Drive transmission device and image forming apparatus

Abstract

To provide a drive transmission device that can accurately rotate a drive transmission target part, while reducing manufacturing cost.SOLUTION: A drive transmission device 30 is arranged opposite to a photoreceptor drum with a body sheet metal 20 therebetween. The drive transmission device 30 comprises: a gear part 32 that rotates around an axis; a coupling part 33 that is connected to the photoreceptor drum and rotates around the same axis as the gear part 32; an urging member 34 that urges the gear part 32 and the coupling part 33 in a direction to approach the photoreceptor drum; and a retreat part 35 that reciprocates around the same axis as the coupling part 33. The body sheet metal 20 is provided with two inclined parts 40 with a through hole 24 therebetween, and the inclined parts project in a direction away from the photoreceptor drum by deforming part of the body sheet metal 20. The retreat part 35 rotates in one direction while in contact with the inclined parts 40, and thereby moves the gear part 32 and the coupling part 33 in the direction away from the photoreceptor drum against urging force of the urging member 34.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a drive transmission device and an image forming apparatus.

Background Art

[0002] A main body side drive unit that transmits a driving force to a photosensitive drum of an image forming apparatus is known (Patent Document 1). The axial center portion (coupling) of the drive input gear of the main body side drive unit is supported by a bearing attached to the main body frame sheet metal. The bearing is formed with another cam portion that contacts a cam portion of a locking member provided on the main body side drive unit. By reciprocally rotating while the cam portion of the locking member contacts the other cam portion of the bearing, the main body side drive unit is connected to or separated from the photosensitive drum.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in an image forming apparatus, in order to form a good image, it is required to rotate the photosensitive drum accurately without vibrating (shaft vibration). In order to rotate the photosensitive drum accurately, it is effective to bring the axial center portion (coupling) of the drive input gear close to and connect it to the photosensitive drum.

[0005] However, in the above-described technology, since the bearing having the cam portion is attached to the main body frame sheet metal, the axial center portion (coupling) of the drive input gear had to be extended by the thickness of the bearing. Therefore, in the above-described technology, the photosensitive drum was likely to vibrate, and there was a risk that a good image could not be formed. Further, in the above-described technology, it was necessary to prepare a bearing that was a separate part from the main body frame sheet metal and attach the bearing to the main body frame sheet metal, and there was a problem that the manufacturing cost of the main body side drive unit increased.

[0006] In view of the above circumstances, the present invention provides a drive transmission device and an image forming apparatus that can rotate a driven transmission portion accurately while reducing manufacturing costs.

Means for Solving the Problems

[0007] The present invention is a drive transmission device disposed to face a driven transmission portion with a metal plate interposed therebetween, and includes a gear portion connected to a drive source and rotating about an axis by the driving force of the drive source, a coupling portion formed in a cylindrical shape, passing through a through hole opened in the metal plate, and connected to the driven transmission portion, and rotating about the same axis as the gear portion, a biasing member that biases the gear portion and the coupling portion in a direction approaching the driven transmission portion, and a retreat portion formed in an annular shape that passes through the coupling portion and reciprocally rotates about the same axis as the coupling portion. The metal plate is formed with at least two inclined portions that project in a direction away from the driven transmission portion by deforming a part of the metal plate, sandwiching the through hole. The retreat portion rotates in one direction while contacting the inclined portion, thereby moving the gear portion and the coupling portion in a direction away from the driven transmission portion against the biasing force of the biasing member.

[0008] In this case, it is preferable that the retreat portion has a retreat main body portion formed in an annular shape and at least two retreat contact portions that project radially outward from the retreat main body portion and contact the inclined portion.

[0009] In this case, the inclined portion may be formed in a mountain shape having a contact inclined surface with which the retracted portion comes into contact and a non-contact inclined surface with which the retracted portion does not come into contact, and the non-contact inclined surface may have a steeper gradient than the contact inclined surface.

[0010] The image forming apparatus of the present invention includes the drive transmission device according to any one of the above.

[0011] In this case, it includes a device main body incorporating the drive transmission device, a cover provided on the device main body so as to be openable and closable, and a lever connecting the cover and the retracted portion of the drive transmission device. When the closed cover is opened, the retracted portion rotates in one direction while contacting the inclined portion, and moves the gear portion and the coupling portion in a direction away from the driven transmission portion. When the opened cover is closed, the retracted portion rotates in the other direction while contacting the inclined portion, and the biasing member moves the gear portion, the coupling portion, and the retracted portion in a direction approaching the driven transmission portion.

Advantages of the Invention

[0012] According to the present invention, while reducing the manufacturing cost, the driven transmission portion can be rotated accurately.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that Fr, Rr, L, R, U, and D shown in the drawings indicate front, rear, left, right, up, and down. In this specification, terms indicating directions and positions are used for convenience of explanation and do not limit the technical scope of the present invention.

[0015] [Image Forming Apparatus] With reference to FIG. 1, the image forming apparatus 1 will be described. FIG. 1 is a schematic view (side view) showing the internal structure of the image forming apparatus 1.

[0016] The image forming apparatus 1 forms an image on a sheet P by an electrophotographic method. The image forming apparatus 1 includes an apparatus main body 2 having a substantially rectangular parallelepiped appearance. A paper feed cassette 3 for accommodating the sheet P (medium) is provided below the apparatus main body 2. A paper discharge tray 4 for receiving the sheet P on which an image is formed is provided on the upper surface of the apparatus main body 2. A conveyance path 8 for conveying the sheet P from the paper feed cassette 3 to the paper discharge tray 4 is formed inside the apparatus main body 2. A paper feed device 5 is provided at the upstream end of the conveyance path 8, an image forming device 6 is provided in the middle of the conveyance path 8, and a fixing device 7 is provided on the downstream side of the conveyance path 8. Note that the sheet P is not limited to paper and may be made of resin or the like.

[0017] The image forming device 6 includes a toner container 10, a drum unit 11, and an optical scanning device 12. The toner container 10 stores, for example, black toner (developer). The drum unit 11 includes a photosensitive drum 13 and a charging device 14. Around the photosensitive drum 13, in the order of the image forming process, a charging device 14, a developing device 15, a transfer roller 16, and a cleaning device 17 are arranged. The transfer roller 16 forms a transfer nip by contacting the photosensitive drum 13 from below. Note that the toner may be a two-component developer in which toner and carrier are mixed, or a one-component developer made of magnetic toner.

[0018] The image forming apparatus 1 forms an image on a sheet P based on image data transmitted from an external terminal (such as a personal computer). A control unit (not shown) provided in the image forming apparatus 1 controls the image forming apparatus 1 based on the input image data, and the following image forming process is executed.

[0019] The charging device 14 charges the surface of the photosensitive drum 13. The photosensitive drum 13 receives the scanning light emitted from the optical scanning device 12 and carries an electrostatic latent image. The developing device 15 develops the electrostatic latent image on the photosensitive drum 13 into a toner image using the toner supplied from the toner container 10. The sheet P is fed from the paper feed cassette 3 to the conveyance path 8 by the paper feed device 5, and the toner image on the photosensitive drum 13 is transferred to the sheet P passing through the transfer nip. The fixing device 7 thermally fixes the toner image to the sheet P. Thereafter, the sheet P is discharged to the paper discharge tray 4. The cleaning device 17 removes the toner remaining on the surface of the photosensitive drum 13.

[0020] [Drive transmission device] Next, referring to FIGS. 2 to 7, a drive transmission device 30 for transmitting a driving force to the drum unit 11 will be described. FIG. 2 is a schematic view (side view) showing the drive transmission device 30, the main body sheet metal 20, etc. FIG. 3 is a sectional view taken along line III-III of FIG. 2. FIG. 4 is a perspective view showing the coupling portion 33 of the drive transmission device 30 and the main body sheet metal 20, etc. FIG. 5 is a perspective view showing the drive transmission device 30. FIG. 6 is a perspective view showing the retracting portion 35, etc. arranged at the retracting position 44. FIG. 7 is a side view showing the retracting portion 35, etc. arranged at the retracting position 44.

[0021] As shown in FIG. 2, the drive transmission device 30 is arranged to face the photosensitive drum 13 (driven transmission portion) with the main body sheet metal 20 (metal sheet) provided inside the device main body 2 interposed therebetween. The main body sheet metal 20 is made of, for example, steel and supports the drum unit 11, the drive motor 21, and the gear train 22. The drum unit 11 is arranged on the inner surface side of the main body sheet metal 20 (the back side (left side) of the paper surface in FIG. 2) and is detachably supported by the main body sheet metal 20. A guide rail 23 for guiding the drum unit 11 to the mounting position is formed on the main body sheet metal 20. A through hole 24 is opened at the rear end portion (mounting position) of the guide rail 23 of the main body sheet metal 20. The drive motor 21 (drive source) is fixed to the inner surface of the main body sheet metal 20 and penetrates the output shaft (not shown) to the outer surface side of the main body sheet metal 20. The gear train 22 is composed of a plurality of gears (spur gears or stepped gears) rotatably supported on the outer surface of the main body sheet metal 20. One of the plurality of gears meshes with the pinion gear 21A fixed to the output shaft of the drive motor 21.

[0022] As shown in FIG. 1, a cover 25 is provided on the device main body 2 incorporating the drive transmission device 30, etc. so as to be openable and closable. The cover 25 is provided, for example, on the front surface of the device main body 2 and rotates with a hinge located at the lower end portion as a fulcrum. The cover 25 constitutes the front surface of the device main body 2 in the closed state and opens forward when detaching and attaching the toner container 10, the drum unit 11, the developing device 15, etc.

[0023] As shown in FIG. 3, the drive transmission device 30 is disposed between the main body sheet metal 20 and the drive sheet metal 31 (for example, made of steel). The drive transmission device 30 includes a gear portion 32, a coupling portion 33, a biasing member 34, and a retraction portion 35.

[0024] <Gear portion> The gear portion 32 is a spur gear that meshes with the final gear of the gear train 22 (see FIG. 2), and is rotatably supported by a support shaft portion 36 that extends from the drive sheet metal 31 toward the main body sheet metal 20 (see FIG. 3). The gear portion 32 is connected to the drive motor 21 via the gear train 22 (see FIG. 2) and rotates about the axis by the driving force of the drive motor 21. Note that the axis of the support shaft portion 36 (gear portion 32) substantially coincides with the axis of the through hole 24 that opens in the main body sheet metal 20 (see FIG. 3).

[0025] <Coupling portion> As shown in FIG. 3, the coupling portion 33 is formed in a generally cylindrical shape and extends from the axial center portion of the gear portion 32 toward the main body sheet metal 20 (photosensitive drum 13). The coupling portion 33 is made of a synthetic resin such as polyacetal and integrally molded with the gear portion 32, and rotates about the same axis as the gear portion 32. An axial cylinder portion 33A for inserting the support shaft portion 36 is molded in the axial center portions of the gear portion 32 and the coupling portion 33. The tip end portion of the coupling portion 33 passes through the through hole 24 that opens in the main body sheet metal 20 and is connected to the photosensitive drum 13. Specifically, as shown in FIG. 4, three engaging claws 33B are formed on the tip end surface of the coupling portion 33 so as to surround the axial cylinder portion 33A. By engaging each engaging claw 33B with a drum coupling 13A (see FIG. 3) attached to the rotation shaft portion of the photosensitive drum 13, the coupling portion 33 is connected to the photosensitive drum 13 (the photosensitive drum 13 is not shown in FIG. 3).

[0026] <Biasing member> As shown in FIG. 3, the biasing member 34 is, for example, a coil spring and is provided so as to wind around the outer peripheral surface of the shaft cylinder portion 33A (and the support shaft portion 36). The biasing member 34 is installed between the drive sheet metal 31 and the inner surface of the tip of the coupling portion 33 in a compressed state. The biasing member 34 biases the gear portion 32 and the coupling portion 33 in the direction approaching the photosensitive drum 13. In other words, the coupling portion 33 (the tip portion thereof) is maintained in a state of being connected to the photosensitive drum 13 by being biased by the biasing member 34.

[0027] <Retreat portion> The retreat portion 35 is made of a synthetic resin such as polyacetal, for example, and is formed in a substantially annular shape that penetrates the coupling portion 33. The retreat portion 35 penetrates the coupling portion 33 and is disposed between the gear portion 32 and the main body sheet metal 20. Although details will be described later, the retreat portion 35 is supported on the outer peripheral surface of the coupling portion 33 and reciprocates around the same axis as the coupling portion 33.

[0028] As shown in FIG. 5, the retreat portion 35 has a retreat main body portion 35A formed in a substantially annular shape, and two retreat contact portions 35B that protrude radially outward from the retreat main body portion 35A. The two retreat contact portions 35B are provided at positions facing each other with the opening of the retreat main body portion 35A interposed therebetween. Each retreat contact portion 35B bends the tip side extending radially outward from the outer peripheral surface of the retreat main body portion 35A toward the main body sheet metal 20 side. That is, each retreat contact portion 35B is bent in a substantially L shape.

[0029] Further, the retreat portion 35 has an arm portion 37 that extends radially outward from the retreat main body portion 35A. The arm portion 37 is formed longer in the radial direction than the retreat contact portion 35B. One end of the lever 26 is rotatably connected to the tip of the arm portion 37. The other end of the lever 26 is rotatably connected to the cover 25 of the apparatus main body 2 (not shown). The lever 26 connects the cover 25 and the retreat portion 35 and interlocks the reciprocating rotation of the retreat portion 35 with the opening and closing of the cover 25.

[0030] <Inclined portion> As shown in FIGS. 4, 6, and 7, on the main body sheet metal 20, two inclined portions 40 protruding in a direction away from the photosensitive drum 13 (driven transmission portion) (rightward) are formed with the through hole 24 interposed therebetween. The two inclined portions 40 are provided so as to face each other in the front-rear direction with the through hole 24 interposed therebetween. The two inclined portions 40 are formed by deforming a part of the main body sheet metal 20. For example, the two inclined portions 40 are integrally formed with the main body sheet metal 20 by performing a drawing process on the main body sheet metal 20.

[0031] The inclined portion 40 is formed in a generally conical shape having a contact inclined surface 41 and a non-contact inclined surface 42. Exactly, the inclined portion 40 has a shape in which the cone is generally cut in half by the through hole 24. The contact inclined surface 41 and the non-contact inclined surface 42 are generally inclined planes and are connected by a curved curved surface 43 to constitute the inclined portion 40. The contact inclined surface 41 and the non-contact inclined surface 42 are inclined so as to approach each other as they move away from the photosensitive drum 13, and the joint portion (the top 40T of the inclined portion 40) between the contact inclined surface 41 and the non-contact inclined surface 42 is rounded into a substantially hemispherical shape.

[0032] Although details will be described later, as the retracting portion 35 reciprocally rotates, the retracting contact portion 35B contacts the inclined portion 40 of the main body sheet metal 20. The contact inclined surface 41 is the surface with which the retracting portion 35 (retracting contact portion 35B) contacts, and the non-contact inclined surface 42 is the surface with which the retracting portion 35 (retracting contact portion 35B) does not contact. The contact inclined surface 41 has a gentler inclination than the non-contact inclined surface 42. As shown in FIGS. 6 and 7, one inclined portion 40 has a shape obtained by rotating the other inclined portion 40 180 degrees around the center of the through hole 24, and the positions of the contact inclined surface 41 and the non-contact inclined surface 42 in the two inclined portions 40 are reversed. That is, the two inclined portions 40 are arranged point-symmetrically with respect to the center of the through hole 24.

[0033] [Function of the drive transmission device] Referring to FIGS. 6 to 9, the functions of the drive transmission device 30 will be described. FIG. 8 is a perspective view showing a retracted portion 35 and the like disposed at the top 40T of the inclined portion 40. FIG. 9 is a side view showing the retracted portion 35 and the like disposed at the top 40T of the inclined portion 40. In this specification, for convenience of explanation, a state in which image forming processing can be executed is defined as an initial state.

[0034] In the initial state, the drum unit 11 is inserted along the guide rail 23 to the mounting position, and the cover 25 of the apparatus main body 2 is closed (see FIG. 1). Further, each retracted main body portion 35A of the drive transmission device 30 is in contact with the edge of the through hole 24 in which the inclined portion 40 is not formed (hereinafter referred to as the "retracted position 44") (see FIGS. 6 and 7). That is, the retracted portion 35 of the drive transmission device 30 is not in contact with the two inclined portions 40, but is in contact with the surface of the main body sheet metal 20. Further, the coupling portion 33 of the drive transmission device 30 is biased by the biasing member 34, and the coupling portion 33 (engagement claw 33B) is pressed against the drum coupling 13A of the photosensitive drum 13 (see FIG. 3). Thereby, the photosensitive drum 13 is connected to the drive motor 21 via the drive transmission device 30 and the gear train 22. The driving force (rotational force) of the drive motor 21 is transmitted to the gear portion 32 and the coupling portion 33 of the drive transmission device 30 via the gear train 22, and is transmitted to the photosensitive drum 13 via the coupling portion 33 (engagement claw 33B). Thereby, the photosensitive drum 13 rotates about its axis.

[0035] Next, when replacing the drum unit 11 or the like, the drive transmission device 30 (coupling portion 33) is separated (connection released) from the photosensitive drum 13 (drum coupling 13A). Specifically, when an operator opens the closed cover 25, the rotational force in the opening direction of the cover 25 is transmitted to the retraction portion 35 via the lever 26. As shown in FIGS. 8 and 9, the retraction portion 35 rotates in one direction (counterclockwise in FIGS. 8 and 9) while contacting the inclined portion 40. Specifically, each retraction contact portion 35B rides up on the contact slope 41 of the inclined portion 40 from the retraction position 44 and moves (rotates) toward the top 40T of the inclined portion 40 while contacting the contact slope 41. As the one-way rotation of each retraction contact portion 35B progresses, the retraction portion 35 gradually moves in a direction away from the photosensitive drum 13 (rightward). Then, the retraction portion 35 moves the gear portion 32 and the coupling portion 33 in a direction away from the photosensitive drum 13 against the biasing force of the biasing member 34. Thereby, the coupling portion 33 is separated from the drum coupling 13A of the photosensitive drum 13. Thereafter, the operator pulls out the drum unit 11 along the guide rail 23 and removes the drum unit 11 from the apparatus main body 2. When the cover 25 is fully opened, each retraction contact portion 35B stops in contact with the top 40T of the inclined portion 40 (see FIGS. 8 and 9).

[0036] Next, when returning to the initial state after replacing the drum unit 11, the drive transmission device 30 (coupling portion 33) is connected to the photosensitive drum 13 (drum coupling 13A). Specifically, when an operator inserts the drum unit 11 along the guide rail 23 into the mounting position and closes the opened cover 25, the rotational force in the closing direction of the cover 25 is transmitted to the retracting portion 35 via the lever 26. As shown in FIGS. 6 and 7, the retracting portion 35 rotates in the other direction (clockwise in FIGS. 6 and 7) while contacting the inclined portion 40. Specifically, each retracting contact portion 35B drops from the top 40T of the inclined portion 40 onto the contact slope 41 and moves (rotates) toward the retracting position 44 (the surface of the main body sheet metal 20) while contacting the contact slope 41. As the rotation of each retracting contact portion 35B in the other direction progresses, the biasing member 34 moves the gear portion 32, the coupling portion 33, and the retracting portion 35 in the direction (leftward) approaching the photosensitive drum 13. Thereby, the coupling portion 33 is connected to the drum coupling 13A of the photosensitive drum 13. When the cover 25 is fully closed, each retracting contact portion 35B stops in contact with the retracting position 44 (see FIGS. 6 and 7).

[0037] In the drive transmission device 30 according to the present embodiment described above, the two inclined portions 40 protrude in a direction away from the photosensitive drum 13 (driven transmission portion) by deforming a part of the main body sheet metal 20 (metal sheet). If, as shown in FIG. 10, an inclined portion 90 that is a separate member is attached to the surface of the main body sheet metal 20, in addition to the thickness of the main body sheet metal 20, the thickness of the fixing piece 91 of the inclined portion 90 must be considered, and there is a possibility that the coupling portion 33 passing through the through hole 24 may become longer in the axial direction. However, according to the drive transmission device 30 according to the present embodiment, since the inclined portion 40 is a part of the main body sheet metal 20, the length of the coupling portion 33 can be determined by considering only the thickness of the main body sheet metal 20 (see FIGS. 3 and 4), and the coupling portion 33 can be made shorter. As a result, the coupling portion 33 can be brought closer to and connected to the photosensitive drum 13, and the photosensitive drum 13 can be rotated accurately. Further, since the inclined portion 40 is a part of the main body sheet metal 20, in addition to the fact that the number of parts can be reduced compared to the case where the conventional inclined portion 90 is prepared as a separate part, the attachment work to the main body sheet metal 20 can be made unnecessary. Thereby, the manufacturing cost of the drive transmission device 30 (image forming apparatus 1) can be reduced.

[0038] Further, in the drive transmission device 30 according to the present embodiment, the two retraction contact portions 35B of the retraction portion 35 protrude radially outward from the retraction main body portion 35A and are in contact with the two inclined portions 40 formed with the through hole 24 interposed therebetween. According to this configuration, the coupling portion 33 can be translated substantially parallel along the axial direction (left - right direction). As a result, the posture of the coupling portion 33 is stabilized, so that the connection to and separation from the photosensitive drum 13 can be properly performed.

[0039] Further, according to the drive transmission device 30 according to the present embodiment, since the inclined portion 40 is formed in a mountain shape having a contact slope 41 and a non-contact slope 42, the rigidity (mechanical strength) of the inclined portion 40 can be improved as compared with the case where the inclined portion 40 is formed only by the contact slope 41. Thereby, the retracted portion 35 riding on the inclined portion 40 can be firmly supported. Further, since the non-contact slope 42 has a steeper gradient than the contact slope 41, the inclined portion 40 can be formed smaller as compared with the case where the non-contact slope 42 has the same gradient as the contact slope 41. As a result, a wider space can be secured around the inclined portion 40, so that interference between the arm portion 37 and the lever 26 with the inclined portion 40 is suppressed, and smooth rotation of the retracted portion 35 can be ensured.

[0040] Also, in the drive transmission device 30 according to the present embodiment, the retracted portion 35 of the drive transmission device 30 is connected to the cover 25 of the device main body 2 via the lever 26. According to this configuration, the opening and closing of the cover 25 and the reciprocating rotation of the retracted portion 35 can be interlocked. Thereby, by opening the cover 25, the coupling portion 33 can be automatically separated from the photosensitive drum 13, and by closing the cover 25, the coupling portion 33 can be automatically connected to the photosensitive drum 13.

[0041] In the drive transmission device 30 according to the present embodiment, the gear portion 32 and the coupling portion 33 are integrally molded. However, the present invention is not limited to this, and the separately formed gear portion 32 and coupling portion 33 may be connected and integrated (not shown).

[0042] Also, in the drive transmission device 30 according to the present embodiment, the contact slope 41 of the inclined portion 40 has a gentler slope than the non-contact slope 42. However, the present invention is not limited to this, and the contact slope 41 and the non-contact slope 42 may have the same slope (not shown). Further, the non-contact slope 42 may be a surface orthogonal to the main body sheet metal 20, and only the contact slope 41 may be an inclined surface (not shown).

[0043] In addition, in the drive transmission device 30 according to the present embodiment, the inclined portion 40 was formed in a substantially conical shape (mountain shape), but the present invention is not limited to this. For example, a pair of cuts (not shown) may be formed in parallel on the main body sheet metal 20, and by extruding the portion between the pair of cuts, a substantially V-shaped (or substantially A-shaped) inclined portion (not shown) may be formed. In this case, the contact slope 41 may be made gentler than the non-contact slope 42, or the contact slope 41 and the non-contact slope 42 may have the same inclination (not shown). Additionally, alternatively, a substantially U-shaped cut (not shown) may be formed in the main body sheet metal 20, and by extruding the area surrounded by the cut, the non-contact slope 42 may be omitted, and an inclined portion having only the contact slope 41 (not shown) may be formed.

[0044] In addition, in the drive transmission device 30 according to the present embodiment, two inclined portions 40 were formed with the through-hole 24 therebetween, but the present invention is not limited to this. For example, three or more inclined portions 40 may be formed so as to surround the through-hole 24 (not shown). Also, the number and formation position of the retraction contact portions 35B of the retraction portion 35 may be adjusted according to the number and formation position of the inclined portions 40 (not shown).

[0045] In addition, in the drive transmission device 30 according to the present embodiment, the retraction portion 35 was composed of the retraction main body portion 35A and two retraction contact portions 35B, but the present invention is not limited to this. For example, the retraction portion 35 may be formed in an elliptical shape, and the major axis portion may be used as the two retraction contact portions (not shown).

[0046] In addition, the drive transmission device 30 according to the present embodiment transmitted the driving force to the photosensitive drum 13 as an example of the driven transmission portion, but the present invention is not limited to this. The drive transmission device 30 may transmit the driving force to a driven transmission portion that rotates about an axis, such as a stirring member of the toner container 10 or a developing roller of the developing device 15 (none of which are shown).

[0047] Also, in the image forming apparatus 1 according to the present embodiment, the retracting unit 35 was connected to the cover 25 via the lever 26, but the present invention is not limited to this. For example, the lever 26 may not be connected to the cover 25, and after an operator opens the cover 25, the operator may operate the lever 26 to reciprocally rotate the retracting unit 35 (not shown). Further, other image forming apparatuses may omit the lever 26 and include a sensor that detects the opening and closing of the cover 25 and a motor that reciprocally rotates the retracting unit 35 based on the detection result of the sensor (not shown).

[0048] Also, in the description of the present embodiment, as an example, the image forming apparatus 1 was a printer, but the present invention is not limited to this. For example, it may be a copier, a facsimile machine, or the like.

[0049] Note that the description of the above embodiment shows one aspect of the drive transmission device and the image forming apparatus according to the present invention, and the technical scope of the present invention is not limited to the above embodiment. The present invention may be variously changed, substituted, and modified without departing from the gist of the technical idea, and the scope of the claims includes all embodiments that can be included within the scope of the technical idea.

Explanation of Reference Numerals

[0050] 1 Image forming apparatus 2 Apparatus main body 13 Photoconductor drum (driven transmission part) 20 Main body sheet metal (metal sheet) 21 Drive motor (drive source) 24 Through hole 25 Cover 26 Lever 30 Drive transmission device 32 Gear part 33 Coupling part 34 Biasing member 35 Retracting unit 35A Retracting main body part 35B Retracting contact part 40 Inclined part 41 Contact inclined surface 42 Non-contact inclined surface

Claims

1. A drive transmission device disposed to face a driven transmission part with a metal plate interposed therebetween, comprising: a gear part connected to a drive source and rotating about an axis by the driving force of the drive source; a coupling part formed in a cylindrical shape, passing through a through hole opened in the metal plate and connected to the driven transmission part, and rotating about the same axis as the gear part; a biasing member that biases the gear part and the coupling part in a direction approaching the driven transmission part; a retreat part formed in an annular shape and passing through the coupling part, and reciprocally rotating about the same axis as the coupling part; and at least two inclined parts are formed on the metal plate with the through hole therebetween, which protrude in a direction away from the driven transmission part by deforming a part of the metal plate; the retreat part moves the gear part and the coupling part in a direction away from the driven transmission part against the biasing force of the biasing member by rotating in one direction while contacting the inclined part. The drive transmission device is characterized by this.

2. The retreat part has a retreat main body part formed in an annular shape, and at least two retreat contact parts protruding radially outward from the retreat main body part and contacting the inclined part. The drive transmission device according to claim 1 is characterized by this.

3. The inclined part is formed in a mountain shape having a contact slope surface with which the retreat part contacts and a non-contact slope surface with which the retreat part does not contact, and the non-contact slope surface has a steeper gradient than the contact slope surface. The drive transmission device according to claim 1 is characterized by this.

4. An image forming apparatus comprising the drive transmission device according to any one of claims 1 to 3.

5. An apparatus main body incorporating the drive transmission device, a cover provided to be openable and closable on the apparatus main body, and a lever connecting the cover and the retreat part of the drive transmission device. When the closed cover is opened, the retreat part rotates in one direction while contacting the inclined part, and moves the gear part and the coupling part in a direction away from the driven transmission part. When the opened cover is closed, the retreat part rotates in the other direction while contacting the inclined part, and the biasing member moves the gear part, the coupling part, and the retreat part in a direction approaching the driven transmission part. The image forming apparatus according to claim 4 is characterized by this.

Images