Image forming apparatus

Abstract

An image forming apparatus is provided with: a first shaft (for example, a shaft (11S)) provided at one of a photosensitive drum and a developing roller; a second shaft (for example, a shaft (32S)) provided at the other of the photosensitive drum and the developing roller; a first housing for supporting the first shaft; a second housing for supporting the second shaft; a cylindrical support portion (22) provided at an end portion in the axial direction of the first shaft of the first housing, surrounding the first shaft without contacting the first shaft; and a first adjustment member (51) fitted outside the support portion (22), rotatable in the circumferential direction of the support portion (22), an outer peripheral surface (51o) of the first adjustment member (51) being a curved surface in the shape of an eccentric circle with respect to the support portion (22), and contacting the second housing. Thus, the accuracy of adjustment of the spacing of the developing roller and the photosensitive drum can be improved.

Description

Technical Field

[0001] This invention relates to an image forming apparatus. Background Technology

[0002] In electrophotographic image forming apparatuses, a known structure includes gap-limiting members, slightly larger than the diameter of the developing roller, located at both axial ends of the developing roller. These gap-limiting members contact a photosensitive drum, thereby establishing a predetermined gap between the outer circumferential surface of the developing roller and the outer circumferential surface of the photosensitive drum. However, in this structure, due to the cumulative effect of tolerances of each component, errors may occur in the gap between the developing roller and the photosensitive drum.

[0003] Typically, research focuses on techniques for adjusting the spacing between the developing roller and the photosensitive drum. For example, known electrophotographic devices include: an axis-to-axis distance adjustment mechanism that adjusts the axis-to-axis distance to displace the developer carrier relative to the photoreceptor along the contact separation direction; a locking mechanism that locks the adjusted position of the developer carrier in the contact separation direction at multiple points; and a fixing mechanism that fixes the adjusted position adjusted by the axis-to-axis distance adjustment mechanism. The axis-to-axis distance adjustment mechanism includes: an eccentric cam that displaces the rotation axis relative to the rotation axis of the developer carrier; and a positioning part disposed on the eccentric cam to position the developer carrier. The locking mechanism includes: an engaging part disposed on the eccentric cam, having multiple protrusions and recesses along the rotation direction of the eccentric cam around the rotation axis; and a locking part having locking claws that lock the protrusions and recesses. Summary of the Invention

[0004] However, in the structure of the aforementioned conventional electrophotographic apparatus, since the end of the developing roller's shaft is embedded in the recess of the eccentric cam, the vibration accompanying the rotation of the developing roller is transmitted to the photosensitive drum via the eccentric cam, potentially causing variations in image quality. To avoid this problem, for example, components can be considered in the developing housing and photosensitive housing that do not contact the shafts of the developing roller and photosensitive drum but can move in directions that allow them to approach or separate from each other. However, in such a structure, the accuracy of the interval adjustment may be reduced due to deformation or positional misalignment of the components.

[0005] In view of the above circumstances, the present invention aims to provide an image forming apparatus that can improve the accuracy of adjusting the interval between the developing roller and the photosensitive drum.

[0006] An image forming apparatus according to one aspect of the present invention includes: a photosensitive drum; a developing roller; a first shaft disposed on one of the photosensitive drum and the developing roller; a second shaft disposed on the other of the photosensitive drum and the developing roller; a first housing for supporting the first shaft; a second housing for supporting the second shaft; a cylindrical support portion disposed at the axial end of the first shaft in the first housing and surrounding the first shaft without contacting it; and a first adjustment member fitted on the outside of the support portion and rotatable along the circumference of the support portion, wherein the outer peripheral surface of the first adjustment member is an arc-shaped curved surface eccentric to the support portion and contacts the second housing.

[0007] According to the present invention, the accuracy of adjusting the gap between the developing roller and the photosensitive drum can be improved. Attached Figure Description

[0008] Figure 1 It is a front view schematically showing the internal structure of the image forming apparatus.

[0009] Figure 2 This is a perspective view showing the appearance of the photosensitive unit according to the first embodiment.

[0010] Figure 3 This is a perspective view showing the appearance of the developing unit according to the first embodiment.

[0011] Figure 4 as well as Figure 5 This is a schematic front view showing the internal structure of the photosensitive unit and the developing unit according to the first embodiment.

[0012] Figure 6 This is a perspective view showing the rear portion of the photosensitive unit and the developing unit according to the first embodiment.

[0013] Figure 7 This is a perspective view showing the case where the first adjustment component and the second adjustment component according to the first embodiment are provided.

[0014] Figure 8 This is a perspective view showing the first adjustment component and the second adjustment component according to the first embodiment.

[0015] Figure 9 This is a rear view showing the first adjustment component and the second adjustment component according to the first embodiment.

[0016] Figure 10 This is a perspective view showing the case where the shaft of the photosensitive drum according to the first embodiment is provided.

[0017] Figure 11 This is a perspective view showing the front portion of the photosensitive unit and the developing unit according to the second embodiment.

[0018] Figure 12 This is a perspective view showing the case where the first contact member and the second contact member according to the second embodiment are provided.

[0019] Figure 13 This is a perspective view showing the first contact component involved in the second embodiment.

[0020] Figure 14 This is a perspective view showing the second contact component according to the second embodiment.

[0021] Figure 15 This is a perspective view showing the case where the first cover and the second cover according to the second embodiment are provided.

[0022] Figure 16 This is a front view of the first cover and the second cover according to the second embodiment.

[0023] Figures 17 to 19 This is a second-line cross-sectional view showing the operation of installing the photosensitive unit while the image forming apparatus has the developing unit installed.

[0024] Figures 20 to 22 This is a second-line cross-sectional view showing the operation of the developing unit when the image forming apparatus has a photosensitive unit installed. Detailed Implementation

[0025] Hereinafter, an image forming apparatus 100 according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0026] First, the overall structure of the image forming apparatus 100 will be explained. Figure 1 This is a schematic front view showing the internal structure of the image forming apparatus 100. Hereinafter, Figure 1 The front side of the paper in the diagram is referred to as the front side (front side) of the image forming apparatus 100, and the left and right directions are described based on the direction of viewing the image forming apparatus 100 from the front. In each figure, U, Lo, L, R, Fr, and Rr represent up, down, left, right, front, and back, respectively.

[0027] The image forming apparatus 100 includes a printer 1, a scanner 110, and a document transport device 120. The scanner 110 is positioned above the printer 1, and the document transport device 120 is positioned above the scanner 110. The document transport device 120 transports the original document via the reading position of the scanner 110. The scanner 110 is a flatbed image scanner. The scanner 110 reads the original document and generates image data. The printer 1 forms an image based on the image data on paper S.

[0028] Printer 1 has a rectangular main body housing 3. Inside the lower part of the main body housing 3, there is a paper tray 4 for holding paper S and a paper feed roller 5 for feeding the paper S from the paper tray 4 to the right. Above the paper tray 4, there is an imaging device 6 for forming a toner image by electrophotography. Above and to the right of the imaging device 6, there is a fixing device 7 for fixing the toner image onto the paper S. Above the fixing device 7, there is an ejector roller 8 for ejecting the paper S with the fixed toner image; and an ejector tray 9 for loading the ejected paper S.

[0029] Inside the main housing 3, a transport path 10 is provided, leading from the paper feed roller 5 through the imaging device 6 and the fixing device 7 to the discharge roller 8. The transport path 10 is formed using plate-shaped members that are positioned opposite each other and separated by gaps for the paper S to pass through. In the transport path 10, multiple transport rollers 17, which hold and transport the paper S, are provided along the transport direction Y. A correction roller 18 is provided upstream of the imaging device 6 in the transport direction Y. To the right of the fixing device 7, a reverse transport path 10R is provided. This reverse transport path 10R branches off from the transport path 10 downstream of the fixing device 7 in the transport direction Y and merges with the transport path 10 upstream of the correction roller 18 in the transport direction Y.

[0030] The imaging device 6 includes: a photosensitive drum 11 whose potential changes upon exposure to light; a charging device 12 that charges the photosensitive drum 11; an exposure device 13 that emits a laser corresponding to image data; a developing unit 14 that supplies toner to the photosensitive drum 11; an intermediate transfer unit 15 that transfers the toner image from the photosensitive drum 11 to paper S; and a cleaning device 16 that removes residual toner from the photosensitive drum 11. The intermediate transfer unit 15 includes: an annular intermediate transfer belt 15B wound around a drive roller 15D and a driven roller 15N; a primary transfer roller 151 positioned opposite the inner circumference of the intermediate transfer belt 15B at a position corresponding to the photosensitive drum 11, generating a primary transfer bias; and a secondary transfer roller 152 positioned opposite the outer circumference of the intermediate transfer belt 15B at a position corresponding to the drive roller 15D, generating a secondary transfer bias. In the developing unit 14, a toner container 20 is connected to supply toner to the developing unit 14.

[0031] The imaging apparatus 6 includes four photosensitive drums 11, a charging device 12, an exposure device 13, a developing unit 14, a primary transfer roller 151, a cleaning device 16, and a toner container 20. The imaging apparatus 6 forms a color image by overlaying four colors of toner images onto an intermediate transfer belt 15B. Furthermore, this invention can also be applied to an image forming apparatus 100 that uses three or fewer colors or five or more colors of toner to form a color image.

[0032] The control unit 2 includes an arithmetic unit and a storage unit. The arithmetic unit is, for example, a CPU (Central Processing Unit). The storage unit includes storage media such as ROM (Read Only Memory), RAM (Random Access Memory), or EEPROM (Electrically Erasable Programmable Read Only Memory). The arithmetic unit performs various processes by reading and executing control programs stored in the storage unit. Furthermore, the control unit 2 can also be implemented using integrated circuits without software.

[0033] A display operation unit is provided on the front side of the scanner 110. The display operation unit includes a display panel, a touch panel that is overlapped on the display surface of the display panel, and a keypad adjacent to the display panel. The control unit 2 causes the display panel to display a screen showing the operation menu or status of the printer 1 and the scanner 110. The control unit 2 controls various parts of the printer 1 and the scanner 110 based on the operations detected by the touch panel and the keypad.

[0034] The basic image forming operation of printer 1 is as follows. If a single-sided printing job is input to printer 1 from a display operation unit or an external computer, the paper feed roller 5 feeds paper S from the paper tray 4 to the transport path 10. The correction roller 18 corrects the skew of the paper S while rotating at a stopped state, and feeds the paper S to the imaging unit 6 at a predetermined time. In the imaging unit 6, the charging device 12 charges the photosensitive drum 11 to a predetermined potential, the exposure device 13 writes a latent image onto the photosensitive drum 11, and the developing unit 14 develops the latent image using toner supplied from the toner container 20, thereby forming a toner image. The primary transfer roller 151 transfers the toner image to the intermediate transfer belt 15B, and the secondary transfer roller 152 transfers the toner image to the paper S. The fixing device 7 fuses the toner image while holding and transporting the paper S, thereby fixing the toner image onto the paper S. The discharge roller 8 discharges the paper S to the paper discharge tray 9. The cleaning device 16 removes residual toner from the photosensitive drum 11. In the case of double-sided printing, the paper S with the toner image fixed on the first side is fed into the transport path 10 via the reverse transport path 10R. As a result, the toner image is transferred to the second side of the paper S.

[0035] Next, the photosensitive unit 24 and the developing unit 14 will be described. Figure 2 This is a three-dimensional view showing the appearance of the photoreceptor unit 24. Figure 3 This is a perspective view showing the appearance of the developing unit 14. Figure 4 as well as Figure 5This is a schematic front view showing the internal structure of the photoreceptor unit 24 and the developing unit 14.

[0036] [Photoreceptor unit 24]

[0037] The photoreceptor unit 24 is an integrated unit that houses the photosensitive drum 11, the charging device 12, and the cleaning device 16 within the photoreceptor housing 21. The lower part of the photoreceptor housing 21 is box-shaped with the longitudinal direction as its long side. The charging device 12 is housed inside the lower part of the photoreceptor housing 21. A support frame 60 is provided in the main housing 3. A photoreceptor housing support part 62 is provided in the support frame 60 and is embedded in the lower part of the photoreceptor housing 21. The photosensitive drum 11 is positioned above the charging device 12. The cleaning device 16 is positioned on the right side of the photosensitive drum 11. The shaft 11S of the photosensitive drum 11 is supported by bearings provided at both the front and rear ends of the photoreceptor housing 21 and protrudes from the outer surfaces of both ends of the photoreceptor housing 21. A driven gear 11G is provided at the rear end of the shaft 11S of the photoreceptor drum 11.

[0038] [Developing Unit 14]

[0039] The developing unit 14 includes two screws 33, a developing roller 32, a developing housing 31, and a scraper 34. The two screws 33 rotate about an axis to agitate the developer. The developing roller 32 holds the developer above the screws 33. The developing housing 31 has an opening 31A that accommodates the screws 33 and the developing roller 32, with a portion of the outer peripheral surface of the developing roller 32 exposed. The scraper 34 is positioned below the opening 31A to limit the thickness of the developer layer held on the developing roller 32. Both the developing roller 32 and the screws 33 are axially arranged in the back-and-forth direction.

[0040] The developer is, for example, a two-component developer comprising a magnetic carrier and non-magnetic toner. Two screws 33 are arranged parallel to each other inside the developing housing 31, delivering the developer in opposite directions. A partition wall 31W is provided between the two screws 33. Gaps are provided between the front end of the partition wall 31W and the inner surface of the developing housing 31, and between the rear end of the partition wall 31W and the inner surface of the developing housing 31. The developer circulates around the partition wall 31W through these gaps. The screws 33 agitate the developer, thereby causing the toner to become triboelectrically charged.

[0041] The developing roller 32 is arranged parallel above the screw 33 on the right side. The developing roller 32 includes a permanent magnet and a developing sleeve formed of a non-magnetic material covering the periphery of the permanent magnet. The shaft 32S of the developing roller 32 is supported by bearings located at both ends of the developing housing 31, protruding from the outer surfaces of both ends of the developing housing 31. A driven gear 32G is provided at the rear end of the shaft 32S of the developing roller 32. An opening 31A is formed on the upper right side of the developing housing 31, and the outer peripheral surface of the developing roller 32 exposed through the opening 31A faces the outer peripheral surface of the photosensitive drum 11. Developer forms a layer of magnetic brushes on the surface of the developing roller 32. A scraper 34 is positioned at a predetermined interval from the developing roller 32 at its front end, adjusting the thickness of the magnetic brush layer to a predetermined thickness.

[0042] The support frame 60 has two fulcrums 61 at the front and rear of the photosensitive unit 24 side supporting the lower part of the developing housing 31. A fulcrum connection portion 31P connected to the fulcrums 61 is provided at the lower part of the developing housing 31. The fulcrums 61 and the fulcrum connection portion 31P function as rotational fulcrums with the front-rear direction as the axis. The developing housing 31 can swing around the fulcrum 61. To the left of the fulcrum 61, a force-applying member 35 is provided. The force-applying member 35 is, for example, a compression coil spring inserted between the support frame 60 and the developing housing 31. The force-applying member 35 applies force to the developing housing 31 towards the photosensitive housing 21. Alternatively, an eccentric cam or a magnetic spring may be used instead of the force-applying member 35, or a structure that pushes the developing housing 31 towards the photosensitive housing 21 by gravity may also be used.

[0043] Figure 4 as well as Figure 5 This indicates the swinging state of the developing housing 31. Figure 4 This indicates that the force resisting the force applied by the force-applying component 35 is not applied, which is the state in which the developing roller 32 is closest to the photosensitive drum 11, that is, the state in which the developing roller 32 is in contact with the photosensitive drum 11. Figure 5 This indicates the state in which the developing housing 31 is pushed back in a counterclockwise direction against the force applied by the force-applying component 35, and the state in which the developing roller 32 leaves the photosensitive drum 11.

[0044] [First Implementation Method]

[0045] Next, the structure used to adjust the spacing between the developing roller 32 and the photosensitive drum 11 on the rear side of the imaging device 6 will be described. Figure 6 This is a perspective view showing the rear portion of the photoreceptor unit 24 and the developing unit 14. Figure 7 This is a perspective view showing the configuration of the first adjustment component 51 and the second adjustment component 52. Figure 8 This is a perspective view showing the first adjustment component 51 and the second adjustment component 52. Figure 9This is a rear view showing the first adjustment component 51 and the second adjustment component 52. Figure 10 This is a perspective view showing the case where the shaft 11S with the photosensitive drum 11 is provided.

[0046] The image forming apparatus 100 includes: a first shaft (e.g., shaft 11S) disposed on one of the photosensitive drum 11 and the developing roller 32; a second shaft (e.g., shaft 32S) disposed on the other of the photosensitive drum 11 and the developing roller 32; a first housing (e.g., photoreceptor housing 21) for supporting the first shaft; a second housing (e.g., developing housing 31) for supporting the second shaft; a cylindrical support portion 22 disposed at the axial end of the first housing and surrounding the first shaft without contacting it; and a first adjustment member 51 fitted onto the outside of the support portion 22 and capable of rotating circumferentially along the support portion 22. The outer peripheral surface 51o of the first adjustment member 51 is an arc-shaped curved surface eccentric to the support portion 22 and contacts the second housing. Furthermore, the shaft 11S, shaft 32S, photoreceptor housing 21, and developing housing 31 are as described above. Hereinafter, the support portion 22 and the first adjustment member 51 will be mainly described.

[0047] [Support section 22]

[0048] Support part 22 (refer to) Figure 6 The photosensitive drum 11 protrudes rearward from the rear end of the photosensitive housing 21. The support portion 22 extends through the entire length in the front-rear direction. The rear end of the shaft 11S of the photosensitive drum 11 (refer to...) Figure 10 The support portion 22 protrudes behind the support portion 22. The inner diameter of the support portion 22 is larger than the diameter of the shaft 11S of the photosensitive drum 11. The center of the support portion 22 coincides with the center of the shaft 11S. The support portion 22 is configured to surround the shaft 11S without contacting it.

[0049] [First Adjustment Component 51]

[0050] First adjustment component 51 (refer to) Figures 7 to 9 The first adjusting component 51 is a ring-shaped part as a whole. The inner circumferential surface of the first adjusting component 51 is circular. The first adjusting component 51 fits onto the outer side of the support portion 22 and can rotate circumferentially along the support portion 22.

[0051] The outer peripheral surface 51o of the first adjusting member 51 is approximately circular in shape as a whole. The portion of the outer peripheral surface 51o on the developing unit 14 side is eccentric relative to the support portion 22. Specifically, the portion of the outer peripheral surface 51o on the developing unit 14 side ( Figure 9 The diameter of the left-hand part gradually increases in a clockwise direction. Figure 9This indicates that the outer circumferential surface 51o gradually moves away from the imaginary line C representing the circle in a clockwise direction. In the portion of the outer circumferential surface 51o where the diameter gradually increases, a scale 51S is provided, serving as a reference for the rotation angle of the first adjustment member 51.

[0052] A threaded hole 26 is provided below the support portion 22 of the photosensitive housing 21 (see reference). Figure 6 At the lower part of the first adjusting member 51, at a position corresponding to the threaded hole 26, there is an elongated hole 51H along the circumferential direction (see reference). Figure 8 as well as Figure 9 When the screw 90 is loosely screwed in through the elongated hole 51H (refer to...) Figure 7 It can adjust the rotation angle of the first adjustment component 51 within the range of the elongated hole 51H.

[0053] [Second Adjustment Component 52]

[0054] Second adjustment component 52 (refer to) Figures 7 to 9 The second adjustment member 52 is located at the rear end of the developing housing 31. Its position in the front-rear direction is the same as that of the first adjustment member 51. The second adjustment member 52 is an elongated plate-shaped component in the left-right direction. The second adjustment member 52 has an opening 52A larger than the diameter of the shaft 32S of the developing roller 32. The shaft 32S protrudes rearward through the opening 52A. The second adjustment member 52 is configured such that the opening 52A does not contact the shaft 32S. At the right end of the second adjustment member 52, a contact surface 52F is provided that bulges out to the right in an arc shape.

[0055] At the rear end of the developing housing 31, to the lower right of the shaft 32S, there is a rearwardly protruding pin 37 (see reference). Figure 6 as well as Figure 7 In the second adjusting component 52, an elongated hole 52Ha is provided for receiving the pin 37 (see reference). Figure 8 as well as Figure 9 At the rear end of the developing housing 31, a threaded hole 36 is provided to the left of the shaft 32S. In the second adjusting member 52, an elongated hole 52Hb is provided at a position corresponding to the threaded hole 36. When the screw 90 is loosely screwed in through the elongated hole 52Hb, the left-right direction of the second adjusting member 52 can be adjusted within the range of the elongated hole 52Hb. The second adjusting member 52 is fixed to the developing housing 31 by welding. After adjusting the gap between the developing roller 32 and the photosensitive drum 11 by rotating the first adjusting member 51, the first adjusting member 51 is fixed to the photosensitive housing 21 by welding.

[0056] Because the developing housing 31 is forced towards the photosensitive housing 21 by the force-applying member 35, the contact surface 52F of the second adjusting member 52 abuts against the left side portion of the outer peripheral surface 51o of the first adjusting member 51 (see reference). Figure 9 The diameter of the left portion of the outer peripheral surface 51o of the first adjusting member 51 gradually increases in the clockwise direction. As a result, by rotating the first adjusting member 51 in the clockwise direction, the developing roller 32 approaches the photosensitive drum 11, and by rotating the first adjusting member 51 in the counterclockwise direction, the developing roller 32 moves away from the photosensitive drum 11.

[0057] As described above, the image forming apparatus 100 according to the first embodiment includes: a first shaft (e.g., shaft 11S) disposed on one of the photosensitive drum 11 and the developing roller 32; a second shaft (e.g., shaft 32S) disposed on the other of the photosensitive drum 11 and the developing roller 32; a first housing (e.g., photosensitive housing 21) for supporting the first shaft; a second housing (e.g., developing housing 31) for supporting the second shaft; a cylindrical support portion 22 disposed at the axial end of the first shaft of the first housing and surrounding the first shaft without contacting it; and a first adjustment member 51 fitted onto the outside of the support portion 22 and capable of rotating circumferentially along the support portion 22. The outer peripheral surface 51o of the first adjustment member 51 is an arc-shaped curved surface eccentric to the support portion 22 and contacts the second housing.

[0058] According to this structure, the first adjusting member 51 is supported throughout the entire circumference by the support portion 22, therefore, it is less prone to deformation compared to members that can move towards or away from the second axis. Furthermore, even when the second adjusting member 52 exerts a force pushing back against the first adjusting member 51, the first adjusting member 51 does not rotate, thus the distance between the first and second axes remains unchanged. Additionally, since the distance adjustment is performed by rotating an arc-shaped surface eccentric to the support portion 22 circumferentially, fine adjustments are easily made. Moreover, since the support portion 22 does not contact the first axis, vibrations caused by the rotation of the first axis are difficult to transmit to the first adjusting member 51 and the second adjusting member 52. Therefore, according to the first embodiment, the accuracy of adjusting the distance between the developing roller 32 and the photosensitive drum 11 can be improved.

[0059] Furthermore, according to the image forming apparatus 100 of the first embodiment, the first housing has a threaded hole 26 adjacent to the support portion 22. The first adjusting member 51 has an elongated hole 51H along the circumferential direction at a position corresponding to the threaded hole 26. With this structure, the first adjusting member 51 can be welded to the first housing while fixing the rotation angle of the first adjusting member 51, thus suppressing the deviation of the rotation angle during the welding process.

[0060] Furthermore, the image forming apparatus 100 according to the first embodiment includes an opening 52A, which is located at the axial end of the second shaft of the second housing and is larger than the diameter of the second shaft. It also includes a second adjustment member 52, which surrounds the second shaft without the opening 52A contacting it, and the second adjustment member 52 contacts a first adjustment member 51. According to this structure, vibrations caused by the rotation of the second shaft are difficult to transmit to the second adjustment member 52 and the first adjustment member 51, thus suppressing changes in the distance between the developing roller 32 and the photosensitive drum 11 caused by vibration.

[0061] Furthermore, the image forming apparatus 100 according to the first embodiment also includes a force-applying member 35, which applies force to the developing roller 32 in a direction approaching the photosensitive drum 11. This structure improves the reliability of the positioning of the developing roller 32.

[0062] [Modifications of the First Embodiment]

[0063] The first embodiment can also be modified as follows.

[0064] In the first embodiment, the support portion 22 and the first adjustment member 51 are provided at the rear end of the photoreceptor housing 21. However, the support portion 22 and the first adjustment member 51 may also be provided at the front end of the photoreceptor housing 21. Alternatively, the support portion 22 and the first adjustment member 51 may also be provided at both the front and rear ends of the photoreceptor housing 21.

[0065] In the first embodiment, the support portion 22 and the first adjustment component 51 are disposed in the photosensitive housing 21. However, the support portion 22 and the first adjustment component 51 may also be disposed in the developing housing 31.

[0066] [Second Implementation]

[0067] Next, the structure used to adjust the spacing between the developing roller 32 and the photosensitive drum 11 on the front side of the imaging device 6 will be described. Figure 11 This is a perspective view showing the front part of the photoreceptor unit 24 and the developing unit 14. Figure 12 This is a perspective view showing the configuration of the first contact member 41 and the second contact member 42. Figure 13 This is a perspective view of the first contact component 41.

[0068] Figure 14 This is a perspective view of the second contact component 42. Figure 15 This is a perspective view showing the configuration of a first cover 71 and a second cover 72. Figure 16 This is a front view of the first cover 71 and the second cover 72. Figure 17 It means Figure 16 A sectional view of section II. Furthermore... Figure 17 This indicates that the photoreceptor unit 24 is being pulled forward.

[0069] The image forming apparatus 100 includes: a first shaft (e.g., shaft 11S) disposed on one of the photosensitive drum 11 and the developing roller 32; a second shaft (e.g., shaft 32S) disposed on the other of the photosensitive drum 11 and the developing roller 32; a first housing (e.g., photoreceptor housing 21) for supporting the first shaft and capable of being inserted and removed axially; a second housing (e.g., developing housing 31) for supporting the second shaft and capable of being inserted and removed axially; a first contact member 41 disposed at an axial end of the first housing; a second contact member 42 disposed at an axial end of the second housing and in contact with the first contact member 41; a first cover 71 covering the first contact member 41; and a first cleaning member 71C disposed on the first cover 71 and rubs against the second contact member 42 when the second housing is inserted or removed. Furthermore, the shaft 11S, shaft 32S, photoreceptor housing 21, and developing housing 31 are as described above. The following mainly describes the first contact component 41, the second contact component 42, the first cleaning component 71C, and the second cleaning component 72C.

[0070] First contact component 41 and second contact component 42 (see reference) Figure 12 The first contact member 41 and the second contact member 42 are generally rectangular plate-shaped components whose long side is oriented along the line intersecting the axis 11S of the photosensitive drum 11 and the axis 32S of the developing roller 32. In the second embodiment, the axis 11S of the photosensitive drum 11 is located slightly above the axis 32S of the developing roller 32. Therefore, the line intersecting the axis 11S of the photosensitive drum 11 and the axis 32S of the developing roller 32 is inclined in a manner that the right side of the photosensitive drum 11 becomes higher. Therefore, the first contact member 41 and the second contact member 42 are also arranged at an angle that is slightly higher on the right side. Hereinafter, the direction of the line intersecting the axis 11S of the photosensitive drum 11 and the axis 32S of the developing roller 32 will be referred to as the adjustment direction A.

[0071] [First contact component 41]

[0072] First adjustment component 41 (refer to) Figure 13 At the left end of the first contact surface 41F, a contact surface 41F is provided that bulges out to the left in an arc shape. To the right of the first contact surface 41F, starting from left, an opening 41A, a clamp insertion part 41J, and an elongated hole 41Ha are provided in sequence. An elongated hole 41Hb is provided in the downward protruding part between the contact surface 41F and the opening 41A. The opening 41A is a roughly circular hole that extends through the front-rear direction, and its diameter is larger than the diameter of the shaft 11S of the photosensitive drum 11. The clamp insertion part 41J is a hole that extends through the front-rear direction. The elongated holes 41Ha and 41Hb extend through the front-rear direction and are formed with the adjustment direction A as the long side direction.

[0073] At the front end of the photoreceptor housing 21 (see reference) Figure 11 The photosensitive drum 11 has a threaded hole 26 corresponding to the elongated hole 41Ha and a pin 27 for insertion into the elongated hole 41Hb. The front end of the shaft 11S of the photosensitive drum 11 is inserted into the opening 41A (see reference). Figure 12 The first contact component 41 is fixed to the photosensitive housing 21 via an elongated hole 41Ha by a screw 90.

[0074] [Second contact component 42]

[0075] Second contact component 42 (refer to) Figure 14 The second contact member 42 has a basic shape that is generally the same as that of the first contact member 41. At the right end of the second contact member 42, a contact surface 42F is provided that bulges out to the right in an arc shape. To the left of the contact surface 42F, starting from the right, an opening 42A, a clamp insertion portion 42J, and an elongated hole 42Ha are provided sequentially. The distance between the contact surface 42F and the opening 42A is shorter than the distance between the contact surface 41F and the opening 41A. An elongated hole 42Hb is provided in the downward protruding portion between the contact surface 42F and the opening 42A. The opening 42A is a generally circular hole that extends through the front-rear direction, and its diameter is larger than the diameter of the shaft 32S of the developing roller 32. The clamp insertion portion 42J is a hole that extends through the front-rear direction. The elongated holes 42Ha and 42Hb extend through the front-rear direction, with the adjustment direction A as the long side direction.

[0076] At the front end of the developing housing 31 (see reference) Figure 11 The developing roller 32 has a threaded hole 36 corresponding to the elongated hole 42Ha and a pin 37 for insertion into the elongated hole 42Hb. The front end of the shaft 32S of the developing roller 32 is inserted into the opening 42A (see reference). Figure 12 The second contact component 42 is fixed to the developing housing 31 via an elongated hole 42Ha by a screw 90.

[0077] Screws 90 are loosely screwed in through elongated holes 41Ha and 42Ha, causing one or both of the first contact member 41 and the second contact member 42 to move along the adjustment direction A, thereby adjusting the distance between the developing roller 32 and the photosensitive drum 11.

[0078] [First cleaning component 71C and second cleaning component 72C]

[0079] The front end of the photosensitive housing 21 and the first contact member 41 are covered by the first cover 71 (see reference). Figure 15 as well as Figure 16The first cover 71 has an opening 71A with a diameter larger than the shaft 11S at a position corresponding to the shaft 11S of the photosensitive drum 11. The shaft 11S protrudes forward from the opening 71A. The upper left portion 71F of the first cover 71 is formed into a convex arc shape along the outer peripheral surface of the photosensitive drum 11. A first cleaning member 71C is provided in the upper left portion 71F of the first cover 71. The first cleaning member 71C is, for example, a brush.

[0080] The front end of the developing housing 31 and the second contact member 42 are covered by a second cover 72. The second cover 72 has an opening 72A with a diameter larger than the shaft 32S at a position corresponding to the shaft 32S of the developing roller 32. The shaft 32S protrudes forward through the opening 72A. The upper right portion 72F of the second cover 72 is formed into a concave arc shape that does not interfere with the first cover 71. A second cleaning member 72C is provided at the upper right portion 72F of the second cover 72. The second cleaning member 72C is, for example, a brush with bristles longer than the first cleaning member 71C.

[0081] Next, the operation of the image forming apparatus 100 according to the second embodiment will be described. Figures 17 to 19 This is a second-line cross-sectional view showing the operation of the photosensitive unit 24 when the image forming apparatus 100 is equipped with the developing unit 14.

[0082] The photosensitive unit 24 is inserted from the front to the rear of the image forming apparatus 100 (see reference). Figure 17 At this time, in order to prevent interference between the photoreceptor unit 24 and the developing unit 14, such as... Figure 5 As shown, resistance is applied to the force-applying component 35 in advance, causing the developing unit 14 to move away from the photosensitive unit 24.

[0083] The front end of the second cleaning member 72C is located inside (rear) of the first contact member 41. As the photosensitive unit 24 is pushed in, the first contact member 41 approaches the second cleaning member 72C. When the rear end of the first contact member 41 passes the position of the front end of the second cleaning member 72C, the first contact member 41 moves rearward while rubbing against the second cleaning member 72C (see reference). Figure 18 As a result, when foreign matter adheres to the first contact member 41, the foreign matter is removed by the second cleaning member 72C.

[0084] When the photoreceptor unit 24 is inserted, the first contact member 41 and the second contact member 42 are positioned opposite each other (see reference). Figure 19 In this state, such as Figure 4As shown, the resistance to the force-applying member 35 is removed, allowing the developing unit 14 to approach the photosensitive unit 24. As a result, the first contact member 41 and the second contact member 42 come into contact, and the photosensitive drum 11 and the developing roller 32 are positioned opposite each other at a predetermined interval.

[0085] Figures 20 to 22 This is a second-line cross-sectional view showing the operation of the developing unit 14 when the image forming apparatus 100 has the photosensitive unit 24 installed.

[0086] The developing unit 14 is inserted from the front to the rear of the image forming apparatus 100 (see reference). Figure 20 Similarly, in this case, to prevent interference between the photoreceptor unit 24 and the developing unit 14, such as... Figure 5 As shown, resistance is applied to the force-applying component 35 in advance, causing the developing unit 14 to move away from the photosensitive unit 24 and insert itself.

[0087] The front end of the first cleaning member 71C is located inside (rear) of the second contact member 42. As the developing unit 14 is pushed in, the second contact member 42 approaches the first cleaning member 71C. When the rear end of the second contact member 42 passes the position of the front end of the first cleaning member 71C, the second contact member 42 moves rearward while rubbing against the first cleaning member 71C (see reference). Figure 21 As a result, when foreign matter adheres to the second contact member 42, the foreign matter is removed by the first cleaning member 71C.

[0088] When the second contact member 42 passes the position of the first cleaning member 71C, the second cleaning member 72C moves backward while rubbing against the first cleaning member 71C. At this time, since the lengths of the bristles of the first cleaning member 71C and the second cleaning member 72C are different, the entanglement between the first cleaning member 71C and the second cleaning member 72C can be suppressed.

[0089] When the development unit 14 is inserted, the second contact member 42 is positioned opposite the first contact member 41 (see reference). Figure 22 In this state, such as Figure 4 As shown, the resistance to the force-applying member 35 is removed, allowing the developing unit 14 to approach the photosensitive unit 24. As a result, the first contact member 41 and the second contact member 42 come into contact, and the photosensitive drum 11 and the developing roller 32 are positioned opposite each other at a predetermined interval.

[0090] As described above, the image forming apparatus 100 according to the second embodiment includes: a first shaft (e.g., shaft 11S) disposed on one of the photosensitive drum 11 and the developing roller 32; a second shaft (e.g., shaft 32S) disposed on the other of the photosensitive drum 11 and the developing roller 32; a first housing (e.g., photosensitive housing 21) for supporting the first shaft and capable of being inserted and removed axially; a second housing (e.g., developing housing 31) for supporting the second shaft and capable of being inserted and removed axially; a first contact member 41 disposed at an axial end of the first housing; a second contact member 42 disposed at an axial end of the second housing and in contact with the first contact member 41; a first cover 71 covering the first contact member 41; and a first cleaning member 71C disposed on the first cover 71 and rubs against the second contact member 42 when the second housing is inserted or removed. According to this structure, foreign matter attached to the second contact member 42 used for adjusting the distance between the developing roller 32 and the photosensitive drum 11 can be removed. As a result, the accuracy of adjusting the distance between the developing roller 32 and the photosensitive drum 11 can be improved.

[0091] Furthermore, the image forming apparatus 100 according to the second embodiment includes: a second cover 72 that covers the second contact member 42; and a second cleaning member 72C that is disposed on the second cover 72 and rubs against the first contact member 41 when the first housing is inserted or removed. According to this structure, foreign matter attached to the second contact member 42 and foreign matter attached to the first contact member 41 can be removed. As a result, the accuracy of adjusting the distance between the developing roller 32 and the photosensitive drum 11 can be further improved.

[0092] Furthermore, according to the image forming apparatus 100 of the second embodiment, the first cleaning member 71C and the second cleaning member 72C are brushes with different bristle lengths. With this structure, compared to the case where the bristle lengths of the first cleaning member 71C and the second cleaning member 72C are the same, entanglement between the first cleaning member 71C and the second cleaning member 72C can be suppressed.

[0093] [Modifications of the Second Embodiment]

[0094] The second embodiment can also be modified as follows.

[0095] In the second embodiment, both the first cleaning component 71C and the second cleaning component 72C are brushes. However, it is also possible that one of the first cleaning component 71C and the second cleaning component 72C is a felt, and the other is a brush. With this structure, entanglement between the first cleaning component 71C and the second cleaning component 72C can also be suppressed.

[0096] In the second embodiment, the first contact member 41 and the second contact member 42 are disposed at the front end of the photoreceptor housing 21 and the developing housing 31, but the first contact member 41 and the second contact member 42 may also be disposed at the rear end of the photoreceptor housing 21 and the developing housing 31.

Claims

1. An image forming apparatus, characterized in that, have: Photosensitive drum; developing roller; The first axis is disposed on one of the photosensitive drum and the developing roller; The second axis is disposed on the other side of the photosensitive drum and the developing roller; A first housing is used to support the first shaft; The second housing is used to support the second shaft; A cylindrical support portion is disposed at the axial end of the first shaft of the first housing and surrounds the first shaft without contacting it. as well as The first adjustment component, which fits onto the outside of the support portion, is capable of rotating circumferentially along the support portion. The outer peripheral surface of the first adjusting component is an arc-shaped curved surface that is eccentric to the support portion and contacts the second housing. The image forming apparatus has an opening located at the axial end of the second shaft of the second housing, which is larger than the diameter of the second shaft, and a second adjustment member that surrounds the second shaft without the opening contacting the second shaft, wherein the second adjustment member contacts the first adjustment member.

2. The image forming apparatus according to claim 1, characterized in that, The first housing has a threaded hole adjacent to the support portion. The first adjusting component has an elongated hole along the circumferential direction at a position corresponding to the threaded hole.

3. The image forming apparatus according to claim 1, characterized in that, It also has a force-applying component that applies force to the developing roller in a direction close to the photosensitive drum.

4. The image forming apparatus according to claim 1, characterized in that, The diameter of the portion of the outer peripheral surface of the first adjustment member on the developing roller side gradually increases in a clockwise direction, and a scale is provided on the portion of the diameter that gradually increases, serving as a reference for the rotation angle of the first adjustment member.

Images