit 30. The image forming unit 30 is detachable from the housing 20 of the color printer 1. Hereinafter, a portion of the color printer 1 excluding the image forming unit 30 is referred to as a main body 2.

  A door that can be opened and closed is provided on the front side of the color printer 1 in FIG. By opening this door, the front end of each image forming unit 30 is exposed. The user can remove the image forming unit 30 from the main body 2 by grasping the exposed end and pulling it toward the front side in the figure. Further, the image forming unit 30 can be attached again by inserting the image forming unit 30 into the space where the image forming unit 30 of the main body 2 is removed and pushing it in the rearward direction in the figure. When the door is closed after the attachment, the front end of the image forming unit 30 is held and fixed by the inner surface of the door.

  Next, FIG. 2 shows an outline of a connecting portion between the main body 2 and the image forming unit 30. This connecting portion is arranged on the back side of the color printer 1 in FIG. An image forming unit 30 shown on the right side in FIG. 2 is held by a housing 31 and has a photosensitive member 21, a flange 32, and a bearing 33 from the right side in the figure. The flange 32 is fixed to the end of the photoconductor 21 and rotates integrally with the photoconductor 21. The bearing 33 is fixed to the housing 31 by rotatably supporting the end portion of the flange 32. A cylindrical fixing portion 33a is formed at the left end of the bearing 33 in the drawing.

  On the main body 2 side, as shown on the left side in FIG. 2, a gear 43, a gear bearing 44, a joint 45, and a spring 46 are attached to frames 41 and 42 fixed to the housing 20. The gear 43 transmits a driving force by a power unit provided inside the main body 2 to the joint 45. The gear 43 is formed with a joint receiving portion 43a extending rightward in the drawing. The joint receiving portion 43a and the joint 45 are in partial contact with each other to transmit rotation. The gear bearing 44 is fixed to the frame 42 and rotatably supports the joint receiving portion 43a of the gear 43. A cylindrical fixing portion 44 a is formed at the right end portion of the gear bearing 44 in the drawing. Further, a retaining portion 44 b protruding in the inner circumferential direction is formed on the inner circumferential side of the central portion of the gear bearing 44.

  Here, the inner peripheral diameter of the fixed portion 44 a of the gear bearing 44 and the outer peripheral diameter of the fixed portion 33 a of the bearing 33 of the image forming unit 30 are formed to be substantially equal. Since the fixing portion 33a and the fixing portion 44a are disposed so as to face each other, when the image forming unit 30 is attached to the main body 2, as shown in FIG. The fixing portion 33a is inserted and fitted. Accordingly, the fixing portion 44a and the fixing portion 33a, and thus the gear bearing 44 and the bearing 33, are directly fixed to each other. Here, the gear bearing 44 is fixed to the frame 42 of the main body 2. On the other hand, the bearing 33 is fixed to the housing 31 of the image forming unit 30. Accordingly, the image forming unit 30 is positioned and fixed with respect to the main body 2 by this fitting.

  Further, as shown in FIG. 3, the joint 45 has a twisted triangular prism main body 45a. The right end portion in the figure is a twisted triangular pyramidal tip portion 45b, and the left end portion in the figure is formed with a cylindrical convex portion 45c into which the spring 46 is fitted. Further, side convex portions 45d are formed on the three side surfaces of the main body portion 45a, respectively, closer to the cylindrical convex portion 45c than the center. The tip side of the side protrusion 45d is formed in a taper shape. The joint 45 is integrally formed of a resin such as POM (polyacetal) or PC (polycarbonate). Further, a meat steal may be formed in the joint 45 as shown in FIG.

  Further, as shown in FIG. 2, a spring 46 is disposed between the gear 43 and the joint 45. As a result, the joint 45 is biased in the right direction in the figure. When the image forming unit 30 is attached, the joint 45 partially abuts both the joint receiving portion 43 a of the gear 43 and the flange 32 of the image forming unit 30. The rotational driving force of the gear 43 is transmitted to the photosensitive member 21 by the joint 45.

  Next, the drive transmission structure by this joint 45 is demonstrated. A substantially triangular prism hole 47 as shown in FIG. 5 is formed in the joint receiving portion 43a of the gear 43 and the flange 32, respectively. This hole 47 is not twisted. In this figure, holes other than triangular prisms are also formed, but this is for weight reduction. When the main body 45a of the joint 45 is inserted into the hole 47 and one of them is rotated, the three ridge lines of the main body 45a and the three inner surfaces of the hole 47 come into contact with each other. At this time, since the main body 45a is twisted, there are three points that come into contact with each other, one for each ridgeline. The three contact points are arranged symmetrically with each other, and rotation is transmitted at the same rotational angular velocity. This contact point is one point on each ridge line whether or not the axial centers of the hole 47 and the main body portion 45a coincide.

  Therefore, the rotation of the gear 43 is transmitted to the joint 45 from the hole 47 of the joint receiving portion 43a of the gear 43, and further transmitted to the hole 47 of the flange 32, thereby transmitting the rotation of the flange 32. Thereby, the rotational driving force by the gear 43 rotates the photosensitive member 21 via the joint 45 and the flange 32. At this time, even if the rotational axis of the joint 45 is slightly deviated from the hole 47, the three cores are overlapped at the same position at the cross-sectional position of the contact point by contacting three points. Further, even if the shaft cores are slightly inclined, the hole 47 and the joint 45 contact at three points, so that drive transmission can be reliably performed in the state as it is. This occurs on both the joint receiving portion 43a side and the flange 32 side.

  Next, FIG. 6 and FIG. 7 show the connecting portion on the main body 2 side with the image forming unit 30 removed. When the image forming unit 30 is removed, the joint 45 protrudes rightward in the figure by the urging force of the spring 46 as shown in FIG. Here, FIG. 7 is a view seen from the right side of FIG. 6, and FIG. 6 shows a cross section taken along the line AA of FIG. At this time, the taper portion of the side convex portion 45 d of the joint 45 is in contact with the retaining portion 44 b of the gear bearing 44. Thereby, the joint 45 does not protrude further. Furthermore, since the contact portion of the side convex portion 45d is tapered, the joint 45 receives an inward force from the retaining portion 44b. Further, as shown in FIG. 7, the side protrusions 45d are provided at three symmetrical positions, so that the joint 45 is held substantially coaxially with the gear bearing 44 in the coaxial direction.

  Further, it is better that a chamfer 44c is formed on the inner peripheral surface of the retaining portion 44b as shown in FIG. The chamfer 44c may be R-shaped or hemispherical. Or the taper part of the side convex part 45d may be R-shaped or hemispherical in the circumferential direction. By doing so, the joint 45 and the gear bearing 44 come into contact with each other more stably, and the joint 45 is reliably held at the center position.

Next, the operation when the image forming unit 30 is replaced in the color printer 1 configured as described above will be described. When replacing the image forming unit 30, the user first opens the door of the main body 2 and pulls the end of the image forming unit 30 rightward in FIG. As a result, the fixing portion 33a of the bearing 33 of the image forming unit 30 and the fixing portion 44a of the gear bearing 44 are disengaged, and the image forming unit 30 is free from the main body 2 of the color printer 1 in the axial direction. Become. Even if the joint 45 is still inside the bearing 33 or the flange 32, the contact between the joint 45 and the hole 47 or the like is not a resistance to the movement in the axial direction. By further pulling out the image forming unit 30 in the axial direction, as shown in FIG. 6, the joint 45 slightly protrudes on the main body 2 side and is held in the axial direction at a substantially central position.

  Next, when attaching the image forming unit 30 to the main body 2, the door of the main body 2 is opened, and the tip of the image forming unit 30 is moved along the guides formed on the housing 20, the frames 41, 42, and the like. insert. At this time, the joint 45 faces substantially in the axial direction, and the tip 45b has a triangular pyramid shape. Therefore, the joint 45 can be easily inserted without hitting the bearing 33 protruding from the housing 31. If the image forming unit 30 is pushed in the axial direction as it is, the inner periphery of the fixing portion 44a of the gear bearing 44 and the outer periphery of the fixing portion 33a of the bearing 33 are fitted and fixed. Accordingly, the axial position of the entire image forming unit 30 is correctly arranged with respect to the main body 2.

  At the same time, when the image forming unit 30 is inserted, the tip 45b of the joint 45 comes into contact with the bottom of the hole 47 of the flange 32. When further inserted, the joint 45 is pushed to the left in FIG. 2 at the bottom of the hole 47, and the spring 46 is compressed. As a result, the contact between the retaining portion 44b and the side convex portion 45d is released, and the joint 45 can rotate. Here, the amount of insertion of the image forming unit 30 in the axial direction is limited by the shortest state of the spring 46 or the fixed portion 33a coming into contact with the retaining portion 44b of the fixed portion 44a. Thereby, the mounting position including the axial direction of the image forming unit 30 is correctly positioned with respect to the main body 2.

  As described above in detail, according to the color printer 1 of the present embodiment, each image forming unit 30 can be easily attached to and detached from the color printer 1 by moving in the axial direction of the photoreceptor 21. Further, since the fixing portion 44a of the gear bearing 44 of the main body 2 and the fixing portion 33a of the bearing 33 of the image forming unit 30 are fitted and fixed to each other, the mounting position of the image forming unit 30 is reliably positioned by these. Is done. The rotational driving force of the gear 43 is transmitted from the gear 43 to the photosensitive member 21 via the joint 45 and the flange 32. Here, the main body 45a of the joint 45 has a twisted triangular prism shape, and the gear 43 and the flange 32 are formed with untwisted triangular prism holes, so that even if their axial positions do not exactly match. The rotation is transmitted reliably. As a result, the image forming unit can be easily attached and detached, the positioning to the apparatus main body is ensured, and the drive is reliably transmitted to the mounted photoreceptor.

In addition, this form is only a mere illustration and does not limit this invention at all. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof.
For example, in the above embodiment, the retaining portion 44 b is formed integrally with the gear bearing 44, but may be configured by inserting another member into the gear bearing 44.
Further, for example, the fixing portion 44a and the fixing portion 33a may be formed separately from the gear bearing 44 and the bearing 33 and attached and fixed.
Further, for example, in the above embodiment, the fixed portion 44a of the gear bearing 44 is fitted to the outer peripheral side, and the fixed portion 33a of the bearing 33 is fitted to the inner peripheral side, but these may be reversed.
Further, for example, in the above embodiment, the joint 45 is attached to the main body 2 side. However, the joint 45 may be included in the photoconductor unit 30.
Further, for example, the present invention is applied to the color printer 1 in the above embodiment, but the present invention is not limited to this, and can also be applied to an image forming apparatus such as a copying machine or a facsimile. Further, the present invention is not limited to a color machine, and may be a monochrome machine having only one image forming unit 30 that can be mounted.

1 is a cross-sectional view illustrating a schematic configuration of a color printer according to an embodiment. It is sectional drawing which shows a connection part. It is a perspective view which shows a joint. It is a perspective view which shows another example of a joint. It is a perspective view which shows the joint receiver by which a joint is fitted. It is sectional drawing which shows the main body side attaching / detaching part which removed the image forming unit. It is a front view which shows the main body side attaching / detaching part which removed the image forming unit. It is the elements on larger scale which show the engaging part of a joint and a bearing.

Explanation of symbols

1 Color printer (image forming device)
2 Main body 30 Image forming unit (photosensitive unit)
32 Flange 33 Bearing (second bearing member)
33a Fixing part (second fitting member)
43 Gear (first drive transmission member)
44 Gear bearing (first bearing member)
44a fixing | fixed part (1st fitting member)
44b Retaining part 45 Joint (second drive transmission member)
45d Side projection (side projection)
46 Spring (biasing member)

Claims (7)

In an image forming apparatus for forming an image by mounting a detachable photosensitive unit,
A first bearing member;
A first drive transmission member that is rotatably supported by the first bearing member and that receives a rotational driving force to the photosensitive member of the photosensitive unit;
A first fitting member provided fixed to the first bearing member and fixedly fitted to one end of the photoreceptor unit;
A second drive transmission member you position between the first drive transmission member and the photosensitive member unit,
Said second drive transmission member, have a biasing member for biasing said first direction away from the drive transmission member,
The second drive transmission member is
In a state where the photoconductor unit is mounted, it rotates with the first drive transmission member to transmit the rotational drive to the photoconductor of the photoconductor unit,
In a state where the photosensitive unit is not mounted, an image forming apparatus according to claim Rukoto spaced from said first drive transmission member. The image forming apparatus according to claim 1,
Side protrusions provided at least at three locations on the side of the second drive transmission member ;
Together provided fixed relative to the front Symbol first bearing member, the image forming apparatus, characterized in that said lateral protrusion and a retaining portion abuts the side of the biasing member. The image forming apparatus according to claim 2,
The retaining portion and the first fitting member are integral with the first bearing member,
2. An image forming apparatus according to claim 1, wherein said side projection part has an inclined shape on the side of said retaining part. The image forming apparatus according to any one of claims 1 to 3,
The second drive transmission member has a twisted triangular prism shape,
An untwisted triangular prism-shaped hole into which the second drive transmission member is inserted is formed in the first drive transmission member ,
The contact between the ridge and the hole in the wall of the triangular prism of the second drive transmission member, rotation, characterized in der Rukoto those transmitted from the first drive transmission member to said second drive transmission member Image forming apparatus. In an image forming apparatus having a main body and a photosensitive unit detachable from the main body, and performing image formation by attaching the photosensitive unit to the main body,
The body is
A first bearing member;
A first drive transmission member that is rotatably supported by the first bearing member and that receives a rotational driving force to the photosensitive member of the photosensitive unit;
A first fitting member fixed to the first bearing member and fixedly fitted to one end of the photosensitive unit;
The photoreceptor unit
A second bearing member;
A flange that is rotatably supported with respect to the second bearing member and that rotates with the photoreceptor;
A second fitting member that is fixedly provided to the second bearing member and that is fixedly fitted to the first fitting member;
One of the main body and the photosensitive member unit,
A second drive transmission member you position between said flange and said first drive transmission member,
Said second drive transmission member, have a biasing member for biasing said to first drive transmission member or a direction away from said flange,
The second drive transmission member is
In a state where the photoconductor unit is mounted on the main body, it rotates together with the first drive transmission member and the flange to transmit rotational drive from the first drive transmission member to the flange,
Wherein in the state where the photosensitive unit is not mounted, an image forming apparatus according to claim Rukoto spaced from said first drive transmission member or said flange to said body. The image forming apparatus according to claim 5 ,
The second drive transmission member has side projections at least at three positions on its side ;
Together provided fixed relative to the front Symbol first bearing member or the second bearing member, the image forming apparatus, characterized in that said lateral protrusion and a retaining portion abuts the side of the urging member . The image forming apparatus according to claim 5 or 6,
The second drive transmission member has a twisted triangular prism shape,
An untwisted triangular prism-shaped hole into which the second drive transmission member is inserted is formed in the first drive transmission member and the flange ,
Rotation is transmitted from the first drive transmission member to the second drive transmission member by the contact between the ridgeline of the second drive transmission member and the wall surface of the triangular prism-shaped hole, and further, the rotation is transmitted to the flange. Monodea Rukoto image forming apparatus according to claim.

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