Image formation device

Abstract

To provide a structure capable of accurately guiding a toner cartridge to a drawer in a configuration in which a drum cartridge and a toner cartridge are mounted on the drawer.SOLUTION: A drawer 2 includes a drum lock spring 62. The drum lock spring 62 presses a drum frame 40 toward positioning surfaces 541 and 542 of the drawer 2, thereby positioning the drum frame 40 with respect to the drawer 2. The drum cartridge 3 has a guide groove 46. When a toner cartridge 4 is mounted on the drawer 2, a collar 24 of the toner cartridge 4 fits into the guide groove 46, thereby allowing the collar 24 of the toner cartridge 4 to be accurately guided.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present disclosure relates to an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art Conventionally, electrophotographic image forming apparatuses such as laser printers, LED printers, etc. A conventional image forming apparatus is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-179132 Summary of the Invention [Problem to be solved by the invention]

[0004] The image forming device has a drum cartridge with a photosensitive drum and a toner cartridge that supplies toner to the photosensitive drum. The drum cartridge and toner cartridge are installed in a drawer. The drawer with the drum cartridge and toner cartridge installed is then installed in the main body frame of the image forming device.

[0005] An object of the present disclosure is to provide a structure in which a drum cartridge and a toner cartridge are attached to a drawer, and which can accurately guide the toner cartridge relative to the drawer. [Means for solving the problem]

[0006] The first disclosure is an image forming apparatus comprising: a main body frame; a drawer detachable from the main body frame; a drum cartridge detachable from the drawer, the drum cartridge having a photosensitive drum rotatable about a drum axis extending in a first direction and a drum frame; and a toner cartridge detachable from the drawer, the toner cartridge having a housing for storing toner, a developing roller rotatable about a developing axis extending in the first direction, and a collar located at an end of the housing in the first direction, wherein the drawer has a positioning surface with which the drum frame contacts when the drum cartridge is attached to the drawer, and a drum lock spring that presses the drum frame toward the positioning surface, and the toner cartridge can be attached to the drawer when the drum cartridge is attached to the drawer and the drum cartridge is pressed against the positioning surface by the drum lock spring, and the drum cartridge has a guide groove into which the collar fits when the toner cartridge is attached to the drawer.

[0007] A second disclosure is the image forming apparatus of the first disclosure, wherein the drawer has a metal plate having the positioning surface.

[0008] The third disclosure is the image forming apparatus of the first disclosure, wherein the positioning surface includes a first positioning surface extending in a second direction intersecting the first direction, and a second positioning surface extending in a third direction intersecting the first direction and the second direction, and the drum frame has an arcuate surface centered on the drum axis, and when the drum cartridge is attached to the drawer, the arcuate surface contacts the first positioning surface and the second positioning surface.

[0009] The fourth disclosure is the image forming apparatus of the third disclosure, characterized in that the drum frame has a protrusion protruding from the arc surface, and when the drum cartridge is attached to the drawer, the protrusion contacts the second positioning surface.

[0010] A fifth disclosure is the image forming apparatus of the third disclosure, characterized in that the drum lock spring presses the arcuate surface in a fourth direction toward the boundary between the first positioning surface and the second positioning surface.

[0011] A sixth disclosure is the image forming apparatus of the fifth disclosure, wherein the guide groove is recessed in the fourth direction.

[0012] The seventh disclosure is an image forming apparatus according to the fifth or sixth disclosure, characterized in that when the drum cartridge and the toner cartridge are attached to the drawer, the photosensitive drum and the developing roller are aligned in the fourth direction.

[0013] The eighth disclosure is the image forming apparatus of the third disclosure, wherein the toner cartridge is attachable to the drawer in the third direction, the toner cartridge further has a lock boss located at the end of the housing in the first direction, and the drawer further has a lock lever that is located farther from the drum cartridge in the third direction than the lock boss when the toner cartridge is attached to the drawer, the lock lever being movable between a locked position facing the lock boss in the third direction and a released position not facing the lock boss in the third direction, and a toner lock spring that urges the lock lever from the released position toward the locked position.

[0014] The ninth disclosure is the image forming apparatus of the eighth disclosure, characterized in that when the drawer in which the drum cartridge and the toner cartridge are installed is attached to the main body frame, the image forming apparatus is capable of moving the toner cartridge between a contact position where the developing roller contacts the photosensitive drum and a separated position where the developing roller is separated from the photosensitive drum, and the lock boss does not contact the lock lever whether the toner cartridge is in the contact position or the separated position.

[0015] The 10th disclosure is the image forming device of the 9th disclosure, characterized in that when the drawer in which the drum cartridge and the toner cartridge are installed is not installed in the main body frame, the toner cartridge is located in the separated position.

[0016] An eleventh disclosure is the image forming apparatus of the tenth disclosure, wherein, when the toner cartridge is located at the separated position, the lock lever faces the lock boss in the third direction.

[0017] The 12th disclosure is the image forming apparatus of the 1st disclosure, characterized in that when the drum cartridge and the toner cartridge are attached to the drawer, the toner cartridge comes into contact with the drawer in the rotational direction around the development axis.

[0018] The 13th disclosure is the image forming apparatus of the 1st disclosure, characterized in that the drum frame further has a guide surface that guides the collar toward the guide groove during the process of installing the toner cartridge in the drawer in which the drum cartridge is installed.

[0019] The 14th disclosure is the image forming apparatus of the 6th disclosure, characterized in that when the toner cartridge is removed from the drawer in which the drum cartridge and the toner cartridge are installed, the collar moves in the fourth direction relative to the guide groove, and after the collar comes out of the guide groove, the collar moves in the third direction away from the drum cartridge. [Effects of the Invention]

[0020] According to the first to fourteenth disclosures, the drum frame is positioned relative to the drawer by the drum lock spring, and the guide groove of the drum frame positioned relative to the drawer can guide the collar of the toner cartridge with high precision.

[0021] Furthermore, according to the second disclosure, by making the positioning surface from metal instead of resin, it is possible to prevent the positioning surface itself from being displaced.

[0022] Furthermore, according to the third disclosure, the drum frame can be positioned relative to the drawer in the second and third directions.

[0023] Furthermore, according to the fourth disclosure, the drum frame can be prevented from rotating about the drum shaft relative to the drawer. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a perspective view of an image forming apparatus. [Figure 2] FIG. 2 is a perspective view of the drawer 2 in which four drum cartridges and four toner cartridges 4 are installed. [Figure 3] FIG. 2 is a perspective view of the drawer, one drum cartridge, and one toner cartridge. [Figure 4] FIG. [Figure 5] FIG. [Figure 6]FIG. 2 is a perspective view of the drum cartridge. [Figure 7] FIG. 4 is a cross-sectional view of the first drum frame. [Figure 8] FIG. [Figure 9] FIG. 2 is a cross-sectional view of a drawer including a first plate. [Figure 10] FIG. 2 is a perspective view of a drawer in which one drum cartridge and one toner cartridge are installed. [Figure 11] 10A to 10C are diagrams illustrating an operation of installing the drum cartridge in the drawer. [Figure 12] 10A to 10C are diagrams illustrating an operation of installing the drum cartridge in the drawer. [Figure 13] 10A and 10B are diagrams illustrating the operation of installing a toner cartridge into the drawer in which the drum cartridge is installed. [Figure 14] 10A and 10B are diagrams illustrating the operation of installing a toner cartridge into the drawer in which the drum cartridge is installed. [Figure 15] 10A and 10B are diagrams illustrating how the toner cartridge is moved between a separated position and a contact position. [Figure 16] 10A and 10B are diagrams illustrating how the toner cartridge is moved between a separated position and a contact position. [Figure 17] 10A and 10B are diagrams illustrating how the toner cartridge is moved between a separated position and a contact position. [Figure 18] FIG. 4 is an enlarged view of the vicinity of a second pressure spring. [Figure 19] FIG. 2 is an enlarged view of the vicinity of a first pressure spring. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0026] In the following, the direction in which the drum axis A2 of the photosensitive drum 30 extends will be referred to as the "first direction." The direction in which the drawer 2 is attached to and detached from the main body frame 1 will be referred to as the "second direction." The direction in which the drum cartridge 3 and toner cartridge 4 are attached to and detached from the drawer 2 will be referred to as the "third direction." The direction in which the photosensitive drum 30 and the developing roller 20 are aligned when the drum cartridge 3 and toner cartridge 4 are attached to the drawer 2 will be referred to as the "fourth direction."

[0027] The first direction and the second direction intersect with each other. Preferably, the first direction and the second direction are perpendicular to each other. The first direction and the third direction intersect with each other. Preferably, the first direction and the third direction are perpendicular to each other. The first direction and the fourth direction intersect with each other. Preferably, the first direction and the fourth direction are perpendicular to each other. The second direction and the third direction intersect with each other. Preferably, the second direction and the third direction are perpendicular to each other. The second direction and the fourth direction intersect with each other. The third direction and the fourth direction intersect with each other.

[0028] <1. Configuration of image forming device> FIG. 1 is a perspective view of an image forming apparatus 100. The image forming apparatus 100 is an electrophotographic printer. Specifically, the image forming apparatus 100 is a laser printer or an LED printer. The image forming apparatus 100 includes a main body frame 1, a drawer 2, four drum cartridges 3, four toner cartridges 4, and a control unit 5.

[0029] FIG. 2 is a perspective view of the drawer 2 in which four drum cartridges 3 and four toner cartridges 4 are installed. FIG. 3 is a perspective view of the drawer 2, one drum cartridge 3, and one toner cartridge 4. As shown in FIGS. 2 and 3, the drum cartridge 3 is detachably attached to the drawer 2. The drum cartridge 3 is attached to the drawer 2 in a third direction. Furthermore, the toner cartridge 4 is detachably attached to the drawer 2 in which the drum cartridge 3 is attached. The toner cartridge 4 is attached to the drawer 2 in the third direction when the drum cartridge 3 is attached to the drawer 2.

[0030] The drawer 2, in which the four drum cartridges 3 and four toner cartridges 4 are mounted, is detachable from the main body frame 1. The drawer 2, in which the four drum cartridges 3 and four toner cartridges 4 are mounted, is mounted in the second direction relative to the main body frame 1.

[0031] When the four drum cartridges 3 are installed in the drawer 2, the four drum cartridges 3 are aligned in the second direction. Furthermore, when the four toner cartridges 4 are installed in the drawer 2, the four toner cartridges 4 are aligned in the second direction. Each of the four toner cartridges 4 contains a different color of toner. The image forming device 100 prints an image on printing paper using toner supplied from the toner cartridges 4.

[0032] <2. Toner cartridge configuration> 4 and 5 are perspective views of the toner cartridge 4. As shown in FIGS. 4 and 5, the toner cartridge 4 has a housing 10 and a developing roller 20.

[0033] <2-1. Cabinet> The housing 10 is a container that stores toner. The housing 10 has a first outer surface 11 and a second outer surface 12. The first outer surface 11 is located at one end of the housing 10 in the first direction. The second outer surface 12 is located at the other end of the housing 10 in the first direction. The first outer surface 11 and the second outer surface 12 are spaced apart from each other in the first direction.

[0034] Toner is stored inside the housing 10. As shown in Figures 4 and 5, the housing 10 has an opening 13. The opening 13 is located at one end of the housing 10 in the fourth direction. The opening 13 communicates with the space inside the housing 10 where the toner is stored.

[0035] The housing 10 has a first lock boss 14. The first lock boss 14 is located on a first outer surface 11 of the housing 10. That is, the first lock boss 14 is located at one end of the housing 10 in the first direction. The first lock boss 14 protrudes from the first outer surface 11 of the housing 10 toward the outside of the housing 10. The shape of the first lock boss 14 is, for example, a cylindrical shape extending in the first direction.

[0036] The housing 10 has a second lock boss 15. The second lock boss 15 is located on the second outer surface 12 of the housing 10. In other words, the second lock boss 15 is located at the other end of the housing 10 in the first direction. The second lock boss 15 protrudes from the second outer surface 12 of the housing 10 toward the outside of the housing 10. The shape of the second lock boss 15 is, for example, a cylindrical shape extending in the first direction.

[0037] The housing 10 has a spacing boss 16. The spacing boss 16 is located on the first outer surface 11 of the housing 10. That is, the spacing boss 16 is located at one end of the housing 10 in the first direction. The spacing boss 16 is located between the developing roller 20 and the first lock boss 14 in the fourth direction. The spacing boss 16 protrudes from the first outer surface 11 of the housing 10 toward the outside of the housing 10. The shape of the spacing boss 16 is, for example, a cylindrical shape extending in the first direction.

[0038] <2-2. Developing roller> The developing roller 20 is a roller that can rotate about a development axis A1 that extends in the first direction. The developing roller 20 is located in the opening 13 of the housing 10. That is, the developing roller 20 is located at one end of the housing 10 in the fourth direction.

[0039] The developing roller 20 has a developing roller body 21 and a developing roller shaft 22. The developing roller body 21 is a cylindrical member extending in a first direction. The developing roller body 21 has elasticity. Specifically, the developing roller body 21 is made of rubber. The developing roller body 21 has a cylindrical outer circumferential surface.

[0040] The developing roller shaft 22 is a cylindrical member that penetrates the developing roller main body 21 and extends in the first direction. The developing roller main body 21 is fixed to the developing roller shaft 22. The developing roller shaft 22 is conductive. Specifically, the developing roller shaft 22 is made of metal or a conductive resin. Both ends of the developing roller shaft 22 are rotatably supported with respect to the housing 10.

[0041] The toner cartridge 4 also has a supply roller (not shown). The supply roller is located inside the housing 10. The toner inside the housing 10 is supplied to the developing roller main body 21 via the supply roller. As a result, the toner is carried on the outer circumferential surface of the developing roller main body 21.

[0042] 4 and 5, the developing roller 20 has two rollers 23. One of the two rollers 23 is located at one end of the developing roller body 21 in the first direction. The other of the two rollers 23 is located at the other end of the developing roller body 21 in the first direction.

[0043] The rollers 23 are attached to the developing roller shaft 22. The rollers 23 are disc-shaped members centered on the development axis A1. The rollers 23 are harder than the developing roller main body 21. The rollers 23 have a cylindrical outer circumferential surface. The diameter of the outer circumferential surface of the rollers 23 is smaller than the diameter of the outer circumferential surface of the developing roller main body 21.

[0044] When the toner cartridge 4 is installed in the drawer 2 in which the drum cartridge 3 is installed and the toner cartridge 4 is positioned at a contact position described below, the developing roller 20 comes into contact with the photosensitive drum 30 described below. Specifically, the outer circumferential surface of the photosensitive drum 30 comes into contact with the outer circumferential surface of the developing roller main body 21. At this time, the developing roller main body 21 is compressed, and the outer circumferential surfaces of the rollers 23 come into contact with the outer circumferential surface of the photosensitive drum 30. This makes it possible to maintain a constant distance between the developing shaft A1 and the drum shaft A2.

[0045] 4 and 5, the developing roller 20 has a first collar 24 and a second collar 25. The first collar 24 is located at one end of the developing roller shaft 22 in the first direction. Specifically, the first collar 24 is attached to one end of the developing roller shaft 22 in the first direction. The second collar 25 is located at the other end of the developing roller shaft 22 in the first direction. Specifically, the second collar 25 is attached to the other end of the developing roller shaft 22 in the first direction. The first collar 24 and the second collar 25 may be rotatable about a development axis A1 relative to the developing roller shaft 22.

[0046] 4, the toner cartridge 4 also has a development coupling 26. The development coupling 26 is located on the first outer surface 11 of the housing 10. The development coupling 26 is a member for inputting driving force to the development roller 20. The development coupling 26 is rotatable about an axis extending in the first direction.

[0047] When the drawer 2, in which the drum cartridge 3 and the toner cartridge 4 are installed, is attached to the main body frame 1, the development drive shaft of the image forming apparatus 100 is connected to the development coupling 26. Then, the rotation of the development drive shaft is transmitted to the development roller 20 via the development coupling 26.

[0048] <3. Drum cartridge configuration> 6 is a perspective view of the drum cartridge 3. As shown in FIG. 6, the drum cartridge 3 includes a photosensitive drum 30 and a drum frame 40.

[0049] <3-1. Photosensitive drum> The photosensitive drum 30 is a drum that can rotate about a drum axis A2 that extends in the first direction. The photosensitive drum 30 is located at one end of the drum frame 40 in the fourth direction. The photosensitive drum 30 has a cylindrical outer surface centered on the drum axis A2. The outer surface of the photosensitive drum 30 is covered with a photosensitive material. When the drum cartridge 3 and the toner cartridge 4 are installed in the drawer 2, the photosensitive drum 30 and the developing roller 20 are aligned in the fourth direction.

[0050] As shown in FIG. 4, the drum cartridge 3 also has a drum coupling 31. The drum coupling 31 is located at one end of the photosensitive drum 30 in the first direction. The drum coupling 31 is a member for inputting driving force to the photosensitive drum 30. The drum coupling 31 is rotatable about the drum axis A2 together with the photosensitive drum 30.

[0051] When the drawer 2, in which the drum cartridge 3 and the toner cartridge 4 are installed, is attached to the main body frame 1, the drum drive shaft of the image forming apparatus 100 is connected to the drum coupling 31. Then, the rotation of the drum drive shaft is transmitted to the photosensitive drum 30 via the drum coupling 31.

[0052] <3-2. Drum frame> The drum frame 40 supports the photosensitive drum 30 rotatably about the drum axis A2. As shown in Fig. 6, the drum frame 40 has a first drum frame 41, a second drum frame 42, and a connecting drum frame 43. Note that Fig. 6 shows the connecting drum frame 43 disassembled from the first drum frame 41 and the second drum frame 42.

[0053] The first drum frame 41 is located at one end of the drum frame 40 in the first direction. The second drum frame 42 is located at the other end of the drum frame 40 in the first direction. The first drum frame 41 and the second drum frame 42 are spaced apart from each other in the first direction. The connecting drum frame 43 extends in the first direction between the first drum frame 41 and the second drum frame 42. The first drum frame 41 and the second drum frame 42 are connected to each other by the connecting drum frame 43.

[0054] One end of the photosensitive drum 30 in the first direction is rotatably supported by the first drum frame 41. The other end of the photosensitive drum 30 in the first direction is rotatably supported by the second drum frame .

[0055] The first drum frame 41 also has an arcuate surface 44 and a protrusion 45. The arcuate surface 44 is an arc-shaped surface centered on the drum axis A2. The arcuate surface 44 is positioned around the drum coupling 31. The protrusion 45 protrudes from a portion of the arcuate surface 44 outward in the radial direction relative to the drum axis A2. More specifically, the protrusion 45 protrudes from a portion of the arcuate surface 44 in the second direction.

[0056] The second drum frame 42 also has an arcuate surface 44 and a protrusion 45 similar to those of the first drum frame 41 .

[0057] FIG. 7 is a cross-sectional view of the first drum frame 41. FIG. 7 shows a cross section perpendicular to the first direction. As shown in FIG. 7, the first drum frame 41 has a first guide groove 46. The first guide groove 46 is a recess for guiding the first collar 24 of the toner cartridge 4 when the toner cartridge 4 is attached to the drawer 2. The first guide groove 46 is formed on the surface of the first drum frame 41 that faces the second drum frame 42. The first guide groove 46 is recessed in the fourth direction from the end of the first drum frame 41 toward the photosensitive drum 30.

[0058] The first drum frame 41 also has a first guide surface 47. The first guide surface 47 is a surface that guides the first collar 24 toward the first guide groove 46 when the toner cartridge 4 is being installed in the drawer 2 in which the drum cartridge 3 is installed. The first guide surface 47 is a surface that is inclined with respect to the third direction. More specifically, the first guide surface 47 is a surface that is inclined so as to approach the first guide groove 46 in the second direction as it approaches the photosensitive drum 30 in the third direction.

[0059] Similarly, the second drum frame 42 has a second guide groove 48. The second guide groove 48 is a recess for guiding the second collar 25 of the toner cartridge 4 when the toner cartridge 4 is attached to the drawer 2. The second guide groove 48 is formed on the surface of the second drum frame 42 that faces the first drum frame 41. The second guide groove 48 is recessed in the fourth direction from the end of the second drum frame 42 toward the photosensitive drum 30.

[0060] The second drum frame 42 also has a second guide surface 49. The second guide surface 49 is a surface that guides the second collar 25 toward the second guide groove 48 during the process of installing the toner cartridge 4 into the drawer 2 in which the drum cartridge 3 is installed. The second guide surface 49 is a surface that is inclined with respect to the third direction. More specifically, the second guide surface 49 is a surface that is inclined so as to approach the second guide groove 48 in the second direction as it approaches the photosensitive drum 30 in the third direction.

[0061] The drum cartridge 3 also has a cleaning roller. The cleaning roller is a roller that cleans the outer peripheral surface of the photosensitive drum 30. The outer peripheral surface of the cleaning roller contacts the outer peripheral surface of the photosensitive drum 30. The cleaning roller and the photosensitive drum 30 are aligned in the second direction. However, the cleaning roller is not shown in Figures 6 and 7. The drum frame 40 has a cleaning roller holder 431. The cleaning roller holder 431 holds the cleaning roller.

[0062] The drum cartridge 3 also has a charger. The charger is a device that charges the outer peripheral surface of the photosensitive drum 30. The charger faces the outer peripheral surface of the photosensitive drum 30. The charger is, for example, a scorotron charger. However, the charger is not shown in Figures 6 and 7. The drum frame 40 has a charger holder 432. The charger holder 432 holds the charger.

[0063] <4. Drawer configuration> 8 is a perspective view of the drawer 2. The drawer 2 has a drawer frame 50, a first drum lock push cover 61, a first drum lock spring 62, a second drum lock push cover 63, a second drum lock spring 64, a first lock lever 71, a first toner lock spring 72, a second lock lever 73, and a second toner lock spring 74.

[0064] <4-1. Drawer frame> The drawer frame 50 is a frame that can accommodate four drum cartridges 3 and four toner cartridges 4. As shown in FIG. 8, the drawer frame 50 has a first side frame 51, a second side frame 52, and a connecting drawer frame 53.

[0065] The first side frame 51 is located at one end of the drawer frame 50 in the first direction. The first side frame 51 extends in the second and third directions. The second side frame 52 is located at the other end of the drawer frame 50 in the first direction. The second side frame 52 extends in the second and third directions. The connecting drawer frame 53 connects the first side frame 51 and the second side frame 52 in the first direction.

[0066] The first side frame 51 and the second side frame 52 are spaced apart in the first direction. When the drum cartridge 3 is attached to the drawer frame 50, the drum cartridge 3 is located between the first side frame 51 and the second side frame 52 in the first direction. When the toner cartridge 4 is attached to the drawer frame 50, the toner cartridge 4 is located between the first side frame 51 and the second side frame 52 in the first direction.

[0067] The drawer frame 50 also has a first plate 54 and a second plate 55 made of metal. The first plate 54 is located at one end of the drawer frame 50 in the first direction. More specifically, the first plate 54 is fixed to the inner surface of the first side frame 51. The first plate 54 extends in the second and third directions. The second plate 55 is located at the other end of the drawer frame 50 in the first direction. More specifically, the second plate 55 is fixed to the inner surface of the second side frame 52. The second plate 55 extends in the second and third directions.

[0068] 9 is a cross-sectional view of the drawer 2 including the first plate 54. FIG. 9 shows a cross section perpendicular to the first direction. As shown in FIG. 9, the first plate 54 has a first positioning surface 541 and a second positioning surface 542. The first positioning surface 541 and the second positioning surface 542 are surfaces for positioning the drum cartridge 3 with respect to the drawer frame 50 when the drum cartridge 3 is attached to the drawer 2.

[0069] The first positioning surface 541 is a surface that extends in the second direction. In other words, the first positioning surface 541 is a surface that intersects with the third direction. The second positioning surface 542 is a surface that extends in the third direction. In other words, the second positioning surface 542 is a surface that intersects with the second direction. When the drum cartridge 3 is attached to the drawer 2, the arc surface 44 of the first drum frame 41 comes into contact with the first positioning surface 541 and the second positioning surface 542.

[0070] The second plate 55 also has a first positioning surface and a second positioning surface similar to those of the first plate 54. When the drum cartridge 3 is attached to the drawer 2, the arc surface 44 of the second drum frame 42 comes into contact with the first positioning surface and the second positioning surface of the second plate 55.

[0071] <4-2. Push cover and drum lock spring> The first drum lock push cover 61 and the first drum lock spring 62 are members for pressing the arcuate surface 44 of the first drum frame 41 toward the first positioning surface 541 and the second positioning surface 542. The first drum lock push cover 61 and the first drum lock spring 62 are located at one end of the drawer frame 50 in the first direction. The first drum lock push cover 61 and the first drum lock spring 62 also face the first positioning surface 541 and the second positioning surface 542 at an interval in the fourth direction.

[0072] The first drum lock push cover 61 is a hollow cover that houses a first drum lock spring 62 therein. The outer surface of one end of the first drum lock push cover 61 in the fourth direction comes into contact with the first drum frame 41 when the drum cartridge 3 is attached to the drawer 2. The first drum lock spring 62 is a spring that can expand and contract in the fourth direction. The first drum lock spring 62 is, for example, a compression coil spring. The first drum lock push cover 61 is attached to one end of the first drum lock spring 62 in the fourth direction. The other end of the first drum lock spring 62 in the fourth direction is attached to the first side frame 51.

[0073] When the drum cartridge 3 is installed in the drawer 2, the first drum frame 41 is positioned between the first positioning surface 541, the second positioning surface 542, and the first drum lock push cover 61. At this time, the first drum lock spring 62 is compressed in the fourth direction beyond its natural length. Therefore, the elastic force of the first drum lock spring 62 presses the first drum frame 41 toward the first positioning surface 541 and the second positioning surface 542 in the fourth direction. In other words, the repulsive force generated by the compression of the first drum lock spring 62 presses the first drum frame 41 toward the first positioning surface 541 and the second positioning surface 542 in the fourth direction. More specifically, the elastic force of the first drum lock spring 62 presses the arc surface 44 toward the boundary between the first positioning surface 541 and the second positioning surface 542 in the fourth direction. As a result, the arcuate surface 44 of the first drum frame 41 is pressed against the first positioning surface 541 and the second positioning surface 542. As a result, the drum frame 40 is positioned relative to the drawer frame 50 in the second and third directions.

[0074] Furthermore, when the drum cartridge 3 is attached to the drawer 2, the protrusion 45 of the first drum frame 41 comes into contact with the second positioning surface 542. This causes the first drum frame 41 to come into contact with the second positioning surface 542 at two locations: the arcuate surface 44 and the protrusion 45. As a result, the drum frame 40 can be prevented from rotating about the drum axis A2 relative to the drawer frame 50.

[0075] The second side frame 52 is also provided with a second drum lock push cover 63 and a second drum lock spring 64 similar to those of the first side frame 51. When the drum cartridge 3 is attached to the drawer 2, the second drum frame 42 is positioned between the first and second positioning surfaces of the second plate 55 and the second drum lock push cover 63 in the fourth direction. The second drum lock spring 64 presses the arcuate surface 44 of the second drum frame 42 against the first and second positioning surfaces of the second plate 55. As a result, the drum frame 40 is positioned relative to the drawer frame 50 in the second and third directions.

[0076] <4-3. Lock lever and toner lock spring> The first lock lever 71, the first toner lock spring 72, the second lock lever 73, and the second toner lock spring 74 are components that prevent the toner cartridge 4 attached to the drawer 2 from falling out of the drawer 2.

[0077] 10 is a perspective view of the drawer 2 with one drum cartridge 3 and one toner cartridge 4 installed. As shown in FIG. 10, the first lock lever 71 and the first toner lock spring 72 are located at one end of the drawer frame 50 in the first direction. More specifically, the first lock lever 71 and the first toner lock spring 72 are attached to the first side frame 51.

[0078] When the toner cartridge 4 is attached to the drawer 2, the first lock lever 71 is located farther from the drum cartridge 3 in the third direction than the first lock boss 14.

[0079] The first lock lever 71 is rotatable about a rotation axis extending in the second direction. This allows the first lock lever 71 to move between a locked position and a released position that is more open toward the outside of the first side frame 51 than the locked position. When the first lock lever 71 is in the locked position, the first lock lever 71 faces the first lock boss 14 in the third direction. When the first lock lever 71 is in the released position, the first lock lever 71 does not face the first lock boss 14 in the third direction.

[0080] The first toner lock spring 72 is a spring that biases the first lock lever 71 from the release position toward the lock position. The first toner lock spring 72 is, for example, a torsion spring. The first toner lock spring 72 is attached to the rotation shaft of the first lock lever 71. One end of the first toner lock spring 72 contacts the first side frame 51. The other end of the first toner lock spring 72 contacts the first lock lever 71. The first lock lever 71 is pressed toward the lock position by the elastic force of the first toner lock spring 72.

[0081] 10, the second lock lever 73 and the second toner lock spring 74 are located at the other end of the drawer frame 50 in the first direction. More specifically, the second lock lever 73 and the second toner lock spring 74 are attached to the second side frame 52. When the toner cartridge 4 is installed in the drawer 2, the second lock lever 73 is located farther from the drum cartridge 3 in the third direction than the second lock boss 15.

[0082] The second lock lever 73 is rotatable about a rotation axis extending in the second direction. This allows the second lock lever 73 to move between a locked position and a released position that is more open toward the outside of the second side frame 52 than the locked position. When the second lock lever 73 is in the locked position, the second lock lever 73 faces the second lock boss 15 in the third direction. When the second lock lever 73 is in the released position, the second lock lever 73 does not face the second lock boss 15 in the third direction.

[0083] The second toner lock spring 74 is a spring that biases the second lock lever 73 from the release position toward the lock position. The second toner lock spring 74 is, for example, a torsion spring. The second toner lock spring 74 is attached to the rotation shaft of the second lock lever 73. One end of the second toner lock spring 74 contacts the second side frame 52. The other end of the second toner lock spring 74 contacts the second lock lever 73. The second lock lever 73 is pressed toward the lock position by the elastic force of the second toner lock spring 74.

[0084] When the toner cartridge 4 is installed in the drawer 2 and is located in a spaced position (described later), the first lock lever 71 faces the first lock boss 14 in the third direction. When the toner cartridge 4 is installed in the drawer 2 and is located in a spaced position (described later), the second lock lever 73 faces the second lock boss 15 in the third direction.

[0085] Therefore, when the toner cartridge 4 attempts to move in the third direction relative to the drawer 2 away from the drum cartridge 3, the first lock boss 14 comes into contact with the first lock lever 71, and the second lock boss 15 comes into contact with the second lock lever 73. This prevents the toner cartridge 4 from falling out of the drawer 2.

[0086] <5. Installing the cartridge> Next, a description will be given of the operation of installing the drum cartridge 3 in the drawer 2. Figures 11 and 12 are views showing the operation of installing the drum cartridge 3 in the drawer 2. Figures 11 and 12 show cross sections perpendicular to the first direction.

[0087] 11 and 12, the drawer frame 50 has a protrusion 56. The protrusion 56 protrudes in the second direction from the connecting drawer frame 53 toward the space in which the drum cartridge 3 is installed.

[0088] When the drum cartridge 3 is installed in the drawer 2, the drum cartridge 3 is moved in the third direction relative to the drawer 2. Then, the drum cartridge 3 is brought closer to the first plate 54 and the second plate 55. As a result, the cleaning roller holder 431 first passes over the protrusion 56, as shown in FIG. 11 . As a result, the cleaning roller holder 431 is positioned between the protrusion 56 and the bottom of the drawer frame 50.

[0089] Thereafter, the drum cartridge 3 is rotated around the photosensitive drum 30. As a result, as shown in FIG. 12 , the first drum frame 41 is positioned between the first positioning surface 541, the second positioning surface 542, and the first drum lock push cover 61. The first drum lock push cover 61 presses the first drum frame 41 toward the first positioning surface 541 and the second positioning surface 542 due to the elastic force of the first drum lock spring 62. This causes the arc surface 44 of the first drum frame 41 to come into contact with the first positioning surface 541 and the second positioning surface 542. As a result, the first drum frame 41 is positioned relative to the drawer frame 50 in the second and third directions.

[0090] Additionally, the protrusion 45 of the first drum frame 41 comes into contact with the second positioning surface 542. This makes it possible to prevent the drum frame 40 from rotating relative to the drawer frame 50 about the drum axis A2.

[0091] 12, the second drum frame 42 is positioned between the first and second positioning surfaces of the second plate 55 and the second drum lock push cover 63. Then, due to the elastic force of the second drum lock spring 64, the arcuate surface 44 of the second drum frame 42 comes into contact with the first and second positioning surfaces of the second plate 55. As a result, the second drum frame 42 is positioned relative to the drawer frame 50 in the second and third directions.

[0092] This completes the installation of the drum cartridge 3 into the drawer frame 50.

[0093] Next, the operation of installing the toner cartridge 4 in the drawer 2 in which the drum cartridge 3 is installed will be described. Figures 13 and 14 are diagrams showing the operation of installing the toner cartridge 4 in the drawer 2 in which the drum cartridge 3 is installed. Figures 13 and 14 show cross sections perpendicular to the first direction.

[0094] When the toner cartridge 4 is to be installed in the drawer 2 in which the drum cartridge 3 is installed, the toner cartridge 4 is moved in the third direction relative to the drawer 2. Then, the toner cartridge 4 is brought closer to the drum cartridge 3.

[0095] At this time, the first lock boss 14 of the toner cartridge 4 comes into contact with the first lock lever 71. However, by further moving the toner cartridge 4 toward the drum cartridge 3, the first lock lever 71 moves from the locked position to the released position. This causes the first lock boss 14 to pass the first lock lever 71. Similarly, the second lock boss 15 of the toner cartridge 4 also comes into contact with the second lock lever 73. However, by further moving the toner cartridge 4 toward the drum cartridge 3, the second lock lever 73 moves from the locked position to the released position. This causes the second lock boss 15 to pass the second lock lever 73.

[0096] Furthermore, during the process of installing the toner cartridge 4 in the drawer 2, the first collar 24 of the toner cartridge 4 comes into contact with the first guide surface 47 of the first drum frame 41. Furthermore, the second collar 25 of the toner cartridge 4 comes into contact with the second guide surface 49 of the second drum frame 42.

[0097] The first collar 24 moves along the first guide surface 47 to the first guide groove 46. Then, as shown in FIG. 14 , the first collar 24 fits into the first guide groove 46. The first collar 24 is guided in the fourth direction by the first guide groove 46. The second collar 25 moves along the second guide surface 49 to the second guide groove 48. Then, the second collar 25 fits into the second guide groove 48. The second collar 25 is guided in the fourth direction by the second guide groove 48. This limits the position of the toner cartridge 4 relative to the drum frame 40. As a result, the position of the developing roller 20 relative to the photosensitive drum 30 is limited.

[0098] 14, when the drum cartridge 3 and toner cartridge 4 are attached to the drawer 2, the housing 10 of the toner cartridge 4 comes into contact with the connecting drawer frame 53 in the rotational direction about the development axis A1. This allows the toner cartridge 4 to be positioned relative to the drawer frame 50 in the rotational direction about the development axis A1.

[0099] When removing the toner cartridge 4 from the drawer 2 in which the drum cartridge 3 and the toner cartridge 4 are installed, first, the first collar 24 is moved in the fourth direction relative to the first guide groove 46 to remove the first collar 24 from the first guide groove 46. Then, the second collar 25 is moved in the fourth direction relative to the second guide groove 48 to remove the second collar 25 from the second guide groove 48.

[0100] Thereafter, the toner cartridge 4 is moved in the third direction so that the first collar 24 and the second collar 25 move in a direction away from the drum cartridge 3. This allows the toner cartridge 4 to be removed from the drawer 2 without removing the drum cartridge 3 from the drawer 2.

[0101] As described above, in the image forming apparatus 100 of this embodiment, the drawer 2, drum cartridge 3, and toner cartridge 4 can be replaced individually. This allows the drawer 2, drum cartridge 3, and toner cartridge 4 to be used effectively throughout their respective lives.

[0102] Furthermore, in the image forming apparatus 100 of this embodiment, the toner cartridge 4 is installed in the drawer 2 with the drum cartridge 3 installed in the drawer 2 and pressed against the first positioning surface 541 and the second positioning surface 542 by the first drum lock spring 62. That is, the toner cartridge 4 is installed in the drawer 2 with the drum cartridge 3 positioned accurately relative to the drawer 2. Therefore, the first guide groove 46 of the drum frame 40 can guide the first collar 24 of the toner cartridge 4 accurately. Furthermore, the second guide groove 48 of the drum frame 40 can guide the second collar 25 of the toner cartridge 4 accurately.

[0103] Furthermore, in the image forming apparatus 100 of this embodiment, the metal first plate 54 has a first positioning surface 541 and a second positioning surface 542. By making the first positioning surface 541 and the second positioning surface 542 out of metal instead of resin, displacement of the first positioning surface 541 and the second positioning surface 542 themselves can be suppressed. Therefore, the drum cartridge 3 can be positioned with respect to the drawer 2 with higher accuracy.

[0104] <6. Movement of the toner cartridge relative to the photosensitive drum> In the image forming apparatus 100, when the drawer 2 in which the drum cartridge 3 and the toner cartridge 4 are installed is attached to the main body frame 1, the toner cartridge 4 can be moved between a separated position and a contact position. When the toner cartridge 4 is located at the separated position, the developing roller 20 is separated from the photosensitive drum 30. Specifically, the developing roller 20 is separated from the photosensitive drum 30 in a fourth direction. When the toner cartridge 4 is located at the contact position, the developing roller 20 is in contact with the photosensitive drum 30. Specifically, the outer circumferential surface of the developing roller 20 and the outer circumferential surface of the photosensitive drum 30 are in contact in the fourth direction.

[0105] 15 to 17 are diagrams showing how the toner cartridge 4 is moved between the separated position and the contact position. In FIGS. 15 to 17, the developing roller 20 and the photosensitive drum 30 are indicated by dashed lines. As shown in FIGS. 15 to 17, the drawer 2 has a switch lever 81, a linear cam 82, a separating spring 83, and a pressing spring 84 as components for moving the toner cartridge 4 between the separated position and the contact position.

[0106] The switch lever 81 is a lever for switching the position of the toner cartridge 4 relative to the photosensitive drum 30. The switch lever 81 has a lever hole 810. The lever hole 810 penetrates the switch lever 81 in a first direction. The first side frame 51 has a lever shaft 511. The lever shaft 511 extends in the first direction from the inner surface of the first side frame 51 toward the switch lever 81. The lever shaft 511 is inserted into the lever hole 810. This allows the switch lever 81 to be rotatably supported about the lever shaft 511.

[0107] The switch lever 81 has a first arm 811, a second arm 812, and a leg 813. The first arm 811 and the second arm 812 are aligned at an interval in the fourth direction. The first arm 811 and the second arm 812 each extend in a direction intersecting the fourth direction. The first arm 811 and the second arm 812 extend from the periphery of the lever hole 810 toward the opposite side from the linear cam 82. The leg 813 extends in the third direction from the periphery of the lever hole 810 toward the linear cam 82.

[0108] When the toner cartridge 4 is installed in the drawer 2 in which the drum cartridge 3 is installed, the spacing boss 16 of the toner cartridge 4 engages with the switch lever 81. Specifically, the spacing boss 16 is located between the first arm portion 811 and the second arm portion 812 of the switch lever 81.

[0109] The switch lever 81 is rotatable relative to the drum frame 40 between a first lever position shown in Fig. 15 and a second lever position shown in Fig. 17. When the switch lever 81 is in the first lever position, the toner cartridge 4 is in the separated position. When the switch lever 81 is in the second lever position, the toner cartridge 4 is in the contact position.

[0110] The linear cam 82 is a member for moving the switch lever 81 between a first lever position and a second lever position. The linear cam 82 is attached to the inner surface of the first side frame 51. The linear cam 82 is movable in a second direction relative to the drum frame 40 between the first cam position and the second cam position. When the linear cam 82 is located at the first cam position, the switch lever 81 is located at the first lever position. When the linear cam 82 is located at the second cam position, the switch lever 81 is located at the second lever position.

[0111] The spacing spring 83 is a spring located between the drawer frame 50 and the linear cam 82. The spacing spring 83 is, for example, a tension coil spring that is expandable and contractible in the second direction. One end of the spacing spring 83 in the second direction is connected to the first side frame 51. The other end of the spacing spring 83 in the second direction is connected to the linear cam 82. The linear cam 82 is biased toward the first cam position by the elastic force of the spacing spring 83. In other words, the linear cam 82 is biased toward the first cam position by the tension force of the spacing spring 83. Therefore, the switch lever 81 is also biased toward the first lever position by the elastic force of the spacing spring 83.

[0112] That is, when the drawer 2 with the drum cartridge 3 and toner cartridge 4 installed is not attached to the main body frame 1, the elastic force of the separation spring 83 positions the linear cam 82 in the first cam position and the switch lever 81 in the first lever position. In this state, as shown in FIG. 15 , the first arm 811 of the switch lever 81 contacts the separation boss 16. The contact of the separation boss 16 with the first arm 811 restricts the separation boss 16 from moving in the fourth direction toward the photosensitive drum 30. As a result, the toner cartridge 4 is positioned in the separation position where the developing roller 20 is separated from the photosensitive drum 30. In this way, when the switch lever 81 is positioned in the first lever position, it holds the toner cartridge 4 in the separation position.

[0113] As shown in FIGS. 15 to 17 , the image forming apparatus 100 includes a pressing mechanism 6. The pressing mechanism 6 is, for example, a solenoid. When performing printing, the control unit 5 sends a signal to the pressing mechanism 6. In response to the signal, the pressing mechanism 6 presses the linear cam 82 in the second direction in accordance with the signal from the control unit 5. As a result, the linear cam 82 moves from the first cam position to the second cam position against the biasing force of the separation spring 83. That is, the pressing mechanism 6 presses the linear cam 82 from the first cam position to the second cam position in accordance with a command from the control unit 5. Then, the switch lever 81 rotates from the first lever position to the second lever position against the biasing force of the separation spring 83. As a result, the second arm 812 of the switch lever 81 presses the separation boss 16 toward the photosensitive drum 30 in the fourth direction. As a result, the toner cartridge 4 moves from the separation position to the contact position. As a result, the developing roller 20 comes into contact with the photosensitive drum 30. When the switch lever 81 is located at the second lever position, the second arm 812 comes into contact with the spacing boss 16, thereby restricting the spacing boss 16 from moving in the fourth direction away from the photosensitive drum 30. In other words, when the switch lever 81 is located at the second lever position, the toner cartridge 4 is held in the contact position.

[0114] As shown in FIGS. 15 to 17 , the translation cam 82 does not overlap with the drum coupling 31 and the development coupling 26 in the first direction. Specifically, the translation cam 82 is located between the drum coupling 31 and the development coupling 26 in the third direction. In this way, the drum drive shaft of the image forming apparatus 100 can be inserted into the drum coupling 31 without being blocked by the translation cam 82. In addition, the development drive shaft of the image forming apparatus 100 can be inserted into the development coupling 26 without being blocked by the translation cam 82.

[0115] The translation cam 82 is positioned outward of the drum coupling 31 in the first direction. That is, in the first direction, the drum coupling 31 is positioned between the translation cam 82 and the outer peripheral surface of the photosensitive drum 30. Therefore, when the drum cartridge 3 is attached to the drawer 2, the drum coupling 31 passes through the translation cam 82 and can move in the third direction without coming into contact with the translation cam 82.

[0116] The pressure spring 84 is a spring located between the linear cam 82 and the switch lever 81. The pressure spring 84 is, for example, a compression coil spring that is expandable and contractible in the second direction. Alternatively, the pressure spring 84 may be a torsion spring. When the linear cam 82 is located at the second cam position, the pressure spring 84 presses the switch lever 81 from the first lever position toward the second lever position. This allows the developing roller 20 to be pressed against the photosensitive drum 30 when the toner cartridge 4 is located at the contact position.

[0117] Hereinafter, of the four drum cartridges 3, the drum cartridge 3 closest to one end of the drawer 2 in the second direction will be referred to as the "first drum cartridge 3A," and the other drum cartridge 3 will be referred to as the "second drum cartridge 3B." Also, of the four toner cartridges 4, the toner cartridge 4 closest to one end of the drawer 2 in the second direction will be referred to as the "first toner cartridge 4A," and the other toner cartridge 4 will be referred to as the "second toner cartridge 4B."

[0118] In the following description, the photosensitive drum 30 of the first drum cartridge 3A will be referred to as the "first photosensitive drum 30A," and the photosensitive drum 30 of the second drum cartridge 3B will be referred to as the "second photosensitive drum 30B." When the first drum cartridge 3A and the second drum cartridge 3B are attached to the drawer 2, the second photosensitive drum 30B is spaced apart from the first photosensitive drum 30A in the second direction.

[0119] In the following, the developing roller 20 of the first toner cartridge 4A will be referred to as the "first developing roller 20A," and the developing roller 20 of the second toner cartridge 4B will be referred to as the "second developing roller 20B." When the first toner cartridge 4A and the second toner cartridge 4B are attached to the drawer 2, the second developing roller 20B is spaced apart from the first developing roller 20A in the second direction.

[0120] In the following, the switch lever 81 that switches the position of the first developing roller 20A relative to the first photosensitive drum 30A will be referred to as the "first switch lever 81A." In the following, the switch lever 81 that switches the position of the second developing roller 20B relative to the second photosensitive drum 30B will be referred to as the "second switch lever 81B."

[0121] In this embodiment, the translation cam 82 has a first translation cam 82A and a second translation cam 82B. The first translation cam 82A and the second translation cam 82B are arranged side by side with a gap in the second direction. The first translation cam 82A is located closer to one end of the drawer 2 in the second direction than the second translation cam 82B. The pressing mechanism 6 comes into contact with the first translation cam 82A.

[0122] When the drawer 2, in which the first drum cartridge 3A, the second drum cartridge 3B, the first toner cartridge 4A, and the second toner cartridge 4B are installed, is attached to the main body frame 1, the first translation cam 82A and the second translation cam 82B are both located at the first cam position, as shown in Figure 15. At this time, the first translation cam 82A and the second translation cam 82B are spaced apart from each other in the second direction.

[0123] When the image forming apparatus 100 uses the toner in the first toner cartridge 4A, it operates the pressing mechanism 6 to move the first linear cam 82A from the first cam position to the second cam position, as shown in FIG. 16. This causes the first switch lever 81A to rotate from the first lever position to the second lever position. This moves the first toner cartridge 4A from the separated position to the contact position. As a result, the first developing roller 20A of the first toner cartridge 4A comes into contact with the first photosensitive drum 30A of the first drum cartridge 3A. This enables printing using the toner in the first toner cartridge 4A.

[0124] The first toner cartridge 4A is, for example, a toner cartridge 4 that supplies black toner. The second toner cartridge 4B is, for example, a toner cartridge 4 that supplies cyan, magenta, or yellow toner. As shown in FIG. 16, by bringing the first developing roller 20A into contact with the first photosensitive drum 30A and separating the second developing roller 20B from the second photosensitive drum 30B, it is possible to use only the first toner cartridge 4A that supplies black toner out of the four toner cartridges 4. This enables the image forming apparatus 100 to print in monochrome.

[0125] When performing multi-color printing, the image forming apparatus 100 further operates the pressing mechanism 6 to move the first translational cam 82A in the second direction from the second cam position shown in FIG. 16 to the third cam position shown in FIG. 17. This causes the first translational cam 82A to abut against the second translational cam 82B in the second direction. The first translational cam 82A then presses the second translational cam 82B in the second direction. This causes the second translational cam 82B to move from the first cam position to the second cam position.

[0126] When the second linear cam 82B moves from the first cam position to the second cam position, the second switch lever 81B rotates from the first lever position to the second lever position. This causes the second toner cartridge 4B to move from the separated position to the contact position. As a result, the second developing roller 20B of the second toner cartridge 4B comes into contact with the second photosensitive drum 30B of the second drum cartridge 3B. This enables multi-color printing using the toner from the first toner cartridge 4A and the toner from the second toner cartridge 4B.

[0127] Hereinafter, the pressure spring 84 located between the first translation cam 82A and the first switch lever 81A will be referred to as the "first pressure spring 84A." Additionally, the pressure spring 84 located between the second translation cam 82B and the second switch lever 81B will be referred to as the "second pressure spring 84B."

[0128] FIG. 18 is an enlarged view of the vicinity of the second pressure spring 84B. The second pressure spring 84B is a compression coil spring that can expand and contract in the second direction. One end of the second pressure spring 84B in the second direction is connected to the second translation cam 82B. The other end of the second pressure spring 84B in the second direction is connected to the leg 813 of the second switch lever 81B. As shown in the lower diagram of FIG. 18, when the second translation cam 82B is located at the second cam position, the second pressure spring 84B presses the second switch lever 81B toward the second lever position. This allows the second developing roller 20B to be pressed against the second photosensitive drum 30B when the toner cartridge 4 is located at the contact position.

[0129] FIG. 19 is an enlarged view of the vicinity of the first pressure spring 84A. The first pressure spring 84A is a torsion spring. The first pressure spring 84A is attached to the lever shaft 511. One end of the first pressure spring 84A contacts the first translation cam 82A. Specifically, the first translation cam 82A has a recess 821. One end of the first pressure spring 84A is inserted into the recess 821. The other end of the first pressure spring 84A contacts the first switch lever 81A. When the first translation cam 82A is located at the second cam position, the first pressure spring 84A presses the first switch lever 81A toward the second lever position. This allows the first developing roller 20A to be pressed against the first photosensitive drum 30A when the toner cartridge 4 is located at the contact position.

[0130] Furthermore, when the first translational cam 82A moves from the second cam position to the third cam position, one end of the first pressure spring 84A comes out of the recess 821. Then, as shown in the lower diagram of FIG. 19 , the first translational cam 82A slides in the second direction relative to the first pressure spring 84A. This allows the first translational cam 82A to move to the third cam position without being restricted by the first pressure spring 84A. Furthermore, while the first translational cam 82A moves from the second cam position to the third cam position, the first pressure spring 84A remains in contact with the first translational cam 82A. Therefore, even when the first translational cam 82A is located at the third cam position, the toner cartridge 4 can be located at the contact position and the first developing roller 20A can be pressed against the first photosensitive drum 30A.

[0131] Whether the toner cartridge 4 is in the contact position or the separated position, the first lock boss 14 of the toner cartridge 4 does not come into contact with the first lock lever 71. Moreover, whether the toner cartridge 4 is in the contact position or the separated position, the second lock boss 15 of the toner cartridge 4 does not come into contact with the second lock lever 73. Therefore, the first lock lever 71 and the second lock lever 73 do not hinder the movement of the toner cartridge 4 between the contact position and the separated position.

[0132] <7. Variations> Although one embodiment has been described above, the present disclosure is not limited to the above embodiment.

[0133] In the above embodiment, the number of drum cartridges 3 that can be attached to the drawer 2 is four. Also, in the above embodiment, the number of toner cartridges 4 that can be attached to the drawer 2 is four. However, the number of drum cartridges 3 that can be attached to the drawer 2 may be one to three, or five or more. Also, the number of toner cartridges 4 that can be attached to the drawer 2 may be one to three, or five or more.

[0134] Furthermore, the elements appearing in the above-described embodiment and modified examples may be combined as appropriate or some may be deleted within the scope of not causing any contradiction. [Explanation of symbols]

[0135] 1: Main frame 2: Drawer 3: Drum cartridge 4: Toner cartridge 5: Control section 6: Pressing mechanism 10: Housing 14: First Rock Boss 15: Second Rock Boss 16: Separation Boss 20: Developing roller 23: Koro 24: First color 25: Second color 26: Development coupling 30: Photosensitive drum 31: Drum coupling 40: Drum frame 44: Arc surface 45: Protrusion 46: First guide groove 47: First guide surface 48: Second guide groove 49: Second guide surface 50: Drawer frame 54: First plate 55: Second plate 61: 1st drum lock push cover 62: First drum lock spring 63: 2nd drum lock push cover 64: Second drum lock spring 71: First lock lever 72: First toner lock spring 73: Second lock lever 74: Second toner lock spring 81: Switch lever 81A: First switch lever 81B: Second switch lever 82: Linear cam 83: Separation spring 84: Compression spring 100: Image forming device 541: First positioning surface 542: Second positioning surface

Claims

1. An image forming apparatus, The body frame and a drawer detachable from the main body frame; a drum cartridge detachably attached to the drawer, the drum cartridge including a photosensitive drum rotatable about a drum axis extending in a first direction and a drum frame; A toner cartridge detachably attached to the drawer, a housing for containing toner; a developing roller rotatable about a developing shaft extending in the first direction; a collar located at an end of the housing in the first direction; a toner cartridge having Equipped with The drawer includes: a positioning surface with which the drum frame comes into contact when the drum cartridge is attached to the drawer; a drum lock spring that presses the drum frame toward the positioning surface; and the toner cartridge can be installed in the drawer in a state where the drum cartridge is installed in the drawer and the drum cartridge is pressed against the positioning surface by the drum lock spring; The image forming apparatus is characterized in that the drum cartridge has a guide groove into which the collar fits when the toner cartridge is attached to the drawer.

2. 2. The image forming apparatus according to claim 1, The drawer includes: a metal plate having the positioning surface; An image forming apparatus comprising:

3. 2. The image forming apparatus according to claim 1, The positioning surface is a first positioning surface extending in a second direction intersecting the first direction; a second positioning surface extending in a third direction intersecting the first direction and the second direction; Including, The drum frame is An arcuate surface centered on the drum axis and an image forming apparatus, wherein the arcuate surface contacts the first positioning surface and the second positioning surface when the drum cartridge is attached to the drawer;

4. 4. The image forming apparatus according to claim 3, The drum frame is a protrusion protruding from the arcuate surface and The image forming apparatus, wherein the protrusion contacts the second positioning surface when the drum cartridge is attached to the drawer.

5. 4. The image forming apparatus according to claim 3, The image forming apparatus, wherein the drum lock spring presses the arcuate surface in a fourth direction toward a boundary between the first positioning surface and the second positioning surface.

6. 6. The image forming apparatus according to claim 5, The image forming apparatus, wherein the guide groove is recessed in the fourth direction.

7. 7. The image forming apparatus according to claim 5, an image forming apparatus, wherein, when the drum cartridge and the toner cartridge are attached to the drawer, the photosensitive drum and the developing roller are aligned in the fourth direction;

8. 4. The image forming apparatus according to claim 3, the toner cartridge is attachable to the drawer in the third direction; The toner cartridge is a lock boss located at an end of the housing in the first direction; and The drawer includes: a lock lever that is located farther from the drum cartridge than the lock boss in the third direction when the toner cartridge is attached to the drawer, and that is movable between a locked position where the lock boss faces the lock boss in the third direction and a released position where the lock lever does not face the lock boss in the third direction; a toner lock spring that biases the lock lever from the release position toward the lock position; An image forming apparatus further comprising:

9. 9. The image forming apparatus according to claim 8, When the drawer in which the drum cartridge and the toner cartridge are installed is attached to the main body frame, the image forming apparatus is capable of moving the toner cartridge between a contact position where the developing roller contacts the photosensitive drum and a separation position where the developing roller is separated from the photosensitive drum, The image forming apparatus according to claim 1, wherein the lock boss does not come into contact with the lock lever whether the toner cartridge is in the contact position or the separated position.

10. 10. The image forming apparatus according to claim 9, an image forming apparatus, characterized in that when the drawer in which the drum cartridge and the toner cartridge are installed is not installed in the main body frame, the toner cartridge is located at the separated position;

11. 11. The image forming apparatus according to claim 10, an image forming apparatus, wherein when the toner cartridge is in the separated position, the lock lever faces the lock boss in the third direction;

12. 2. The image forming apparatus according to claim 1, an image forming apparatus, characterized in that, when the drum cartridge and the toner cartridge are attached to the drawer, the toner cartridge comes into contact with the drawer in a rotation direction about the development shaft.

13. 2. The image forming apparatus according to claim 1, The drum frame is a guide surface that guides the collar toward the guide groove during the process of installing the toner cartridge into the drawer in which the drum cartridge is installed; An image forming apparatus further comprising:

14. 7. The image forming apparatus according to claim 6, An image forming apparatus characterized in that, when the toner cartridge is removed from the drawer in which the drum cartridge and the toner cartridge are installed, the collar moves in the fourth direction relative to the guide groove, and after the collar comes out of the guide groove, the collar moves in the third direction away from the drum cartridge.

Images