Image forming apparatus

Abstract

To prevent wear of a slide member, the rotation of which is regulated while a drive gear rotates.SOLUTION: An image forming apparatus comprises: a rotating body that is removably mounted in an apparatus body; a drive gear that is supported on the apparatus body movably in a rotation axis direction of the rotating body, has a connection part in drive connection with the rotating body in the rotation axis direction of the rotating body, and drives the rotating body; an urging member that urges the drive gear in the rotation axis direction toward the rotating body; a slide member that is provided between the drive gear and the urging member in the rotation axis direction of the rotating body, and is urged by the urging member in the rotation axis direction toward the drive gear; a locking member that is fixed to the apparatus body, and is engaged with the slide member to regulate the rotation of the slide member while the drive gear rotates; and a receiving member that is provided between the drive gear and the slide member in the rotation axis direction of the rotating body, has a slide surface slidable in contact with the slide member, and is engaged with the drive gear to rotate together with the drive gear, while the drive gear rotates, in a state where the contact between the slide member and the slide surface is maintained.SELECTED DRAWING: Figure 14

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, such as a printer, a copier, a facsimile, or a combination machine thereof, that utilizes an electrophotographic system. [Background technology]

[0002] In an image forming apparatus, an electrostatic latent image is formed by selectively exposing a photosensitive drum uniformly charged by a charging device, and the electrostatic latent image is developed with a developer by a developing device, and then transferred to an intermediate transfer body and then to a recording medium to form an image. A drum cartridge that houses the photosensitive drum and an intermediate transfer unit that constitutes the intermediate transfer body are detachably mounted in the main body of the image forming apparatus. The photosensitive drum and the intermediate transfer unit are connected to a drum drive gear and an intermediate transfer body drive gear provided in the main body of the image forming apparatus by their respective connecting parts, and the rotational driving force of each drive gear is transmitted to the photosensitive drum and the intermediate transfer unit via the connecting parts. As such a connecting part, a configuration is known in which a convex part protruding in the axial direction and a concave part recessed in the axial direction are detachably fitted to connect the photosensitive drum and the drum drive gear, or the intermediate transfer unit and the intermediate transfer body drive gear (see Patent Document 1).

[0003] The connecting portion has a convex portion of a substantially triangular shape as viewed from the direction of the rotation axis provided on each drive gear, and a concave portion of a substantially triangular shape as viewed from the direction of the rotation axis provided on the photosensitive drum or the intermediate transfer body unit and capable of engaging with the convex portion. The convex portion and the concave portion are twisted in the direction of the rotation axis. Therefore, when the photosensitive drum or the intermediate transfer body rotates in the forward rotation direction, the convex portion and the concave portion are adapted to pull into each other in the direction of the rotation axis. In addition, since the connecting portion needs to be connected and disconnected with the attachment and detachment operation of the drum cartridge or the intermediate transfer unit to and from the device main body, each drive gear is movable in the direction of the rotation axis. Furthermore, each drive gear is urged toward the photosensitive drum or the intermediate transfer body, which is the driven body, by an urging spring, for example a compression coil spring, with respect to the device main body.

[0004] When the drum cartridge or intermediate transfer unit is mounted to the device body, the convex and concave portions of the connecting portion face each other in the direction of the rotation axis. At this time, the phases of the vertices of the triangles of the convex and concave portions may not match. In this case, to prevent the convex and concave portions from interfering with each other and making it impossible to mount the drum cartridge or intermediate transfer unit, each driving gear is pushed against the biasing spring in the direction of the rotation axis in the opposite direction to the photosensitive drum or intermediate transfer unit, making it possible to mount it. By rotating each driving gear in this state, when the phases of the convex and concave portions match, the biasing force of the biasing spring moves the driving gear to the photosensitive drum or intermediate transfer body, which is the driven body, and the connection of the connecting portion is completed.

[0005] Here, in the configuration of the photosensitive drum, intermediate transfer body, and drive gear connection portion described in Patent Document 1, the biasing spring is provided in contact with the drive gear. Therefore, as the drive gear rotates, the biasing spring and the drive gear rotate while generating friction. In particular, in Patent Document 1, the biasing spring is a compression coil spring, and the end of the wire constituting the compression coil spring slides against the drive gear, which may cause excessive wear or generate loud noise. For this reason, a configuration that does not generate friction between the drive gear and the biasing spring has been desired.

[0006] In view of this, a configuration is known in which a sliding member is provided between the drive gear and the biasing spring, which engages with the device body to restrict rotation in the rotational direction when the drive gear is rotating and forms a sliding surface that can slide against the drive gear (see Patent Document 2).This configuration makes it possible to prevent excessive friction between the drive gear and the end of the biasing member. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2011-154407 A [Patent Document 2] JP 2020-56923 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, the driving gear is restricted in shape for high precision, for example, in a shape with ribs provided radially from the center of rotation, and there are cases where the area with the sliding surface of the sliding member is not sufficient. In this case, depending on the shape of the driving gear, pressure is applied locally to the sliding surface of the sliding member, which may cause wear of the sliding member and lead to breakage.

[0009] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to suppress wear of a sliding member whose rotation is restricted when a drive gear rotates, regardless of the shape of the drive gear. [Means for solving the problem]

[0010] A representative configuration of the present invention includes an apparatus main body, a rotatable rotor that is detachably attached to the apparatus main body, a drive gear that is supported by the apparatus main body so as to be movable in the rotation axis direction of the rotor, and has a coupling portion that is drivingly coupled to the rotor in the rotation axis direction of the rotor, and drives the rotor, a biasing member that biases the drive gear in the rotation axis direction toward the rotor, and a biasing member that is provided between the drive gear and the biasing member in the rotation axis direction of the rotor, and biases the drive gear in the rotation axis direction toward the drive gear by the biasing member. a sliding member that is biased toward the driving gear, a locking member that is fixed to the device body and that engages with the sliding member to regulate the rotation of the sliding member when the drive gear is rotating, and a receiving member that is provided between the drive gear and the sliding member in the rotational axial direction of the rotating body, has a sliding surface that is in contact with the sliding member and is slidable against the sliding member, and that engages with the drive gear and rotates together with the drive gear while maintaining contact between the sliding member and the sliding surface when the drive gear is rotating. Effect of the Invention

[0011] According to the present invention, wear of the sliding member, the rotation of which is restricted when the drive gear rotates, can be suppressed regardless of the shape of the drive gear. [Brief description of the drawings]

[0012] [Figure 1] Schematic cross-sectional view of an image forming apparatus [Diagram 2] An explanatory diagram of the drum cartridge configuration [Diagram 3] FIG. 1 is a perspective view showing a cartridge mounting tray. [Figure 4] FIG. 1 is a perspective view showing a state in which the drum cartridge is mounted in the main body of the apparatus; [Diagram 5] A partial cross-sectional view of the downstream end of the drum cartridge and the cartridge mounting portion. [Figure 6] A perspective view of a connection portion between a drum drive gear and a photosensitive drum [Figure 7] FIG. 1 is a perspective view showing a state in which an intermediate transfer unit is attached to an image forming apparatus; [Figure 8] FIG. 3 is a perspective view of a unit mounting portion of the intermediate transfer unit; [Figure 9] A perspective view showing a unit rail [Figure 10] FIG. 2 is a perspective view of a regulating member in the intermediate transfer unit rail; [Figure 11] FIG. 1 is a perspective view of a connection portion between a drive roller and a belt drive gear of an intermediate transfer unit; [Figure 12] A perspective view of a connection portion between a photosensitive drum and a drum drive gear. [Figure 13] Front cross-sectional view of the connection between the photosensitive drum and the drum drive gear [Figure 14] Cross-sectional view showing the pressure applying structure of the belt drive gear [Figure 15] FIG. 13 is a perspective view showing the relationship between the sliding plate and the bearing member; [Figure 16] DD cross section of Figure 14 [Figure 17] FIG. 1A is a perspective view of a sliding plate receiving member; FIG. [Figure 18] FIG. 11 is a cross-sectional view showing a pressure applying configuration of a belt drive gear and a sliding plate in a comparative example. [Figure 19] 1A and 1B are explanatory diagrams showing a rubbing portion of a belt drive gear of a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the following embodiments may be changed as appropriate depending on the configuration of the device to which the present invention is applied and various conditions, and are not intended to limit the scope of the present invention to these alone.

[0014] [Image forming equipment] The image forming apparatus will be described with reference to Figures 1 and 2. Figure 1 is a schematic cross-sectional view of the image forming apparatus. Figure 2 is an explanatory diagram of the structure of a drum cartridge.

[0015] The image forming apparatus 100 is a tandem type intermediate transfer type full-color printer in which image forming units, which are cartridges 1y, 1m, 1c, and 1k, are arranged along the downward surface of an intermediate transfer belt 8 serving as an intermediate transfer body when installed. The image forming apparatus 100 has an apparatus main body 101.

[0016] The drum cartridges 1y, 1m, 1c, and 1k are almost identical in configuration, except that the colors of toner used in the developing devices 4y, 4m, 4c, and 4k are different: yellow, magenta, cyan, and black. In the following, the drum cartridge 1y will be described, and the other drum cartridges 1m, 1c, and 1k will be described by replacing the suffix y with m, c, and k. The drum cartridge 1y has a charging roller 3y, a developing device 4y, and a cleaning device 6y surrounding a photosensitive drum 2y. The drum cartridge 1y will be described in detail later.

[0017] An exposure device 7 is disposed below the drum cartridge 1y, and a primary transfer roller 5y is disposed at a position facing the photosensitive drum 2y with the intermediate transfer belt 8 interposed therebetween. The photosensitive drum 2y has a negatively charged photosensitive layer formed on the outer peripheral surface of an aluminum cylinder, and rotates in the direction of the arrow (see FIG. 2) at a predetermined process speed by receiving a driving force from a driving motor as a driving source. Toner bottles 70y, 70m, 70c, and 70k are disposed below the developing devices 4y, 4m, 4c, and 4k, respectively. Toner consumed by the developing devices 4y, 4m, 4c, and 4k during image formation is replenished from the toner bottles 70y, 70m, 70c, and 70k, respectively.

[0018] The intermediate transfer belt 8 constitutes an intermediate transfer unit that is supported by being stretched across a tension roller 11, a drive roller 10 that also serves as a secondary transfer counter roller, and a tension roller 13, and is driven by the drive roller 10 to rotate in the direction of arrow R2.

[0019] The secondary transfer section T2 is configured by bringing a secondary transfer roller 12 into contact with the intermediate transfer belt 8, the inner surface of which is stretched by a drive roller 10. A positive DC voltage is applied to the secondary transfer roller 12, thereby forming a transfer electric field for a toner image between the secondary transfer roller 12 and the drive roller 10, which is connected to a ground potential. The belt cleaning device 9 rubs a cleaning blade against the intermediate transfer belt 8 to remove the residual toner adhering to the surface of the intermediate transfer belt 8 that has passed through the secondary transfer section T2.

[0020] Next, a procedure for forming an image by the image forming apparatus 100 will be described below. In the drum cartridge 1y, a yellow toner image is formed on the photosensitive drum 2y as an image carrier and is primarily transferred to the intermediate transfer belt 8. In the drum cartridges 1m, 1c, and 1k, a magenta toner image, a cyan toner image, and a black toner image are formed on the photosensitive drums 2m, 2c, and 2k, respectively, and are primarily transferred to the intermediate transfer belt 8.

[0021] The separation roller 19 separates the sheets S, which are recording materials conveyed from the sheet cassette 18, one by one, and sends them to the registration rollers 14. The registration rollers 14 receive the sheets S in a stopped state and make them wait, and then send the sheets S to the secondary transfer section T2 in synchronization with the toner image on the intermediate transfer belt 8.

[0022] The four-color toner images primarily transferred onto the intermediate transfer belt 8 are transported to secondary transfer section T2 and secondarily transferred all at once onto sheet S. Sheet S onto which the four-color toner images have been secondarily transferred is transported to fixing device 16. Fixing device 16 presses pressure roller 16b against fixing roller 16a, which is provided with a heater, to form a heating nip. Sheet S is heated and pressurized in the heating nip to melt the toner image, and the full-color image is fixed onto the surface. The sheet with the toner image fixed onto its surface by fixing device 16 is discharged via discharge rollers 15 to upper tray 17.

[0023] As shown in FIG. 2, the charging roller 3y rotates following the photosensitive drum 2y, and charges the photosensitive drum 2y to a uniform negative potential by applying an oscillating voltage in the form of a negative DC voltage superimposed on an AC voltage. The exposure device 7 (see FIG. 1) scans a laser beam, which is ON-OFF modulated based on scanning line image data of a yellow separation color image, with a rotating mirror, to write an electrostatic image of the image on the charged surface of the photosensitive drum 2y. The exposure device 7 similarly writes electrostatic images for the magenta, cyan, and black separation color images on the respective photosensitive drums 2m, 2c, and 2k. The development device 4y transfers toner to the photosensitive drum 2y to develop the electrostatic image into a toner image.

[0024] As shown in FIG. 1, the primary transfer roller 5y presses the intermediate transfer belt 8 to form a primary transfer portion T1y between the photosensitive drum 2y and the intermediate transfer belt 8. A positive DC voltage is applied to the primary transfer roller 5y, so that a negative toner image carried on the photosensitive drum 2y is primarily transferred to the intermediate transfer belt 8 passing through the primary transfer portion T1y. The cleaning device 6y rubs a cleaning blade against the photosensitive drum 2y to remove the residual toner adhering to the surface of the photosensitive drum 2y that has passed through the primary transfer portion T1y. The removed toner is transported by a toner transport screw 60y, and is transported to a toner discharge port (not shown), and then discharged from the toner discharge port. Each member, such as the photosensitive drum 2y, the charging roller 3y, the developing device 4y, and the cleaning device 6y, is integrally combined into a cartridge to form the drum cartridge 1y. Each of the drum cartridges 1y, 1m, 1c, and 1k is detachably mounted to the device body 101 of the image forming device 100.

[0025] [Inserting and removing the drum cartridge into the image forming device] Next, the insertion and removal of the drum cartridge 1 into and from the main body 101 of the image forming apparatus 100 will be described with reference to Figs. 3 to 6. Fig. 3 is a perspective view of a cartridge mounting tray. Fig. 4 is a perspective view showing a state in which only the drum cartridge 1y including the yellow photosensitive drum 2y is mounted in the main body. Fig. 5 is a partial cross-sectional view of the shape of the downstream end of the drum cartridge 1y in the insertion direction (arrow A direction) and the cartridge mounting portion 31y. Fig. 6 is a perspective view of the connection portion between the drum drive gear and the photosensitive drum.

[0026] One end of the cartridge mounting tray 102 in the mounting direction (arrow A direction) is supported by a main body rear plate 101R which is a part of a frame that forms the image forming apparatus 100, and the other end is supported by a main body front plate (not shown). The main body rear plate 101R is disposed in a position facing the main body front plate (not shown). The main body rear plate 101R, the main body front plate (not shown), and the cartridge mounting tray 102 are included in the apparatus main body 101 of the image forming apparatus 100.

[0027] The cartridge mounting tray 102 includes cartridge mounting portions 31y, 31m, 31c, and 31k for holding the drum cartridges 1y, 1m, 1c, and 1k inside the image forming apparatus 100. The cartridge mounting portions 31y, 31m, 31c, and 31k are provided with guide portions 32y, 32m, 32c, and 32k that serve as guides when inserting the drum cartridges 1y, 1m, 1c, and 1k, respectively.

[0028] As shown in Fig. 4, when the drum cartridge 1y is mounted in the apparatus main body 101, the cartridge mounting portion 31y supports the drum cartridge 1y from the bottom of the drum cartridge. The drum cartridge 1y is guided in the direction of arrow A in Fig. 4 by a guide portion 32y (see Fig. 3) of the cartridge mounting portion 31y, and is mounted in the image forming apparatus 100. The drum cartridges 1m, 1c, and 1k are inserted and mounted in the same manner as the drum cartridge 1y.

[0029] As shown in Fig. 5, the cartridge mounting section 31y includes a mounting restricting section 311y. The mounting restricting section 311y includes a guide section 312 for guiding the drum cartridge 1y in the direction of the arrow A when the drum cartridge 1y is inserted, and a restricting section 313 for restricting the movement of the drum cartridge 1y in the opposite direction to the direction of the arrow A after the mounting is complete. Here, the drum cartridge 1y includes a mounting restricted section 33y. The mounting restricted section 33y is restricted by the mounting restricting section 311y of the cartridge mounting section 31y, and the drum cartridge 1y is fixed so as not to move in the opposite direction to the direction of the arrow A after the mounting is complete. The drum cartridges 1m, 1c, and 1k are also fixed in the same manner as the drum cartridge 1y.

[0030] 6, the drum fitting member 21y attached to the longitudinal end of the photosensitive drum 2y by the above-mentioned installation is fitted with the drum drive gear 22y, and the drive is transmitted from the drum drive gear 22y to the photosensitive drum 2y. Note that the relationship between the corresponding drum fitting members 21m, 21c, 21k and the drum drive gears 22m, 22c, 22k in the photosensitive drums 2m, 2c, 2k is the same as that between the drum fitting member 21y and the drum drive gear 22y.

[0031] [Inserting and removing the intermediate transfer unit into the image forming device] Next, the insertion and removal of the intermediate transfer unit 40 into and from the main body 101 of the image forming apparatus 100 will be described with reference to Figs. 7 and 8. Fig. 7 is a perspective view showing a state in which the intermediate transfer unit 40 is mounted in the image forming apparatus 100. Fig. 8 is a perspective view of a unit mounting portion of the intermediate transfer unit 40. Fig. 9 is an enlarged perspective view showing the rear unit rail 41 and the unit insertion and removal restricting member 411. Here, the intermediate transfer unit 40 is inserted from the right side when viewed from the front of the image forming apparatus 100 in the direction of arrow B in the figure (a direction perpendicular to the direction of arrow A).

[0032] The image forming apparatus 100 has a rear unit rail 41 and a front unit rail 42 arranged at a position facing the rear unit rail 41 in the front-rear direction (arrow A direction) of the image forming apparatus 100 as a unit mounting portion of the intermediate transfer unit 40. Here, the rear unit rail 41 is supported by a main body rear side plate 101R which is a part of the frame forming the image forming apparatus 100. The front unit rail 42 is supported by a main body front side plate (not shown) which is a part of the frame forming the image forming apparatus 100. The intermediate transfer unit 40 is supported so as to be sandwiched between the front and rear unit rails 42 and 41, and is movable in the direction of arrow B in FIG. 7.

[0033] The rear unit rail 41 and the front unit rail 42 are respectively provided with unit insertion / removal restricting members 411, 421. When the intermediate transfer unit 40 is mounted on the image forming apparatus 100 as shown in FIG. 7, the movement of the intermediate transfer unit 40 in the insertion / removal direction is restricted by the unit insertion / removal restricting member 421 provided on the front unit rail 42 and the unit insertion / removal restricting member 411 provided on the rear unit rail 41.

[0034] Here, we will explain the rear unit rail 41 and the unit insertion / removal restricting member 411. Note that while we will explain the rear unit rail 41 side here, the opposite side, the front unit rail 42 side, has the same configuration, so its explanation will be omitted.

[0035] When the intermediate transfer unit 40 is inserted into or removed from the image forming apparatus 100, it is supported so as to be movable along the guide surface 41a of the rear unit rail 41 shown in FIG. 9. The unit insertion / removal restricting member 411 has a restricting surface 411a angled with respect to the guide surface 41a of the rear unit rail 41, and restricts the movement of the intermediate transfer unit 40 in the direction of arrow B', which is the direction of removal of the intermediate transfer unit 40 that has been completely attached. The unit insertion / removal restricting member 411 is supported so as to be movable in the vertical direction (the direction of arrow Z in FIG. 9) with respect to the guide surface 41a. The unit insertion / removal restricting member 411 is biased by a biasing member (not shown) such as a compression spring so that the restricting surface 411a is at a higher position in the direction of arrow Z than the guide surface 41a (the restricted position shown in FIG. 9). Here, when the intermediate transfer unit 40 is inserted or removed, a pressing member (not shown) presses down the unit insertion / removal restricting member 411 so that the restricting surface 411a is at a lower position in the direction of arrow Z than the guide surface 41a (the restricted position). This allows the intermediate transfer unit 40 to move in the direction of arrow B' only when the intermediate transfer unit 40 is inserted or removed, and allows the intermediate transfer unit 40 to be removed from the image forming apparatus 100.

[0036] In this case, the push-down member that pushes down the unit insertion / removal restricting member 411 is a guide member (not shown) of the intermediate transfer unit 40 that is supported movably along the guide surface 41a of the rear unit rail 41. However, the push-down member that pushes down the unit insertion / removal restricting member 411 is not limited to this. The push-down operation of the push-down member may be performed by a user operation or the like.

[0037] Furthermore, when the intermediate transfer unit 40 is moved in the directions of arrows B1 and B2, which are directions for inserting and removing the intermediate transfer unit 40 into and from the main body 101 of the image forming apparatus 100, the belt drive gear 44 is moved in the directions of arrows X1 and X2 relative to the intermediate transfer unit 40. This will be described with reference to Figures 10(a) to 10(c) and 11.

[0038] Fig. 10(a) is a diagram for explaining the separation operation of the belt drive gear 44 and the intermediate transfer unit 40 when the intermediate transfer unit 40 moves in the direction of the arrow B', which is the insertion / removal direction of the image forming apparatus 100, and the part surrounded by the dashed line is a partial cross-sectional view. Fig. 10(b) is a partial cross-sectional view showing a state in which the shutter member 45 hits the end of the belt drive gear 44 due to the movement. Fig. 10(c) is a partial cross-sectional view showing a state in which the separation of the belt drive gear 44 from the intermediate transfer unit 40 is completed. Fig. 11 is a perspective view of a connection portion between the drive roller 10 of the intermediate transfer unit 40 and the belt drive gear 44.

[0039] The intermediate transfer unit 40 is moved in the direction of arrow B1, which is the direction in which the intermediate transfer unit 40 is inserted into the main body 101 of the image forming apparatus 100, and the belt drive gear 44 is connected to the intermediate transfer unit 40 when the attachment is completed.

[0040] Here, the belt drive gear 44 is pressed in the direction of the arrow X2 toward the intermediate transfer unit 40 with respect to the rotation axis direction (the direction of the arrows X1 and X2 in the figure) of the drive roller 10, which is a rotating body, by a pressure applying configuration of the drive gear described later. The drive roller 10 included in the intermediate transfer unit 40 has a drive roller fitting member 43 fixed integrally to an end portion. The drive roller fitting member 43 has a connection configuration with the belt drive gear 44 described later. The drive roller 10 of the intermediate transfer unit 40 is connected to the belt drive gear 44 and receives rotational drive from the belt drive gear 44, thereby rotating the intermediate transfer belt 8.

[0041] First, when the intermediate transfer unit 40 starts to be inserted into the image forming apparatus 100 in the direction of arrow B1, the belt drive gear 44 is pushed in the direction of arrow X1 (see FIG. 10(a)), which is the opposite direction to the direction of arrow X2, by a guide member (not shown) including the shutter member 45 of the intermediate transfer unit 40. As a result, the belt drive gear 44 is released from connection with the intermediate transfer unit 40, and is moved to a retracted position (position shown in FIG. 10(c)) separated from the intermediate transfer unit 40.

[0042] Then, with the belt drive gear 44 moved to the retracted position, the intermediate transfer unit 40 is inserted into the apparatus body 101 of the image forming apparatus 100. Then, as the intermediate transfer unit 40 moves in the direction of arrow B1, the belt drive gear 44 gradually moves in the direction of arrow X2 along the shutter member 45 and the tapered surface C of the belt drive gear 44. Finally, the contact between the shutter member 45 and the belt drive gear 44 is released, and the belt drive gear 44 is connected to the intermediate transfer unit 40 as shown in FIG.

[0043] On the other hand, when the intermediate transfer unit 40 is moved in the direction of arrow B′, which is the direction in which the intermediate transfer unit 40 is removed from the main body 101 of the image forming apparatus 100 , the belt drive gear 44 is separated from the intermediate transfer unit 40 .

[0044] The intermediate transfer unit 40 includes a shutter member 45 that is supported so as to be movable in the insertion / removal direction of the intermediate transfer unit 40. The shutter member 45 moves in the directions of arrows B1 and B2 due to a user operation or the like when inserting or removing the intermediate transfer unit 40 from the image forming apparatus 100. The end faces of the shutter member 45 and the belt drive gear 44 include tapered surfaces C.

[0045] When the intermediate transfer unit 40 starts to move in the direction of arrow B2 relative to the image forming apparatus 100, the shutter member 45 moves in the direction of arrow B2 in conjunction with the movement of the intermediate transfer unit 40 in the direction of arrow B2. Then, due to the movement of the intermediate transfer unit 40 in the direction of arrow B2, the shutter member 45 and the tapered surface C of the belt drive gear 44 come into contact with each other, and the belt drive gear 44 gradually moves in the direction of arrow X1 along the tapered surface C. As a result, the belt drive gear 44 is released from connection with the drive roller fitting member 43 against the pressure configuration of the drive gear, and is moved to a retracted position (position shown in FIG. 10(c)) spaced apart from the intermediate transfer unit 40 (drive roller 10).

[0046] Then, with the belt drive gear 44 moved to the retracted position, the intermediate transfer unit 40 is removed from the main body 101 of the image forming apparatus 100.

[0047] As described above, when removing the intermediate transfer unit 40 from the image forming apparatus 100, the connection between the belt drive gear 44 and the intermediate transfer unit 40 is released and they are separated, making it possible to insert or remove the intermediate transfer unit 40 from the image forming apparatus 100.

[0048] [Drive gear connection configuration] Next, the connection structure of the drive gear will be described with reference to Figs. 12 and 13. Here, the connection structure between the photosensitive drum 2 as a rotating body and the drum drive gear 22 that is connected to and drives the photosensitive drum 2 will be described as an example. Fig. 12 is a perspective view of the connection portion between the photosensitive drum 2 and the drum drive gear 22. Fig. 13 is a front sectional view of the connection portion between the photosensitive drum 2 and the drum drive gear 22.

[0049] In the following description, the photosensitive drums 2y, 2m, 2c, and 2k are assumed to have the same connection configuration. In this case, the photosensitive drums 2y, 2m, 2c, and 2k, the drum fitting members 21y, 21m, 21c, and 21k, the drum driving gears 22y, 22m, 22c, and 22k, and other elements that are made up of a plurality of them are collectively referred to as the photosensitive drum 2, the drum fitting member 21, and the drum driving gear 22, respectively (see FIGS. 6 and 12).

[0050] The direction from the photosensitive drum 2 to the drum drive gear 22 in the direction of the rotation axis of the drum drive gear 22 is defined as X1, and the clockwise direction when the drum drive gear 22 is viewed from the photosensitive drum 2 in the direction of the rotation axis is defined as θ1.

[0051] In addition, the connection configuration between the intermediate transfer unit 40 and the belt drive gear 44 is similar to the connection configuration between the photosensitive drum 2 and the drum drive gear 22. Therefore, the photosensitive drum 2 as a rotating body may be read as the drive roller 10, the drum fitting member 21 as the drive roller fitting member 43, and the drum drive gear 22 as the belt drive gear 44 (see FIG. 11). However, although the rotation axis direction X1 of the belt drive gear 44 in this embodiment is the same as the rotation axis direction X1 of the drum drive gear 22, the rotation direction θ2 of the belt drive gear 44 is opposite to the rotation direction θ1 of the drum drive gear 22, so the description must be read as the counterclockwise direction θ2.

[0052] 12, a drum fitting member 21 is fixed integrally to an end of the photosensitive drum 2. When the photosensitive drum 2 and the drum fitting member 21 receive a rotational driving force from a drum drive gear 22, they rotate integrally.

[0053] The drum driving gear 22 has a fitting portion 221 as a connection portion that is drivingly connected to the photosensitive drum 2 in the rotation axis direction of the photosensitive drum 2. Specifically, as shown in FIG. 13, the drum driving gear 22 is provided with a hole (recess) having a substantially triangular cross section, which forms the fitting portion 221. The fitting portion 221 is shaped recessed in the rotation axis direction of the drum driving gear 22. The drum fitting member 21 is provided with a fitted portion 211 (convex portion) having a substantially triangular cross section and a convex shape. The fitted portion 211 is shaped to protrude in the rotation axis direction of the drum driving gear 22. The fitted portion 211 of the drum fitting member 21 can be detachably fitted into and connected to the fitting portion 221 of the drum driving gear 22. The fitted portion 211 of the drum fitting member 21 fits into a fitting portion 221 of the drum driving gear 22, so that the photosensitive drum 2 and the drum driving gear 22 are drivingly connected to each other.

[0054] Here, as a connecting portion between the photosensitive drum 2 and the drum drive gear 22, a configuration in which a recess (fitting portion 221) is provided on one drum drive gear 22 and a protrusion (fitted portion 211) connectable to the recess is provided on the other photosensitive drum 2 has been exemplified, but the present invention is not limited to this. A configuration in which a protrusion is provided on one drum drive gear 22 and a recess connectable to the protrusion is provided on the other photosensitive drum 2 may also be used.

[0055] During image recording operation of the image forming device, the drum drive gear 22 rotates in the direction of arrow θ1, and the forward rotation abutment portion 222 provided on the drum drive gear 22 comes into contact with the forward rotation abutted portion 212 provided on the drum fitting member 21, the rotational drive of the drum drive gear 22 is transmitted to the drum fitting member 21, and the photosensitive drum 2 rotates.

[0056] The fitting portion 221 of the drum driving gear 22 has a cross section of a hole that is twisted in the θ2 direction as it approaches the X1 direction. The fitted portion 211 of the drum fitting member 21 also has a convex cross section that is twisted in the same X1 direction. That is, the fitted portion 211 and the fitting portion 221 are twisted in the same direction around the rotation axis of the photosensitive drum 2 so that a pulling force is generated between them when the drum driving gear 22 rotates forward.

[0057] When the image forming apparatus is performing an image recording operation, the drum drive gear 22 rotates in the θ1 direction, and the drum fitting member 21 receives a force in the X1 direction so that the fitted portion 211 of the drum fitting member 21 bites into the fitting portion 221 of the drum drive gear 22. This prevents the connection between the drum drive gear 22 and the drum fitting member 21 from being unintentionally released due to, for example, misalignment between the drum drive gear 22 and the drum fitting member 21 or external disturbance in the X2 direction being applied to the drum fitting member 21.

[0058] [Drive gear pressure configuration] Next, a pressure applying structure for applying pressure to the belt driving gear 44 against the driving roller 10 and a sliding surface when the belt driving gear 44 rotates will be described with reference to Fig. 14. Fig. 14 is a cross-sectional view showing the pressure applying structure of the belt driving gear 44.

[0059] Incidentally, although a configuration for pressing the belt drive gear 44 toward the drive roller 10 (intermediate transfer unit 40) will be described here as an example, the same applies to a configuration for pressing the drum drive gear 22 toward the photosensitive drum 2. In this case, the belt drive gear 44 may be read as the drum drive gear 22, and the drive roller 10 may be read as the photosensitive drum 2. However, as described above, since the rotation direction θ1 of the drum drive gear 22 is opposite to the rotation direction θ2 of the belt drive gear 44, the description must be read as the clockwise direction θ1.

[0060] The bearing member 225 is supported and fixed to the apparatus body 101 of the image forming apparatus 100 .

[0061] The bearing member 225 rotatably supports the belt drive gear 44. The belt drive gear 44 has a shaft portion 226 supported by the bearing member 225 and rotates in the θ2 direction. The biasing member 224 has a fixed end 227 fixed to the device main body side and a free end 228 in contact with a sliding plate 229. The biasing member 224 biases the belt drive gear 44 in the rotation axis direction toward the drive roller 10. Note that, although a compression coil spring is exemplified as the biasing member 224 here, the biasing member 224 is not limited to this.

[0062] A sliding plate 229 serving as a sliding member is provided between the belt driving gear 44 and the biasing member 224 in the rotational axis direction of the drive roller 10. The sliding plate 229 is biased in the rotational axis direction toward the belt driving gear 44 by the biasing member 224. As will be described later, the bearing member 225 also serves as a locking member that engages with the sliding plate 229 to restrict the rotation of the sliding plate 229 when the belt driving gear 44 is rotating.

[0063] Furthermore, a sliding plate receiving member 231 is disposed between the belt driving gear 44 and the sliding plate 229 in the rotation axis direction of the drive roller 10. The sliding plate receiving member 231 has a sliding surface 231b that is in contact with and can slide on the sliding plate 229. The sliding plate receiving member 231 has an abutment surface 231e on the opposite side to the sliding surface 231b in the rotation axis direction of the drive roller 10. The sliding plate receiving member 231 abuts against the sliding plate 229 via the sliding surface 231b. The sliding plate receiving member 231 abuts against the belt driving gear 44 via the abutment surface 231e. Therefore, the pressure (biasing force) of the biasing member 224 presses the belt driving gear 44 in the direction of the arrow X2 via the sliding plate 229 and the sliding plate receiving member 231.

[0064] As will be described later, when the belt drive gear 44 is rotating, the sliding plate receiving member 231 engages with the belt drive gear 44 and rotates together with the belt drive gear 44 while maintaining contact between the sliding plate 229 and the sliding surface 231b.

[0065] [Configuration of sliding plate] The configuration of the sliding plate 229 will be described with reference to Fig. 15. Fig. 15 is a perspective view showing the positional relationship between the sliding plate 229 and the bearing member 225.

[0066] The sliding plate 229 has an opposing surface 229b that faces the belt driving gear 44 in the direction of the rotation axis of the drive roller 10. The opposing surface 229b is a disk-shaped flat surface centered on the rotation center of the belt driving gear. The opposing surface 229b of the sliding plate 229 is in contact with a sliding surface 231b of the sliding plate receiving member 231 by the biasing force of the biasing member 224.

[0067] The sliding plate 229 has a locking claw 229a as a locking portion that protrudes from the opposing surface 229b toward the bearing member 225 in the rotation axis direction. The locking claw 229a locks with the bearing member 225 when the belt driving gear 44 rotates in the direction of the arrow θ2. The bearing member 225 has a rotation restriction rib 225a that locks the locking claw 229a of the sliding plate 229 and restricts the rotation of the belt driving gear 44 when the belt driving gear 44 rotates in the direction of the arrow θ2.

[0068] When the belt drive gear 44 rotates in the direction of the arrow θ2, the locking claw 229a of the sliding plate 229 abuts against the rotation restricting rib 225a of the bearing member 225, stopping the rotation of the sliding plate 229. Therefore, the sliding plate 229 does not continue to rotate together with the rotation of the belt drive gear 44. Here, the rotation restricting rib 225a and the locking claw 229a may each be one or more, and it is sufficient that at least one of the multiple locking claws 229a abuts against the rotation restricting rib 225a.

[0069] The sliding plate 229 has a positioning hole 229d at the center of the disk-shaped opposing surface 229b. The positioning hole 229d of the sliding plate 229 fits into a positioning boss 231d (see FIG. 17(a)) of a sliding plate receiving member 231 described later, whereby the sliding plate 229 positions the sliding plate receiving member 231 and rotatably supports it.

[0070] [Configuration of sliding plate receiving member] The configuration of the sliding plate receiving member 231 will be described with reference to Figures 16, 17(a) and 17(b). Figure 16 is a diagram showing the relationship between the sliding plate receiving member 231 and the belt drive gear 44, and is a cross-sectional view of the D-D section in Figure 14 as viewed from the X1 direction. Figure 17(a) is a perspective view of the sliding plate receiving member 231, and Figure 17(b) is a front view of the sliding plate receiving member 231.

[0071] As described above, the sliding plate receiving member 231 has the sliding surface 231b that can come into contact with and slide on the sliding plate 229, and the abutting surface 231e that abuts against the belt driving gear 44. The sliding surface 231b of the sliding plate receiving member 231 is a disk-shaped flat surface centered on the rotation center of the belt driving gear 44. The sliding surface 231b faces the opposing surface 229b of the sliding plate 229 in the rotation axis direction of the driving roller 10, and can come into contact with and slide on the opposing surface 229b of the sliding plate 229.

[0072] The sliding plate receiving member 231 has an engaging claw 231a as an engaging portion that engages with the belt driving gear 44. The engaging claw 231a is provided to protrude from the sliding surface 231b toward the belt driving gear 44 in the rotation axis direction. The belt driving gear 44 is provided with engaging ribs 44a radially. When the belt driving gear 44 rotates in the direction of the arrow θ2, the engaging claw 231a engages (abuts) with the engaging rib 44a of the belt driving gear 44. As a result, the sliding plate receiving member 231 rotates together with the rotation of the belt driving gear 44 in the direction of the arrow θ2, and the sliding surface 231b of the sliding plate receiving member 231 is rubbed against the opposing surface 229b of the sliding plate 229 whose rotation is restricted. Here, the engaging rib 44a and the engaging claw 231a may be one or more, and at least one of the multiple engaging ribs 44a may abut against the engaging claw 231a.

[0073] The sliding plate receiving member 231 has a positioning boss 231d as a positioning member that fits into a positioning hole 229d of the sliding plate 229. The positioning boss 231d is provided at the rotation center of the disk-shaped sliding surface 231b of the sliding plate receiving member 231, and protrudes toward the sliding plate 229 in the direction of the rotation axis. The sliding plate receiving member 231 is rotatably supported by the sliding plate 229 by fitting the positioning boss 231d into the positioning hole 229d of the sliding plate.

[0074] The sliding plate receiving member 231 has a groove portion 231c, which is an annular recess, provided on a sliding surface 231b between the sliding plate 229 and the sliding plate receiving member 231. The annular groove portion 231c is provided on the sliding surface 231b to create a space between the sliding plate 229 and the sliding plate receiving member 231, and when a lubricant such as grease is applied to the sliding surface 231b, the lubricant is held on the sliding surface 231b.

[0075] [Effects of this embodiment] Next, the effect of reducing sliding wear by the sliding plate receiving member 231 in this embodiment will be described in comparison with a comparative example.

[0076] Comparative examples are shown in Figures 18 and 19. Figure 18 is a cross-sectional view showing the pressure applying configuration of the belt drive gear and sliding plate of the comparative example. Figure 19(a) is a perspective view showing the rubbing portion of the belt drive gear of the comparative example, and Figure 19(b) is a front view showing the rubbing portion of the belt drive gear of the comparative example.

[0077] In this embodiment, a sliding plate receiving member 231 is disposed between the belt driving gear 44 and the sliding plate 229. In contrast, in the comparative example, as shown in Fig. 18, the sliding plate receiving member 231 is not disposed between the belt driving gear 44 and the sliding plate 229.

[0078] In this embodiment, a sliding plate receiving member 231 is disposed between the belt driving gear 44 and the sliding plate 229. Therefore, as the belt driving gear 44 rotates in the direction of the arrow θ2, the opposing surface 229b of the sliding plate 229 comes into surface contact with the sliding surface 231b of the sliding plate receiving member 231, and sliding wear occurs between them. The sliding area S1 in the configuration of this embodiment corresponds to the total area of ​​the sliding surface 231b in Fig. 17(b), and in this embodiment, the sliding area S1 = 190.4 [mm2].

[0079] On the other hand, in the comparative example, the sliding plate receiving member 231 is not disposed between the belt driving gear 44 and the sliding plate 229. Therefore, as the belt driving gear 44 rotates in the direction of the arrow θ2, the opposing surface 229b of the sliding plate 229 comes into contact with the end surface 44b of the engaging rib 44a of the belt driving gear 44, causing sliding wear between them.

[0080] Here, in order to improve the accuracy of the gear tooth surface during mass production molding of resin material, it is desirable to provide a rib shape such as an engagement rib 44a in the approximate center of the gear, i.e., a portion suitable for applying pressure in the rotation axis direction (arrow X1 direction), of the belt drive gear 44. Here, the end face 44b refers to the end face in the rotation axis direction (arrow X1 direction) of the above-mentioned engagement rib 44a.

[0081] The sliding area S2 in the comparative example that does not include the sliding plate receiving member 231 corresponds to the total area of ​​the end face 44b (the shaded area in the figure) in FIG. 19(b), and in the comparative example, the sliding area S2=16.2 mm2 ].

[0082] Here, the surface pressure in the direction of the arrow X1 that the opposing surface 229b of the sliding plate 229 receives is inversely proportional to the sliding areas S1 and S2, respectively.

[0083] That is, when comparing the surface pressure P1 in the configuration of this embodiment (FIG. 14) having the sliding plate receiving member 231 with the surface pressure P2 in the configuration of the comparative example (FIG. 18) not having the sliding plate receiving member 231, the following formula 1 is obtained from the above-mentioned sliding area S1 / S2 ratio (=190.4 / 16.2).

[0084] [Formula 1] S1 ≒ 11.7 × S2

[0085] Therefore, from the above formula 1, the surface pressure P1 in the configuration of this embodiment is given by the following formula 2.

[0086] [Formula 2] P1 ≒ P2 / 11.7

[0087] Generally, the amount of wear of a component on a sliding surface depends on the PV value, which is the product of the surface pressure P and the sliding velocity V on the sliding surface. Therefore, the configuration of this embodiment, which includes the sliding plate support member 231, is capable of reducing the amount of sliding wear compared to the configuration of the comparative example, which does not include the sliding plate support 231.

[0088] Therefore, according to this embodiment, regardless of the shape of the drive gear, it is possible to suppress wear of the sliding plate 229, the rotation of which is restricted when the drive gear rotates.

[0089] In the above-described embodiment, the photosensitive drum 2 and the drive roller 10 of the intermediate transfer unit 40 are exemplified as rotating bodies, but the present invention is not limited to these. For example, if the rotating body is a developing roller included in a developing device, which is detachably mounted on the main body of the device and is connected to a drive gear on the device side, the same effect can be expected by applying the present invention.

[0090] In the above-described embodiment, four image forming units are used, but the number of units used is not limited to this, and may be set appropriately as required.

[0091] In the above embodiment, a printer is used as an example of an image forming apparatus, but the present invention is not limited to this and may be applied to other image forming apparatuses such as a copier, a facsimile machine, or a multifunction machine that combines the functions of these. Similar effects can be obtained by applying the present invention to these image forming apparatuses. [Explanation of symbols]

[0092] 1y, 1m, 1c, 1k ... drum cartridge 2, 2y, 2m, 2c, 2k ... Photosensitive drum (rotating body) 8...Intermediate transfer belt 10 ... Drive roller (rotating body) 21, 21y, 21m, 21c, 21k ... Drum fitting members 22, 22y, 22m, 22c, 22k ... Drum drive gear (drive gear) 40...Intermediate transfer unit 44 ... Belt drive gear (drive gear) 44a ... Engagement rib 44b...End face 45...Shutter material 100 ... Image forming device 101 ... device body 211 ... Engaged portion (recess) 221 ... Fitting portion (convex portion) 224 ... Urging member 225 ... Bearing member (locking member) 225a …Rotation restriction rib 229 ... Sliding plate (sliding member) 229a ... Locking claw (locking part) 229b...Opposite surface 229d … Positioning hole 231 ... Sliding plate receiving member (receiving member) 231a...Engaging claw (engaging part) 231b…Sliding surface 231c … Groove (recess) 231d ... Positioning boss (positioning member) 231e ...butting surface

Claims

1. A device body, a rotating body that is detachably provided on the device body and is rotatable; a drive gear that is supported by the device body so as to be movable in a rotation axis direction of the rotor, has a coupling portion that is drivingly coupled to the rotor in the rotation axis direction of the rotor, and drives the rotor; a biasing member that biases the drive gear in a rotation axis direction toward the rotor; a sliding member provided between the drive gear and the biasing member in the rotational axis direction of the rotating body, the sliding member being biased by the biasing member toward the drive gear in the rotational axis direction; a locking member that is fixed to the device body and engages with the sliding member to restrict rotation of the sliding member when the drive gear is rotating; a receiving member that is provided between the drive gear and the sliding member in the direction of the rotation axis of the rotating body, has a sliding surface that is in contact with the sliding member and can slide on the sliding member, and engages with the drive gear and rotates together with the drive gear while maintaining contact between the sliding member and the sliding surface when the drive gear rotates.

2. 2. The image forming apparatus according to claim 1, wherein the sliding surface of the receiving member is a disk-shaped flat surface centered on the rotation center of the drive gear, faces the sliding member in the direction of the rotation axis of the rotating body, and is capable of sliding in contact with the sliding member.

3. 2. The image forming apparatus according to claim 1, wherein the receiving member has a positioning member provided at a rotation center of the receiving member and rotatably supported by the sliding member.

4. 2. The image forming apparatus according to claim 1, wherein the receiving member has an annular recess on the sliding surface between the sliding member and the receiving member, and the recess holds a lubricant on the sliding surface when the lubricant is applied to the sliding surface.

5. 2. The image forming apparatus according to claim 1, wherein the receiving member protrudes from the sliding surface toward the drive gear in the direction of the rotation axis of the rotating body, and has an engagement portion that engages with the drive gear when the drive gear rotates.

6. 2. The image forming apparatus according to claim 1, wherein the sliding member is a disk-shaped flat surface centered on the rotation center of the drive gear, and has an opposing surface facing the drive gear in the direction of the rotation axis of the rotating body.

7. 7. The image forming apparatus according to claim 6, wherein the sliding member protrudes from the opposing surface toward the locking member in the direction of the rotation axis of the rotating body, and has a locking portion that engages with the locking member when the drive gear is rotating.

8. 2. The image forming apparatus according to claim 1, wherein the engaging member is a bearing member that rotatably supports the drive gear.

9. the connecting portion is provided on one of the rotor and the drive gear, and has a convex portion protruding in the direction of the rotation axis, and a concave portion is provided on the other of the rotor and the drive gear, and has a concave portion in the direction of the rotation axis, into which the convex portion can be detachably fitted for connection; 2. The image forming apparatus according to claim 1, wherein the convex portion and the concave portion are shaped to be twisted in the same direction about the rotation axis of the rotating body so that a pulling force is generated between the convex portion and the concave portion when the driving gear rotates forward.

10. 10. The image forming apparatus according to claim 1, wherein the biasing member is a compression coil spring.

Images