Drum cartridge

Abstract

To reduce the size of a drum cartridge having a photoreceptor drum, a charging roller, and a cleaning roller, and stabilize the pressure applied in bringing the cleaning roller into contact with the charging roller.SOLUTION: A drum cartridge is removably attached to an image forming apparatus, and comprises a housing, a drum bearing, a photoreceptor drum, a charging roller, a charging roller bearing, a charging roller urging member, a cleaning roller bearing, and a cleaning roller urging member. The charging roller is regulated by the charging roller bearing in a circumferential direction, and is in contact with the photoreceptor drum and the charging roller bearing in a radial direction. The cleaning roller is regulated by the charging roller bearing in the circumferential direction, and is in contact with the charging roller and the charging roller bearing in the radial direction. In a rotation axis direction of the charging roller, the cleaning roller bearing is regulated by the cleaning roller and the charging roller bearing. In the circumferential direction of the charging roller, the cleaning roller bearing is regulated by the charging roller bearing.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a drum cartridge having a photosensitive drum, a charging roller, and a cleaning roller. [Background technology]

[0002] A drum cartridge is known in which a photosensitive drum, a charging roller that charges the surface of the photosensitive drum, and a cleaning roller that cleans the surface of the charging roller are all assembled within a frame to form a cartridge that can be detached from the main body of an image forming device (see Patent Document 1).

[0003] In this drum cartridge, a charging roller serving as a charging means made of a conductive material is brought into contact with the surface of the photosensitive drum, and the surface of the photosensitive drum is charged by applying a voltage between the photosensitive drum and the charging roller.

[0004] When the surface of the photosensitive drum is charged by the charging roller, if foreign matter adheres to the surface of the charging roller, the photosensitive drum will not be charged uniformly, which may result in poor images. Therefore, in this drum cartridge, a cleaning roller as a cleaning means comes into contact with the charging roller to clean the surface of the charging roller in order to remove foreign matter from the surface of the charging roller. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2022-84516 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the drum cartridge described in Patent Document 1, one end and the other end of the rotating shaft of the charging roller are held by the charging roller bearings, so that the charging roller is rotatably supported. Also, in the drum cartridge described in Patent Document 1, one end and the other end of the rotating shaft of the cleaning roller are held by the cleaning roller bearings, so that the cleaning roller is rotatably supported. Also, in the drum cartridge described in Patent Document 1, a pressure spring is provided as a biasing member between the charging roller bearing and the cleaning roller bearing. The cleaning roller is biased in the biasing direction by the pressure spring, so that the cleaning roller is pressurized and contacts the surface of the charging roller.

[0007] In order to uniformly clean the surface of the charging roller along the longitudinal direction of the charging roller, it is necessary to stabilize the pressure applied when the cleaning roller is brought into contact with the charging roller. On the other hand, if a mechanism for stabilizing the pressure applied when the cleaning roller is brought into contact with the charging roller is provided, the size of the components constituting the drum cartridge (e.g., the cleaning roller bearing) increases, and the size of the drum cartridge tends to increase.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide a drum cartridge that is capable of miniaturizing a drum cartridge having a photosensitive drum, a charging roller, and a cleaning roller, while stabilizing the pressure applied when the cleaning roller is brought into contact with the charging roller. [Means for solving the problem]

[0009] In order to achieve the above object, a drum cartridge according to one aspect of the present invention has the following configuration: That is, the drum cartridge is detachable from an image forming apparatus, and includes a housing, a drum bearing attached to the housing and fixed to the housing, a photosensitive drum supported by the drum bearing and rotatably mounted on the drum bearing, a charging roller that contacts the surface of the photosensitive drum and charges the photosensitive drum, a charging roller bearing attached to the housing and movably mounted in the radial direction of the photosensitive drum, a charging roller urging member that compresses the photosensitive drum in the radial direction, one side of which abuts against the housing and the other side of which abuts against the charging roller bearing, a cleaning roller that contacts the surface of the charging roller and cleans the charging roller, a cleaning roller bearing disposed on the charging roller bearing, and a charging roller urging member that urges the charging roller in the radial direction of the photosensitive drum, the charging roller urging member abuts against the housing and the charging roller bearing, the cleaning roller bearing disposed on the charging roller bearing, and the charging roller urging member abuts against the surface of the charging roller and cleans the charging roller. and a cleaning roller urging member which compresses the charging roller in a radial direction, one side of which abuts against the charging roller bearing and the other side of which abuts against the cleaning roller bearing, wherein the charging roller is restricted in a circumferential direction by the charging roller bearing and abuts against the photosensitive drum and the charging roller bearing in a radial direction, the cleaning roller is restricted in a circumferential direction by the charging roller bearing and abuts against the charging roller and the charging roller bearing in a radial direction, the cleaning roller bearing is restricted by the cleaning roller and the charging roller bearing in the direction of the rotation axis of the charging roller, and the cleaning roller bearing is restricted by the charging roller bearing in the circumferential direction of the charging roller.

[0010] In order to achieve the above object, a drum cartridge according to another aspect of the present invention has the following configuration: That is, the drum cartridge is detachable from an image forming apparatus, and includes a housing, a drum bearing attached to the housing and fixed to the housing, a photosensitive drum supported by the drum bearing and rotatably mounted on the drum bearing, a charging roller that contacts the surface of the photosensitive drum and charges the photosensitive drum, a charging roller bearing attached to the housing and movably mounted in the radial direction of the photosensitive drum, a charging roller urging member that compresses the photosensitive drum in the radial direction, one side of which abuts against the housing and the other side of which abuts against the charging roller bearing, a cleaning roller that contacts the surface of the charging roller and cleans the charging roller, and a charging roller urging member that urges the charging roller in the radial direction of the photosensitive drum, the charging roller urging member abutting against the housing and the charging roller bearing, a cleaning roller that contacts the surface of the charging roller and cleans the charging roller, and a cleaning roller that urges the charging roller against the charging roller. the cleaning roller bearing is disposed on a charge roller bearing, and a cleaning roller urging member that is compressed in the radial direction of the charge roller, one side of which abuts the charge roller bearing and the other side of which abuts the cleaning roller bearing, wherein the charge roller is restricted in the circumferential direction by the charge roller bearing and abuts the photosensitive drum and the charge roller bearing in the radial direction, the cleaning roller is restricted in the circumferential direction by the charge roller bearing and abuts the charge roller and the charge roller bearing in the radial direction, and the cleaning roller bearing is restricted by the housing and the charge roller bearing in the direction of the rotation axis of the cleaning roller. Effect of the Invention

[0011] According to the present invention, it is possible to reduce the size of a drum cartridge having a photosensitive drum, a charging roller, and a cleaning roller, while stabilizing the pressure applied when the cleaning roller is brought into contact with the charging roller. [Brief description of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing a configuration of an image forming apparatus according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view illustrating a configuration of the drum cartridge according to the first embodiment. [Diagram 3]1 is a cross-sectional view (exploded view) showing a configuration of a drum container and a drum bearing according to a first embodiment. [Figure 4] 1 is a cross-sectional view showing a configuration of a drum cartridge according to a first embodiment in a longitudinal direction. [Diagram 5] FIG. 2 is a perspective view showing the configurations of a charging roller bearing and a cleaning roller bearing according to the first embodiment. [Figure 6] FIG. 2 is a perspective view (exploded view) showing the configurations of a charging roller bearing and a cleaning roller bearing according to the first embodiment. [Figure 7] FIG. 11 is a cross-sectional view (exploded view) showing the configuration of a drum container and a drum bearing according to a second embodiment. [Figure 8] FIG. 11 is a cross-sectional view showing the configuration of a drum cartridge according to a second embodiment in the longitudinal direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the present invention, and not all of the combinations of features described in the first embodiment are necessarily essential to the solution of the present invention. The present invention can be implemented in various applications, such as printers, various printing machines, copiers, FAX machines, and multifunction machines.

[0014] [First embodiment] In the first embodiment, the direction of the rotation axis of the electrophotographic photosensitive drum is defined as the “longitudinal direction”. In addition, in the longitudinal direction, the side where the electrophotographic photosensitive drum receives a driving force from the main body of the image forming apparatus is defined as the “driving side”, and the opposite side is defined as the “non-driving side”.

[0015] (Configuration of Image Forming Apparatus) First, the overall configuration of an image forming apparatus and an image forming process according to the first embodiment will be described with reference to the cross-sectional view of FIG.

[0016] The image forming apparatus 1 is an intermediate transfer type color digital printer that includes four drum cartridges 7 (7a, 7b, 7c, 7d) that are detachably attached to the main body of the image forming apparatus 1 along an intermediate transfer belt 32.

[0017] The surfaces of the four photoconductor drums 2 (2a, 2b, 2c, 2d) are uniformly charged by the charging rollers 4 (4a, 4b, 4c, 4d).

[0018] If the charging roller 4 becomes contaminated by floating toner or the like, it will be unable to uniformly charge the photosensitive drum 2. For this reason, cleaning rollers 5 (5a, 5b, 5c, 5d) arranged opposite the charging rollers 4 (4a, 4b, 4c, 4d) clean the surfaces of the charging rollers 4 (4a, 4b, 4c, 4d) to reduce contamination.

[0019] Yellow, magenta, cyan, and black image signals are input to the laser scanner 8, and in response to these image signals, the surfaces of the photosensitive drums 2 (2a, 2b, 2c, 2d) are irradiated with laser light, neutralizing the electric charge and forming latent images.

[0020] The latent images formed on the photoconductor drums 2 (2a, 2b, 2c, 2d) are developed with yellow, magenta, cyan, and black toners by the developing devices 3 (3a, 3b, 3c, 3d), respectively.

[0021] The toner images developed on the photosensitive drums 2 (2a, 2b, 2c, 2d) are sequentially primarily transferred to the intermediate transfer belt 32 by primary transfer rollers 31 (31a, 31b, 31c, 31d), and a full-color toner image is formed on the surface of the intermediate transfer belt 32. Then, the residual toner on the photosensitive drums 2 (2a, 2b, 2c, 2d) is collected by drum cleaners 6 (6a, 6b, 6c, 6d) and transported to a collected toner container.

[0022] Meanwhile, a transferred member P such as paper fed from a paper feed unit is transported to a secondary transfer unit 33 in synchronization with the toner image on the intermediate transfer belt 32. The toner image on the intermediate transfer belt 32 is transferred to the transferred member P at the secondary transfer unit 33, and the transferred member P to which the toner image has been transferred is transported to a fixing unit 34. Thereafter, the transferred member P transported to the fixing unit 34 has the toner image fixed to the transferred member P by heat and pressure in the fixing unit 34, and is then discharged outside the image forming apparatus 1.

[0023] (Drum cartridge configuration) Next, the configuration of the drum cartridge 7 according to the first embodiment will be described with reference to FIGS.

[0024] FIG. 2 is a perspective view showing the configuration of the drum cartridge 7 according to the first embodiment.

[0025] The drum cartridge 7 includes a photosensitive drum 2 , a charging roller 4 , and a cleaning roller 5 .

[0026] The drum cartridge 7 is detachably disposed in the main body of the image forming apparatus 1, and is attached to both ends in the longitudinal direction of a drum container 21 serving as a housing.

[0027] Drum bearings 22 are disposed at one end and the other end of the photosensitive drum 2 in the longitudinal direction. The rotation shaft of the photosensitive drum 2 is held by the two drum bearings 22, thereby rotatably supporting the photosensitive drum 2. With the rotation shaft of the photosensitive drum 2 held by the two drum bearings 22, the photosensitive drum 2 is rotated by receiving a driving force from a driving unit disposed at the rear side of the main body of the image forming apparatus 1.

[0028] The charging roller 4 is disposed opposite the photosensitive drum 2, and is rotated by being pressed by the photosensitive drum 2. The charging roller 4 applies a uniform charge to the surface of the photosensitive drum 2 by applying a high voltage thereto.

[0029] Furthermore, charging roller bearings 51 are disposed at one end and the other end in the longitudinal direction of the charging roller 4. The rotation shaft of the charging roller 4 is held by the two charging roller bearings 51, so that the charging roller 4 is rotatably supported.

[0030] Furthermore, charging roller biasing members 53 are disposed at both ends in the longitudinal direction of the drum container 21. The charging roller biasing member 53 is attached to the charging roller bearing 51. The charging roller biasing member 53 presses the charging roller bearing 51, thereby pressing the charging roller 4 held by the charging roller bearing 51 against the photosensitive drum 2.

[0031] Both the charging roller bearing 51 and the charging roller biasing member 53 are made of a conductive material. Therefore, by electrically connecting the main body power supply unit and the charging roller biasing member 53, it becomes possible to apply a high voltage to the charging roller 4.

[0032] Furthermore, cleaning roller bearings 52 are disposed at one end and the other end in the longitudinal direction of the cleaning roller 5. The rotation shaft of the cleaning roller 5 is held by the two cleaning roller bearings 52, so that the cleaning roller 5 is rotatably supported.

[0033] Furthermore, cleaning roller biasing members 54 are disposed at both ends in the longitudinal direction of the drum container 21. The cleaning roller biasing member 54 is attached to the cleaning roller bearing 52. The cleaning roller biasing member 54 presses the cleaning roller bearing 52, thereby pressing the cleaning roller 5 held by the cleaning roller bearing 52 against the charging roller 4. In this way, the cleaning roller 5 rotates in response to the charging roller 4, and scrapes off toner and the like adhering to the charging roller 4, thereby reducing contamination of the surface of the charging roller 4.

[0034] Fig. 3 is a cross-sectional view (exploded view) showing the configuration of the drum container 21 and the drum bearing 22 according to the first embodiment. As shown in Fig. 3, the drum container 21 is made of a resin material, and a C-shaped hole 211 is provided at one end and the other end of the drum container 21 in the longitudinal direction. In addition, the drum container 21 is provided with a first guide portion 214 on the inner side in the longitudinal direction of the C-shaped hole 211, and a second guide portion 215 facing the first guide portion 214. A first contact surface 212 and a first convex portion 213 are provided between the first guide portion 214 and the second guide portion 215.

[0035] The drum bearing 22 has an outer diameter portion 221 and an inner diameter portion 222 .

[0036] Fig. 4 is a cross-sectional view showing the configuration of the drum cartridge 7 according to the first embodiment. As shown in Fig. 4, the photosensitive drum 2 is composed of a cylindrical portion 200 made of an aluminum material, and a driving side flange 201 and a non-driving side flange 202 provided on both ends of the photosensitive drum 2 in the longitudinal direction.

[0037] The charging roller 4 is composed of a rubber portion 401 made of a conductive material, and a first core portion 404. The first core portion 404 has two diameters, and is composed of a first large diameter portion 402 and a first small diameter portion 403 having a diameter smaller than that of the first large diameter portion 402.

[0038] The cleaning roller 5 is composed of a sponge portion 501 made of a sponge material such as urethane, and a second core metal portion 504. The second core metal portion 504 has two diameters, and is composed of a second large diameter portion 502 and a second small diameter portion 503 having a diameter smaller than that of the second large diameter portion 502.

[0039] The charging roller bearing 51 is made of a conductive resin material, and is provided at one end and the other end in the longitudinal direction on the driving side and non-driving side, respectively, of the drum container 21. A cleaning roller bearing 52 is disposed on the charging roller bearing 51.

[0040] Fig. 5(a) is a perspective view showing the configuration around the charging roller bearing 51, and Fig. 5(b) is a perspective view from behind of Fig. 5(a). Also, Fig. 6(a) is a perspective view (exploded view) showing the configuration around the charging roller bearing 51, and Fig. 6(b) is a perspective view (exploded view) from behind of Fig. 6(a).

[0041] 5 and 6, the charge roller bearing 51 is made up of a second contact surface 517, a second convex portion 518, a second side surface portion 508, a third side surface portion 509, and a fourth side surface portion 510. The charge roller bearing 51 is also made up of a first support portion 513 having an elongated hole shape, a first guide groove 511, a second guide groove 512, a third contact surface 519, and a third convex portion 520.

[0042] The second side surface portion 508 is located at a position facing the first side surface portion 507 in the longitudinal direction. The third side surface portion 509 is located in a direction in which the thickness of the charging roller bearing 51 is thinner than the first side surface portion 507. The fourth side surface portion 510 is located in a direction in which the thickness of the charging roller bearing 51 is thinner than the second side surface portion 508.

[0043] The cleaning roller bearing 52 is made of a resin material, and includes a fourth contact surface 523 , a fourth convex portion 524 , a third guide portion 525 , and a pressing portion 526 .

[0044] The charging roller biasing member 53 and the cleaning roller biasing member 54 are coil-shaped compression springs made of a material such as stainless steel wire or hard steel wire.

[0045] Next, a method for positioning the above-mentioned components constituting the drum cartridge 7 will be described.

[0046] As shown in FIG. 3, the drum bearings 22 are fixed to the drum container 21 by fitting the C-shaped hole 211 of the drum container 21 into the outer diameter portions 221 of the two drum bearings 22 .

[0047] A driving side flange 201 and a non-driving side flange 202 of the photosensitive drum 2 are supported by the inner diameter portion 222 of the drum bearing 22, respectively, so that the photosensitive drum 2 is rotatably supported by the drum bearing 22.

[0048] 5 and 6, the first guide portion 214 provided on the drum container 21 engages with the first guide groove 511 of the charging roller bearing 51. Also, the second guide portion 215 of the drum container 21 engages with the second guide groove 512 of the charging roller bearing 51. As a result, the position of the charging roller bearing 51 in the longitudinal direction and circumferential direction is restricted, and the charging roller bearing 51 is movable in the radial direction of the photosensitive drum 2.

[0049] 5 and 6, the first convex portion 213 provided on the drum container 21 fits into the inner diameter of the charge roller urging member 53, and the second convex portion 518 of the charge roller bearing 51 fits into the inner diameter of the charge roller urging member 53. As a result, the charge roller urging member 53 is restricted in the longitudinal and radial directions, and is compressed by the first contact surface 212 of the drum container 21 and the second contact surface 517 of the charge roller bearing 51, so that the charge roller urging member 53 can press the charge roller bearing 51 toward the photosensitive drum 2.

[0050] When the first small diameter portion 403 of the charging roller 4 and the first support portion 513 of the charging roller bearing 51 engage with each other, one end and the other end of the charging roller 4 in the longitudinal direction are supported and pressed against the photosensitive drum 2 so as to be rotatable.

[0051] In addition, the first large diameter portion 402 of the charging roller 4 is regulated by a first side portion 507 of the non-driving side charging roller bearing 51 arranged at both ends of the drum container 21 and a second side portion 508 of the driving side charging roller bearing 51, and thus the longitudinal position of the charging roller 4 is regulated.

[0052] In addition, by engaging the second support portion 514 of the charging roller bearing 51 arranged on the drive side and non-drive side of the drum container 21 with the second small diameter portion 503 of the cleaning roller 5, the circumferential position of the cleaning roller 5 is restricted but the cleaning roller 5 is movable in the radial direction.

[0053] Further, the second large diameter portion 502 of the cleaning roller 5 is regulated by a first side surface portion 507 of the non-driving side charging roller bearing 51 arranged at both ends in the longitudinal direction of the drum container 21 and a second side surface portion 508 of the driving side charging roller bearing 51. This regulates the position of the cleaning roller 5 in the longitudinal direction.

[0054] Furthermore, the cleaning roller biasing member 54 is regulated in the longitudinal and radial directions by fitting the third convex portion 520 provided on the charging roller bearing 51 into the inner diameter of the cleaning roller biasing member 54 and fitting the inner diameter into the fourth convex portion 524 of the cleaning roller bearing 52.

[0055] At this time, a gap may be provided between the inner diameter of the cleaning roller biasing member 54 and the third convex portion 520, and between the inner diameter of the cleaning roller biasing member 54 and the outer diameter of the fourth convex portion 524. On the other hand, by making the outer dimensions of the third convex portion 520 and the fourth convex portion 524 larger than the inner diameter of the cleaning roller biasing member 54, it is possible to make it difficult for the cleaning roller bearing 52 to fall off during assembly.

[0056] Furthermore, the cleaning roller biasing member 54 is compressed by the third contact surface 519 of the charging roller bearing 51 and the fourth contact surface 523 of the cleaning roller bearing 52, thereby pressing the cleaning roller 5 against the charging roller 4 via the cleaning roller bearing 52. Two guide grooves of the cleaning roller bearing 52 engage with two guide portions of the charging roller bearing 51, respectively. As a result, the position of the cleaning roller bearing 52 in the longitudinal direction and circumferential direction is restricted, and it is movable in the radial direction.

[0057] Furthermore, the third guide portion 525 of the cleaning roller bearing 52 is disposed between the third side surface portion 509 of the charging roller bearing 51 arranged on the non-driving side and the second large diameter portion 502 of the cleaning roller 5. Also, the third guide portion 525 of the cleaning roller bearing 52 is disposed between the fourth side surface portion 510 of the charging roller bearing 51 arranged on the driving side and the second large diameter portion 502 of the cleaning roller 5. This restricts the position of the cleaning roller bearing 52 in the longitudinal direction.

[0058] The charging roller 4 and the cleaning roller 5 may move to the driving side or non-driving side during rotation due to a thrust force generated by the parallelism between the rotation shaft of the photosensitive drum 2 and the rotation shaft of the charging roller 4 and the rotation shaft of the cleaning roller 5.

[0059] For this reason, one of the two third guide portions 525 arranged in the longitudinal direction is arranged closer to the third side surface portion 509 than the first side surface portion 507. In addition, the other of the two third guide portions 525 arranged in the longitudinal direction is arranged closer to the third side surface portion 509 than the fourth side surface portion 510.

[0060] By arranging the third guide portion 525 in this manner, the thrust force of the cleaning roller 5 is not received by the third guide portion 525. As a result, the size of the cleaning roller bearing 52 can be reduced.

[0061] According to the first embodiment described above, it is possible to reduce the size of the drum cartridge 7 having the photosensitive drum 2, charging roller 4, and cleaning roller 5, while stabilizing the pressure applied when the cleaning roller 5 is brought into contact with the charging roller.

[0062] [Second embodiment] The basic configuration of the drum cartridge of the second embodiment is the same as that of the drum cartridge 7 of the first embodiment. Therefore, in the cartridge of the second embodiment, elements having the same or corresponding functions or configurations as those of the drum cartridge 7 of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and detailed explanations thereof will be omitted.

[0063] In the second embodiment, the configuration of the drum container is different from that of the first embodiment. The configuration of the drum container and the drum bearing according to the second embodiment will be described with reference to the cross-sectional view (exploded view) of FIG. 7. Note that in the second embodiment, different reference numerals are used for the drum container compared to the first embodiment (see FIG. 7). Also, the longitudinal configuration of the drum cartridge according to the second embodiment will be described with reference to the cross-sectional view of FIG. 8.

[0064] 7, the drum container 210 is made of a resin material, and has a C-shaped hole 211 at each of both ends in the longitudinal direction. The drum container 210 is also provided with a first guide portion 214 on the inner side in the longitudinal direction of the C-shaped hole 211, and a second guide portion 215 arranged to face the first guide portion 214. A first contact surface 212 and a first convex portion 213 are provided between the first guide portion 214 and the second guide portion 215, and a sixth guide portion 208 is provided between the first contact surface 212 and the C-shaped hole 211.

[0065] The drum bearing 22 has an outer diameter portion 221 and an inner diameter portion 222 .

[0066] As shown in FIG. 8, the photosensitive drum 2 is composed of a cylindrical portion 200 made of an aluminum material, a driving side flange 201 and a non-driving side flange 202 on both ends.

[0067] The charging roller 4 is composed of a rubber portion 401 made of a conductive material, and a first core portion 404. The first core portion 404 has two diameters, and is composed of a first large diameter portion 402 and a first small diameter portion 403 having a diameter smaller than that of the first large diameter portion 402.

[0068] The cleaning roller 5 is made up of a sponge portion 501 made of a sponge material such as urethane, and a second core metal portion 504. The second core metal portion 504 has a second large diameter portion 502 and a second small diameter portion 503 having a diameter smaller than that of the second large diameter portion 502.

[0069] The charging roller bearings 51 are made of a resin material, and are provided at both ends in the longitudinal direction of the driving side and the non-driving side of the drum container 21. On the charging roller bearing 51, a cleaning roller bearing 52 is arranged.

[0070] In addition, the longitudinal direction of the charging roller 4 is regulated by the first large diameter portion 402 of the charging roller 4, which is arranged on the non-driving side at both ends of the drum container 2, and the second side portion 508 of the charging roller bearing 51 arranged on the driving side.

[0071] Furthermore, the second large diameter portions 502 of the cleaning roller 5 are disposed on both ends of the drum container 21. The longitudinal position of the cleaning roller 5 is regulated by a first side surface portion 507 of the charging roller bearing 51 disposed on the non-driving side and a second side surface portion 508 of the charging roller bearing 51 disposed on the driving side.

[0072] At this time, the third guide portion 525 of the cleaning roller bearing 52 is disposed between the fourth side surface portion 510 of the charging roller bearing 51 disposed on the non-driving side, the third side surface portion 509 of the charging roller bearing 51 disposed on the driving side, and the sixth guide portion 208 of the drum container 21. This restricts the position of the cleaning roller bearing 52 in the longitudinal direction.

[0073] Further, the convex portion of the charging roller bearing 51 is inserted into the inner diameter portion of the cleaning roller urging member 54 , and the convex portion of the cleaning roller bearing 52 is inserted into the inner diameter portion of the cleaning roller urging member 54 .

[0074] (Other embodiments) The present invention is not limited to the above-described embodiments, and various modifications (including organic combinations of the respective embodiments) are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0075] In the above embodiment, as shown in FIG. 1, the image forming apparatus 1 performs primary transfer of the toner images carried on each of the photosensitive drums 2 (2a, 2b, 2c, 2d) onto the intermediate transfer belt 32. Thereafter, the image forming apparatus 1 brings the intermediate transfer belt 32 into contact with the transferred member P to perform secondary transfer of the toner images carried on the intermediate transfer belt 32 onto the transferred member P. In the above embodiment, the image forming apparatus 1 configured as described above has been described as an example, but is not limited to this. It is also possible to apply the present invention to an image forming apparatus configured to directly transfer the toner images carried on each of the photosensitive drums 2 (2a, 2b, 2c, 2d) onto the transferred member P by directly bringing the photosensitive drums 2 (2a, 2b, 2c, 2d) into contact with the transferred member P. [Explanation of symbols]

[0076] 2 Photoconductor drum 4. Charging roller 5 Cleaning roller 7 Drum Cartridge 21 Drum container 22 Drum bearing 51 Charge roller bearing 52 Cleaning roller bearing 53 Charging roller biasing member 54 Cleaning roller biasing member

Claims

1. A drum cartridge that is detachable from an image forming apparatus, A housing and a drum bearing attached to the housing and fixed to the housing; a photosensitive drum supported by the drum bearing and rotatably mounted on the drum bearing; a charging roller that contacts the surface of the photosensitive drum and charges the photosensitive drum; a charging roller bearing attached to the housing and movable in a radial direction of the photosensitive drum; a charging roller biasing member that compresses the photosensitive drum in a radial direction, one end of which is in contact with the housing and the other end of which is in contact with the charging roller bearing; a cleaning roller that contacts the surface of the charging roller and cleans the charging roller; a cleaning roller bearing disposed on the charging roller bearing; a cleaning roller biasing member that compresses the charging roller in a radial direction, one end of which is in contact with the charging roller bearing and the other end of which is in contact with the cleaning roller bearing; Equipped with the charging roller is circumferentially restricted by the charging roller bearing and is in contact with the photosensitive drum and the charging roller bearing in the radial direction, the cleaning roller is circumferentially restricted by the charging roller bearing and is in contact with the charging roller and the charging roller bearing in the radial direction; the cleaning roller bearing is regulated by the cleaning roller and the charging roller bearing in the direction of the rotation axis of the charging roller, The cleaning roller bearing is regulated by the charging roller bearing in the circumferential direction of the charging roller. A drum cartridge comprising:

2. the charge roller bearing has a first side surface portion disposed at one end in a rotational axis direction of the charge roller and a second side surface portion disposed at the other end in the rotational axis direction of the charge roller, The cleaning roller is restricted in a rotational axial direction by the first side surface portion and the second side surface portion.

2. The drum cartridge according to claim 1,

3. A drum cartridge that is detachable from an image forming apparatus, A housing and a drum bearing attached to the housing and fixed to the housing; a photosensitive drum supported by the drum bearing and rotatably mounted on the drum bearing; a charging roller that contacts the surface of the photosensitive drum and charges the photosensitive drum; a charging roller bearing attached to the housing and movable in a radial direction of the photosensitive drum; a charging roller biasing member that compresses the photosensitive drum in a radial direction, one end of which is in contact with the housing and the other end of which is in contact with the charging roller bearing; a cleaning roller that contacts the surface of the charging roller and cleans the charging roller; a cleaning roller bearing disposed on the charging roller bearing; a cleaning roller biasing member that compresses the charging roller in a radial direction, one end of which is in contact with the charging roller bearing and the other end of which is in contact with the cleaning roller bearing; Equipped with the charging roller is circumferentially restricted by the charging roller bearing and is in contact with the photosensitive drum and the charging roller bearing in the radial direction, the cleaning roller is circumferentially restricted by the charging roller bearing and is in contact with the charging roller and the charging roller bearing in the radial direction; The cleaning roller bearing is regulated by the housing and the charging roller bearing in the direction of the rotation axis of the cleaning roller. A drum cartridge comprising:

4. the charge roller bearing has a first side surface portion disposed at one end in a rotational axis direction of the charge roller and a second side surface portion disposed at the other end in the rotational axis direction of the charge roller, The cleaning roller is restricted in a rotational axial direction by the first side surface portion and the second side surface portion.

4. The drum cartridge according to claim 3.

Images