Image forming apparatus

Abstract

An image forming apparatus is provided. The image forming apparatus has a developing device, a photosensitive drum unit, a side plate, a notch portion, a swing member, and a force applying member. The developing device has a developing roller. The photosensitive drum unit includes a photosensitive drum configured such that an outer circumferential surface thereof faces an outer circumferential surface of the developing roller, and has a protruding portion protruding in an axial direction of the photosensitive drum. The side plate faces an end surface of the photosensitive drum unit in the axial direction. The notch portion is provided at a mounting position of the side plate at which the photosensitive drum unit is mounted, and is open upward. The swing member swings in a direction intersecting the axial direction toward a direction in which the protruding portion protrudes into the notch portion and a direction in which the protruding portion is away from the notch portion. The force applying member applies a force to the swing member in a direction in which the protruding portion approaches the notch portion. In a case where the swing member is pushed back by the protruding portion of the photosensitive drum unit inserted into the notch portion from above and the protruding portion reaches a bottom of the notch portion, the swing member pushes the protruding portion against the notch portion by a load including a downward component. Accordingly, it is possible to reduce an operation required for dismounting the photosensitive drum unit.

Description

Technical Field

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

[0002] In electrophotographic image forming apparatuses, the structure is generally configured such that a photosensitive drum unit with a photosensitive drum and a developing unit are detachable. For example, sometimes a positioning part and a supporting part are provided on the side plate of the main body of the image forming apparatus, and the processing cartridge is mounted to the image forming apparatus main body by pressing a first protrusion of the process cartridge onto the positioning part and a second protrusion onto the supporting part. Alternatively, sometimes the two ends of the photosensitive drum shaft are engaged with guide rails of the printer main body, and the developing unit's mounting ribs are mounted from above onto the mounting surface of the printer main body, thereby supporting the processing unit on the printer main body by the mounting surface bearing part or all of the load of the developing unit from below.

[0003] However, in structures where the photosensitive drum unit is installed after the developing unit, the photosensitive drum unit has traditionally been secured by operating a lever or similar mechanism. Additionally, a mechanism is needed to prevent forgetting to operate it. Summary of the Invention

[0004] In view of the above, the object of the present invention is to provide an image forming apparatus that can reduce the operation required for disassembling and assembling the photosensitive drum unit.

[0005] The image forming apparatus of the present invention includes a developing apparatus, a photosensitive drum unit, a side plate, a notch, a swinging member, and a force-applying member. The developing apparatus includes a developing roller. The photosensitive drum unit includes a photosensitive drum arranged with its outer peripheral surface facing the outer peripheral surface of the developing roller, and has a protrusion extending axially toward the photosensitive drum. The side plate faces the axial end face of the photosensitive drum unit. The notch is provided at a mounting position on the side plate for mounting the photosensitive drum unit and opens upwards. The swinging member is capable of swinging in a direction intersecting the axial direction, both in a direction protruding into the notch and in a direction away from the notch. The force-applying member applies force to the swinging member toward the notch. When the swinging member is pushed back by the protrusion inserted into the notch from above and the protrusion reaches the bottom of the notch, the swinging member presses the protrusion against the notch with a load including a downward component. Attached Figure Description

[0006] Figure 1 This is a schematic front view illustrating the internal structure of a printer according to an embodiment of the present invention.

[0007] Figure 2This is a perspective view of a photosensitive drum unit and a developing apparatus according to an embodiment of the present invention.

[0008] Figure 3 This is a front view showing the developing apparatus according to an embodiment of the present invention located at a predetermined position during image formation.

[0009] Figure 4 This is a front view showing the developing apparatus according to an embodiment of the present invention located on the side of the photosensitive drum unit, which is closer to the predetermined position than the specified position.

[0010] Figure 5 This is a perspective view of the front portion of the photosensitive drum unit of the main body shell according to an embodiment of the present invention.

[0011] Figure 6 This is a perspective view of the front portion of the photosensitive drum unit of the main body shell according to an embodiment of the present invention.

[0012] Figure 7 This is a perspective view of the front portion of the photosensitive drum unit of the main body shell according to an embodiment of the present invention.

[0013] Figure 8 This is a front view showing the operation of the hook according to an embodiment of the present invention.

[0014] Figure 9 This is a front view showing the operation of the hook according to an embodiment of the present invention.

[0015] Figure 10 This is a front view showing the operation of the hook according to an embodiment of the present invention.

[0016] Figure 11 This is a front view showing the operation of the hook according to an embodiment of the present invention.

[0017] Figure 12 This is a front view showing the direction of the loads acting on each part of the photosensitive drum unit according to an embodiment of the present invention. Detailed Implementation

[0018] First, the overall structure of printer 1 (an example of an image forming apparatus) will be explained. Figure 1 This is a schematic front view showing the internal structure of printer 1. The following will... Figure 1 The front side of the paper in the diagram is referred to as the front side (front side) of printer 1, and the left and right orientations are explained based on the direction from which printer 1 is viewed from the front. In each diagram, U, Lo, L, R, Fr, and Rr represent up, down, left, right, front, and back, respectively.

[0019] Printer 1 has a rectangular parallelepiped-shaped main body casing 3 (an example of a main body). Inside the lower part of the main body casing 3, a paper feed tray 4 and a paper feed roller 5 are provided. The paper feed tray 4 is used to hold sheet material S, and the paper feed roller 5 feeds the sheet material S to the right from the paper feed tray 4. Above the paper feed tray 4, an imaging device 6 is provided. This imaging device 6 forms a toner image by electrophotography. Above the upper right of the imaging device 6, a fixing device 7 is provided, which fixes the toner image onto the sheet material S. Above the fixing device 7, a paper discharge roller 8 and a paper discharge tray 9 are provided. The paper discharge roller 8 discharges the sheet material S with the fixed toner image, and the paper discharge tray 9 is used to stack the discharged sheet material S.

[0020] A conveying path 10 is provided inside the main housing 3, which extends from the paper feed roller 5 through the imaging device 6 and the fixing device 7 to the paper discharge roller 8. The conveying path 10 is mainly formed by plate-shaped components facing each other, separated by gaps that allow the sheet S to pass through. Conveyor rollers 17, which hold and convey the sheet S, are positioned at multiple locations in the conveying direction Y. A repositioning roller 18 is provided upstream of the imaging device 6 in the conveying direction Y. A reversing conveying path 10R is provided to the right of the fixing device 7. This reversing conveying path 10R branches off from the conveying path 10 downstream of the fixing device 7 in the conveying direction Y and merges with the conveying path 10 upstream of the repositioning roller 18 in the conveying direction Y.

[0021] The imaging device 6 includes a photosensitive drum 11, a charging device 12, an exposure device 13, a developing device 14, an intermediate transfer unit 15, and a cleaning device 16. The photosensitive drum 11 changes its potential when irradiated with light. The charging device 12 charges the photosensitive drum 11. The exposure device 13 emits a laser corresponding to the image data. The developing device 14 supplies toner to the photosensitive drum 11. The intermediate transfer unit 15 transfers the toner image from the photosensitive drum 11 to the sheet S. The cleaning device 16 removes the toner residue on the photosensitive drum 11.

[0022] The intermediate transfer unit 15 includes an intermediate transfer belt 15B, a primary transfer roller 151, and a secondary transfer roller 152. The intermediate transfer belt 15B is annular and wound around a drive roller 15D and a driven roller 15N. The primary transfer roller 151 faces the inner circumferential surface of the intermediate transfer belt 15B at a position corresponding to the photosensitive drum 11, generating a primary transfer bias. The secondary transfer roller 152 faces the outer circumferential surface of the intermediate transfer belt 15B at a position corresponding to the drive roller 15D, generating a secondary transfer bias. A toner container 20 is connected to the developing unit 14, supplying toner to the developing unit 14.

[0023] The imaging apparatus 6 includes four photosensitive drums 11, a charging device 12, an exposure device 13, a developing device 14, a primary transfer roller 151, a cleaning device 16, and a toner container 20. A color image is formed by overlaying four colors of toner images onto an intermediate transfer belt 15B. Furthermore, this invention can also be applied to image forming apparatuses that use three or fewer colors or five or more colors of toner to form color images.

[0024] The control unit 2 has 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), and EEPROM (Electrically Erasable Programmable Read Only Memory). The arithmetic unit performs various processes by reading and executing the control program stored in the storage unit. Alternatively, the control unit 2 can also be implemented using integrated circuits without software.

[0025] The basic image forming operation of printer 1 is as follows. When a single-sided printing task is input to printer 1 from an external computer or other source, the paper feed roller 5 feeds the sheet S from the paper tray 4 to the transport path 10. The registration roller 18, which stops rotating, corrects the skewed movement (tilted travel) of the sheet S. At a predetermined time, the registration roller 18 feeds the sheet S to the imaging device 6. In the imaging device 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. The developing device 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 sheet S. Next, the fixing device 7, while holding and conveying the sheet S, melts the toner image, thereby fixing the toner image onto the sheet S. The paper discharge roller 8 discharges the sheet S to the paper discharge tray 9. The cleaning device 16 removes the toner residue on the photosensitive drum 11. In the case of duplex printing, the sheet S with the toner image fixed on the first surface is conveyed to the transport path 10 via the flip transport path 10R, thereby transferring the toner image to the second surface.

[0026] The photosensitive drum unit 21 and the developing device 14 will be described in detail below. Figure 2 This is a perspective view of the photosensitive drum unit 21 and the developing device 14. Figure 3 This is a front view showing the developing apparatus 14 in a predetermined position during image formation. Figure 4This is a front view showing the position of the developing apparatus 14 on the side of the photosensitive drum unit 21, which is closer to the specified position than the designated position.

[0027] [Photosensitive Drum Unit]

[0028] Photosensitive drum unit 21 (reference) Figure 2 The photosensitive drum unit 21 is a unit formed by integrating the photosensitive drum 11, charging device 12, and cleaning device 16 through a photosensitive drum frame 22. The photosensitive drum frame 22 is provided with a photosensitive drum bearing 23, which supports the drum shaft of the photosensitive drum 11 (not shown). The photosensitive drum bearing 23 protrudes from the outer surface of the photosensitive drum frame 22 (an example of a protrusion). The paper tray 9 is hinged to the main body housing 3, and the photosensitive drum unit 21 is installed from above at a predetermined position on the main body housing 3 with the paper tray 9 open.

[0029] [Developing apparatus]

[0030] The developing apparatus 14 includes a developer, a screw (not shown), a developing roller 31, and a developing housing 32. The screw agitates the developer, the developing roller 31 holds the developer, and the developing housing 32 houses the developer, the screw, and the developing roller 31. The developer contains a toner and a magnetic carrier. The developing roller 31 has a rotating sleeve, inside which a magnet (not shown) is disposed. The developing roller 31 magnetically attracts the developer, forming a magnetic brush on the surface of the sleeve. A portion of the developing roller 31 protrudes from the developing housing 32. Annular spacer members 31S, larger in diameter than the sleeve, are provided at both ends of the developing roller 31. These spacer members 31S contact the outer peripheral surface of the photosensitive drum 11, and the outer peripheral surface of the sleeve faces the outer peripheral surface of the photosensitive drum 11 at a predetermined interval.

[0031] The support portion 41 faces the front and rear ends of the developing housing 32 and supports the developing housing 32 swayably with respect to the swing shaft 42 located below the developing roller 31. The support portion 41 is connected to the developing housing 32 via the swing shaft 42, thus becoming integrated with the developing apparatus 14. The developing apparatus 14 can be detached from the main housing 3 in the vertical direction, and the support portion 41 is fixed to the main housing 3.

[0032] The force-applying part 43 is, for example, a compression coil spring, and is provided on the main body housing 3 to apply force to the developing housing 32 in a manner toward the photosensitive drum frame 22. Figure 3 This indicates the designated position of the developing apparatus 14 when the photosensitive drum unit 21 is installed in the main housing 3 (the designated position during image formation). On the other hand, Figure 4 This indicates the state before the photosensitive drum unit 21 is installed in the main housing 3, and indicates the state where the developing apparatus 14 is located on the side of the photosensitive drum unit 21, which is closer than the specified position.

[0033] Next, the structure of the supporting photosensitive drum unit 21 will be described. Figures 5 to 7 This is a perspective view of the front portion of the photosensitive drum unit 21 of the main body housing 3. The front portion of the photosensitive drum unit 21 of the main body housing 3 will be described below; since the rear portion is also constructed in the same way, the description of the rear portion will be omitted.

[0034] Printer 1 includes a developing device 14, a photosensitive drum unit 21, an inner side plate 50 (an example of a side plate), a first notch 51 (an example of a notch), a hook 60 (an example of a swinging member), and a force-applying member 64. The developing device 14 includes a developing roller 31. The photosensitive drum unit 21 includes a photosensitive drum 11 arranged with its outer peripheral surface facing the outer peripheral surface of the developing roller 31, and has a photosensitive drum bearing 23 (an example of a protrusion) protruding axially from the photosensitive drum 11. The inner side plate 50 is aligned with the axial end face of the photosensitive drum unit 21. The first notch 51 opens above the inner side plate 50 at the mounting position of the photosensitive drum unit 21. The hook 60 is able to swing along the inner side plate 50 in a direction intersecting the axial direction. The force-applying member 64 applies force to the hook 60 in a direction approaching the first notch 51. When the hook 60 is pushed back by the photosensitive drum bearing 23 inserted into the first notch 51 from above, and the photosensitive drum bearing 23 reaches the bottom 51B of the first notch 51, the hook 60 presses the photosensitive drum bearing 23 against the first notch 51 with a load including a downward component.

[0035] An inner side plate 50 (an example of a side plate) and an outer side plate 55 are provided on the main body shell 3. The inner side plate 50 is located rearward of the outer side plate 55, i.e., on the side of the photosensitive drum unit 21. The inner side plate 50 has an upper part 50T, a lower part 50B located below the upper part 50T, and a middle part 50M connecting the upper part 50T and the lower part 50B. The lower part 50B is located rearward of the upper part 50T (on the side of the photosensitive drum unit 21), and the middle part 50M is inclined such that its rear end is located below its front end. A first notch 51 and a second notch 52 that open upward are provided on the inner side plate 50. The first notch 51 and the second notch 52 extend from the middle part 50M to a predetermined position of the lower part 50B.

[0036] The photosensitive drum bearing 23 on the front side of the photosensitive drum unit 21 is inserted into the first notch 51. The first notch 51 has a side portion 51S and a bottom portion 51B, wherein the side portions 51S face each other from left to right, and the bottom portion 51B connects the lower ends of the side portions 51S to each other. The side portions 51S are formed generally in a vertical direction, and the bottom portion 51B is generally horizontal.

[0037] The front end of the cleaning device 16 of the photosensitive drum unit 21 is inserted into the second notch 52. The second notch 52 has a side portion 52S and a bottom portion 52B, wherein the side portions 52S face each other from left to right, and the bottom portion 52B is semi-circular and connects the lower ends of the side portions 52S to each other. A connecting portion 53 is provided in front of the bottom portion 52B to connect with the front end of the cleaning device 16. A through hole 53H in the vertical direction is provided on the connecting portion 53, through which waste toner discharged from the cleaning device 16 is guided to the waste toner container (not shown). A seal 54 is provided around the hole 53H to seal the gap between the cleaning device 16 and the connecting portion 53.

[0038] A hook 60 is provided in the space between the inner side plate 50 and the outer side plate 55, positioned to the left of the first notch 51. The hook 60 is fixedly inserted into the photosensitive drum bearing 23 of the first notch 51. The hook 60 is a component with its length in the vertical direction, and its lower end is supported on the outer side plate 55 via a swing shaft 61 with its axial direction in the front-back direction. On the upper right side of the hook 60 (the side of the first notch 51), there is a curved portion 62 and an inclined portion 63, wherein the curved portion 62 bulges to the right in an arc shape, and the inclined portion 63 is flat and connected to the lower end of the curved portion 62. The inclined portion 63 is inclined such that its lower end is positioned to the left of its upper end.

[0039] The force-applying component 64 is, for example, a compression coil spring, and applies force to the hook portion 60 to the right. An opposing portion 55F is provided on the outer side plate 55, facing the left side of the upper part of the hook portion 60, and the force-applying component 64 is provided between the left side of the hook portion 60 and the opposing portion 55F.

[0040] The operation of the above structure will be explained below. Figures 8 to 11 This is a front view showing the movement of the hook 60. Here, the operation when installing the photosensitive drum unit 21 after the developing apparatus 14 has been installed will be explained. Before installing the photosensitive drum unit 21, as follows... Figure 5 and Figure 8 As shown, the upper end of the hook 60 is tilted toward the first notch 51 by the force-applying member 64, thus becoming a state that protrudes into the first notch 51.

[0041] When the user holds the photosensitive drum unit 21, aligning the photosensitive drum bearing 23 with the upper end of the first notch 51 and the front end of the cleaning device 16 with the upper end of the second notch 52, and lowers the photosensitive drum unit 21, the photosensitive drum bearing 23 initially contacts the upper end of the bent portion 62 of the hook portion 60 (see reference). Figure 8 As the photosensitive drum unit 21 is lowered, the contact position between the photosensitive drum bearing 23 and the bent portion 62 moves downward, and the hook portion 60 is pushed to the left (see reference). Figure 9 When the photosensitive drum bearing 23 reaches the lower end of the bent portion 62, the hook portion 60 is pressed to the leftmost position (see reference). Figure 10 Furthermore, when the photosensitive drum unit 21 is lowered, the photosensitive drum bearing 23 contacts the inclined portion 63 of the hook 60, and the hook 60 is pushed back to the right by the force-applying member 64 (see reference). Figure 11 ).

[0042] At this time, the inclined portion 63 of the hook 60 contacts the upper left portion of the outer peripheral surface of the photosensitive drum bearing 23, and applies a load F1 to the photosensitive drum bearing 23 in the lower right direction. The load F1 pushes the photosensitive drum bearing 23 against the side portion 51S and the bottom portion 51B on the right side of the first notch 51. As a result, since the photosensitive drum bearing 23 is constrained by the inclined portion 63 of the hook 60, the side portion 51S on the right side of the first notch 51, and the bottom portion 51B, the photosensitive drum bearing 23 can be accurately positioned.

[0043] If a planar inclined portion is used instead of the curved portion 62, the inclined portion will approach a horizontal position as the photosensitive drum unit 21 descends. Therefore, the upward component of the force by which the hook portion 60 pushes the photosensitive drum bearing 23 back will increase. Consequently, the force required for the user to push the photosensitive drum unit 21 will also need to be increased.

[0044] In contrast, in this embodiment, during the descent of the photosensitive drum unit 21, the tangential direction of the bending portion 62 at the contact position between the photosensitive drum bearing 23 and the bending portion 62 remains essentially constant. Therefore, when the photosensitive drum unit 21 is lowered, the upward component of the force by which the hook portion 60 pushes back the photosensitive drum bearing 23 remains almost unchanged, and the user can push the photosensitive drum unit 21 in with a substantially constant force.

[0045] Here, the loads acting on each part of the photosensitive drum unit 21 are examined. Figure 12 This is a front view showing the direction of the loads acting on each part of the photosensitive drum unit 21. Furthermore, the arrows in the illustration only indicate the direction of the load; the length of the arrows does not indicate the magnitude of the load.

[0046] The photosensitive drum drive gear 24 meshes with the photosensitive drum driven gear (not shown) disposed on the drum shaft of the photosensitive drum 11. The photosensitive drum drive gear 24 drives the photosensitive drum 11 by transmitting the driving force generated by the motor (not shown) to the photosensitive drum driven gear.

[0047] As described above, the hook 60 applies a load F1 to the photosensitive drum bearing 23. The force-applying part 43 of the developing device 14 applies a load F2 to the photosensitive drum 11 via the spacing limiting member 31S. The engaging part 53 pushes the cleaning device 16 upwards with a load F3 via the seal 54. The photosensitive drum drive gear 24 applies a load F4 to the photosensitive drum driven gear along the direction of the line of action. The line of action is a straight line that intersects the direction forming a pressure angle with respect to the common tangent of the pitch circle of the photosensitive drum drive gear 24 and the pitch circle of the photosensitive drum driven gear.

[0048] When considering the load in the vertical direction, the upward load acting on the photosensitive drum unit 21 is the sum of the upward component of load F2 and load F3. The downward load acting on the photosensitive drum unit 21 is the sum of the downward component of load F1, the downward component of load F4, and the gravity acting on the photosensitive drum unit 21. If the downward load is greater than the upward load, it can prevent the photosensitive drum unit 21 from lifting.

[0049] Since load F4 includes a downward component, in other words, the lines of action of the photosensitive drum drive gear 24 and the photosensitive drum driven gear are inclined to the lower left, thus creating a pulling effect on the photosensitive drum unit 21 downward. This effect has the same effect as the reinforcing load F1, thus enabling the use of a low-cost force-applying component 64.

[0050] On the other hand, when focusing on the load in the horizontal direction, the load acting to the right on the photosensitive drum unit 21 is the sum of the rightward components of load F1 and load F2. The load acting to the left on the photosensitive drum unit 21 is the leftward component of load F4. If the load acting to the right is greater than the load acting to the left, the photosensitive drum bearing 23 is pressed against the side portion 51S on the right side of the first notch portion 51, thereby accurately positioning the photosensitive drum unit 21 in the horizontal direction.

[0051] The printer 1 according to the above-described embodiment includes a developing device 14, a photosensitive drum unit 21, an inner side plate 50 (an example of a side plate), a first notch 51 (an example of a notch), a hook 60 (an example of a swinging member), and a force-applying member 64. The developing device 14 includes a developing roller 31. The photosensitive drum unit 21 includes a photosensitive drum 11 arranged with its outer peripheral surface facing the outer peripheral surface of the developing roller 31, and has a photosensitive drum bearing 23 (an example of a protrusion) protruding axially from the photosensitive drum 11. The inner side plate 50 and the photosensitive drum unit 21 are axially... With the ends (end faces) facing each other, the first notch 51 opens above the mounting position of the photosensitive drum unit 21 on the inner side plate 50. The hook 60 can swing along the inner side plate 50 in a direction intersecting the axial direction. The force-applying member 64 applies force to the hook 60 in a direction approaching the first notch 51. When the hook 60 is pushed back by the photosensitive drum bearing 23 inserted into the first notch 51 from above, and the photosensitive drum bearing 23 reaches the bottom 51B of the first notch 51, the hook 60 presses the photosensitive drum bearing 23 against the first notch 51 with a load including a downward component. According to this structure, the photosensitive drum unit 21 can be installed simply by pushing it down, and can be disassembled simply by pulling it up. Therefore, the operations required to install and remove the photosensitive drum unit 21 can be reduced.

[0052] Furthermore, according to the printer 1 of this embodiment, the first notch 51 has a pair of sides 51S facing each other. When the photosensitive drum bearing 23 reaches the bottom 51B of the first notch 51, the hook 60 pushes the photosensitive drum bearing 23 against one of the pair of sides 51S and the bottom 51B of the first notch 51, thus enabling accurate positioning of the photosensitive drum unit 21.

[0053] Furthermore, according to the printer 1 of this embodiment, the hook portion 60 has a curved portion 62 and an inclined portion 63, wherein the curved portion 62 bulges out toward the first notch portion 51 in an arc-shaped manner, and the inclined portion 63 is planar and connected to the lower end of the curved portion 62. The hook portion 60 is pushed back by the photosensitive drum bearing 23, which is inserted into the first notch portion 51 from above, and contacts the curved portion 62, so that the photosensitive drum bearing 23 reaches the bottom 51B of the first notch portion 51. In this case, the inclined portion 63 presses the photosensitive drum bearing 23 against one of the pair of sides 51S and the bottom 51B of the first notch portion 51, thus suppressing the variation of the force pushing into the photosensitive drum unit 21.

[0054] Furthermore, according to the printer 1 of this embodiment, the developing unit 14 is forced in a direction that brings the developing roller 31 closer to the photosensitive drum 11. When the photosensitive drum bearing 23 reaches the bottom 51B of the first notch 51, the tilting portion 63 applies a load to the photosensitive drum bearing 23 in a direction intersecting the force applied to the developing unit 14. With this structure, since the load applied to the photosensitive drum bearing 23 by the tilting portion 63 is not easily offset by the force applied to the developing unit 14, the photosensitive drum unit 21 can be reliably fixed with a smaller load.

[0055] The above implementation method can also be modified as follows.

[0056] In the above embodiment, an example is shown where the photosensitive drum bearing 23 also serves as a protrusion, but the protrusion may also be located at a different position than the photosensitive drum bearing 23.

[0057] Alternatively, instead of the inclined portion 63 of the hook portion 60, the curved portion 62 can be extended further downward than the lower end of the curved portion 62 in the above embodiment.

Claims

1. An image forming apparatus, characterized in that, It includes a developing unit, a photosensitive drum unit, side plates, a notch, a swinging component, and a force-applying component, among which, The developing apparatus has a developing roller. The photosensitive drum unit includes a photosensitive drum arranged with its outer peripheral surface facing the outer peripheral surface of the developing roller, and has a protrusion extending axially toward the photosensitive drum. The side plate faces the axial end face of the photosensitive drum unit. The notch opens above the mounting position of the photosensitive drum unit on the side plate. The swinging component is capable of swinging along a direction intersecting the axis, in a direction protruding into the notch and in a direction away from the notch. The force-applying component applies force to the swing component in a direction approaching the notch. The protrusion is a photosensitive drum bearing that supports the drum shaft of the photosensitive drum. The developing apparatus is subjected to a force in a direction that brings the developing roller closer to the photosensitive drum. When the protrusion reaches the bottom of the notch, the angle between the direction of the load applied from the swing member to the protrusion and the direction of the force applied by the developing apparatus is 90°±5°. When the oscillating member is pushed back by the protrusion inserted into the notch from above and the protrusion reaches the bottom of the notch, the oscillating member abuts the protrusion against the notch by a load containing a downward component.

2. The image forming apparatus according to claim 1, characterized in that, The notch has a pair of sides facing each other. When the protrusion reaches the bottom of the notch, the swinging member pushes the protrusion against one of the pair of sides of the notch and the bottom.

3. The image forming apparatus according to claim 2, characterized in that, The swing component has a curved portion and an inclined portion, wherein... The curved portion bulges out in an arc shape towards the notch, and the inclined portion is planar and connected to the lower end of the curved portion. By inserting the protrusion into the notch from above and contacting the curved portion, the swinging member is pushed back. When the protrusion reaches the bottom of the notch, the inclined portion presses the protrusion against one of the pair of sides of the notch and the bottom.

4. The image forming apparatus according to claim 3, characterized in that, When the protrusion is inserted into the notch at a position lower than the bend, the swinging member is pushed back to one of the pair of sides of the notch by the force-applying member.

5. The image forming apparatus according to claim 2, characterized in that, The pair of sides of the notch are formed in the vertical direction, and the bottom is formed in the horizontal direction.

Images