Photoreceptor drum device and image forming apparatus

Abstract

To provide a photoreceptor drum device that can reduce the occurrence of conduction failure as much as possible when a photoreceptor drum is grounded through its shaft.SOLUTION: In a photoreceptor drum device, a photoreceptor drum has a hollow cylindrical conductive base material and a photoreceptor layer on an outer peripheral surface of the base material, and an insulating flange into which a shaft for supporting the rotation of the photoreceptor drum is inserted is mounted on one end opening of the photoreceptor drum. A grounding plate 70 includes a base plate part 78 that is attached to an inner surface side of the flange and connected to the conductive base material, and a plurality of contactors 84 that is formed on one principal surface side of the base plate part. The contactor has a rising piece 86 that rises from the base plate part, a shaft contact piece 90 that is in contact with an outer peripheral surface of the shaft, and a plate spring part 88 that has a principal surface extending along the radial direction of the photoreceptor drum and integrally connecting the rising piece and the shaft contact piece. The spring properties of the plate spring part 88 presses the shaft contact piece 90 against the shaft and reduces the occurrence of conduction failure as much as possible.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a photosensitive drum device and an image forming apparatus, and more particularly to a photosensitive drum device and an image forming apparatus in which a photosensitive drum is earthed (grounded) via a shaft using, for example, an earth plate. [Background technology]

[0002] In Patent Document 1 and other documents, a configuration is well known in which a photosensitive drum is fixed to the photosensitive body and opposing contacts slide against the shaft to ground the photosensitive surface of the photosensitive drum that rotates around a fixed shaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-39409 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, the positions of the opposing contacts and the shaft are not aligned in a straight line, which can result in poor conductivity. Even if there is no problem initially, poor conductivity can occur over time as the photosensitive drum is rotated repeatedly.

[0005] Therefore, a primary object of the present disclosure is to provide a novel photosensitive drum device and image forming apparatus.

[0006] Another object of the present disclosure is to provide a photosensitive drum device and an image forming apparatus that can reduce as much as possible the occurrence of poor conduction when grounding through the shaft of the photosensitive drum. [Means for solving the problem]

[0007] A first embodiment of the present disclosure is a photosensitive drum device comprising: a photosensitive drum having a photosensitive layer formed on the outer peripheral surface of a hollow cylindrical conductive substrate; an insulating flange attached to at least one end opening of the photosensitive drum; a metal shaft inserted through the flange and supporting the rotation of the photosensitive drum; an earth plate attached to the inner surface of the flange within the hollow portion of the photosensitive drum and having a base plate portion connected to the conductive substrate of the photosensitive drum; and a plurality of contacts formed on one main surface of the earth plate, each contact having a rising piece rising from the base plate portion, a shaft contact piece contacting the outer peripheral surface of the shaft, and a leaf spring portion having a main surface along the radial direction of the photosensitive drum and integrally connecting the rising piece and the shaft contact piece.

[0008] In the first embodiment, a photosensitive drum device (100: reference numerals illustrating corresponding parts in the embodiments and not intended to be limiting in any way; the same applies below) includes a photosensitive drum (26) having a cylindrical conductive substrate (26a) and a photosensitive layer (26b) formed on its outer circumferential surface. An insulating flange (60) is attached to at least one end opening of the photosensitive drum (26). A metal shaft (64) that supports the rotation of the photosensitive drum (26) is inserted through the flange (60). A ground plate (70) is attached to the inner surface of the flange (60) within the hollow portion of the photosensitive drum (26) and has a base plate portion (78) connected to the conductive substrate by, for example, fixing claws (82). The ground plate (70) further includes a plurality of contacts (84) formed on one main surface of the base plate portion (78). This contactor (84) has a rising piece (86) rising from the base plate portion (78), a shaft contact piece (90) that contacts the outer peripheral surface of the shaft (64), and a leaf spring portion (88) that has a main surface along the radial direction of the photosensitive drum and integrally connects the rising piece (86) and the shaft contact piece (90).

[0009] According to the first embodiment, the spring property of the leaf spring portion acts to effectively press the shaft contact piece against the shaft, thereby reducing the occurrence of poor conduction as much as possible.

[0010] The second embodiment is a photosensitive drum device dependent on the first embodiment, in which the rising piece has a main surface parallel to the axial direction of the photosensitive drum, the leaf spring portion is formed by bending from one end of the drum contact piece in the circumferential direction of the photosensitive drum, and the shaft contact piece is formed by bending from the tip of the leaf spring portion in the same direction as the drum contact piece.

[0011] In the second embodiment, the rising piece (86) of the contact (84) is, for example, rectangular or approximately rectangular including two opposing sides in the circumferential direction of the photosensitive drum (26), and has a main surface parallel to the axial direction of the photosensitive drum (26). A leaf spring portion (88) is bent from one side of the drum contact piece (86) in the circumferential direction of the photosensitive drum (26). The shaft contact piece (90) is formed by bending the tip of the leaf spring portion (88) in the same direction as the drum contact piece (86).

[0012] According to the second embodiment, the respective main surfaces of the rising piece, the leaf spring portion, and the shaft contact piece are offset by, for example, 90°, so that the pressure of the leaf spring portion acts effectively on the shaft contact piece, which makes it difficult for the shaft contact piece to shift position over time and minimizes the occurrence of poor electrical continuity when grounding through the photosensitive drum shaft.

[0013] The third embodiment is a photosensitive drum device subordinate to the first embodiment, in which the contacts are formed integrally with the base plate portion of the earth plate from the same metal.

[0014] According to the third embodiment, the earth plate can be integrally formed from a single metal plate.

[0015] The fourth embodiment is a photosensitive drum device subordinate to the first embodiment, in which a plurality of contacts are formed at intervals equally dividing 360°.

[0016] In the fourth embodiment, when there are three contacts, the contacts are provided at intervals of 120°, and when there are two contacts, the contacts are provided at intervals of 180°.

[0017] According to the fourth embodiment, each contact can act uniformly in the circumferential direction of the photosensitive drum, so that the occurrence of poor conduction when grounding through the shaft of the photosensitive drum can be further reduced.

[0018] The fifth embodiment is an image forming apparatus equipped with the photosensitive drum device of any one of the first to fourth embodiments. [Effects of the Invention]

[0019] According to the present disclosure, the spring properties of the leaf spring portion of the contactor act effectively on the shaft contact piece, etc., thereby providing a photosensitive drum device and an image forming device that can minimize the occurrence of poor conductivity when grounding through the shaft of the photosensitive drum.

[0020] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description of the embodiments, which proceeds with reference to the drawings. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a diagram illustrating the configuration of an image forming apparatus according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram illustrating an example of a photosensitive drum device of the image forming apparatus of FIG. [Figure 3] FIG. 3 is a simplified cross-sectional diagram illustrating an example of the mounting state of the photosensitive drum device shown in FIG. 2, taken in a direction perpendicular to the axial direction of the photosensitive drum. [Figure 4] 4A and 4B are diagrams showing an example of an earth plate of the photosensitive drum device shown in FIG. 2, where FIG. 4A is a perspective view of the earth plate from the inside, and FIG. 4B is a diagram showing only one contact. [Figure 5] FIG. 5 is an illustrative view showing a state in which the earth plate shown in FIG. 4 is attached to a flange. [Figure 6] FIG. 6 is a diagram showing a state in which the earth plate is attached to the flange from the state shown in FIG. [Figure 7]FIG. 7 is a diagram showing the contact state between the contact and the shaft as viewed from the ground plate side in a state in which the ground plate shown in FIG. 6 is attached to a flange. [Figure 8] FIG. 8 is a diagram showing the contact state between the contact and the shaft as viewed from the ground plate side with the ground plate attached to the flange in the second embodiment of the present disclosure, and corresponds to FIG. [Figure 9] FIG. 9 is a diagram showing an example of the earth plate used in the second embodiment shown in FIG. [Figure 10] FIG. 10 is a diagram showing the contact state between the contact and the shaft as viewed from the ground plate side with the ground plate attached to the flange in the third embodiment of the present disclosure, and corresponds to FIG. [Figure 11] FIG. 11 is a diagram showing an example of the earth plate used in the third embodiment shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] [First Example] Referring to FIG. 1, an image forming apparatus 10 according to a first embodiment of the present disclosure is a so-called multifunction peripheral (MFP) that forms multicolor or monochrome images on paper by electrophotography.

[0023] 1 is a view of image forming apparatus 10 as seen from the front side. That is, in FIG. 1, the up-down direction corresponds to the up-down direction of image forming apparatus 10, and the left-right direction corresponds to the left-right direction of image forming apparatus 10. The front side of the paper surface of FIG. 1 corresponds to the front of image forming apparatus 10, and the back side of the paper surface of FIG. 1 corresponds to the rear of image forming apparatus 10.

[0024] First, we will briefly explain the basic configuration of the image forming apparatus 10. As shown in Figure 1, the image forming apparatus 10 includes an apparatus main body 12. An image reading device 14 is provided above the apparatus main body 12.

[0025] The image reading device 14 includes a document scanner 16, which reads a document (not shown) and outputs image data.

[0026] The apparatus main body 12 houses a control unit 18 that controls each part of the image forming apparatus 10, an image forming unit 20, and the like.

[0027] The image forming section 20 includes an exposure unit 22, a developing device 24, a photosensitive drum 26, a cleaner unit 28, a charger 30, an intermediate transfer belt unit 32, an intermediate transfer belt 34, a drive roller 36, etc., and forms an image on paper conveyed from a paper feed tray 38 or a manual paper feed tray 40, and discharges the paper with the image formed on it to a paper discharge tray 42. Image data used to form an image on paper is image data read by a document scanner 16 or image data sent from an external computer, etc.

[0028] The image data handled by the image forming apparatus 10 corresponds to color images of four colors: black (K), cyan (C), magenta (M), and yellow (Y). Therefore, four developing devices 24, four photosensitive drums 26, four cleaner units 28, and four chargers 30 are provided so as to form four types of latent images corresponding to each color, and these constitute four image stations.

[0029] The intermediate transfer belt unit 32 includes an intermediate transfer belt 34, a drive roller 36, a driven roller 44, and four intermediate transfer rollers 46, and is disposed above the photosensitive drums 26. The intermediate transfer belt 34 rotates (circularly moves) in a predetermined direction as the drive roller 36 rotates. The intermediate transfer rollers 46 are disposed at positions facing each of the photosensitive drums 26 across the intermediate transfer belt 34. During image formation, the intermediate transfer rollers 46 are used to transfer the toner images of each color formed on each photosensitive drum 26 onto the intermediate transfer belt 34 in succession, superimposing them on top of each other, thereby forming a multi-color toner image on the intermediate transfer belt 34.

[0030] The secondary transfer roller 48 is disposed opposite the drive roller 36 across the intermediate transfer belt 34. When a sheet of paper passes through the secondary transfer nip between the secondary transfer roller 48 and the intermediate transfer belt 34, the toner image formed on the intermediate transfer belt 34 is transferred to the sheet of paper.

[0031] The fixing device 50 is disposed above the secondary transfer roller 48 (downstream in the paper transport direction), and fixes the toner image transferred onto the paper, for example by heating. Thereafter, the paper is discharged onto the paper discharge tray 42.

[0032] Inside the device main body 12, a first paper transport path L1 is formed for transporting paper from the paper feed tray 38 or manual paper feed tray 40 by transport rollers 52, passing through registration rollers 54, secondary transfer rollers 48 and fixing device 50, and sending the paper to the paper output tray 42. When double-sided printing is performed on the paper, a second paper transport path L2 is formed for returning the paper, after single-sided printing is completed and the paper has passed through the fixing device 50, to the first paper transport path L1 upstream of the secondary transfer rollers 48 in the paper transport direction.

[0033] 2 is a diagram showing a photosensitive drum device 100 including a photosensitive drum 26, which is depicted by a dashed line in Fig. 2. The photosensitive drum device 100 will be outlined below with reference to Figs. 2 and 3.

[0034] As is well known, the photosensitive drum 26 comprises a cylindrical substrate 26a having openings at both ends and made of a conductive metal such as aluminum, and a photosensitive layer 26b formed on the outer peripheral surface thereof, as shown in FIG. 7, for example.

[0035] In photosensitive drum device 100, photosensitive drum 26 is supported by flanges 60 and 62 fitted into the left and right open ends. A shaft 64 is rotatably supported by flange 60. Shaft 64 is made of a conductive metal, such as nickel-plated stainless steel.

[0036] In this embodiment, the shaft 64 only needs to support the rotation of the flange 60, and is therefore not provided over the entire axial length of the photosensitive drum 26. However, the shaft 64 may be provided over the entire axial length of the photosensitive drum 26, reaching all the way to the flange 62.

[0037] Both flanges 60 and 62 are molded from insulating synthetic resin and are insulators. A coupler 68 having an internal gear is formed on flange 62. An external gear of a coupler (neither shown) provided on a drive shaft of a drive force transmission mechanism can engage with the internal gear of coupler 68, and by driving the drive shaft with the driving force of a drive source, coupler 68, and therefore photosensitive drum 26, can be rotated.

[0038] The rotation of the photosensitive drum 26 is supported by a shaft 64 that is pivotally supported on the flange 60 .

[0039] An earth plate 70 made of, for example, a metal having spring properties is attached to the inside of the flange 60. Furthermore, as shown in Fig. 3, a shaft hole 72 for inserting a shaft 64 is formed in the center of the flange 60, and a bearing (not shown) provided in the shaft hole 72 supports the shaft 64 so that it can rotate freely.

[0040] The earth plate 70 has a contactor 84 (FIG. 4) on one main surface thereof, which contacts the inner circumferential surface of the conductive substrate of the photosensitive drum 26 and the shaft 64, as described below, and functions to drain residual charges on the photosensitive drum 26 through the contactor 84 to the shaft 64, i.e., the ground potential.

[0041] Such a ground plate 70 is formed from a single metal plate by, for example, press molding using a press die (not shown).

[0042] A fixing pin 74 for fixing the earth plate 70 to the inner surface of the flange 60 is formed on the inner surface of the flange 60 .

[0043] A waste toner recovery device 76 is provided below the photosensitive drum 26 of the photosensitive drum device 100 as shown in the drawing. The waste toner recovery device 76 is provided with a waste toner screw, which transports waste toner scraped off the surface of the photosensitive drum 26 to a waste toner box.

[0044] The earth plate 70 will now be described in detail with reference to Figure 4. The earth plate 70 has a disk-shaped base plate portion 78 that matches the shape of the inner surface of the flange 60. A plurality of mounting holes 80 are formed within the surface of the base plate portion 78. A plurality of fixing claws 82 are also formed around the periphery of the base plate portion 78. Furthermore, an opening 79 is formed in the center of the base plate portion 78 to allow the shaft 64 to pass through.

[0045] At positions different from the fixed claws 82, a plurality of contacts 84 (three in this embodiment) are formed rising from the periphery of the base plate portion 78 towards the inner surface.

[0046] Referring also to Figure 4(B), which shows only the contactor 84, the contactor 84 has a rising piece 86 that rises from the periphery of the base plate portion 78 toward the inner surface, a leaf spring portion 88, and a shaft contact piece 90 that contacts the outer periphery of the shaft 64, and is a single continuous strip-shaped body as a whole.

[0047] The rising piece 86 rises from the periphery of the base plate portion 78 perpendicular to the main surface of the base plate portion 78. The rising piece 86 is a substantially rectangular shape having two sides facing each other in the circumferential direction of the photosensitive drum 26 and one side facing the base end rising from the base plate portion 78, and has a main surface parallel to the axial direction of the photosensitive drum 26. The leaf spring portion 88 is bent from one side of the rising piece 86, i.e., from one side of the rising piece 86 in the circumferential direction of the photosensitive drum 26, at an angle AA and is formed so as to extend radially toward the center of the photosensitive drum 26.

[0048] In this embodiment, the angle AA is set to 90°, but the angle AA is not limited to 90°.

[0049] As described above, the leaf spring portion 88 extends along the radial direction of the photosensitive drum 26, and therefore its main surface is parallel to the axial direction of the photosensitive drum 26.

[0050] The contact 84 further includes a shaft contact piece 90 consisting of a first portion 90a bent at an angle BB from the tip of the leaf spring portion 88 and a second portion 90b bent at an angle CC from the first portion 90a. The first portion 90a is bent on the same side as the drum contact piece 86 with respect to the main surface of the leaf spring portion 88, and the second portion 90b is bent in a direction that curves back from the first portion 90a. In other words, the second portion 90b of the shaft contact piece 90 has a contact surface with the shaft 64 that is parallel to the main surface of the leaf spring portion 88.

[0051] However, the angles BB and CC are both obtuse angles.

[0052] In the shaft contact piece 90, only the second portion 90b comes into contact with the shaft 64, but since the first portion 90a is bent from the plate spring portion 88 at an obtuse angle BB, a pressing force can be applied to the second portion 90b in the direction in which the second portion 90b comes into contact with the shaft 64 (the direction of the arrow DD).

[0053] A notch 89 is formed at the boundary of the leaf spring portion 88 where the first portion 90a is formed. Therefore, the leaf spring portion 88 is easily bent in the vicinity of this notch 89, allowing the leaf spring portion 88 to exert an appropriate spring force.

[0054] However, this notch 89 may be omitted.

[0055] When such a grounding plate 70 is fixed to the flange 60, the grounding plate 70 is first placed on the inner surface of the flange 60 as shown in Fig. 5. In other words, the back surface of the grounding plate 70 (the surface on which the contacts 84 are not formed, i.e., the other main surface) is placed facing the inner surface of the flange 60.

[0056] Although the shaft 64 has not yet been inserted when the grounding plate 70 is attached to the flange 60, the shaft 64 is shown in Figure 5 for the sake of convenience in order to make it easier to understand the positional relationship between the grounding plate 70 and the shaft 64. This is also true for Figure 6. In other words, even when the grounding plate 70 is attached to the flange 60, the shaft 64 has not yet been installed.

[0057] Two bosses 61a and 61b of different diameters are formed on the inner surface of the flange 60. The base ends of these bosses 61a and 61b are integral with the flange 60. The first boss 61b on the outer side (large diameter) is a boss that supports the fixing claws 82 to prevent them from bending, as the fixing claws 82 come into strong contact with the inner surface of the conductive base 26a when the flange 60 with the earth plate 70 attached is press-fitted into the conductive base 26a. The second boss 61a on the inner side (small diameter) is a boss whose end face functions as the abutment surface for the earth plate 70.

[0058] The earth plate 70 is placed inside the flange 60. At this time, the earth plate 70 is placed in such a position that the fixing pin 74 of the flange 60 can be inserted into the mounting hole 80 of the base plate portion 78.

[0059] In this state, the ground plate 70 is pressed firmly against the inner surface of the flange 60 until the back surface of the ground plate 70 abuts against the end surface of the second boss 61b. In this state, the ground plate 70 is attached to the abutting surface (end surface) of the second boss 61b using a fixing pin 74, as shown in FIG.

[0060] Thereafter, the fixing claws 82 of the base plate portion 78 are bent along the outer peripheral surface of the first boss 61a, and the earth plate 70 is more firmly fixed to the inner surface of the flange 60. The fixing pins 74 restrict displacement of the earth plate 70 in the axial direction of the photosensitive drum 26, and the fixing claws 82 restrict displacement of the earth plate 70 in the circumferential direction (i.e., the circumferential direction of the photosensitive drum 26).

[0061] FIG. 7 shows the state in which the earth plate 70 is attached to the flange 60 in this manner, as viewed from the earth plate 70 side.

[0062] As shown in FIG. 6, after the ground plate 70 is attached to the flange 60, the ground plate 70 and flange 60 are integrated and inserted into the photosensitive drum 26 from the ground plate 70 side.

[0063] When the integrated assembly shown in FIG. 6 is mounted on the photosensitive drum 26, the raised pieces 86 of the contacts 84 of the ground plate 70 are positioned inside the base 26b of the photosensitive drum 26 (FIG. 7).

[0064] At this time, the fixed claws 82 are each pressed firmly against the base body 26b of the photosensitive drum 26. As a result, the ground plate 70 is electrically connected to the base body 26b.

[0065] Thereafter, the photosensitive drum 26, to which the integrated ground plate 70 and flange 60 are already attached, is attached to the shaft 64, which is fixed to the frame (not shown) of the process unit. At this time, the shaft contact piece 90 comes into contact with the outer circumferential surface of the shaft 64, which protrudes inward from the opening 79 (FIG. 4), as shown in FIG.

[0066] 4, the position of each shaft contact piece 90 is designed to be slightly inward from the position of the outer circumferential surface of the shaft 64. When the shaft 64 is inserted into the opening 79 as described above, the shaft contact piece 90 comes into strong contact with the outer circumferential surface of the shaft 64.

[0067] 7, the leaf spring portion 88 bends slightly and presses the shaft contact piece 90 inward, i.e., in the direction of arrow EE, relatively strongly. In other words, because the main surface of the leaf spring portion 88 is parallel to the axial direction of the photosensitive drum 26, the springiness (spring force) of the leaf spring portion 88 acts in a direction pressing the shaft contact piece 90 against the shaft 64. Therefore, the shaft contact piece 90 is reliably in contact with the shaft 64, and as a result, the residual potential of the photosensitive drum 26 reliably flows to the shaft 64 through the earth plate 70, i.e., the contactor 84.

[0068] In this manner, in this embodiment, the rising piece 86 and the shaft contact piece 90 are connected by the leaf spring portion 88, and the leaf spring portion 88 can reliably press the shaft contact piece 90 against the shaft 64.

[0069] More specifically, in this embodiment, the main surface of the rising piece 86 is parallel to the axial direction of the photosensitive drum 26, the main surface of the leaf spring portion 88 is parallel to the axial direction of the photosensitive drum 26 in a direction different from that of the rising piece 86, and the shaft contact piece 90 formed at the tip thereof is bent in a different direction from that main surface, i.e., the main surfaces of the rising piece 86, leaf spring portion 88, and shaft contact piece 90 are offset by, for example, 90°, so that the pressing force of the leaf spring portion 88 acts effectively on the shaft contact piece 90. Therefore, the shaft contact piece 90 is less likely to shift position over time, and the occurrence of poor conductivity when grounding through the shaft of the photosensitive drum can be reduced as much as possible.

[0070] Furthermore, since the leaf spring portion 88 is connected to the base plate portion 78 through the rising piece 86, the base end of the leaf spring portion 88 does not move as if it were fixed, and the spring force acting on the tip of the leaf spring portion 88, i.e., the shaft contact piece 90, is strong, so that the leaf spring portion 88 effectively presses the shaft contact piece 90 against the shaft 64.

[0071] In the above-described embodiment, in order to apply uniform contact pressure to the shaft contact piece 90 in the circumferential direction of the shaft 64, three contacts 84 are provided at 120° intervals so as to divide the 360° circumferential direction of the photosensitive drum 26 into thirds.

[0072] However, the number of contacts 84 may be two or more, or may be two as in the second embodiment of the present disclosure shown in Fig. 8. In this case, the contacts 84 are provided at 180° intervals so as to divide 360° into two equal parts.

[0073] The embodiment shown in Fig. 8 uses the earth plate 70 shown in Fig. 9. Fig. 8 is a diagrammatic view corresponding to Fig. 7.

[0074] 8 and 9 differs from the previous embodiment in that the second embodiment has two contacts 84, whereas the previous embodiment has three contacts 84. However, all other points, such as the shape of the contacts 84 and the bending angles AA, BB, and CC, are the same as those of the previous embodiment. Also, the shaft contact piece 90 is pressed strongly in the direction of the arrow DD, as in the first embodiment.

[0075] In this second embodiment, the drum contact piece 86 and the shaft contact piece 90 of the two contactors 84 are each evenly pressed against the inner surface of the base 26a of the photosensitive drum 26 and the outer surface of the shaft 64, so that, as in the previous embodiment, the occurrence of poor conductivity when grounding through the shaft of the photosensitive drum can be reduced as much as possible.

[0076] 10 and 11 is similar to the first embodiment in that it has three contacts 84. However, unlike the first embodiment, in which the angle AA at which the leaf spring portion 88 is bent from one side of the drum contact piece 86 is 90°, the angle AA in this third embodiment is an acute angle, which is a difference from the first embodiment. In other respects, the third embodiment is the same as or nearly the same as the first embodiment.

[0077] In order to bend the leaf spring portion 88 from the drum contact piece 86 at an acute angle AA, the leaf spring portion 88 may be extended from the side of the drum contact piece 86 opposite to the circumferential side of the photosensitive drum 26 from which the leaf spring portion 88 was extended in the first embodiment.

[0078] Because angle AA is set to an acute angle, in this third embodiment, as shown in Fig. 10, the shaft contact piece 90 is pressed against the shaft 64 in the opposite direction to the drum contact piece 86, in relation to the main surface of the leaf spring portion 88. That is, in the first embodiment, as shown in Fig. 7, the drum contact piece 86 and the shaft contact piece 90 both contact the base 26a and the shaft 64 on the same main surface side of the leaf spring portion 88. In contrast, in the third embodiment shown in Fig. 10, the drum contact piece 86 and the shaft contact piece 90 contact the base 26a and the shaft 64 on different main surface sides of the leaf spring portion 88, in relation to the main surface of the leaf spring portion 88.

[0079] In the third embodiment as well, the leaf spring portion 88 can bend appropriately to apply a strong pressure to the drum contact piece 86 and the shaft contact piece 90.

[0080] In the second embodiment, a contact in which the leaf spring portion 88 is bent at an acute angle from the drum contact piece 86 of the earth plate in the third embodiment may also be used.

[0081] Furthermore, in all of the above-described embodiments, the contacts 84 are integrally formed from the same metal as the base plate portion 78 of the earth plate 70, but the contacts 84 do not necessarily have to be integral with the base plate portion 78. In this case, however, the base plate portion 78 does not have to be made of metal, but it is desirable that the contacts 84 be made of metal, and it is even more desirable if the metal is elastic (springy).

[0082] Furthermore, the specific numerical values ​​and materials given above are merely examples and can be changed as appropriate according to the needs of the product specifications, etc. [Explanation of symbols]

[0083] 10...Image forming device 26...Photosensitive drum 26a...Base 26b...Photoreceptor layer 60, 62... flange 64...shaft 70...Earth plate 78...Base plate section 80 Mounting hole 82…Fixed claw 84...contact 86...Rising piece 88... Leaf spring part 89 ...Notch 90...Shaft contact piece 90a…Part 1 90b…Part 2 100...Photosensitive drum device AA, BB, CC…Angle

Claims

1. a photosensitive drum having a photosensitive layer formed on the outer peripheral surface of a hollow cylindrical conductive substrate; an insulating flange attached to at least one end opening of the photosensitive drum; a metal shaft that is inserted through the flange and supports the rotation of the photosensitive drum; a ground plate attached to the inner surface side of the flange within the hollow portion of the photosensitive drum and having a base plate portion connected to the conductive substrate of the photosensitive drum; a plurality of contacts formed on one main surface of the base plate portion; The contactor has a rising piece rising from the base plate portion, a shaft contact piece that contacts the outer peripheral surface of the shaft, and a leaf spring portion having a main surface that follows the radial direction of the photosensitive drum and integrally connects the rising piece and the shaft contact piece.

2. 2. The photosensitive drum device according to claim 1, wherein the raised piece has a main surface parallel to the axial direction of the photosensitive drum, the leaf spring portion is formed by bending from one end of the drum contact piece in the circumferential direction of the photosensitive drum, and the shaft contact piece is formed by bending from the tip of the leaf spring portion in the same direction as the drum contact piece.

3. 2. The photosensitive drum device according to claim 1, wherein said contactor is formed integrally with said base plate portion of said earth plate from the same metal.

4. 2. The photosensitive drum device according to claim 1, wherein said plurality of contacts are formed at intervals equally dividing 360 degrees.

5. An image forming apparatus comprising the photosensitive drum device according to claim 1 .

Images