drum cartridge

Abstract

To stably ground a photoreceptor drum even if the photoreceptor drum is miniaturized in a radial direction.SOLUTION: A drum cartridge comprises a photoreceptor drum 51, a drum flange 160 capable of rotating together with the photoreceptor drum, a drum earth shaft 150 for grounding the photoreceptor drum, and a drum earth plate 170. The drum earth plate 170 includes an electric contact 171, a spiral spring portion 172, a ring portion 173, a first pawl 174, and a second pawl 175. The electric contact 171 elastically contacts one end 151 of the drum earth shaft 150 and extends about the electric contact 171 from the electric contact 171 in a spiral shape. The ring portion 173 is fixed on an inner peripheral surface of the drum flange 160. The first pawl 174 protrudes outward in a radial direction from the ring portion 173 and contacts the inner peripheral surface of the photoreceptor drum 51. The second pawl 175 protrudes outward in the radial direction from the ring portion 173 and fixes the drum earth plate 170 to the drum flange 160.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a drum cartridge including a photosensitive drum. [Background technology]

[0002] A drum cartridge equipped with a photosensitive drum is known (see Patent Document 1). In this drum cartridge, a drum ground plate is disposed inside the photosensitive drum to ground the photosensitive drum. The drum ground plate is electrically connected to the shaft of the photosensitive drum. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-173346 Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable to reduce the size of the photosensitive drum in the radial direction, but reducing the size of the photosensitive drum in the radial direction poses a problem in that it becomes difficult to achieve stable contact between the drum ground plate and the photosensitive drum.

[0005] Therefore, an object of the present disclosure is to stably ground the photosensitive drum even when the photosensitive drum is made smaller in size in the radial direction. [Means for solving the problem]

[0006] The drum cartridge for solving the above problem includes a photosensitive drum, a drum flange, a drum ground shaft, and a drum ground plate. The photosensitive drum is rotatable about an axis extending in the axial direction. The drum flange is located on one end side of the photosensitive drum in the axial direction. The drum flange is rotatable together with the photosensitive drum. The drum earth shaft grounds the photosensitive drum. The drum earth plate electrically connects the photosensitive drum and the drum earth shaft. The drum earth plate is located inside the photosensitive drum. The drum earth plate has an electrical contact, a spiral spring portion, a ring portion, a first claw, and a second claw. The electrical contact elastically contacts one end of the drum earth shaft. The spiral spring portion extends spirally from the electrical contact, with the electrical contact as its center. The ring portion is located radially outward from the spiral spring portion. The ring portion is fixed to the inner peripheral surface of the drum flange. The first claw protrudes radially outward from the ring portion. The first claw contacts the inner peripheral surface of the photosensitive drum. The second claw protrudes radially outward from the ring portion. The second claw contacts the inner peripheral surface of the drum flange, thereby fixing the drum earth plate to the drum flange.

[0007] With this configuration, the second claw of the drum ground plate protrudes radially outward from the ring portion, ensuring the length of the spiral spring portion and allowing the electrical contact of the drum ground plate and the drum ground shaft to contact with appropriate elastic force even when the photosensitive drum is made smaller in the radial direction, thereby enabling the photosensitive drum to be stably grounded even when the photosensitive drum is made smaller in the radial direction.

[0008] In the above-described configuration, a plurality of first claws may be provided, a plurality of second claws may be provided, and the first claws and the second claws may be positioned alternately in the circumferential direction.

[0009] In the above-described configuration, the tip of the first claw may be positioned farther from the electrical contact than the tip of the second claw.

[0010] In the above-described configuration, the drum earth plate may further include a third claw that protrudes radially outward from the ring portion and fits into the inner periphery of the drum flange.

[0011] According to this configuration, when assembling the drum cartridge, the drum flange is attached to the photosensitive drum with the third claw fitted into the inner periphery of the drum flange, making it easy to assemble the drum cartridge.

[0012] In the above-described configuration, the tip of the third claw may be positioned closer to one end of the photosensitive drum in the axial direction than the tip of the second claw.

[0013] With this configuration, when assembling the drum earth plate to the drum flange, the third claw enters the inner surface of the drum flange before the second claw, so that the drum earth plate can be positioned by the third claw while being fixed to the drum flange by the second claw.

[0014] In the above-described configuration, the drum earth plate may be configured to have an elongated hole located between the base end of the spiral spring portion that is farthest from the electrical contact and the first claw that is closest to the base end, and which extends in the circumferential direction of the drum earth plate.

[0015] According to this configuration, the stress generated by the elastic deformation of the spiral spring portion is divided by the elongated hole, so that even if the base end portion of the spiral spring portion is deformed, the first claw can be prevented from being deformed.

[0016] The above-described configuration may further include a drum bearing that rotatably supports the drum flange, the drum bearing having the drum earth shaft fixed thereto.

[0017] In the above-mentioned configuration, the drum bearing may be configured to cover the other end of the drum earth shaft.

[0018] With this configuration, the other end of the drum earth shaft can be prevented from coming into contact with other members.

[0019] In the above-described configuration, the other end of the drum earth shaft may be embedded in the drum bearing.

[0020] The above-described configuration may further include a leaf spring that grounds the drum ground shaft, the leaf spring having one end that contacts the outer peripheral surface of the drum ground shaft and the other end that is exposed to the outer surface of the drum cartridge. [Effects of the Invention]

[0021] According to the present disclosure, the photosensitive drum can be stably grounded even when the photosensitive drum is made smaller in size in the radial direction. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a diagram showing a schematic configuration of a color printer equipped with a drum cartridge according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a perspective view of the drum cartridge. [Figure 3] FIG. 2 is a view of the drum cartridge as seen from the axial direction. [Figure 4] FIG. [Figure 5] FIG. 2 is an exploded perspective view showing the structure of one end of the photosensitive drum as viewed from the other end. [Figure 6] FIG. 2 is an exploded perspective view showing the structure of one end of the photosensitive drum, as viewed from the one end side. [Figure 7] 1A is a perspective view of the drum earth plate as seen from the other end side in the axial direction, and FIG. 1B is a perspective view as seen from one side. [Figure 8] FIG. 4 is a cross-sectional view illustrating an electrical connection from the photosensitive drum to the leaf spring. [Figure 9] 3 is a cross-sectional view illustrating the positional relationship between a photosensitive drum, a drum flange, and a drum ground plate. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] Next, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. 1, the image forming apparatus 1 is a color printer. The image forming apparatus 1 includes a main body 10, a top cover 11, a paper feed unit 20, and an image forming unit 30.

[0024] The top cover 11 is a cover that opens and closes an opening 10A formed in the top of the device body 10. The top cover 11 is disposed on the top of the device body 10. The top cover 11 is provided on the device body 10 so as to be rotatable around a rotation shaft 11A. The top surface of the top cover 11 serves as a paper discharge tray 11B on which the discharged paper P is placed.

[0025] The paper feed unit 20 is provided at the bottom of the device main body 10, and includes a paper feed tray 21 that stores paper P, and a paper feed mechanism 22 that supplies paper P from the paper feed tray 21 to the image forming unit 30. The paper P in the paper feed tray 21 is separated one sheet at a time by the paper feed mechanism 22 and supplied to the image forming unit 30.

[0026] The image forming section 30 includes four exposure heads 40, four drum cartridges 50, a transfer unit 70, and a fixing unit 80.

[0027] The exposure head 40 has a plurality of LEDs. The exposure head 40 is held by the top cover 11 so as to be suspended from the top cover 11. The exposure head 40 exposes the surface of the photosensitive drum 51 by lighting up the plurality of LEDs based on image data.

[0028] Each drum cartridge 50 is disposed between the top cover 11 and the paper feed tray 21. When the top cover 11 is open, each drum cartridge 50 can be attached and detached through an opening 10A of the device main body 10. A developing cartridge 60 can be attached and detached to each drum cartridge 50. The drum cartridge 50 is attached to the device main body 10 with the developing cartridge 60 attached.

[0029] The drum cartridge 50 includes a photosensitive drum 51, a charger 52, a pressure spring 53, a cleaning roller 54, and a drum frame 55. The photosensitive drum 51 is rotatable about an axis X1 extending in the axial direction. In the following description, the axial direction of the photosensitive drum 51 will be simply referred to as the "axial direction." The charger 52 charges the photosensitive drum 51. The pressure spring 53 biases the developer cartridge 60 toward the photosensitive drum 51. The drum frame 55 rotatably supports the photosensitive drum 51 and the cleaning roller 54.

[0030] The cleaning roller 54 is a roller that removes foreign matter such as toner remaining on the photosensitive drum 51. The cleaning roller 54 is in contact with the photosensitive drum 51 and is rotatable.

[0031] The developing cartridge 60 includes a developing housing 61 and a developing roller 62. The developing housing 61 contains toner. The developing roller 62 supplies the toner in the developing housing 61 to the photosensitive drum 51. The developing roller 62 is rotatable while being biased toward the photosensitive drum 51 by a pressure spring 53.

[0032] The transfer unit 70 is located between the paper feed tray 21 and the drum cartridge 50. The transfer unit 70 includes a drive roller 71, a driven roller 72, an endless conveyor belt 73, and four transfer rollers 74. The drive roller 71 and the driven roller 72 support the conveyor belt 73.

[0033] The conveyor belt 73 is a belt that conveys the paper P. The outer surface of the conveyor belt 73 is in contact with each photosensitive drum 51. The conveyor belt 73 is sandwiched between each transfer roller 74 and each photosensitive drum 51.

[0034] The fixing unit 80 includes a heating roller 81 and a pressure roller 82. The pressure roller 82 is pressed against the heating roller 81.

[0035] In the image forming unit 30, first, the charger 52 charges the surface of the photosensitive drum 51. Then, the exposure head 40 exposes the surface of the photosensitive drum 51 to light. As a result, an electrostatic latent image is formed on the photosensitive drum 51.

[0036] Next, the developing roller 62 supplies toner to the electrostatic latent image on the photosensitive drum 51. As a result, a toner image is formed on the photosensitive drum 51.

[0037] When the paper P passes between the conveyor belt 73 and the photosensitive drum 51, the toner image on the photosensitive drum 51 is transferred onto the paper P. The toner image on the paper P is then fixed by the fixing unit 80. Next, the paper P is discharged onto the paper discharge tray 11B by the discharge rollers 91.

[0038] Next, a configuration for grounding the photosensitive drum 51 will be described in detail with reference to FIGS.

[0039] 2, the drum cartridge 50 has a drum bearing 130 and a leaf spring 140. The drum bearing 130 and the leaf spring 140 are located on one end side of the drum cartridge 50 in the axial direction.

[0040] The drum bearing 130 is a member that rotatably supports the photosensitive drum 51. Specifically, the drum bearing 130 rotatably supports a drum flange 160 (described later). As shown in FIGS. 3 and 4 , the drum bearing 130 has a support portion 131, a hole 132, and a protrusion 133.

[0041] The support portion 131 is a cylindrical portion that extends in the circumferential direction around the axis X1. The outer surface of the support portion 131 is a circumferential surface that extends in the circumferential direction of the axis X1. The hole 132 is a hole that penetrates in the axial direction. The inner circumferential surface of the support portion 131 rotatably supports the drum flange 160.

[0042] The protrusion 133 protrudes in a direction away from the axis X1 from the support portion 131. After protruding from the support portion 131 in a direction away from the axis X1, the protrusion 133 extends toward one end in the axial direction. As shown in Fig. 3, the protrusion 133 is a portion that receives a load from the device body 10 of the image forming device 1 when the drum cartridge 50 is installed in the image forming device 1. The device body 10 is provided with a pressing member PU (shown by a two-dot chain line in Fig. 3) that presses the drum cartridge 50 when the drum cartridge 50 is installed. The pressing member PU presses the protrusion 133 with a biasing member such as a spring.

[0043] The leaf spring 140 is a member for grounding the photosensitive drum 51. The leaf spring 140 is made of a material having spring properties and conductivity, such as metal. The leaf spring 140 contacts the drum ground shaft 150 (described later). In this way, the leaf spring 140 grounds the drum ground shaft 150. The leaf spring 140 has one end 141, the other end 142, and a connecting portion 143.

[0044] 8, the one end 141 comes into contact with the circumferential surface of the drum earth shaft 150. This electrically connects the one end 141 to the drum earth shaft 150. The portion of the one end 141 that comes into contact with the drum earth shaft 150 is located closer to the other end in the axial direction than the drum bearing 130.

[0045] The other end 142 of the leaf spring 140 is located on a part of the outer surface of the drum bearing 130. As shown in FIG. 4, the other end 142 is exposed to the outer surface of the drum cartridge 50. The other end 142 extends in the axial direction. As shown in FIG. 3, when the drum cartridge 50 is installed in the image forming apparatus 1, the other end 142 comes into contact with the ground contact EC of the image forming apparatus 1. The other end 142 is located on the opposite side of the axis X1 from the protrusion 133 of the drum bearing 130.

[0046] 5 and 6, the connecting portion 143 connects the one end portion 141 and the other end portion 142. The connecting portion 143 extends in the radial direction.

[0047] In addition to the components such as the drum bearing 130 described above, the drum cartridge 50 further includes a drum ground shaft 150, a drum flange 160, and a drum ground plate 170. The drum ground shaft 150, the drum flange 160, and the drum ground plate 170 are located on one end side of the photosensitive drum 51 in the axial direction.

[0048] 5, the drum ground shaft 150 is located at the rotation center of the photosensitive drum 51. The drum ground shaft 150 is a member for grounding the photosensitive drum 51. The drum ground shaft 150 is made of a conductive material, such as a metal.

[0049] One end 151 of the drum earth shaft 150 is exposed from the drum bearing 130, and the other end 152 of the drum earth shaft 150 is embedded and fixed in the drum bearing 130. In other words, the drum bearing 130 covers the other end 152 of the drum earth shaft 150.

[0050] The drum flange 160 is a member that rotates together with the photosensitive drum 51. The drum flange 160 has a shaft portion 161, a flange portion 162, a fitting portion 163, a notch portion 164, and a through hole 165.

[0051] The shaft portion 161 is a cylindrical portion. The shaft portion 161 is rotatably supported by the support portion 131 of the drum bearing 130. A through hole 165 is provided in the shaft portion 161. The through hole 165 extends in the axial direction. The through hole 165 is a hole through which the drum earth shaft 150 passes.

[0052] The flange portion 162 extends from the outer peripheral surface of the fitting portion 163 radially outward beyond the fitting portion 163. The flange portion 162 contacts one end of the photosensitive drum 51 (see FIG. 8).

[0053] The fitting portion 163 is a substantially cylindrical portion that fits into the inner circumferential surface of one end of the photosensitive drum 51. The fitting portion 163 extends from the flange portion 162 toward the other end in the axial direction. The drum flange 160 is able to rotate integrally with the photosensitive drum 51 by fitting the fitting portion 163 into one end of the photosensitive drum 51. A drum earth plate 170 is adapted to fit into the inner circumferential surface of the fitting portion 163.

[0054] The four notches 164 are formed in the fitting portion 163. The notches 164 extend from the other end of the fitting portion 163 in the axial direction to one end.

[0055] The drum ground plate 170 is located inside the photosensitive drum 51. The drum ground plate 170 is a disk-shaped member. The drum ground plate 170 is made of a material having spring properties and conductivity, such as metal. The drum ground plate 170 electrically connects the photosensitive drum 51 and the drum ground shaft 150. As shown in FIGS. 7(a) and (b), the drum ground plate 170 has an electrical contact 171, a spiral spring portion 172, a ring portion 173, a first claw 174, a second claw 175, a third claw 176, and an elongated hole 177.

[0056] The electrical contact 171 elastically contacts one end 151 of the drum earth shaft 150. Specifically, the electrical contact 171 is connected to the ring portion 173 via the elastically deformable spiral spring portion 172, and therefore, the electrical contact 171 is always in contact with the one end 151 of the drum earth shaft 150 due to the elastic force of the spiral spring portion 172.

[0057] The spiral spring portion 172 extends in a spiral shape from the electrical contact 171, with the electrical contact 171 as the center. The spiral spring portion 172 is elastically deformable in the axial direction.

[0058] The ring portion 173 is a portion located radially outward of the spiral spring portion 172. The ring portion 173 is fixed to the inner circumferential surface of the drum flange 160 by a second claw 175.

[0059] The first claws 174 protrude radially outward from the ring portion 173. The first claws 174 fit into the cutout portions 164 of the drum flange 160. The first claws 174 come into contact with the inner circumferential surface of the photosensitive drum 51. The tip of the first claws 174 is located farther from the electrical contact 171 than the tip of the second claws 175. The first claws 174 come into contact with the inner circumferential surface of the photosensitive drum 51, thereby electrically connecting the drum earth plate 170 and the inner circumferential surface of the photosensitive drum 51. A plurality of first claws 174 are provided. In this embodiment, four first claws 174 are provided.

[0060] The second claws 175 protrude radially outward from the ring portion 173. A plurality of second claws 175 are provided. In this embodiment, four second claws 175 are provided. The tips of the second claws 175 are slightly bent toward the other end in the axial direction (see also FIG. 8). The second claws 175 are members that fix the drum earth plate 170 to the drum flange 160 by coming into contact with the inner circumferential surface of the drum flange 160.

[0061] The third claws 176 protrude radially outward from the ring portion 173. Multiple third claws 176 are provided. In this embodiment, four third claws 176 are provided. The tips of the third claws 176 are not bent toward one end or the other end in the axial direction. That is, the tips of the third claws 176 are located closer to one end of the photosensitive drum 51 in the axial direction than the tips of the second claws 175. The tips of the third claws 176 fit into the inner periphery of the drum flange 160. The third claws 176 are members for positioning the drum earth plate 170 on the drum flange 160 by fitting into the inner periphery of the drum flange 160.

[0062] There are four each of the first claws 174, second claws 175, and third claws 176. The first claws 174, second claws 175, and third claws 176 in one set are arranged in the order of first claw 174, second claw 175, and third claw 176. The first claws 174 and second claws 175 are positioned alternately in the circumferential direction. The second claw 175 is positioned between the first claw 174 and the third claw 176.

[0063] The elongated hole 177 is located between the base end 172A of the spiral spring portion 172, which is the farthest from the electrical contact 171, and the first claw 174, which is the closest to the base end 172A. The elongated hole 177 extends in the circumferential direction of the drum earth plate 170.

[0064] 8, the first claw 174 of the drum ground plate 170 comes into contact with the inner circumferential surface of the photosensitive drum 51, electrically connecting the drum ground plate 170 and the photosensitive drum 51. The electrical contact 171 of the drum ground plate 170 and one end 151 of the drum ground shaft 150 then come into elastic contact, electrically connecting the drum ground plate 170 and the drum ground shaft 150. The one end 141 of the leaf spring 140 comes into contact with the outer circumferential surface of the drum ground shaft 150, electrically connecting the leaf spring 140 and the drum ground shaft 150. In this way, the inner circumferential surface of the photosensitive drum 51 is electrically connected to the leaf spring 140 via the drum ground plate 170 and the drum ground shaft 150.

[0065] Here, the procedure for assembling the drum flange 160 and the drum earth plate 170 to the photosensitive drum 51 will be described with reference to FIGS. In this case, to assemble the drum ground plate 170 to the drum flange 160, the drum ground plate 170 is first inserted into the inside of the fitting portion 163 of the drum flange 160. At this time, while the first claw 174 is inserted into the notch 164, the multiple second claws 175 and multiple third claws 176 are inserted into the inner circumferential surface of the fitting portion 163. Because the tip of the third claw 176 is located closer to one end in the axial direction than the tip of the second claw 175, the third claw 176 enters the inner circumferential surface of the drum flange 160 before the second claw 175. Therefore, the third claw 176 positions the drum ground plate 170, and the second claw 175 enters the inside of the drum flange 160 while bending, and is fixed to the drum flange 160. Note that when the drum ground plate 170 is fixed to the drum flange 160, the multiple third claws 176 may or may not be in contact with the inner circumferential surface of the drum flange 160. Thereafter, with the drum earth plate 170 attached to the drum flange 160, the drum flange 160 is attached to the photosensitive drum 51. Then, the first claw 174 of the drum earth plate 170 bends and enters the inside of the photosensitive drum 51, and comes into contact with the inner circumferential surface of the photosensitive drum 51.

[0066] As described above, the following effects can be obtained in this embodiment. The drum cartridge 50 described above grounds the photosensitive drum 51 via the drum ground shaft 150 and the drum ground plate 170. The electrical contact 171 of the drum ground plate 170 elastically contacts one end 151 of the drum ground shaft 150 due to the elastic force of the spiral spring portion 172. In this case, if the second claw 175 of the drum ground plate 170 were located radially inward from the outer periphery of the ring portion 173, the spiral spring portion 172 would be too short, preventing the appropriate elastic force from being obtained. However, in this embodiment, the second claw 175 of the drum ground plate 170 protrudes radially outward from the ring portion 173, ensuring the length of the spiral spring portion 172. This allows the electrical contact 171 of the drum ground plate 170 and the drum ground shaft 150 to contact with each other with appropriate elastic force even when the photosensitive drum 51 is made smaller in diameter. As a result, the photosensitive drum 51 can be stably grounded even when the photosensitive drum 51 is made smaller in diameter.

[0067] The drum ground plate 170 also has a third claw 176 that protrudes radially outward from the ring portion 173 and fits into the inner periphery of the drum flange 160. Therefore, when assembling the drum cartridge 50, the drum flange 160 can be attached to the photosensitive drum 51 with the third claw 176 fitted into the inner periphery of the drum flange 160, making it easy to assemble the drum cartridge 50.

[0068] Furthermore, the tip of the third claw 176 is located closer to one end of the photosensitive drum 51 in the axial direction than the tip of the second claw 175. As a result, when assembling the drum earth plate 170 to the drum flange 160, the third claw 176 enters the inner peripheral surface of the drum flange 160 before the second claw 175, so that the drum earth plate 170 can be fixed to the drum flange 160 by the second claw 175 while being positioned by the third claw 176.

[0069] Drum earth plate 170 also has an elongated hole 177 located between base end 172A of spiral spring portion 172 and first claw 174 that is closest to base end 172A. Stress generated by elastic deformation of spiral spring portion 172 is separated by elongated hole 177, so that deformation of first claw 174 can be suppressed even if base end 172A of spiral spring portion 172 is deformed.

[0070] Furthermore, the spiral spring portion 172 extends in a spiral shape of 270 to 360 degrees, which allows the spiral spring portion 172 to exert appropriate strength and appropriate elastic force.

[0071] Furthermore, the drum bearing 130 covers the other end of the drum ground shaft 150. This prevents the other end of the drum ground shaft 150 from coming into contact with other members.

[0072] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments. The specific configurations can be appropriately changed without departing from the spirit of the present disclosure.

[0073] In the above-described embodiment, the spiral spring portion is configured to extend in a spiral shape of 270 to 360 degrees, but the angle of the spiral portion of the spiral spring portion can be set arbitrarily as long as the appropriate strength and appropriate elastic force are ensured.

[0074] In the above-described embodiment, the drum bearing covers the other end of the drum earth shaft, but the drum bearing may not cover the other end of the drum earth shaft.

[0075] In the above-described embodiment, the other end 142 of the leaf spring 140 extends in the axial direction, but it does not have to extend in the axial direction, and the shape of the other end 142 is not particularly limited as long as it can make electrical contact with the earth contact EC.

[0076] The elements described in the above-described embodiment and modifications may be implemented in any combination. [Explanation of symbols]

[0077] 50 drum cartridges 51 Photosensitive drum 130 drum bearing 140 Leaf spring 141 One end 142 Other end 143 Connecting part 150 Drum Earth Shaft 151 one end 152 other end 160 drum flange 170 Drum Earth Plate 171 Electrical contacts 172 Spiral spring part 172A Proximal end 173 Ring Section 174 First Claw 175 Second Claw 176 Third Claw 177 Slot

Claims

1. A drum cartridge, a photosensitive drum rotatable about an axially extending shaft; a drum flange located on one end side of the photosensitive drum in the axial direction and rotatable together with the photosensitive drum; a drum ground shaft for grounding the photosensitive drum; A drum earth plate electrically connecting the photosensitive drum and the drum earth shaft, the drum earth plate being located inside the photosensitive drum, an electrical contact that elastically contacts one end of the drum earth shaft; a spiral spring portion extending in a spiral shape from the electrical contact, the spiral spring portion being centered on the electrical contact; a ring portion located radially outward of the spiral spring portion and fixed to an inner peripheral surface of the drum flange; a first claw that protrudes radially outward from the ring portion and contacts the inner circumferential surface of the photosensitive drum; a drum ground plate having a second claw that protrudes radially outward from the ring portion and contacts the inner circumferential surface of the drum flange to fix the drum ground plate to the drum flange; Equipped with The drum earth plate further includes a third claw that protrudes radially outward from the ring portion and fits into the inner periphery of the drum flange, A drum cartridge according to claim 1, wherein a tip of the third claw is located closer to one end of the photosensitive drum in the axial direction than a tip of the second claw.

2. A drum cartridge, a photosensitive drum rotatable about an axially extending shaft; a drum flange located on one end side of the photosensitive drum in the axial direction and rotatable together with the photosensitive drum; a drum ground shaft for grounding the photosensitive drum; A drum earth plate electrically connecting the photosensitive drum and the drum earth shaft, the drum earth plate being located inside the photosensitive drum, an electrical contact that elastically contacts one end of the drum earth shaft; a spiral spring portion extending in a spiral shape from the electrical contact, the spiral spring portion being centered on the electrical contact; a ring portion located radially outward of the spiral spring portion and fixed to an inner peripheral surface of the drum flange; a first claw that protrudes radially outward from the ring portion and contacts the inner circumferential surface of the photosensitive drum; a drum ground plate having a second claw that protrudes radially outward from the ring portion and contacts the inner circumferential surface of the drum flange to fix the drum ground plate to the drum flange; Equipped with A drum cartridge characterized in that the drum earth plate has an elongated hole located between the base end of the spiral spring portion that is farthest from the electrical contact and the first claw that is closest to the base end, and the elongated hole extends in the circumferential direction of the drum earth plate.

3. A drum cartridge, a photosensitive drum rotatable about an axially extending shaft; a drum flange located on one end side of the photosensitive drum in the axial direction and rotatable together with the photosensitive drum; a drum ground shaft for grounding the photosensitive drum; A drum earth plate electrically connecting the photosensitive drum and the drum earth shaft, the drum earth plate being located inside the photosensitive drum, an electrical contact that elastically contacts one end of the drum earth shaft; a spiral spring portion extending in a spiral shape from the electrical contact, the spiral spring portion being centered on the electrical contact; a ring portion located radially outward of the spiral spring portion and fixed to an inner peripheral surface of the drum flange; a first claw that protrudes radially outward from the ring portion and contacts the inner circumferential surface of the photosensitive drum; a drum ground plate having a second claw that protrudes radially outward from the ring portion and contacts the inner circumferential surface of the drum flange to fix the drum ground plate to the drum flange; Equipped with The drum cartridge further comprises a drum bearing for rotatably supporting the drum flange, the drum bearing having the drum earth shaft fixed thereto.

4. 4. The drum cartridge according to claim 3, wherein the drum bearing covers the other end of the drum ground shaft.

5. 5. The drum cartridge according to claim 4, wherein the other end of the drum ground shaft is embedded in the drum bearing.

6. A leaf spring for grounding the drum ground shaft, One end portion contacting the outer circumferential surface of the drum earth shaft; 6. The drum cartridge according to claim 3, further comprising a leaf spring having another end exposed on an outer surface of the drum cartridge.

7. The first claws are provided in plurality, The second claws are provided in plurality, 7. The drum cartridge according to claim 1, wherein the first claws and the second claws are positioned alternately in the circumferential direction.

8. 8. The drum cartridge according to claim 1, wherein the tip of the first claw is located farther from the electrical contact than the tip of the second claw.

Images