Image forming apparatus

Abstract

Provided is a structure capable of guiding a toner cartridge with high accuracy with respect to a drawer in a structure in which the drawer is equipped with a drum cartridge and a toner cartridge. A drawer (2) is provided with a drum locking spring (62). The drum locking spring (62) presses a drum frame (40) toward a positioning surface (541, 542) of the drawer (2). Thereby, the drum frame (40) is positioned with respect to the drawer (2). In addition, the drum cartridge (3) is provided with a guide groove (46). When the toner cartridge (4) is equipped to the drawer (2), a collar (24) of the toner cartridge (4) is inserted into the guide groove (46). Thereby, the collar (24) of the toner cartridge (4) can be guided with high accuracy.

Description

Technical Field

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

[0002] Previously, image forming apparatuses using electrophotographic methods, such as laser printers and LED printers, were known. For example, conventional image forming apparatuses are described in Patent Document 1.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent document 1: Japanese Patent Application Publication No. 2019-179132.

[0006] The problem that the invention aims to solve

[0007] The image forming apparatus includes a drum housing with a photosensitive drum and a toner cartridge for supplying toner to the photosensitive drum. The drum housing and toner cartridge are mounted in a drawer. Furthermore, the drawer containing the drum housing and toner cartridge is mounted in the main frame of the image forming apparatus. Summary of the Invention

[0008] The purpose of this invention is to provide a structure that can guide the toner cartridge with high precision relative to the drawer in a structure that assembles the toner cartridge and the toner box in the drawer.

[0009] Methods for solving problems

[0010] The first disclosure is an image forming apparatus comprising: a main frame; a drawer detachable from the main frame; a drum cartridge detachable from the drawer and having a photosensitive drum and a drum frame, the photosensitive drum being rotatable about a drum axis extending in a first direction; and a toner cartridge detachable from the drawer and having a housing, a developing roller, and a collar, wherein the housing contains toner, the developing roller is rotatable about a developing axis extending in the first direction, and the collar is located at an end of the housing in the first direction; the drawer having: a positioning surface, in which the drum frame contacts the positioning surface when the drum cartridge is fitted into the drawer; and a drum locking spring that presses the drum frame toward the positioning surface, wherein the toner cartridge is fitted into the drawer when the drum cartridge is fitted into the drawer and the drum cartridge is pressed against the positioning surface by the drum locking spring; the drum cartridge having a guide groove, in which the collar engages when the toner cartridge is fitted into the drawer.

[0011] The second disclosure is an image forming apparatus as disclosed in the first disclosure, wherein the drawer has a metal plate having the positioning surface.

[0012] The third disclosure is an image forming apparatus of the first disclosure, wherein the positioning surface includes: a first positioning surface extending along a second direction intersecting the first direction; and a second positioning surface extending along a third direction intersecting the first direction and the second direction, the drum frame having an arcuate surface centered on the drum axis, wherein the arcuate surface contacts the first positioning surface and the second positioning surface when the drum box is assembled in the drawer.

[0013] The fourth disclosure is an image forming apparatus as disclosed in the third disclosure, wherein the drum frame has a protrusion projecting from the arcuate surface, and the protrusion contacts the second positioning surface when the drum box is assembled in the drawer.

[0014] The fifth disclosure is an image forming apparatus as disclosed in the third disclosure, wherein the drum locking spring presses the arcuate surface along a fourth direction toward the boundary between the first positioning surface and the second positioning surface.

[0015] The sixth disclosure is an image forming apparatus as disclosed in the fifth disclosure, wherein the guide groove is recessed in the fourth direction.

[0016] The seventh disclosure is an image forming apparatus as disclosed in the fifth or sixth disclosure, wherein, with the drum and the toner cartridge assembled in the drawer, the photosensitive drum and the developing roller are arranged in the fourth direction.

[0017] The eighth disclosure is an image forming apparatus as disclosed in the third disclosure, wherein the toner cartridge is mountable relative to the drawer in the third direction, the toner cartridge further having a locking boss located at the end of the housing in the first direction, and the drawer further having: a locking lever, wherein, with the toner cartridge mounted in the drawer, the locking lever is located in the third direction further away from the drum than the locking boss, the locking lever being movable between a locked position opposite to the locking boss in the third direction and a released position not opposite to the locking boss in the third direction; and a toner locking spring, the toner locking spring applying force to the locking lever from the released position toward the locked position.

[0018] The ninth disclosure is the image forming apparatus of the eighth disclosure, wherein, with the drawer, in which the drum and the toner cartridge are assembled, mounted on the main frame, the image forming apparatus enables the toner cartridge to move between a contact position where the developing roller contacts the photosensitive drum and a separation position where the developing roller separates from the photosensitive drum, and the locking boss does not contact the locking lever when the toner cartridge is in either the contact position or the separation position.

[0019] The tenth disclosure is the image forming apparatus of the ninth disclosure, wherein, in a state where the drawer, which is equipped with the drum and the toner cartridge, is not assembled to the main frame, the toner cartridge is located in the separated position.

[0020] The eleventh disclosure is the image forming apparatus of the tenth disclosure, wherein, in the state where the toner cartridge is in the separated position, the locking lever and the locking boss are opposite each other in the third direction.

[0021] The twelfth disclosure is an image forming apparatus of the first disclosure, wherein, with the drum and the toner cartridge assembled in the drawer, the toner cartridge contacts the drawer in a rotational direction centered on the developing axis.

[0022] The thirteenth disclosure is an image forming apparatus of the first disclosure, wherein the drum frame further has a guide surface that guides the collar toward the guide groove during the assembly of the toner cartridge into the drawer on which the drum cartridge is fitted.

[0023] The fourteenth disclosure is the sixth disclosure of an image forming apparatus, wherein, when the toner cartridge is removed from the drawer on which the drum and the toner cartridge are assembled, the collar moves relative to the guide groove in the fourth direction, thereby moving the collar away from the drum in the third direction after the collar disengages from the guide groove.

[0024] Invention Effects

[0025] According to the first to fourteenth disclosures, the drum frame is positioned relative to the drawer by means of a drum locking spring. Furthermore, the guide groove of the drum frame positioned relative to the drawer allows for high-precision guidance of the toner cartridge's collar.

[0026] Furthermore, according to the second disclosure, by making the positioning surface metal instead of resin, it is possible to suppress the displacement of the positioning surface itself.

[0027] Furthermore, according to the third disclosure, the drum frame can be positioned relative to the drawer in the second and third directions.

[0028] Furthermore, according to the fourth disclosure, it is possible to suppress the rotation of the drum frame relative to the drawer about the drum axis. Attached Figure Description

[0029] Figure 1 This is a three-dimensional view of the image forming apparatus.

[0030] Figure 2 It is a three-dimensional view of drawer 2, which is equipped with four drum boxes and four color powder boxes 4.

[0031] Figure 3 It is a 3D diagram of a drawer, a drum box, and a powder box.

[0032] Figure 4 This is a 3D image of the powder box.

[0033] Figure 5 This is a 3D image of the powder box.

[0034] Figure 6 It is a 3D diagram of the drum box.

[0035] Figure 7 This is a sectional view of the first drum frame.

[0036] Figure 8 It's a 3D model of the drawer.

[0037] Figure 9 It is a cross-sectional view of the drawer including the first panel.

[0038] Figure 10 It is a three-dimensional drawing of a drawer equipped with a drum box and a color powder box.

[0039] Figure 11 This diagram illustrates the action of assembling the drum box into the drawer.

[0040] Figure 12 This diagram illustrates the action of assembling the drum box into the drawer.

[0041] Figure 13 This diagram shows the action of assembling a color powder box into a drawer equipped with a drum.

[0042] Figure 14 This diagram shows the action of assembling a color powder box into a drawer equipped with a drum.

[0043] Figure 15 This diagram illustrates the movement of the toner cartridge between a separated position and a contact position.

[0044] Figure 16 This diagram illustrates the movement of the toner cartridge between a separated position and a contact position.

[0045] Figure 17 This diagram illustrates the movement of the toner cartridge between a separated position and a contact position.

[0046] Figure 18 This is an enlarged view of the area near the second pressing spring.

[0047] Figure 19 This is a magnified view of the vicinity of the first pressing spring. Detailed Implementation

[0048] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0049] Furthermore, the direction in which the drum axis A2 of the photosensitive drum 30 extends is referred to as the "first direction". The loading / unloading direction of the drawer 2 relative to the main frame 1 is referred to as the "second direction". The loading / unloading direction of the drum cartridge 3 and the toner cartridge 4 relative to the drawer 2 is referred to as the "third direction". The direction in which the photosensitive drum 30 and the developing roller 20 are arranged with the drum cartridge 3 and the toner cartridge 4 assembled in the drawer 2 is referred to as the "fourth direction".

[0050] The first and second directions intersect each other. Preferably, the first and second directions are orthogonal. The first direction and the third direction intersect each other. Preferably, the first direction and the third direction are orthogonal. The first direction and the fourth direction intersect each other. Preferably, the first direction and the fourth direction are orthogonal. The second direction and the third direction intersect each other. Preferably, the second direction and the third direction are orthogonal. The second direction and the fourth direction intersect each other. The third direction and the fourth direction intersect each other.

[0051] <1. Structure of the image forming apparatus>

[0052] Figure 1 This is a perspective view of the 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 frame 1, a drawer 2, four drum cartridges 3, four toner cartridges 4, and a control unit 5.

[0053] Figure 2 It is a three-dimensional view of a drawer 2 equipped with four drum boxes 3 and four color powder boxes 4. Figure 3 It is a 3D diagram of drawer 2, a drum box 3, and a powder box 4. (Example) Figure 2 and Figure 3 As shown, the drum cartridge 3 can be installed and removed relative to the drawer 2. The drum cartridge 3 is installed relative to the drawer 2 in a third direction. Additionally, the toner cartridge 4 can be installed and removed relative to the drawer 2 where the drum cartridge 3 is installed. With the drum cartridge 3 installed in the drawer 2, the toner cartridge 4 is installed relative to the drawer 2 in a third direction.

[0054] Additionally, the drawer 2, equipped with four drum cartridges 3 and four toner cartridges 4, can be installed and removed relative to the main frame 1. The drawer 2, equipped with four drum cartridges 3 and four toner cartridges 4, is installed relative to the main frame 1 along a second direction.

[0055] With the four drum cartridges 3 assembled in drawer 2, the four drum cartridges 3 are arranged along the second direction. Similarly, with the four toner cartridges 4 assembled in drawer 2, the four toner cartridges 4 are arranged along the second direction. Each of the four toner cartridges 4 contains toner of a different color. The image forming apparatus 100 prints an image on printing paper using toner supplied from the toner cartridges 4.

[0056] <2. Structure of the Powder Box>

[0057] Figure 4 and Figure 5 This is a 3D image of powder box 4. (See image below.) Figure 4 and Figure 5 As shown, the toner cartridge 4 has a housing 10 and a developing roller 20.

[0058] <2-1. Shell>

[0059] The housing 10 is a container for holding pigment. 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 a 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 separated from each other in the first direction.

[0060] Color powder is contained inside the housing 10. Additionally, as... Figure 4 and Figure 5 As shown, the housing 10 has an opening 13. The opening 13 is located at one end of the housing 10 in a fourth direction. The opening 13 communicates with the space within the housing 10 containing the color powder.

[0061] The housing 10 has a first locking boss 14. The first locking boss 14 is located on the first outer surface 11 of the housing 10. That is, the first locking boss 14 is located at one end of the housing 10 in a first direction. The first locking 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 locking boss 14 is, for example, a cylinder extending in the first direction.

[0062] The housing 10 has a second locking boss 15. The second locking boss 15 is located on the second outer surface 12 of the housing 10. That is, the second locking boss 15 is located at the other end of the housing 10 in the first direction. The second locking 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 locking boss 15 is, for example, a cylinder extending in the first direction.

[0063] The housing 10 has a separation boss 16. The separation boss 16 is located on the first outer surface 11 of the housing 10. That is, the separation boss 16 is located at one end of the housing 10 in a first direction. The separation boss 16 is located between the developing roller 20 and the first locking boss 14 in a fourth direction. The separation boss 16 protrudes from the first outer surface 11 of the housing 10 toward the outside of the housing 10. The shape of the separation boss 16 is, for example, a cylinder extending along the first direction.

[0064] <2-2. Developing Roller>

[0065] The developing roller 20 is a roller capable of rotating about a developing axis A1 extending in a first direction. The developing roller 20 is located at the opening 13 of the housing 10. That is, the developing roller 20 is located at one end of the housing 10 in a fourth direction.

[0066] The developing roller 20 has a developing roller body 21 and a developing roller shaft 22. The developing roller body 21 is a cylindrical component extending in a first direction. The developing roller body 21 is elastic. Specifically, the developing roller body 21 is formed of rubber. The developing roller body 21 has a cylindrical outer peripheral surface.

[0067] The developing roller shaft 22 is a cylindrical component that passes through the developing roller body 21 and extends along a first direction. The developing roller body 21 is fixed to the developing roller shaft 22. The developing roller shaft 22 is conductive. Specifically, the developing roller shaft 22 is formed of metal or conductive resin. Both ends of the developing roller shaft 22 are supported relative to the housing 10 so that they can rotate.

[0068] Additionally, the toner cartridge 4 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 body 21 via the supply roller. Thus, the toner is carried on the outer peripheral surface of the developing roller body 21.

[0069] In addition, such as Figure 4 and Figure 5 As shown, 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 a 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.

[0070] Roller 23 is mounted on developing roller shaft 22. Roller 23 is a disc-shaped component centered on developing axis A1. Roller 23 is harder than developing roller body 21. Roller 23 has a cylindrical outer peripheral surface. The diameter of the outer peripheral surface of roller 23 is smaller than the diameter of the outer peripheral surface of developing roller body 21.

[0071] With the toner cartridge 4 installed in the drawer 2 containing the drum housing 3, and the toner cartridge 4 in the contact position described later, the developing roller 20 contacts the photosensitive drum 30. Specifically, the outer peripheral surface of the photosensitive drum 30 contacts the outer peripheral surface of the developing roller body 21. At this time, the developing roller body 21 is compressed, and the outer peripheral surface of the roller 23 contacts the outer peripheral surface of the photosensitive drum 30. As a result, the interval between the developing axis A1 and the drum axis A2 can be kept constant.

[0072] In addition, such as Figure 4 and Figure 5As shown, 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 a first direction. Specifically, the first collar 24 is mounted at 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 mounted at the other end of the developing roller shaft 22 in the first direction. The first collar 24 and the second collar 25 are rotatable about the developing axis A1 relative to the developing roller shaft 22.

[0073] In addition, such as Figure 4 As shown, the toner cartridge 4 has a developer coupling 26. The developer coupling 26 is located on the first outer surface 11 of the housing 10. The developer coupling 26 is a component for inputting drive to the developer roller 20. The developer coupling 26 is rotatable about an axis extending in a first direction.

[0074] When the drawer 2, which contains the drum cartridge 3 and the toner cartridge 4, is assembled into the main frame 1, the developing drive shaft of the image forming apparatus 100 is connected to the developing coupling 26. Then, the rotation of the developing drive shaft is transmitted to the developing roller 20 via the developing coupling 26.

[0075] <3. Structure of the Drum Box>

[0076] Figure 6 This is a 3D view of the drum kit 3. (Example) Figure 6 As shown, the drum box 3 has a photosensitive drum 30 and a drum frame 40.

[0077] <3-1. Photosensitive Drum>

[0078] The photosensitive drum 30 is a drum capable of rotating about a drum axis A2 extending along a first direction. The photosensitive drum 30 is located at one end of the drum frame 40 in a fourth direction. The photosensitive drum 30 has a cylindrical outer peripheral surface centered on the drum axis A2. The outer peripheral surface of the photosensitive drum 30 is covered with a photosensitive material. With the drum cartridge 3 and toner cartridge 4 assembled in the drawer 2, the photosensitive drum 30 and the developing roller 20 are arranged along the fourth direction.

[0079] In addition, such as Figure 4 As shown, the drum housing 3 has a drum connector 31. The drum connector 31 is located at one end of the photosensitive drum 30 in a first direction. The drum connector 31 is a component for inputting drive to the photosensitive drum 30. The drum connector 31 rotates together with the photosensitive drum 30 about the drum axis A2.

[0080] When the drawer 2, which contains the drum cartridge 3 and the toner cartridge 4, is assembled into the main frame 1, the drum drive shaft of the image forming apparatus 100 is connected to the drum connector 31. Then, the rotation of the drum drive shaft is transmitted to the photosensitive drum 30 via the drum connector 31.

[0081] <3-2. Drum Frame>

[0082] The drum frame 40 supports the photosensitive drum 30 so that it can rotate about the drum axis A2. For example... Figure 6 As shown, the drum frame 40 includes a first drum frame 41, a second drum frame 42, and a connecting drum frame 43. Furthermore, in... Figure 6 In the image, the connecting drum frame 43 is shown in a state of being separated from the first drum frame 41 and the second drum frame 42.

[0083] The first drum frame 41 is located at one end of the drum frame 40 in a 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 separated from each other in the first direction. The connecting drum frame 43 extends along 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.

[0084] One end of the photosensitive drum 30 in a first direction is supported relative to the first drum frame 41 and is rotatable. The other end of the photosensitive drum 30 in the first direction is supported relative to the second drum frame 42 and is rotatable.

[0085] Additionally, the first drum frame 41 has an arcuate surface 44 and a protrusion 45. The arcuate surface 44 is an arcuate surface centered on the drum axis A2. The arcuate surface 44 is located around the drum connector 31. The protrusion 45 protrudes from a portion of the arcuate surface 44 toward the radially outward direction relative to the drum axis A2. More specifically, the protrusion 45 protrudes from a portion of the arcuate surface 44 along a second direction.

[0086] The second drum frame 42 also has the same arc surface 44 and protrusion 45 as the first drum frame 41.

[0087] Figure 7 This is a sectional view of the first drum frame 41. Figure 7 A cross-section perpendicular to the first direction is shown. For example... Figure 7 As shown, the first drum frame 41 has a first guide groove 46. The first guide groove 46 is a recess in the first collar 24 of the toner cartridge 4 for guiding the toner cartridge 4 when it is assembled into the drawer 2. The first guide groove 46 is formed on the surface of the first drum frame 41 opposite to the second drum frame 42. The first guide groove 46 is recessed in a fourth direction from the end of the first drum frame 41 toward the photosensitive drum 30.

[0088] Additionally, the first drum frame 41 has a first guide surface 47. The first guide surface 47 is the surface that guides the first collar 24 toward the first guide groove 46 during the assembly of the toner cartridge 4 toward the drawer 2 where the drum cartridge 3 is mounted. The first guide surface 47 is inclined relative to a third direction. More specifically, the first guide surface 47 is inclined in a manner that, as it moves toward the photosensitive drum 30 in a third direction, it approaches the first guide groove 46 in a second direction.

[0089] Similarly, the second drum frame 42 has a second guide groove 48. The second guide groove 48 is a recess in the second collar 25 of the toner cartridge 4 for guiding the toner cartridge 4 when it is assembled into the drawer 2. The second guide groove 48 is formed on the surface of the second drum frame 42 opposite to the first drum frame 41. The second guide groove 48 is recessed in a fourth direction from the end of the second drum frame 42 toward the photosensitive drum 30.

[0090] Additionally, the second drum frame 42 has a second guide surface 49. The second guide surface 49 is the surface that guides the second collar 25 toward the second guide groove 48 during the assembly of the toner cartridge 4 toward the drawer 2 where the drum cartridge 3 is mounted. The second guide surface 49 is inclined relative to a third direction. More specifically, the second guide surface 49 is inclined in a second direction toward the second guide groove 48 as it moves toward the photosensitive drum 30 in a third direction.

[0091] Additionally, the drum unit 3 has a cleaning roller. The cleaning roller 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 arranged in a second direction. However, in... Figure 6 and Figure 7 The cleaning roller is not shown in the diagram. The drum frame 40 has a cleaning roller holder 431. The cleaning roller holder 431 holds the cleaning roller.

[0092] Additionally, the drum unit 3 includes a charger. The charger is a device for charging the outer peripheral surface of the photosensitive drum 30. The charger is positioned opposite the outer peripheral surface of the photosensitive drum 30. The charger is, for example, a corona charger. However, in... Figure 6 and Figure 7 The charger illustration is omitted. The drum frame 40 has a charger holder 432. The charger holder 432 holds the charger.

[0093] <4. Drawer Structure>

[0094] Figure 8 This is a 3D view of drawer 2. Drawer 2 has a drawer frame 50, a first drum locking push cover 61, a first drum locking spring 62, a second drum locking push cover 63, a second drum locking spring 64, a first locking lever 71, a first color powder locking spring 72, a second locking lever 73, and a second color powder locking spring 74.

[0095] <4-1. Drawer Frame>

[0096] The drawer frame 50 is a frame capable of assembling four drum boxes 3 and four toner boxes 4. For example... Figure 8 As shown, the drawer frame 50 has a first side frame 51, a second side frame 52, and a connecting drawer frame 53.

[0097] The first side frame 51 is located at one end of the drawer frame 50 in a first direction. The first side frame 51 extends upward in a second direction and a third direction. 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 upward in a second direction and a third direction. The connecting drawer frame 53 connects the first side frame 51 and the second side frame 52 in the first direction.

[0098] The first side frame 51 and the second side frame 52 are separated in a first direction. When the drawer frame 50 is fitted with the drum box 3, the drum box 3 is positioned between the first side frame 51 and the second side frame 52 in the first direction. Furthermore, when the drawer frame 50 is fitted with the toner cartridge 4, the toner cartridge 4 is positioned between the first side frame 51 and the second side frame 52 in the first direction.

[0099] Additionally, the drawer frame 50 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 a 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 upward in a second direction and a third direction. 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 upward in a second direction and a third direction.

[0100] Figure 9 It is a cross-sectional view of drawer 2, including the first plate 54. Figure 9 A cross-section perpendicular to the first direction is shown. For example... Figure 9 As shown, 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 used to position the drum box 3 relative to the drawer frame 50 when the drawer 2 is equipped with the drum box 3.

[0101] The first positioning surface 541 is a surface extending along the second direction. That is, the first positioning surface 541 is a surface intersecting with the third direction. The second positioning surface 542 is a surface extending along the third direction. That is, the second positioning surface 542 is a surface intersecting with the second direction. When the drawer 2 is equipped with the drum box 3, the arc surface 44 of the first drum frame 41 is in contact with the first positioning surface 541 and the second positioning surface 542.

[0102] The second plate 55 also has the same first positioning surface and second positioning surface as the first plate 54. When the drawer 2 is equipped with the drum box 3, the arc surface 44 of the second drum frame 42 contacts the first positioning surface and second positioning surface of the second plate 55.

[0103] <4-2. Sliding cover and drum locking spring>

[0104] The first drum locking push cover 61 and the first drum locking spring 62 are components used to press the arc surface 44 of the first drum frame 41 toward the first positioning surface 541 and the second positioning surface 542. The first drum locking push cover 61 and the first drum locking spring 62 are located at one end of the drawer frame 50 in a first direction. In addition, the first drum locking push cover 61 and the first drum locking spring 62 are spaced apart from the first positioning surface 541 and the second positioning surface 542 in a fourth direction.

[0105] The first drum locking push cover 61 is a hollow cover that internally houses the first drum locking spring 62. With the drum housing 3 assembled into the drawer 2, the outer surface of one end of the first drum locking push cover 61 in the fourth direction contacts the first drum frame 41. The first drum locking spring 62 is a spring capable of extension and retraction in the fourth direction. The first drum locking spring 62 is, for example, a compression coil spring. The first drum locking push cover 61 is mounted on one end of the first drum locking spring 62 in the fourth direction. The other end of the first drum locking spring 62 in the fourth direction is mounted on the first side frame 51.

[0106] When the drum housing 3 is assembled into the drawer 2, the first drum frame 41 is located between the first positioning surface 541, the second positioning surface 542, and the first drum locking push cover 61. At this time, the first drum locking spring 62 is compressed in the fourth direction beyond its natural length. Therefore, by the elastic force of the first drum locking spring 62, the first drum frame 41 is pressed towards the first positioning surface 541 and the second positioning surface 542 in the fourth direction. In other words, by the reaction force accompanying the compression of the first drum locking spring 62, the first drum frame 41 is pressed towards the first positioning surface 541 and the second positioning surface 542 in the fourth direction. More specifically, by the elastic force of the first drum locking spring 62, the arcuate surface 44 is pressed towards 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.

[0107] Furthermore, with the drawer 2 equipped with the drum housing 3, the protrusion 45 of the first drum frame 41 contacts the second positioning surface 542. Thus, the first drum frame 41 contacts the second positioning surface 542 through both the arc surface 44 and the protrusion 45. As a result, rotation of the drum frame 40 relative to the drawer frame 50 about the drum axis A2 can be suppressed.

[0108] The second side frame 52 is also equipped with the same second drum locking push cover 63 and second drum locking spring 64 as the first side frame 51. When the drum housing 3 is assembled into the drawer 2, the second drum frame 42 is located in the fourth direction between the first and second positioning surfaces of the second plate 55 and the second drum locking push cover 63. Furthermore, the arcuate surface 44 of the second drum frame 42 is pressed against the first and second positioning surfaces of the second plate 55 by the second drum locking spring 64. As a result, the drum frame 40 is positioned relative to the drawer frame 50 in the second and third directions.

[0109] <4-3. Locking lever and color powder locking spring>

[0110] The first locking lever 71, the first toner locking spring 72, the second locking lever 73, and the second toner locking spring 74 are components used to prevent the toner cartridge 4 assembled in the drawer 2 from falling off the drawer 2.

[0111] Figure 10 It is a three-dimensional diagram of a drawer 2 equipped with a drum box 3 and a toner box 4. (Example) Figure 10 As shown, the first locking lever 71 and the first pigment locking spring 72 are located at one end of the drawer frame 50 in a first direction. More specifically, the first locking lever 71 and the first pigment locking spring 72 are mounted on the first side frame 51.

[0112] With the color powder box 4 installed in drawer 2, the first locking lever 71 is located further away from the drum box 3 in the third direction than the first locking boss 14.

[0113] The first locking lever 71 is rotatable about a rotation axis extending in the second direction. Thus, the first locking lever 71 can move between a locked position and a released position that is open further outward from the first side frame 51 than the locked position. When the first locking lever 71 is in the locked position, it is opposite to the first locking boss 14 in the third direction. When the first locking lever 71 is in the released position, it is not opposite to the first locking boss 14 in the third direction.

[0114] The first pigment locking spring 72 is a spring that applies force to the first locking lever 71 from the released position toward the locked position. The first pigment locking spring 72 is, for example, a torsion spring. The first pigment locking spring 72 is mounted on the rotation axis of the first locking lever 71. One end of the first pigment locking spring 72 contacts the first side frame 51. The other end of the first pigment locking spring 72 contacts the first locking lever 71. The first locking lever 71 is pressed toward the locked position by the elastic force of the first pigment locking spring 72.

[0115] In addition, such as Figure 10As shown, the second locking lever 73 and the second toner locking spring 74 are located at the other end of the drawer frame 50 in the first direction. More specifically, the second locking lever 73 and the second toner locking spring 74 are mounted on the second side frame 52. When the drawer 2 is equipped with the toner cartridge 4, the second locking lever 73 is located further away from the drum 3 in the third direction than the second locking boss 15.

[0116] The second locking lever 73 is rotatable about a rotation axis extending in the second direction. Therefore, the second locking lever 73 can move between a locked position and a released position that is open further outward from the second side frame 52 than the locked position. When the second locking lever 73 is in the locked position, it is opposite to the second locking boss 15 in the third direction. When the second locking lever 73 is in the released position, it is not opposite to the second locking boss 15 in the third direction.

[0117] The second toner locking spring 74 is a spring that applies force to the second locking lever 73 from the release position toward the locking position. The second toner locking spring 74 is, for example, a torsion spring. The second toner locking spring 74 is mounted on the rotation axis of the second locking lever 73. One end of the second toner locking spring 74 contacts the second side frame 52. The other end of the second toner locking spring 74 contacts the second locking lever 73. The second locking lever 73 is pressed toward the locking position by the elastic force of the second toner locking spring 74.

[0118] With the toner cartridge 4 assembled in drawer 2 and in the separated position described later, the first locking lever 71 and the first locking boss 14 face each other in the third direction. Furthermore, with the toner cartridge 4 assembled in drawer 2 and in the separated position described later, the second locking lever 73 and the second locking boss 15 face each other in the third direction.

[0119] Therefore, when the toner cartridge 4 moves relative to the drawer 2 in a direction away from the drum 3, the first locking boss 14 contacts the first locking lever 71, and the second locking boss 15 contacts the second locking lever 73. This prevents the toner cartridge 4 from falling out of the drawer 2.

[0120] <5. Regarding the assembly of the box>

[0121] Next, the action of assembling the drum box 3 into drawer 2 will be explained. Figure 11 and Figure 12 This diagram shows the action of assembling the drum box 3 into drawer 2. Figure 11 and Figure 12 A cross section perpendicular to the first direction is shown.

[0122] like Figure 11 and Figure 12As shown, the drawer frame 50 has a protrusion 56. The protrusion 56 protrudes in a second direction from the space connecting the drawer frame 53 toward the space for assembling the drum box 3.

[0123] When assembling the drum housing 3 into drawer 2, move the drum housing 3 relative to drawer 2 in a third direction. Then, bring the drum housing 3 closer to the first plate 54 and the second plate 55. Thus, firstly, as... Figure 11 As shown, the cleaning roller retainer 431 passes through the protrusion 56. Thus, the cleaning roller retainer 431 is located between the protrusion 56 and the bottom of the drawer frame 50.

[0124] Then, the drum housing 3 is rotated around the photosensitive drum 30. Thus, as... Figure 12 As shown, the first drum frame 41 is located between the first positioning surface 541 and the second positioning surface 542 and the first drum locking push cover 61. The first drum locking push cover 61, through the elastic force of the first drum locking spring 62, presses the first drum frame 41 towards the first positioning surface 541 and the second positioning surface 542. Consequently, the arc surface 44 of the first drum frame 41 contacts 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 direction and the third direction.

[0125] Furthermore, the protrusion 45 of the first drum frame 41 contacts the second positioning surface 542. This prevents the drum frame 40 from rotating relative to the drawer frame 50 about the drum axis A2.

[0126] Similarly, in Figure 12 In this state, the second drum frame 42 is located between the first and second positioning surfaces of the second plate 55 and the second drum locking push cover 63. Furthermore, through the elastic force of the second drum locking spring 64, the arc surface 44 of the second drum frame 42 contacts 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 both the second and third directions.

[0127] The assembly of the drum box 3 into the drawer frame 50 is now complete.

[0128] Next, the action of assembling the color powder box 4 into the drawer 2 equipped with the drum box 3 will be explained. Figure 13 and Figure 14 This diagram shows the action of assembling the color powder box 4 into the drawer 2, which is equipped with the drum box 3. Figure 13 and Figure 14 A cross section perpendicular to the first direction is shown.

[0129] When the toner cartridge 4 is installed in the drawer 2 containing the drum cartridge 3, the toner cartridge 4 is moved relative to the drawer 2 in a third direction. Then, the toner cartridge 4 is brought closer to the drum cartridge 3.

[0130] At this point, the first locking protrusion 14 of the toner cartridge 4 is in contact with the first locking lever 71. However, by moving the toner cartridge 4 further toward the drum cartridge 3, the first locking lever 71 moves from the locked position to the released position. Thus, the first locking protrusion 14 passes the first locking lever 71. Similarly, the second locking protrusion 15 of the toner cartridge 4 is also in contact with the second locking lever 73. However, by moving the toner cartridge 4 further toward the drum cartridge 3, the second locking lever 73 moves from the locked position to the released position. Thus, the second locking protrusion 15 passes the second locking lever 73.

[0131] Furthermore, during the assembly of the toner cartridge 4 into drawer 2, the first collar 24 of the toner cartridge 4 contacts the first guide surface 47 of the first drum frame 41. Additionally, the second collar 25 of the toner cartridge 4 contacts the second guide surface 49 of the second drum frame 42.

[0132] The first collar 24 moves along the first guide surface 47 toward the first guide groove 46. Then, as... Figure 14 As shown, the first collar 24 is embedded in the first guide groove 46. The first collar 24 is guided by the first guide groove 46 in the fourth direction. Meanwhile, the second collar 25 moves along the second guide surface 49 into the second guide groove 48. Then, the second collar 25 is embedded in the second guide groove 48. The second collar 25 is guided by the second guide groove 48 in the fourth direction. Thus, the position of the toner cartridge 4 relative to the drum frame 40 is restricted. As a result, the position of the developing roller 20 relative to the photosensitive drum 30 is restricted.

[0133] In addition, such as Figure 14 As shown, with the drum cartridge 3 and toner cartridge 4 assembled in drawer 2, the housing 10 of toner cartridge 4 contacts the connecting drawer frame 53 in the rotational direction centered on the developing axis A1. Therefore, the toner cartridge 4 can also be positioned relative to the drawer frame 50 in the rotational direction centered on the developing axis A1.

[0134] When removing the toner cartridge 4 from the drawer 2 containing the drum cartridge 3 and the toner cartridge 4, firstly, the first collar 24 is moved relative to the first guide groove 46 in the fourth direction, thereby disengaging the first collar 24 from the first guide groove 46. Secondly, the second collar 25 is moved relative to the second guide groove 48 in the fourth direction, thereby disengaging the second collar 25 from the second guide groove 48.

[0135] Then, the toner cartridge 4 is moved along the third direction by moving the first collar 24 and the second collar 25 in a direction away from the drum box 3 in a third direction. Thus, the toner cartridge 4 can be removed from the drawer 2 without removing the drum box 3 from the drawer 2.

[0136] 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. Therefore, the lifespan of the drawer 2, drum cartridge 3, and toner cartridge 4 can be utilized effectively.

[0137] Furthermore, in the image forming apparatus 100 of this embodiment, the toner cartridge 4 is assembled into the drawer 2 with the drum cartridge 3 mounted on the drawer 2 and the drum cartridge 3 pressed against the first positioning surface 541 and the second positioning surface 542 by the first drum locking spring 62. That is, the toner cartridge 4 is assembled into the drawer 2 with the drum cartridge 3 precisely positioned relative to the drawer 2. Therefore, the first collar 24 of the toner cartridge 4 can be precisely guided by the first guide groove 46 of the drum frame 40. In addition, the second collar 25 of the toner cartridge 4 can be precisely guided by the second guide groove 48 of the drum frame 40.

[0138] 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 metal instead of resin, displacement of the first positioning surface 541 and the second positioning surface 542 themselves can be suppressed. Therefore, the drum box 3 can be positioned relative to the drawer 2 with higher precision.

[0139] <6. Regarding the movement of the toner cartridge relative to the photosensitive drum>

[0140] With the drawer 2, which houses the drum cartridge 3 and the toner cartridge 4, mounted on the main frame 1, the image forming apparatus 100 allows the toner cartridge 4 to move between a separated position and a contact position. When the toner cartridge 4 is in the separated position, the developing roller 20 separates from the photosensitive drum 30. Specifically, the developing roller 20 separates from the photosensitive drum 30 along a fourth direction. When the toner cartridge 4 is in the contact position, the developing roller 20 contacts the photosensitive drum 30. Specifically, the outer peripheral surface of the developing roller 20 and the outer peripheral surface of the photosensitive drum 30 contact each other along a fourth direction.

[0141] Figures 15 to 17 This diagram illustrates the movement of the toner cartridge 4 between a separated position and a contact position. Figures 15 to 17 In the image, the developing roller 20 and the photosensitive drum 30 are shown with dashed lines. For example... Figures 15 to 17 As shown, as a structure for moving the toner cartridge 4 between the separated position and the contact position, the drawer 2 has a switch lever 81, a direct-acting cam 82, a separation spring 83, and a pressing spring 84.

[0142] The switch lever 81 is used to switch 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 extends through the switch lever 81 in a first direction. The first side frame 51 has a lever shaft 511. The lever shaft 511 extends from the inner surface of the first side frame 51 toward the switch lever 81 in the first direction. The lever shaft 511 is inserted into the lever hole 810. Thus, the switch lever 81 is supported so that it can rotate about the lever shaft 511.

[0143] 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 arranged at a distance from each other in a fourth direction. The first arm 811 and the second arm 812 extend in directions intersecting with the fourth direction. The first arm 811 and the second arm 812 extend from the portion around the lever hole 810 toward the side opposite to the direct-acting cam 82. The leg 813 extends from the portion around the lever hole 810 toward the direct-acting cam 82 in a third direction.

[0144] With the toner cartridge 4 installed in the drawer 2 containing the drum housing 3, the separation boss 16 of the toner cartridge 4 engages with the switch lever 81. Specifically, the separation boss 16 is located between the first arm 811 and the second arm 812 of the switch lever 81.

[0145] Switch lever 81 can Figure 15 The position of the first rod shown and Figure 17 Between the second lever positions shown, it rotates relative to the drum frame 40. When the switch lever 81 is in the first lever position, the toner cartridge 4 is in the disengaged position. When the switch lever 81 is in the second lever position, the toner cartridge 4 is in the engaged position.

[0146] The direct-acting cam 82 is a component used to move the switch lever 81 between a first lever position and a second lever position. The direct-acting cam 82 is mounted on the inner surface of the first side frame 51. The direct-acting cam 82 is movable relative to the drum frame 40 in a second direction between the first cam position and the second cam position. When the direct-acting cam 82 is in the first cam position, the switch lever 81 is in the first lever position. When the direct-acting cam 82 is in the second cam position, the switch lever 81 is in the second lever position.

[0147] The release spring 83 is a spring located between the drawer frame 50 and the direct-acting cam 82. The release spring 83 is, for example, a tension coil spring capable of extending and retracting in a second direction. One end of the release spring 83 in the second direction is connected to the first side frame 51. The other end of the release spring 83 in the second direction is connected to the direct-acting cam 82. The direct-acting cam 82 is forced toward the first cam position by the elastic force of the release spring 83. In other words, the direct-acting cam 82 is forced toward the first cam position by the tension force of the release spring 83. Therefore, the switch lever 81 is also forced toward the first lever position by the elastic force of the release spring 83.

[0148] That is, when the drawer 2, which contains the drum box 3 and the toner box 4, is not assembled to the main frame 1, the direct-acting cam 82 is in the first cam position and the switch lever 81 is in the first lever position due to the spring force of the release spring 83. In this state, as... Figure 15 As shown, the first arm 811 of the switch lever 81 contacts the separation boss 16. Furthermore, by the contact between the separation boss 16 and the first arm 811, the movement of the separation boss 16 in the fourth direction toward the photosensitive drum 30 is restricted. Thus, the toner cartridge 4 is positioned in a separated position away from the photosensitive drum 30 by the developing roller 20. In this way, when the switch lever 81 is in the first lever position, it holds the toner cartridge 4 in the separated position.

[0149] like Figures 15 to 17 As shown, the image forming apparatus 100 includes a pressing mechanism 6. The pressing mechanism 6 is, for example, a solenoid. During printing, the control unit 5 sends a signal to the pressing mechanism 6. Then, based on the signal from the control unit 5, the pressing mechanism 6 presses the linear cam 82 in the second direction. As a result, the linear cam 82 overcomes the force of the separating spring 83 and moves from the first cam position to the second cam position. In other words, the pressing mechanism 6 presses the linear cam 82 from the first cam position toward the second cam position according to the instruction from the control unit 5. Then, the switch lever 81 overcomes the force of the separating spring 83 and rotates from the first lever position to the second lever position. Then, the second arm 812 of the switch lever 81 presses the separating boss 16 toward the photosensitive drum 30 in the fourth direction. As a result, the toner cartridge 4 moves from the separated position to the contact position. Consequently, the photosensitive drum 30 comes into contact with the developing roller 20. Furthermore, when the switch lever 81 is in the second lever position, the second arm 812 contacts the separation boss 16, restricting the separation boss 16 from moving away from the photosensitive drum 30 in the fourth direction. That is, when the switch lever 81 is in the second lever position, it holds the toner cartridge 4 in the contact position.

[0150] like Figures 15 to 17As shown, the direct-acting cam 82 does not overlap with the drum connector 31 and the developing connector 26 in the first direction. Specifically, the direct-acting cam 82 is located between the drum connector 31 and the developing connector 26 in the third direction. In this way, the drum drive shaft of the image forming apparatus 100 can be inserted into the drum connector 31 without being obstructed by the direct-acting cam 82. In addition, the developing drive shaft of the image forming apparatus 100 can be inserted into the developing connector 26 without being obstructed by the direct-acting cam 82.

[0151] The direct-acting cam 82 is located further outward than the drum connector 31 in the first direction. That is, in the first direction, the drum connector 31 is located between the direct-acting cam 82 and the outer peripheral surface of the photosensitive drum 30. Therefore, when assembling the drum housing 3 into the drawer 2, the drum connector 31 can move along the third direction without contacting the direct-acting cam 82.

[0152] The pressing spring 84 is a spring located between the direct-acting cam 82 and the switch lever 81. The pressing spring 84 is, for example, a compression coil spring capable of extending and retracting in a second direction. Alternatively, the pressing spring 84 may also be a torsion spring. With the direct-acting cam 82 in the second cam position, the pressing spring 84 presses the switch lever 81 from the first lever position toward the second lever position. Thus, with the toner cartridge 4 in the contact position, the developing roller 20 can be pressed against the photosensitive drum 30.

[0153] Hereinafter, the drum box 3 closest to the drawer 2 at one end in the second direction among the four drum boxes 3 will be referred to as "first drum box 3A", and the other drum boxes 3 will be referred to as "second drum box 3B". In addition, the color powder box 4 closest to the drawer 2 at one end in the second direction among the four color powder boxes 4 will be referred to as "first color powder box 4A", and the other color powder boxes 4 will be referred to as "second color powder box 4B".

[0154] Furthermore, hereinafter, the photosensitive drum 30 of the first drum housing 3A will be referred to as "first photosensitive drum 30A", and the photosensitive drum 30 of the second drum housing 3B will be referred to as "second photosensitive drum 30B". With the first drum housing 3A and the second drum housing 3B assembled in the drawer 2, the second photosensitive drum 30B moves away from the first photosensitive drum 30A in a second direction.

[0155] Furthermore, hereinafter, the developing roller 20 of the first toner cartridge 4A will be referred to as "first developing roller 20A", and the developing roller 20 of the second toner cartridge 4B will be referred to as "second developing roller 20B". With the first toner cartridge 4A and the second toner cartridge 4B assembled in the drawer 2, the second developing roller 20B moves away from the first developing roller 20A in a second direction.

[0156] Furthermore, 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 "first switch lever 81A" below. Furthermore, 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 "second switch lever 81B" below.

[0157] In this embodiment, the direct-acting cam 82 has a first direct-acting cam 82A and a second direct-acting cam 82B. The first direct-acting cam 82A and the second direct-acting cam 82B are arranged at a distance from each other in a second direction. The first direct-acting cam 82A is located at one end of the drawer 2 in the second direction, closer to the second direct-acting cam 82B. The pressing mechanism 6 contacts the first direct-acting cam 82A.

[0158] When drawer 2, which contains the first drum box 3A, the second drum box 3B, the first color powder box 4A, and the second color powder box 4B, is assembled on the main frame 1, as follows: Figure 15 As shown, both the first direct-acting cam 82A and the second direct-acting cam 82B are located in the first cam position. At this time, the first direct-acting cam 82A and the second direct-acting cam 82B are separated from each other in the second direction.

[0159] When the image forming apparatus 100 uses toner from the first toner cartridge 4A, it activates the pressing mechanism 6, such as... Figure 16 As shown, the first direct-acting cam 82A is moved from the first cam position to the second cam position. Consequently, the first switch lever 81A rotates from the first lever position to the second lever position. This causes the first toner cartridge 4A to move 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 cassette 3A. This enables printing using the toner from the first toner cartridge 4A.

[0160] The first powder box 4A is, for example, a powder box 4 that supplies black powder. The second powder box 4B is, for example, a powder box 4 that supplies cyan, magenta, or yellow powder. Figure 16 As shown, by setting the first developing roller 20A to contact the first photosensitive drum 30A and the second developing roller 20B to be away from the second photosensitive drum 30B, it is possible to use only the first toner cartridge 4A, which supplies black toner, out of the four toner cartridges 4. Therefore, the image forming apparatus 100 can perform monochrome printing.

[0161] During multicolor printing, the image forming apparatus 100 further actuates the pressing mechanism 6, causing the first direct-acting cam 82A to move from... Figure 16 The second cam position shown is towards Figure 17The third cam position shown is moved along the second direction. Thus, the first direct-acting cam 82A abuts against the second direct-acting cam 82B in the second direction. Then, the first direct-acting cam 82A presses the second direct-acting cam 82B along the second direction. As a result, the second direct-acting cam 82B moves from the first cam position to the second cam position.

[0162] When the second direct-acting 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 cassette 3B. Consequently, multicolor printing using toner from the first toner cartridge 4A and the second toner cartridge 4B becomes possible.

[0163] Hereinafter, the pressing spring 84 located between the first direct-acting cam 82A and the first switch lever 81A will be referred to as "first pressing spring 84A". In addition, the pressing spring 84 located between the second direct-acting cam 82B and the second switch lever 81B will be referred to as "second pressing spring 84B".

[0164] Figure 18 This is an enlarged view of the vicinity of the second pressing spring 84B. The second pressing spring 84B is a compression coil spring capable of extending and retracting in a second direction. One end of the second pressing spring 84B in the second direction is connected to the second direct-acting cam 82B. The other end of the second pressing spring 84B in the second direction is connected to the leg 813 of the second switch lever 81B. Figure 18 As shown in the figure below, when the second direct-acting cam 82B is in the second cam position, the second pressing spring 84B presses the second switch lever 81B toward the second lever position. Thus, with the toner cartridge 4 in the contact position, the second developing roller 20B can be pressed against the second photosensitive drum 30B.

[0165] Figure 19 This is an enlarged view of the vicinity of the first pressing spring 84A. The first pressing spring 84A is a torsion spring. The first pressing spring 84A is mounted on the rod shaft 511. One end of the first pressing spring 84A contacts the first direct-acting cam 82A. Specifically, the first direct-acting cam 82A has a recess 821. One end of the first pressing spring 84A is inserted into the recess 821. The other end of the first pressing spring 84A contacts the first switch lever 81A. When the first direct-acting cam 82A is in the second cam position, the first pressing spring 84A presses the first switch lever 81A toward the second lever position. Thus, with the toner cartridge 4 in the contact position, the first developing roller 20A can be pressed against the first photosensitive drum 30A.

[0166] Furthermore, when the first direct-acting cam 82A moves from the second cam position to the third cam position, one end of the first pressing spring 84A disengages from the recess 821. And, as... Figure 19 As shown in the figure below, the first direct-moving cam 82A slides relative to the first pressing spring 84A in the second direction. Therefore, the first direct-moving cam 82A can move to the third cam position without being restricted by the first pressing spring 84A. Furthermore, during the movement of the first direct-moving cam 82A from the second cam position to the third cam position, the first pressing spring 84A remains in contact with the first direct-moving cam 82A. Therefore, when the first direct-moving cam 82A is in the third cam position, the toner cartridge 4 can also be in the contact position, and the first developing roller 20A can be pressed against the first photosensitive drum 30A.

[0167] Furthermore, when the toner cartridge 4 is in either the contact position or the separation position, the first locking boss 14 of the toner cartridge 4 does not contact the first locking lever 71. Similarly, when the toner cartridge 4 is in either the contact position or the separation position, the second locking boss 15 of the toner cartridge 4 does not contact the second locking lever 73. Therefore, the first locking lever 71 and the second locking lever 73 do not impede the movement of the toner cartridge 4 between the contact position and the separation position.

[0168] <7. Variations>

[0169] The above describes one embodiment, but the present invention is not limited to the above embodiment.

[0170] In the above embodiment, the number of drum cartridges 3 that can be fitted into drawer 2 is four. Additionally, in the above embodiment, the number of toner cartridges 4 that can be fitted into drawer 2 is four. However, the number of drum cartridges 3 that can be fitted into drawer 2 may be one to three, or five or more. Similarly, the number of toner cartridges 4 that can be fitted into drawer 2 may be one to three, or five or more.

[0171] Furthermore, for the elements appearing in the above-described implementation methods and variations, some may be appropriately combined or deleted without causing contradictions.

[0172] Symbol Explanation

[0173] 1: Main Framework

[0174] 2: Drawer

[0175] 3: Drum Box

[0176] 4: Powder box

[0177] 5: Control Department

[0178] 6: Pressing mechanism

[0179] 10: Shell

[0180] 14: First locking boss

[0181] 15: Second locking boss

[0182] 16: Separating boss

[0183] 20: Developing roller

[0184] 23: Roller

[0185] 24: First collar

[0186] 25: Second collar

[0187] 26: Developer connector

[0188] 30: Photosensitive drum

[0189] 31: Drum Connector

[0190] 40: Drum frame

[0191] 44: Arc surface

[0192] 45: Protrusion

[0193] 46: First guide groove

[0194] 47: First guiding surface

[0195] 48: Second guide groove

[0196] 49: Second guiding surface

[0197] 50: Drawer frame

[0198] 54: First board

[0199] 55: Second board

[0200] 61: First drum locks the cover

[0201] 62: First drum locking spring

[0202] 63: Second drum locks the cover

[0203] 64: Second drum locking spring

[0204] 71: First locking lever

[0205] 72: First color powder locking spring

[0206] 73: Second locking lever

[0207] 74: Second color powder locking spring

[0208] 81: Switch lever

[0209] 81A: First switch lever

[0210] 81B: Second switch lever

[0211] 82: Direct-acting cam

[0212] 83: Release spring

[0213] 84: Pressing spring

[0214] 100: Image forming apparatus

[0215] 541: First positioning surface

[0216] 542: Second positioning surface.

Claims

1. An image forming apparatus, characterized in that, have: Main framework; A drawer that can be attached to or detached relative to the main frame; A drum housing that can be loaded and unloaded relative to the drawer and has a photosensitive drum and a drum frame that can rotate about a drum axis extending in a first direction; as well as A toner cartridge, which is removable relative to the drawer, and includes a housing, a developing roller, and a collar, wherein... The shell contains the color powder. The developing roller is capable of rotating about a developing axis extending along the first direction. The collar is located at the end of the housing in the first direction. The drawer has: The positioning surface, in which the drum housing is assembled into the drawer, is in contact with the positioning surface; and A drum locking spring presses the drum frame toward the positioning surface. With the drum housing assembled into the drawer and the drum housing pressed against the positioning surface by the drum locking spring, the toner cartridge can be assembled into the drawer. The drum box has a guide groove, and the collar is embedded in the guide groove when the toner cartridge is assembled into the drawer.

2. The image forming apparatus according to claim 1, characterized in that, The drawer has a metal plate with the aforementioned positioning surface.

3. The image forming apparatus according to claim 1, characterized in that, The positioning surface includes: A first positioning surface, the first positioning surface extending along a second direction intersecting the first direction; and The second positioning surface extends along a third direction that intersects the first direction and the second direction. The drum frame has an arc surface centered on the drum axis. When the drum box is assembled into the drawer, the arc surface is in contact with the first positioning surface and the second positioning surface.

4. The image forming apparatus according to claim 3, characterized in that, The drum frame has protrusions extending from the arcuate surface. With the drum housing assembled in the drawer, the protrusion contacts the second positioning surface.

5. The image forming apparatus according to claim 3, characterized in that, The drum locking spring presses the arc surface along a fourth direction toward the boundary between the first positioning surface and the second positioning surface.

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

7. The image forming apparatus according to claim 5 or 6, characterized in that, With the drum and toner cartridge assembled in the drawer, the photosensitive drum and the developing roller are arranged in the fourth direction.

8. The image forming apparatus according to claim 3, characterized in that, The toner cartridge can be assembled relative to the drawer along the third direction. The toner cartridge also has a locking boss located at the end of the housing in the first direction. The drawer also has: The locking lever, when the toner cartridge is assembled in the drawer, is located further away from the drum than the locking boss in the third direction. The locking lever is movable between a locking position opposite to the locking boss in the third direction and a releasing position not opposite to the locking boss in the third direction. as well as A toner locking spring that applies force to the locking lever from the released position toward the locked position.

9. The image forming apparatus according to claim 8, characterized in that, With the drawer containing the drum and toner cartridge assembled in the main frame, the image forming apparatus allows the toner cartridge to move between a contact position where the developing roller contacts the photosensitive drum and a separation position where the developing roller separates from the photosensitive drum. When the toner cartridge is in either the contact position or the separation position, the locking boss does not contact the locking lever.

10. The image forming apparatus according to claim 9, characterized in that, When the drawer containing the drum and the toner cartridge is not assembled to the main frame, the toner cartridge is in the separated position.

11. The image forming apparatus according to claim 10, characterized in that, With the toner cartridge in the separated position, the locking lever and the locking boss are opposite each other in the third direction.

12. The image forming apparatus according to claim 1, characterized in that, With the drum and the toner cartridge assembled in the drawer, the toner cartridge contacts the drawer in a rotational direction centered on the developing axis.

13. The image forming apparatus according to claim 1, characterized in that, The drum frame also has a guide surface that guides the collar toward the guide groove during the assembly of the toner cartridge into the drawer containing the drum cartridge.

14. The image forming apparatus according to claim 6, characterized in that, When the toner cartridge is removed from the drawer containing the drum and the toner cartridge, the collar moves relative to the guide groove in the fourth direction, thereby moving the collar away from the drum in the third direction after it disengages from the guide groove.

Images