Photoreceptor drum and image forming apparatus

Abstract

The present invention provides a photoreceptor drum and an image forming apparatus that can suppress wear of the conductive support shaft by multiple connection points when the photoreceptor drum rotates around the rotation axis relative to the conductive support shaft, thereby enabling stable grounding of the photoreceptor drum. [Solution] The photoreceptor drum 13 comprises a drum body 131 and a conductive member 132. The conductive member 132 has a plurality of connection parts (1321~1321) that are electrically connected to the conductive support shaft 101. Of the contact parts 1321a of the plurality of connection parts (1321~1321) that contact the conductive support shaft 101, at least one contact part 1321a is located at a position offset in the axial direction G of the conductive support shaft 101 relative to the other contact parts 1321a.

Description

Technical Field

[0001] The present disclosure relates to a photosensitive drum provided in an image forming apparatus such as a copying machine, a multifunction peripheral, a printer, and a facsimile apparatus, and an image forming apparatus.

Background Art

[0002] When light is irradiated onto a photosensitive drum provided in an image forming apparatus with a photosensitive layer formed on its outer peripheral surface being charged, the electrical resistance value of the portion irradiated with light is decreased, and the surface potential of the portion with the decreased electrical resistance value is decreased. Thus, in order to decrease the surface potential of the portion irradiated with light, it is necessary to ground (earth) the photosensitive drum.

[0003] As such a photosensitive drum, for example, a drum body having a photosensitive layer formed on its outer peripheral surface and rotating around a rotation axis with respect to a conductive support shaft, and a conductive member for grounding the inner peripheral surface of the drum body via the conductive support shaft are provided, and the conductive member having a plurality of connection portions electrically connected to the conductive support shaft has been conventionally known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a conventional photosensitive drum including a drum body and a conductive member, when the photosensitive drum rotates around a rotation axis with respect to a conductive support shaft, if a plurality of connection portions are in sliding contact with the conductive support shaft at one location in the axial direction with respect to the conductive support shaft, the conductive support shaft is likely to wear at the sliding contact locations with the plurality of connection portions of the conductive support shaft. Then, at the worn portion, grounding becomes unstable, and thus, the photosensitive drum cannot be stably grounded.

[0006] Therefore, the present disclosure aims to provide a photoreceptor drum and an image forming apparatus that can suppress wear of the conductive support shaft by multiple connection points when the photoreceptor drum rotates around the rotation axis relative to the conductive support shaft, thereby enabling stable grounding of the photoreceptor drum. [Means for solving the problem]

[0007] To solve the aforementioned problems, the photoreceptor drum according to the present disclosure comprises a drum body having a photosensitive layer formed on its outer circumferential surface and rotating around a rotation axis with respect to a conductive support shaft, and a conductive member for grounding the inner circumferential surface of the drum body via the conductive support shaft, wherein the conductive member is a photoreceptor drum having a plurality of connection parts electrically connected to the conductive support shaft, and at least one of the contact parts of the plurality of connection parts that contact the conductive support shaft is located at a position offset in the axial direction of the conductive support shaft relative to the other contact parts. Furthermore, the image forming apparatus according to the present disclosure is characterized by comprising the photoreceptor drum according to the present disclosure and the conductive support shaft. [Effects of the Invention]

[0008] According to this disclosure, when the photoreceptor drum rotates around the rotation axis relative to the conductive support shaft, wear of the conductive support shaft due to multiple connection points can be suppressed, thereby enabling stable grounding of the photoreceptor drum. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view showing an example of the basic configuration of the image forming apparatus according to this embodiment. [Figure 2] This is a perspective view showing an example of a process unit equipped with a first-type photoreceptor drum. [Figure 3] This is a perspective view showing the conductive component portion of the Type 1 photoreceptor drum with the drum body removed. [Figure 4]This is an exploded perspective view showing the conductive component portion of the first type of photoreceptor drum. [Figure 5] This is a perspective view showing an example of a conductive member in a first-type photoreceptor drum. [Figure 6] This is a perspective view showing another example of a conductive member in a first-type photoreceptor drum. [Figure 7] This is a perspective view showing a process unit equipped with a second type of photoreceptor drum. [Figure 8] This is a perspective view showing the conductive component portion of the second type photoreceptor drum with the drum body removed. [Figure 9] This is an exploded perspective view showing the conductive component portion of the second type of photoreceptor drum. [Figure 10] This is a perspective view showing an example of a conductive member in a second-type photoreceptor drum. [Figure 11] This is a perspective view showing a process unit equipped with a third type of photoreceptor drum. [Figure 12] This is a perspective view showing the conductive component portion of a third-type photoreceptor drum with the drum body removed. [Figure 13] This is an exploded perspective view showing the conductive component portion of the third type photoreceptor drum. [Figure 14] This is a perspective view showing an example of a conductive component in a third-type photoreceptor drum. [Figure 15] This diagram schematically shows the state before (upper diagram) and after (lower diagram) the conductive support shaft, coated with conductive grease, is inserted into the insertion hole of the flange member provided at the end of the drum body, when the conductive support shaft of the Type 1 to Type 3 photoreceptor drum does not have a recess. [Figure 16] This is a schematic cross-sectional view showing the state before (upper figure) and after (lower figure) that a conductive support shaft coated with conductive grease is inserted into the insertion hole of a flange member provided at the end of the drum body, when a recess is provided in the conductive support shaft of a first-type photoreceptor drum. [Figure 17]In the case where a recess is provided in the conductive support shaft of the second type of photoreceptor drum, a cross-sectional view schematically showing the state before (upper figure) and after (lower figure) the insertion of the conductive support shaft coated with conductive grease into the insertion hole of the flange member provided at the end of the drum body. [Figure 18] In the case where a recess is provided in the conductive support shaft of the third type of photoreceptor drum, a cross-sectional view schematically showing the state before (upper figure) and after (lower figure) the insertion of the conductive support shaft coated with conductive grease into the insertion hole of the flange member provided at the end of the drum body.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0011] <00 / 00090>[Image Forming Apparatus] FIG. 1 is a cross-sectional view showing an example of the basic configuration of an image forming apparatus 100 according to the present embodiment. In the figure, reference numeral X represents the left-right direction (lateral direction) as viewed from the front, and reference numerals X1 and X2 represent the left side and the right side, respectively. Reference numeral Y represents the depth direction (front-rear direction) orthogonal to the left-right direction X, and reference numerals Y1 and Y2 represent the front side (front surface side, operation side) and the rear side (back surface side, opposite side to the operation side), respectively. Reference numeral Z represents the up-down direction, the vertical direction.

[0012] As shown in FIG. 1, the image forming apparatus 100 has a copying function of reading a document and printing it on a recording sheet. The image forming apparatus 100 includes an image reading device 2, a document conveying device 3, an image forming unit 4, a paper feed cassette 5, a primary transfer device 7, a secondary transfer device 22, a belt cleaning device 23, and a fixing device 17. The image forming unit 4 and the paper feed cassette 5 are provided in the image forming apparatus main body 6. The image reading device 2 and the document conveying device 3 are mounted on the upper part of the image forming apparatus main body 6.

[0013] The image data handled by the image forming apparatus 100 corresponds to a color image using black (K), cyan (C), magenta (M), and yellow (Y), or to a monochrome image using a single color (for example, black). The image forming apparatus 100 may also be a monochrome image forming apparatus.

[0014] The image forming unit 4 is equipped with four charging devices 10 (charging roller units), four exposure devices 11 (LED heads in this example), four developing devices 12, four photoreceptor drums 13 that act as image carriers, and four photoreceptor cleaning devices 14, each corresponding to black, cyan, magenta, and yellow, to form four types of toner images corresponding to each color. The charging devices 10-10, exposure devices 11-11, developing devices 12-12, photoreceptor drums 13-13, and photoreceptor cleaning devices 14-14 each constitute four image stations Pa, Pb, Pc, and Pd, respectively.

[0015] The charging devices 10-10 charge the surfaces of the photoreceptor drums 13-13. The charging devices 10-10 are equipped with a charging roller 15 and a cleaning roller 16. The exposure devices 11-11 expose the surfaces of the photoreceptor drums 13-13, which have been uniformly charged by the charging devices 10-10, according to the image data, and form an electrostatic latent image on the surface of the photoreceptor drums 13-13 according to the image data. The developing devices 12-12 develop the electrostatic latent image formed on the surface of the photoreceptor drums 13-13 by the exposure devices 11-11 using a developer contained in the developing tank, and form a toner image on the surface of the photoreceptor drums 13-13.

[0016] The primary transfer device 7 has an intermediate transfer belt 21. The intermediate transfer belt 21 moves in a circular motion in the direction of arrow D1. The primary transfer device 7 sequentially transfers the toner images of each color formed on the surface of the photoreceptor drums 13-13 in the developing devices 12-12 onto the intermediate transfer belt 21 and superimposes them to form a color toner image on the intermediate transfer belt 21.

[0017] The photoreceptor cleaning devices 14-14 are equipped with cleaning members such as cleaning blades. The photoreceptor cleaning devices 14-14 collect the remaining toner that was not transferred to the intermediate transfer belt 21 by the primary transfer device 7 and remains on the photoreceptor drums 13-13 as waste toner using the cleaning members, and transport it toward a toner collection container (not shown).

[0018] A nip region N is formed between the intermediate transfer belt 21 and the transfer roller 22a of the secondary transfer device 22, and the recording paper P that has been transported through the S-shaped paper transport path R1 is trapped in the nip region N and transported.

[0019] The secondary transfer device 22 transfers the toner image that was primary transferred to the intermediate transfer belt 21 to the recording paper P. In this example, the secondary transfer device 22 is equipped with a transfer roller 22a. The transfer roller 22a electrostatically transfers the toner image that was transferred to the intermediate transfer belt 21 by the primary transfer device 7 to the recording paper P, forming an unfixed toner image on the recording paper P.

[0020] The belt cleaning device 23 collects the remaining toner that was not transferred to the recording paper P by the secondary transfer device 22 and remains on the intermediate transfer belt 21 as waste toner, and transports it to the toner collection container.

[0021] The fixing device 17 heats and pressurizes the recording paper P, on which the unfixed toner image has been transferred, while sandwiching it between the heating roller 24 and the pressure roller 25, thereby heat-fixing the unfixed toner image to the recording paper P.

[0022] Meanwhile, the recording paper P is pulled out from the paper feed cassette 5 by the pickup roller 31 and transported through the paper transport path R1, passing through the secondary transfer device 22 and the fuser device 17, and then delivered to the discharge tray 33 via the discharge roller 32. The paper transport path R1 is equipped with a registration roller 34 and a transport roller 35. The registration roller 34 temporarily stops the recording paper P, aligns the leading edge of the recording paper P, and then starts transporting the recording paper P in accordance with the timing of toner image transfer in the nip region N between the intermediate transfer belt 21 and the transfer roller 22a. The transport roller 35 facilitates the transport of the recording paper P.

[0023] Furthermore, when image formation (printing) is performed not only on the front surface but also on the back surface of the recording paper P, the recording paper P is transported in the reverse direction from the discharge roller 32 to the reversal path Rr to reverse the front and back surfaces of the recording paper P, guided back to the register roller 34, and discharged to the discharge tray 33 via the nip area N and the fixing device 17, just like the front surface of the recording paper P.

[0024] [Photoconductor Drum] Here, since the photoreceptor drums 13-13 all have essentially the same configuration, we will use one photoreceptor drum 13 as a representative example for the following explanation. Furthermore, although we will describe three types of photoreceptor drums 13 (13A-13C) below, the image forming apparatus 100 shown in Figure 1 is, as mentioned above, an example of the basic configuration of an image forming apparatus, and is capable of accommodating any of the three types of photoreceptor drums 13 (13A-13C).

[0025] Figures 2, 7, and 11 are perspective views showing examples of process units 300 (300A to 300C) equipped with first to third type photoreceptor drums 13 (13A to 13C), respectively. Figures 3, 8, and 12 are perspective views showing the conductive member 132 (132A to 132C) portion of the first to third type photoreceptor drums 13 (13A to 13C) with the drum body 131 (131A to 131C) removed, respectively. Figures 4, 9, and 13 are exploded perspective views showing the conductive member 132 (132A to 132C) portion of the first to third type photoreceptor drums 13 (13A to 13C), respectively. Figures 5 and 6 are perspective views showing an example and another example of the conductive member 132 (132A) in the first type photoreceptor drum 13 (13A), respectively. Figures 10 and 14 are perspective views showing examples of conductive members 132 (132B, 132C) in the second and third type photoreceptor drums 13 (13B, 13C), respectively.

[0026] In this embodiment, the photoreceptor drum 13 (13A~13C) comprises a drum body 131 (131A~131C) and conductive members 132 (132A~132C). The drum body 131 (131A~131C) has a photoreceptor layer formed on its outer circumferential surface 13a and rotates around the rotation axis α with respect to the conductive support shaft 101 (101A~101C). The conductive members 132 (132A~132C) are members for grounding (earthing) the inner circumferential surface 13b of the drum body 131 (131A~131C) via the conductive support shaft 101 (101A~101C). The conductive members 132 (132A~132C) have a plurality of connection parts 1321~1321. The connecting parts 1321-1321 are electrically connected to the conductive support shafts 101 (101A-101C). The conductive members 132 (132A-132C) further have one or more (three in this example) main body-side connecting parts 1322-1322. The main body-side connecting parts 1322-1322 are electrically connected to the inner circumferential surface 13b of the drum body 131 (131A-131C). In this example, conductive member 132A is provided at the rear end Y2 of drum body 131A, and conductive members 132B and 132C are provided at the front ends Y1 of drum bodies 131B and 131C.

[0027] In this embodiment, the photoreceptor drum 13 (13A to 13C) further comprises a pair of flange members 133, 133 (see Figures 2 to 4) provided at both ends of the drum body 131 (131A to 131C) in the axial direction G (depth direction Y in this example). At least one of the pair of flange members 133, 133 has an insertion hole 133a (see Figures 4, 9, and 13) into which a conductive support shaft 101 is rotatably inserted. The connecting parts 1321 to 1321 are electrically connected to the conductive support shaft 101 (101A to 101C) inserted into the insertion hole 133a of at least one of the pair of flange members 133 (133A to 133C). The main body side connection parts 1322-1322 have sharpened tips and are fitted into the drum body 131 (131A-131C) while contacting the inner circumferential surface 13b of the drum body 131 (131A-131C).

[0028] In the first type photoreceptor drum 13A shown in Figures 2 to 4, the flange members 133A, 133A on both sides have insertion holes 133a, 133a, and conductive support shafts 101 (101A) are inserted into the insertion holes 133a, 133a, respectively. In the second type photoreceptor drum 13B shown in Figures 7 to 9 and the third type photoreceptor drum 13B shown in Figures 11 to 13, the front flange member 133B Y1 has an insertion hole 133a, and conductive support shafts 101 (101B, 101C) are inserted into the insertion hole 133a.

[0029] More specifically, the conductive support shafts 101 (101A~101C) are fixed to the main frame FL (see Figure 6) of the image forming apparatus body 6. In the first type of photoreceptor drum 13A shown in Figures 2 to 4, the conductive support shafts 101A inserted into the insertion holes 133a, 133a in the flange members 133A, 133A on both sides are fixed to the main frame on both sides (Y1, Y2) in the depth direction Y. In the second type of photoreceptor drum 13B shown in Figures 7 to 9 and the third type of photoreceptor drum 13B shown in Figures 11 to 13, the conductive support shafts 101B, 101C fixed to the main frame on the front side Y1 in the depth direction Y are inserted into the insertion holes 133a in the flange members 133B, 133C on the front side Y1.

[0030] The flange members 133 (133A~133C) have an outer diameter that gradually increases from the inside to the outside in the axial direction G, and are designed to be press-fitted into the drum body 131 (131A~131C). The flange members 133 (133A~133C) are provided with a plurality of protrusions 133b, 133c and a ring-shaped locking portion 133d that surrounds the insertion hole 133a and locks the through hole 132a in the conductive member 132 (132A~132C). The conductive member 132 (132A~132C) is provided with a through hole 132a through which the conductive support shaft 101 passes, a positioning through hole 132b, and a positioning elongated through hole 132c.

[0031] In the flange member 133 (133A~133C), multiple projections 133b, 133c extend along the axial direction G. The outer diameter of the locking portion 133d gradually increases as it moves away from the inside to the outside in the axial direction G. Of the multiple projections 133b, 133c, one projection 133b is inserted through the positioning through hole 132b, and the other projections 133c are inserted through the positioning through elongated hole 132c. The conductive member 132 (132A~132C) is fixed to the locking portion 133d in the flange member 133 (133A~133C) by press-fitting the through hole 132a into the locking portion 133d. As a result, the flange member 133 (133A~133C) can fix the conductive member 132 (132A~132C) in a positioned state.

[0032] Furthermore, the flange members 133 (133A to 133C) are provided with coupling gears 133e [male coupling gear in the example shown in Figure 2, female coupling gear (not shown) in the example shown in Figure 7, and female coupling gear in the example shown in Figure 11]. As a result, the coupling gears 133e of the flange members 133 (133A to 133C) are fitted into the drive-side coupling gear provided on the image forming apparatus body 6, thereby enabling the photoreceptor drum 13 (13A to 13C) to be rotationally driven around the rotation axis α.

[0033] <About this figure> Of the contact portions 1321a of the multiple connection portions 1321-1321 that contact the conductive support shafts 101 (101A-101C), at least one (all in this example) of the contact portions 1321a is located at a position offset in the axial direction G of the conductive support shafts 101 (101A-101C) relative to the other contact portions 1321a. Here, "position offset in the axial direction G" can refer to, for example, a configuration in which at least one contact portion 1321a is offset in an overlapping state relative to the other contact portions 1321a in the axial direction G, or a configuration in which it is offset in a non-overlapping state.

[0034] In this example, the contact points 1321a at the multiple connection points 1321-1321 contact the conductive support shaft 101 (101A-101C) at equal positions in the circumferential direction F. In the first type photoreceptor drum 13A shown in Figures 2 to 6, the conductive member 132A has two connection points 1321, 1321 that are offset by 180 degrees in the circumferential direction F. In the second type photoreceptor drum 13B shown in Figures 7 to 10, the conductive member 132B, and in the third type photoreceptor drum 13C shown in Figures 11 to 14, the conductive member 132C has three connection points 1321-1321 that are offset by 120 degrees each in the circumferential direction F.

[0035] According to this embodiment, of the contact portions 1321a of the plurality of connection portions 1321 to 1321 that contact the conductive support shaft 101 (101A to 101C), at least one contact portion 1321a is located at a position offset in the axial direction G from the other contact portions 1321a. This allows the contact area between the contact portions 1321a of the plurality of connection portions 1321 to 1321 and the conductive support shaft 101 (101A to 101C) to be dispersed in the axial direction G. As a result, when the photoreceptor drum 13 (13A to 13C) rotates around the rotation axis α relative to the conductive support shaft 101 (101A to 101C), wear of the conductive support shaft 101 (101A to 101C) at the sliding contact points with the contact portions 1321a of the plurality of connection portions 1321 to 1321 is made less likely. Therefore, wear of the conductive support shaft 101 (101A to 101C) due to the multiple connection parts 1321 to 1321 can be suppressed, thereby enabling stable grounding of the photoreceptor drum 13 (13A to 13C).

[0036] <First Embodiment> In this embodiment, the conductive support shaft 101 (101A~101C) has one or more recesses 101a, 101a~101a that are recessed around its entire circumference. The contact portions 1321a of the multiple connection portions 1321~1321 contact the recesses 101a.

[0037] Here, examples of how the contact portions 1321a of multiple connection portions 1321~1321 contact the recess 101a include, for example, when a conductive support shaft 101 (101A~101C) has one recess 101a, all of the contact portions 1321a of multiple connection portions 1321~1321 are contained within and in contact with one recess 101a (see Figures 12 and 13); and when a conductive support shaft 101 (101A~101C) has multiple recesses 101a~101a, each of the contact portions 1321a of multiple connection portions 1321~1321 contacts one recess 101a (see Figures 3, 4, 6, 8, and 9). Furthermore, it is not necessary for all of the contact portions 1321a of the multiple connection portions 1321 to 1321 to be in contact with the recess 101a, and some may be in contact with the conductive support shaft 101 (101A to 101C) at locations other than the recess 101a.

[0038] In this configuration, the contact portions 1321a of the multiple connection portions 1321-1321 contact the recess 101a. As the photoreceptor drum 13 (13A-13C) rotates around the rotation axis α relative to the conductive support shaft 101 (101A-101C), the contact portions 1321a of the multiple connection portions 1321-1321 can be stably slid into contact within the recesses 101a, 101a-101a of the conductive support shaft 101 (101A-101C) compared to the case where there are no recesses 101a, 101a-101a.

[0039] In this embodiment, the cross-sectional shape of the recess 101a can be a semicircle, an arc shape (an arc shape in this example), a rectangle, a trapezoid or V-shape in which the width in the axial direction G increases towards the open side.

[0040] <Second Embodiment> Figure 15 is a schematic cross-sectional view showing the state before (upper figure) and after (lower figure) the conductive support shafts 101 (101A to 101C), to which conductive grease W has been applied, are inserted into the insertion hole 133a of the flange member 133 (133A to 133C) provided at the end of the drum body 131 (131A to 131C), in the case where the conductive support shafts 101 (101A to 101C) of the first to third type photoreceptor drums 13A to 13C do not have a recess 101a.

[0041] Furthermore, Figures 16 to 18 are schematic cross-sectional views illustrating the state before (upper figure) and after (lower figure) insertion of the conductive support shafts 101 (101A to 101C) coated with conductive grease W into the insertion holes 133a of the flange members 133 (133A to 133C) provided at the end of the drum body 131 (131A to 131C), when recesses 101a are provided in the conductive support shafts 101 (101A to 101C) of the first to third type photoreceptor drums 13A to 13C, respectively.

[0042] Incidentally, from the viewpoint of reducing wear on the conductive support shafts 101 (101A~101C), conductive grease W is usually placed at the sliding contact points between the contact points 1321a (not shown in Figure 15) of the multiple connection parts 1321~1321 and the conductive support shafts 101 (101A~101C) and their vicinity. However, when assembling the photoreceptor drum 13 (13A~13C), it is difficult to apply conductive grease W to the conductive support shafts 101 (101A~101C) after they have been inserted into the insertion holes 133a of the flange members 133 (133A~133C).

[0043] Therefore, as shown in the upper diagram of Figure 15, conductive grease W is applied to the conductive support shaft 101 (101A~101C) before it is inserted into the insertion hole 133a of the flange member 133 (133A~133C). However, if the conductive support shaft 101 (101A~101C) does not have a recess 101a, the following inconveniences arise. In other words, when a conductive support shaft 101 (101A~101C) coated with conductive grease W is inserted into the insertion hole 133a of the flange member 133 (133A~133C), as shown in the lower diagram of Figure 15, only the amount of conductive grease W that has slipped through the gap between the insertion hole 133a of the flange member 133 (133A~133C) and the conductive support shaft 101 (101A~101C) remains, and the majority is discarded to the outside of the flange member 133 (133A~133C).

[0044] In this embodiment, the conductive support shaft 101 (101A~101C) has a recess 101a, so conductive grease W is applied to the recess 101a. That is, as shown in the upper figures from Figures 16 to 18, conductive grease W is applied to the recess 101a or the portion including the recess 101a of the conductive support shaft 101 (101A~101C), and the conductive support shaft 101 (101A~101C) with conductive grease W applied is inserted into the insertion hole 133a of the flange member 133 (133A~133C). In this case, as shown in the lower diagrams from Figures 16 to 18, in addition to remaining in the recess 101a, if the conductive grease W is protruding from the surface of the conductive support shaft 101 (101A~101C) and / or if the conductive grease W is applied to the portion including the recess 101a, then an amount remains that has slipped through the gap between the insertion hole 133a of the flange member 133 (133A~133C) and the conductive support shaft 101 (101A~101C) downstream in the direction of movement M of the photoreceptor drum 13 (13A~13C) from the position where the conductive grease W was applied, and almost none remains on the outside of the flange member 133 (133A~133C).

[0045] Therefore, a volume equivalent to or close to the volume of the recess 101a, or an amount of conductive grease W, can be contained within the recess 101a.

[0046] In this configuration, since conductive grease W is applied to the recess 101a, a sufficient amount of conductive grease W can be secured in the recess 101a for long-term use. Therefore, the conductive grease W makes it possible to prevent wear on the conductive support shaft 101 (101A~101C) over a long period of time.

[0047] Furthermore, even if some of the contact portions 1321a in the multiple connection portions 1321~1321 make contact at locations other than the recesses 101a in the conductive support shaft 101 (101A~101C), if conductive grease W remains downstream in the direction of movement M of the photoreceptor drum 13 (13A~13C) from the position where the conductive grease W was applied, the conductive support shaft 101 (101A~101C) can be made less susceptible to wear by the conductive grease W by bringing the contact portion 1321a into contact with the conductive grease W.

[0048] <Third Embodiment> In this embodiment, the width d1 (see Figure 6) in the axial direction G of the contact portion 1321a of the multiple connection portions 1321 to 1321 with the conductive support shaft 101 (101A to 101C) is smaller than the width d2 (see Figure 6) in the axial direction G of the portion of the flange member 133 (133A to 133C) into which the conductive support shaft 101 (101A to 101C) is inserted, facing the conductive support shaft 101 (101A to 101C). Note that the widths d1 and d2 are shown in the example in Figure 6, but the same applies to other examples.

[0049] In this configuration, the contact area of ​​the contact portion 1321a at the multiple connection portions 1321-1321 with the conductive support shaft 101 (101A-101C) can be made as small as possible, thereby making the conductive support shaft 101 (101A-101C) less susceptible to wear.

[0050] <Fourth Embodiment> In this embodiment, the configuration of the first type of photoreceptor drum 13A shown in Figures 2 to 6 will be described.

[0051] In the first type of photoreceptor drum 13A, the conductive member 132A further has a flat portion 1320. The flat portion 1320 is plate-shaped and oriented in a direction perpendicular to the axial direction G, and has a through hole 132a through which the conductive support shaft 101A passes. The through hole 132a is provided in the center of the flat portion 1320. The flat portion 1320 is also provided with a positioning through hole 132b and a positioning elongated through hole 132c.

[0052] Each of the multiple (two in this example) connection points 1321, 1321 has a plate-shaped, elastically deformable grounding plate 1321b.

[0053] The grounding plate 1321b in the multiple connection parts 1321, 1321 has a contact part 1321a at its tip, and the contact part 1321a contacts the conductive support shaft 101A by the central part of the planar part 1320 in the radial direction E curving along the conductive support shaft 101A (see Figures 3 to 5) or by the outer peripheral edge in the radial direction E being bent toward the conductive support shaft 101A (see Figure 6).

[0054] In this configuration, the grounding plates 1321b at multiple connection points 1321, 1321 contact the conductive support shaft 101A at the contact points 1321a because the central part of the planar portion 1320 in the radial direction E is curved along the conductive support shaft 101A, or because the outer peripheral edge in the radial direction E is bent toward the conductive support shaft 101A. This makes it easy and simple to realize a configuration in which the contact points 1321a at multiple connection points 1321, 1321 contact the conductive support shaft 101A. Furthermore, the conductive member 132A, which is composed of the planar portion 1320 and the grounding plates 1321b, can be easily manufactured by bending or cutting a single metal plate.

[0055] More specifically, in the photoreceptor drum 13A example shown in Figures 3 to 5, the grounding plates 1321b at multiple connection points 1321, 1321 are connected to bases 1321c (see Figure 5) at multiple locations (two locations in this example) in the circumferential direction F of the inner peripheral edge of the through hole 132a in the flat portion 1320. The grounding plates 1321b at multiple connection points 1321, 1321 are curved from the base 1321c along the conductive support shaft 101A, thereby contacting the conductive support shaft 101A at the contact portion 1321a. In the photoreceptor drum 13A example shown in Figure 6, the grounding plates 1321b at multiple connection points 1321, 1321 are connected to bases 1321c (see Figure 6) at multiple locations (two locations in this example) in the circumferential direction F of the outer peripheral edge. The grounding plates 1321b at multiple connection points 1321, 1321 are bent towards the conductive support shaft 101A after the base portion 1321c is bent, so that they come into contact with the conductive support shaft 101A at the contact portion 1321a.

[0056] The lengths L1 and L2 from the base 1321c of the ground plate 1321b to the contact portion 1321a (central portion in the axial direction G) with the conductive support shaft 101A are different (L1 > L2). In this example, the length L1 of one of the two ground plates 1321b is longer than the length L2 of the other. The tip 1321d of the ground plate 1321b is bent or curved so as to make point contact with the conductive support shaft 101A at the contact portion 1321a.

[0057] <Fifth Embodiment> In this embodiment, the configurations of the second type photoreceptor drum 13B shown in Figures 7 to 10 and the third type photoreceptor drum 13C shown in Figures 11 to 14 will be described.

[0058] In this embodiment, the conductive members 132B and 132C further have a flat portion 1320. The flat portion 1320 is plate-shaped and oriented in a direction perpendicular to the axial direction G, and has a through hole 132a through which the conductive support shafts 101B and 101C pass. The through hole 132a is provided in the center of the flat portion 1320. The flat portion 1320 is also provided with a positioning through hole 132b and a positioning elongated through hole 132c.

[0059] Each of the multiple (three in this example) connection points 1321-1321 has an earth plate support plate 1321e (see Figures 10 and 14) bent from the flat portion 1320 toward the conductive support shafts 101B and 101C, and a plate-shaped, elastically deformable earth plate 1321b (see Figures 10 and 14).

[0060] The grounding plates 1321b in the multiple connection sections 1321-1321 have a contact portion 1321a at their tip, and are bent towards the conductive support shaft 101A in the radial direction E from one of the ends 1321h (see Figures 10 and 14) of the two ends in the direction along the first bent portion 1321f (see Figures 10 and 14) with the flat portion 1320 of the grounding plate support plate 1321e, so that the contact portion 1321a contacts the conductive support shafts 101B and 101C.

[0061] In this configuration, the grounding plates 1321b at multiple connection points 1321-1321 are bent from one end 1321h in the direction along the first bent portion 1321f with the flat portion 1320 of the grounding plate support plate 1321e toward the conductive support shaft 101A in the radial direction E, so that they contact the conductive support shafts 101B and 101C at the contact portion 1321a, and can withstand stress in the circumferential direction F. Therefore, even if force is inadvertently applied to the photoreceptor drums 13B and 13C, they can be easily restored by elastic force against stress in the circumferential direction F. As a result, even if the photoreceptor drums 13B and 13C are biased by micro-vibrations during operation, stress on the opposite side, or excessive force is applied during assembly, the conductivity between the contact portion 1321a at multiple connection points 1321-1321 and the conductive support shafts 101B and 101C can be reliably maintained. Furthermore, conductive members 132B and 132C, which consist of a flat portion 1320, an earth plate support plate 1321e, and an earth plate 1321b, can be easily manufactured by cutting and bending a single metal sheet.

[0062] In this embodiment, the grounding plate support plates 1321e at the multiple connection portions 1321-1321 are bent parallel to the conductive support shafts 101B and 101C toward the conductive support shafts 101B and 101C from multiple first bend portions 1321f-1321f in the circumferential direction F of the outer edge of the flat portion 1320. The second bend portion 1321g between the grounding plate 1321b and the grounding plate support plate 1321e is along the axial direction G.

[0063] More specifically, the grounding plate support plate 1321e at multiple connection points 1321-1321 is bent along the axial direction G from multiple first bending points 1321f (see Figures 10 and 14) in the circumferential direction F of the outer edge of the flat portion 1320 (three points in this example). The grounding plate 1321b at multiple connection points 1321-1321 is bent towards the conductive support shaft 101A in the radial direction E from a second bending point 1321g at the end of the grounding plate support plate 1321e along the axial direction G opposite to the flat portion 1320, thereby contacting the conductive support shafts 101B and 101C at the contact point 1321a.

[0064] This configuration facilitates the cutting and bending process when manufacturing the conductive member 132 (132B, 132C), which is composed of a flat section 1320, an earth plate support plate 1321e, and an earth plate 1321b.

[0065] In the photoreceptor drums 13B and 13C, the lengths L3 to L5 in the axial direction G from the first bent portion 1321f to the contact portion (central part in the axial direction G) of the contact portion 1321a with the conductive support shafts 101B and 101C are different from each other (L5 > L4 > L3). In this example, the lengths L3, L4, and L5 of the three ground plate support plates 1321e, which are arranged in a rotational direction around the rotation axis α, are increasing in this order. The tip portion 1321d of the ground plate 1321b is bent or curved so as to make point contact with the conductive support shafts 101B and 101C at the contact portion 1321a.

[0066] <Sixth Embodiment> In this embodiment, the conductive members 132 (132A to 132C) are positioned and fixed to the flange members 133 (133A to 133C) into which the conductive support shafts 101 (101A to 101C) are inserted.

[0067] In this configuration, the conductive members 132 (132A to 132C) can be securely fixed to the flange members 133 (133A to 133C), thereby ensuring that the multiple contact points 1321a to 1321a at the connection portion 1321 of the conductive members 132 (132A to 132C) make secure contact with the conductive support shaft 101 (101A to 101C).

[0068] This disclosure is not limited to the embodiments described above, and can be implemented in a variety of other ways. Therefore, these embodiments are merely illustrative in all respects and should not be constrained. The scope of this disclosure is defined by the claims and is not restricted by the text of the specification. Furthermore, any variations or modifications falling within the equivalent scope of the claims are all within the scope of this disclosure. [Explanation of symbols]

[0069] 100 Image forming apparatus 101 Conductive support shaft 101a Recess 13 Photoconductor drum 131 Drum body 132 Conductive material 1320 Plane section 1321 Connection part 1321a Contact part 1321b Grounding plate 1321c base 1321d Tip 1321e Grounding plate support plate 1321f First folding section 1321g Second fold section 1321h End 1322 Main unit side connection part 132a Through hole 133 Flange member 133a Insertion hole 13a Outer surface 13b Inner surface 300 process units E radial direction F Circumferential direction FL main frame G-axis direction M Direction of movement W conductive grease X Left / right direction Y (depth direction) Z vertical direction α rotation axis

Claims

1. A photoreceptor drum comprising: a drum body having a photosensitive layer formed on its outer surface and rotating around a rotation axis with respect to a conductive support shaft; and a conductive member for grounding the inner surface of the drum body via the conductive support shaft, wherein the conductive member has a plurality of connection parts electrically connected to the conductive support shaft, A photoreceptor drum characterized in that, of the contact portions of the plurality of connection portions that contact the conductive support shaft, at least one contact portion is located at a position offset in the axial direction of the conductive support shaft relative to the other contact portions.

2. A photoreceptor drum according to claim 1, The conductive support shaft has one or more recesses that extend around its entire circumference. A photoreceptor drum characterized in that the contact portion in the plurality of connection portions contacts the recess.

3. A photoreceptor drum according to claim 2, The drum body further comprises a pair of flange members provided at both ends in the axial direction, At least one of the pair of flange members has an insertion hole into which the conductive support shaft is inserted. A photoreceptor drum characterized in that conductive grease is applied to the recess.

4. A photoreceptor drum according to claim 1, The drum body further comprises a pair of flange members provided at both ends in the axial direction, At least one of the pair of flange members has an insertion hole into which the conductive support shaft is inserted. A photoreceptor drum characterized in that the width in the axial direction of the contact portion of the contact portion with the conductive support shaft in the plurality of connection portions is smaller than the width in the axial direction of the portion of the flange member into which the conductive support shaft is inserted that faces the conductive support shaft.

5. A photoreceptor drum according to claim 1, The conductive member further has a plate-shaped planar portion oriented in a direction perpendicular to the axial direction, The planar portion has a through hole through which the conductive support shaft passes, Each of the aforementioned multiple connection parts has a plate-shaped, elastically deformable grounding plate, A photoreceptor drum characterized in that the ground plate in the plurality of connection portions has the contact portion at its tip, and the contact portion contacts the conductive support shaft by the central portion in the radial direction of the planar portion curving along the conductive support shaft side or by being bent from the outer peripheral edge in the radial direction toward the conductive support shaft side.

6. A photoreceptor drum according to claim 1, The conductive member further has a plate-shaped planar portion oriented in a direction perpendicular to the axial direction, The planar portion has a through hole through which the conductive support shaft passes, Each of the aforementioned multiple connection portions includes an earth plate support plate bent from the flat portion toward the conductive support shaft, and a plate-shaped, elastically deformable earth plate. The photoreceptor drum is characterized in that the ground plate in the plurality of connection portions has the contact portion at its tip, and is bent radially toward the conductive support shaft from one of the ends on both sides in the direction along the first bend portion with the flat portion of the ground plate support plate, thereby making contact with the conductive support shaft at the contact portion.

7. A photoreceptor drum according to claim 6, The earth plate support plate in the plurality of connection portions is bent parallel to the conductive support shaft from the plurality of first bend portions in the circumferential direction of the outer edge of the flat portion toward the conductive support shaft, A photoreceptor drum characterized in that the second bent portion of the ground plate with respect to the ground plate support plate is aligned with the axial direction.

8. A photoreceptor drum according to claim 1, The drum body further comprises a pair of flange members provided at both ends in the axial direction, At least one of the pair of flange members has an insertion hole into which the conductive support shaft is inserted. The photoreceptor drum is characterized in that the conductive member is positioned and fixed to the flange member into which the conductive support shaft is inserted.

9. An image forming apparatus characterized by comprising a photoreceptor drum according to any one of claims 1 to 8, and the conductive support shaft.

Images