Drum unit and image forming apparatus

Abstract

To prevent an increase in size of a drum unit or an image forming apparatus.SOLUTION: An image forming apparatus (color printer 1) comprises: a main body housing 10 that has an opening 10A; a front cover 11 that opens and closes the opening 10A; a toner cartridge TC that stores toner; and a drum unit 50 that can mount the toner cartridge TC therein and is movable in a first direction with respect to the main body housing 10 through the opening 10A. The drum unit 50 has a photoreceptor drum 51 and a developing unit 60. The developing unit 60 is located between the toner cartridge TC and the photoreceptor drum 51, and includes a magnetic roller 61 that is rotatable about a second axis X2 extending in a second direction, a developer container 62 that stores carrier, a first auger 63 that circulates the carrier and toner in the developer container 62, and a second auger 64 that can convey the carrier and toner in the developer container 62 toward the magnetic roller 61.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a drum unit and an image forming apparatus that are provided with a mechanism for transporting toner together with a carrier. [Background technology]

[0002] Conventionally, there is known an image forming apparatus that includes a main body housing, a drum unit, and a toner cartridge (see Patent Document 1). The drum unit includes a developer container. The developer container contains toner and carrier. In addition to the developer container, the image forming apparatus also includes a replenishing device between the toner cartridge and the developer container. The replenishing device includes a toner replenishing device that temporarily stores and agitates toner in the toner cartridge in order to replenishing the toner from the toner cartridge to the developer container. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-171105 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional technology, a toner supply device is required in addition to the toner cartridge, the developer container, and the drum unit, which may result in an increase in size of the drum unit or the image forming apparatus.

[0005] Therefore, an object of the present disclosure is to prevent an increase in the size of a drum unit or an image forming apparatus. [Means for solving the problem]

[0006] In order to solve the above problem, the image forming apparatus according to the first disclosure of the present disclosure includes a main body housing, a toner cartridge, and a drum unit. The main body housing has an opening. The main body housing has a front cover. The front cover is movable between an open position where the opening is opened and a closed position where the opening is closed. The toner cartridge stores toner. The drum unit is mountable with the toner cartridge. The drum unit is movable in a first direction through the opening with respect to the main body housing with the toner cartridge mounted on the drum unit. The drum unit is movable between a storage position where the drum unit is located within the main body housing and a pull-out position where the drum unit is pulled out from the main body housing. The drum unit includes a photosensitive drum and a developing unit. The photosensitive drum is rotatable about a first axis extending in a second direction. The developing unit is positioned between the toner cartridge and the photosensitive drum. The developing unit includes a magnetic roller, a developing container, a first auger, and a second auger. The magnetic roller is located between the toner cartridge and the photosensitive drum. The magnetic roller is rotatable about a second axis extending in the second direction. The magnetic roller faces the surface of the photosensitive drum. The developer container contains a carrier. The developer container has a supply port. The supply port allows the toner to be replenished from the toner cartridge. The first auger is located within the developer container. The first auger is rotatable about a third axis extending in the second direction. The first auger circulates the carrier and the toner in the developing container. The second auger is located in the developing container. The second auger is rotatable about a fourth axis extending in the second direction. The second auger is capable of transporting the carrier and the toner in the developing container toward the magnetic roller.

[0007] According to this configuration, the toner cartridge can be attached to the drum unit, and toner is replenished from the toner cartridge attached to the drum unit to the developing container, eliminating the need for a toner replenishment device as in the conventional case, and preventing the drum unit or image forming device from becoming larger.

[0008] A second disclosure may be the image forming apparatus of the first disclosure, wherein the first direction is a direction intersecting with the second direction.

[0009] A third disclosure is the image forming apparatus of the first or second disclosure, wherein the supply port may be located on the opposite side of the magnetic roller with respect to the first auger and the second auger.

[0010] Further, a fourth disclosure may be an image forming apparatus according to any one of the first to third disclosures, wherein the drum unit may include a plurality of the photosensitive drums arranged in the first direction and a plurality of the developing units arranged in the first direction.

[0011] Further, a fifth disclosure is an image forming apparatus according to any one of the first to fourth disclosures, wherein the image forming apparatus may further include a transfer member that transfers the toner image on the photosensitive drum to a sheet.

[0012] A sixth disclosure is the image forming apparatus of any one of the first to fifth disclosures, wherein the drum unit may have a sheet guide that guides a sheet toward the photosensitive drum.

[0013] A seventh disclosure is the image forming apparatus according to any one of the first to sixth disclosures, wherein the drum unit may include a cleaning roller that cleans the photosensitive drum.

[0014] Furthermore, an eighth disclosure is an image forming apparatus according to any one of the first to seventh disclosures, wherein the supply port is located above the first auger and the second auger, and the second shaft is located below the first auger and the second auger.

[0015] Further, a ninth disclosure is an image forming apparatus according to the eighth disclosure, wherein the developing unit may be provided with a layer thickness regulating member that regulates the thickness of the toner layer on the magnetic roller, the layer thickness regulating member being non-contact with the magnetic roller.

[0016] A tenth disclosure is the image forming apparatus of the ninth disclosure, wherein the layer thickness regulating member may be located below the first auger and the second auger.

[0017] An eleventh disclosure is the image forming apparatus according to any one of the first to tenth disclosures, wherein the magnetic roller may be spaced apart from the surface of the photosensitive drum.

[0018] A twelfth disclosure is the image forming apparatus of any one of the first to eleventh disclosures, wherein the first auger may be located closer to the supply port than the second auger.

[0019] Further, a thirteenth disclosure is an image forming apparatus according to any one of the first to twelfth disclosures, wherein the first auger transports toner supplied from the supply port to the second auger, the second auger supplies toner to the magnetic roller, and the magnetic roller supplies toner to the photosensitive drum.

[0020] Further, a 14th disclosure is an image forming apparatus according to any one of the 1st to 13th disclosures, wherein the drum unit comprises a first side plate having a first hole that allows one end of the developing unit in the second direction to be inserted and supported, and a second side plate facing the first side plate in the second direction and having a second hole, and the image forming apparatus may further comprise a tubular member that fits into the second hole and has an opening into which the other end of the developing unit in the second direction fits.

[0021] Further, a 15th disclosure is the image forming apparatus of the 14th disclosure, wherein the developing unit may have at one end a boss extending in the second direction that fits into the first hole, and a protrusion protruding from the boss in a direction perpendicular to the second direction that contacts the surface of the first side plate facing the second side plate to position the developing unit in the second direction.

[0022] Further, a 16th disclosure is the image forming apparatus of the 15th disclosure, wherein the tubular member may have an outer peripheral surface and a flange protruding from the outer peripheral surface, the flange being positioned on the opposite side of the second side plate from the first side plate.

[0023] According to this, since the flange is located on the second side plate opposite to the first side plate, it is possible to prevent the cylindrical member from coming off the second side plate.

[0024] Further, a 17th disclosure is an image forming apparatus according to the 16th disclosure, wherein the drum unit has a third side plate located on the opposite side of the second side plate from the first side plate, and the flange may be located between the second side plate and the third side plate.

[0025] According to this, the flange is sandwiched between the second side plate and the third side plate, so that the tubular member can be further prevented from coming off the second side plate.

[0026] Further, an 18th disclosure is an image forming apparatus of the 17th disclosure, wherein the drum unit has a fourth side plate located on the opposite side of the first side plate from the second side plate, and the first side plate and the second side plate may be sandwiched between the third side plate and the fourth side plate in the second direction.

[0027] According to this, the first side plate and the second side plate can be protected by the third side plate and the fourth side plate.

[0028] A nineteenth disclosure is the image forming apparatus of any one of the first to eighteenth disclosures, wherein the drum unit may further include a charger that charges the photosensitive drum.

[0029] A twentieth disclosure is the image forming apparatus of the nineteenth disclosure, in which the charger may be a scorotron charger.

[0030] Further, the 21st disclosure is the image forming apparatus of the 18th disclosure, wherein the image forming apparatus is configured such that after the boss is inserted into the first hole in a direction from the second side plate toward the first side plate, the protrusion comes into contact with the surface of the first side plate facing the second side plate, and after the protrusion comes into contact with the surface of the first side plate facing the second side plate, the tubular member is inserted into the second hole in a direction from the second side plate toward the first side plate and attached to the other end of the developing unit, the flange is positioned on the side of the second side plate opposite the first side plate, the third side plate is attached to the side of the second side plate opposite the first side plate, and the fourth side plate is attached to the side of the first side plate opposite the second side plate.

[0031] In order to solve the above-mentioned problem, a drum unit according to a 22nd disclosure of the present disclosure is a drum unit to which a toner cartridge that contains toner can be attached, and is movable in a first direction with respect to a main body housing of an image forming apparatus with the toner cartridge attached to the drum unit, and is a developing unit located between the toner cartridge and the photosensitive drum, the developing unit including a photosensitive drum that can rotate about a first axis that extends in a second direction, and a magnetic roller that is located between the toner cartridge and the photosensitive drum and can rotate about a second axis that extends in the second direction, The developing unit comprises a magnetic roller facing the surface of the photosensitive drum, a developing container that contains a carrier and has a supply port that allows the toner to be replenished from the toner cartridge, a first auger located within the developing container and rotatable about a third axis extending in the second direction, the first auger circulating the carrier and the toner within the developing container, and a second auger located within the developing container and rotatable about a fourth axis extending in the second direction, the second auger transporting the carrier and the toner in the developing container toward the magnetic roller.

[0032] According to this configuration, it is possible to prevent the drum unit or the image forming apparatus from becoming large. Effect of the Invention

[0033] According to the present disclosure, it is possible to prevent the drum unit or the image forming apparatus from becoming large. [Brief description of the drawings]

[0034] [Figure 1] 1 is a cross-sectional view showing a color printer according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a cross-sectional view showing a state in which the drum unit is located at a pulled-out position. [Diagram 3] FIG. 2 is a cross-sectional view showing the drum unit in which the toner cartridge is mounted. [Figure 4] 1A and 1B are perspective views showing a developing unit. [Diagram 5] FIG. 2 is a cross-sectional view showing a developing unit. [Figure 6] FIG. 2 is a perspective view showing the drum unit. [Figure 7] 11 is an exploded perspective view showing the structure of the other end side of the drum unit in the second direction. FIG. [Figure 8] 11 is an exploded perspective view showing the structure of one end side of the drum unit in the second direction. FIG. [Figure 9] 5A to 5C are diagrams showing a method of assembling the drum unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Next, an embodiment of the present disclosure will be described in detail with reference to the drawings as appropriate. As shown in FIG. 1, a color printer 1, which is an example of an image forming apparatus, includes a main body housing 10, a sheet supply section 20, an image forming section 30, and a discharge section 90.

[0036] The main body housing 10 has an opening 10A and a front cover 11. The front cover 11 is movable between an open position where the opening 10A is open and a closed position where the opening 10A is closed. Specifically, the front cover 11 is rotatable between an open position and a closed position.

[0037] The sheet supply unit 20 includes a supply tray 21 and a sheet transport mechanism 22. The supply tray 21 stores the sheets S. The sheet transport mechanism 22 transports the sheets S from the supply tray 21 to the image forming unit 30.

[0038] The image forming section 30 includes a scanner unit 40, a process unit U, a transfer member 70, and a fixing device 80.

[0039] The scanner unit 40 includes a laser emitting unit, a polygon mirror, a lens, a reflecting mirror, etc. (not shown). The scanner unit 40 emits a laser beam to the photoconductor drum 51.

[0040] The process unit U includes a drum unit 50 and four toner cartridges TC.

[0041] The toner cartridge TC contains non-magnetic toner. As shown in Fig. 2, the toner cartridge TC is detachable from the drum unit 50. More specifically, the toner cartridge TC is detachable in a direction perpendicular to a second direction described later.

[0042] The drum unit 50 is movable in a first direction relative to the main body housing 10 through the opening 10A.

[0043] The drum unit 50 is movable in a first direction relative to the main body housing 10 between a storage position where the drum unit 50 is located inside the main body housing 10 and a pull-out position where the drum unit 50 is pulled out from the main body housing 10. As shown in FIG. 3, the drum unit 50 has four photosensitive drums 51, four Scorotron chargers 52, four cleaning rollers 53, four developing units 60, and a sheet guide 54.

[0044] The photoconductor drums 51 are rotatable about a first axis X1 extending in a second direction. The second direction is a direction intersecting the first direction. More specifically, the second direction is a direction perpendicular to the first direction. The four photoconductor drums 51 are aligned in the first direction.

[0045] The scorotron charger 52 is a charger that charges the photosensitive drum 51. A charging roller may be used instead of the scorotron charger 52. The cleaning roller 53 is a roller that cleans the photosensitive drum 51. A cleaning blade may be used instead of the cleaning roller 53.

[0046] The four developing units 60 are aligned in the first direction. The developing units 60 are positioned between the toner cartridge TC and the photoconductor drum 51. The developing units 60 include a magnetic roller 61, a developing container 62, a first auger 63, a second auger 64, and a layer thickness regulating member 65.

[0047] The magnetic roller 61 is a roller that supplies toner to the photosensitive drum 51. The magnetic roller 61 has a magnetic shaft member 61A and a magnetic sleeve 61B. The magnetic shaft member 61A has different magnetic poles arranged in a predetermined pattern in the circumferential direction. The magnetic shaft member 61A is, for example, a cylindrical member in which multiple permanent magnets are embedded. The magnetic shaft member 61A is fixed to the developing container 62.

[0048] The magnetic sleeve 61B is made of, for example, a cylindrical member mainly made of a non-magnetic metal material. The magnetic sleeve 61B is rotatable about the magnetic shaft member 61A. The magnetic sleeve 61B holds the toner by the magnetic force of the magnetic shaft member 61A.

[0049] The magnetic roller 61 is located between the toner cartridge TC and the photosensitive drum 51. The magnetic sleeve 61B is rotatable about a second axis X2 extending in the second direction. The magnetic roller 61 faces the surface of the photosensitive drum 51. The magnetic roller 61 is spaced from the surface of the photosensitive drum 51.

[0050] The developing container 62 is a container that contains a carrier, which is a magnetic material. The carrier is, for example, iron powder. The developing container 62 has a supply port 62A that allows toner to be supplied from the toner cartridge TC. The supply port 62A is located on the opposite side of the magnetic roller 61 with respect to the first auger 63 and the second auger 64.

[0051] The supply port 62A is located above the first auger 63 and the second auger 64. More specifically, the supply port 62A is located above the first auger 63. The second axis X2 is located below the first auger 63 and the second auger 64. More specifically, the second axis X2 is located below the second auger 64.

[0052] The first auger 63 is located inside the developing container 62. The first auger 63 is rotatable about a third axis X3 extending in the second direction. The first auger 63 is aligned with the second auger 64 in the first direction. The first auger 63 is located closer to the supply port 62A than the second auger 64.

[0053] The first auger 63 circulates the carrier and toner in the developing container 62. The first auger 63 transports to the second auger 64 the toner supplied from the supply port 62A.

[0054] The second auger 64 is located in the developing container 62. The second auger 64 is rotatable about a fourth axis X4 extending in the second direction. The second auger 64 is capable of transporting the carrier and toner in the developing container 62 toward the magnetic roller 61. The second auger 64 supplies the toner to the magnetic roller 61. The second auger 64 circulates the carrier and toner in the developing container 62.

[0055] The layer thickness regulating member 65 is a member that regulates the thickness of the toner layer on the magnetic roller 61. The layer thickness regulating member 65 is not in contact with the magnetic roller 61. The layer thickness regulating member 65 is located below the first auger 63 and the second auger 64. More specifically, the layer thickness regulating member 65 is located below the first auger 63.

[0056] The layer thickness regulating member 65 is aligned in the first direction with the magnetic roller 61. The second axis X2 is located between the layer thickness regulating member 65 and the first axis X1 in the first direction.

[0057] The sheet guide 54 is a guide that guides the sheet S toward the photosensitive drum 51. The sheet guide 54 is aligned with the photosensitive drum 51 in the first direction. The sheet guide 54 is located upstream of the four photosensitive drums 51 in the conveying direction of the sheet S.

[0058] The magnetic roller 61 located most upstream in the conveying direction of the sheet S is located between the sheet guide 54 and the second auger 64. The layer thickness regulating member 65 located most upstream in the conveying direction of the sheet S is located between the sheet guide 54 and the first auger 63.

[0059] 1, the transfer member 70 is a member that transfers a toner image on a photosensitive drum to a sheet S. The transfer member 70 is located between the sheet supply section 20 and the drum unit 50. The transfer member 70 includes a drive roller 71, a driven roller 72, a conveyor belt 73, and a transfer roller 74.

[0060] The driving roller 71 and the driven roller 72 are spaced apart in the first direction. The driving roller 71 and the driven roller 72 support a conveyor belt 73 made of an endless belt. The transfer roller 74 is located inside the conveyor belt 73. The transfer roller 74 holds the conveyor belt 73 between itself and the photoconductor drum 51.

[0061] The fixing device 80 includes a heating roller 81 and a pressure roller 82. The pressure roller 82 sandwiches the sheet S between the heating roller 81 and the pressure roller 82.

[0062] In the image forming section 30, the scorotron charger 52 charges the surface of the photoconductor drum 51. Thereafter, the scanner unit 40 exposes the surface of the photoconductor drum 51 to light. As a result, an electrostatic latent image is formed on the photoconductor drum 51.

[0063] The toner cartridge TC supplies toner to the developing container 62. The first auger 63 transports the toner and carrier in the developing container 62 to the second auger 64. The second auger 64 supplies the toner to the electrostatic latent image on the photoconductor drum 51. As a result, a toner image is formed on the photoconductor drum 51.

[0064] The conveyor belt 73 conveys the sheet S. The sheet S passes between the photosensitive drum 51 and the transfer roller 74. At this time, the toner image on the photosensitive drum 51 is transferred to the sheet S. Thereafter, the sheet S passes between the heating roller 81 and the pressure roller 82. At this time, the toner image on the sheet S is thermally fixed.

[0065] The discharge section 90 includes a plurality of transport rollers 91. The transport rollers 91 discharge the sheet S to the outside of the main body housing 10.

[0066] 4(a), the developing unit 60 has a boss 60A and two protrusions 60B at one end in the second direction. The boss 60A extends in the second direction. The boss 60A has an outer circumferential surface centered on the second axis X2.

[0067] The protrusion 60B protrudes from the outer circumferential surface of the boss 60A in a direction perpendicular to the second direction. The second axis X2 is located between the two protrusions 60B. The boss 60A protrudes in a direction away from the developing container 62 further than the protrusions 60B.

[0068] As shown in FIG. 4(b), the developing unit 60 has a shaft 60C at the other end in the second direction. The shaft 60C extends in the second direction. The shaft 60C has an outer circumferential surface centered on the second axis X2. The outer diameter of the shaft 60C is smaller than the outer diameter of the boss 60A. The supply port 62A is located at the other end of the developing container 62 in the second direction.

[0069] 5, the developing container 62 has a first storage chamber 62B, a second storage chamber 62C, a partition wall 62D, a supply opening 62E, and a recovery opening 62F. The first storage chamber 62B is a space that houses the first auger 63. The second storage chamber 62C is a space that houses the second auger 64. The first storage chamber 62B and the second storage chamber 62C are filled with carrier.

[0070] The partition wall 62D is a wall that separates the first storage chamber 62B and the second storage chamber 62C. The supply opening 62E is located at one end of the partition wall 62D in the second direction. The supply opening 62E connects the first storage chamber 62B and the second storage chamber 62C. The supply opening 62E allows the movement of toner and carrier from the first storage chamber 62B to the second storage chamber 62C.

[0071] The recovery opening 62F is located at the other end of the partition wall 62D in the second direction. The recovery opening 62F connects the first storage chamber 62B and the second storage chamber 62C. The recovery opening 62F allows the movement of toner and carrier from the second storage chamber 62C to the first storage chamber 62B.

[0072] The replenishing port 62A is connected to the first storage chamber 62B. The distance from the replenishing port 62A to the supply opening 62E is greater than the distance from the replenishing port 62A to the recovery opening 62F.

[0073] The first auger 63 transports the toner supplied from the supply port 62A to the first storage chamber 62B together with the carrier to the supply opening 62E. The second auger 64 transports the toner supplied from the supply opening 62E to the second storage chamber 62C together with the carrier toward the other end in the second direction. The toner transported in the second direction by the second auger 64 adheres to the surface of the magnetic roller 61 by the magnetic force of the magnetic roller 61. The toner and carrier transported to the other end of the developing container 62 by the second auger 64 move to the first storage chamber 62B via the recovery opening 62F.

[0074] 6, the drum unit 50 has a third side plate W3, a fourth side plate W4, a front plate W5, and a rear plate W6. The third side plate W3, the fourth side plate W4, the front plate W5, and the rear plate W6 are made of, for example, resin.

[0075] Each developing unit 60 is located between the third side plate W3 and the fourth side plate W4 in the second direction. The front plate W5 is located at one end of the third side plate W3 and the fourth side plate W4 in the first direction. The rear plate W6 is located at the other end of the third side plate W3 and the fourth side plate W4 in the first direction.

[0076] The third side plate W3 has a cartridge support portion W31. The cartridge support portion W31 is a portion that supports the outer peripheral surface of the toner cartridge TC. The fourth side plate W4 has a cartridge support portion similar to the cartridge support portion W31.

[0077] 7 and 8, the drum unit 50 further includes a first side plate W1 and a second side plate W2. The first side plate W1 and the second side plate W2 are plates that support the ends in the second direction of each photoconductor drum 51 and each developing unit 60. The first side plate W1 and the second side plate W2 are made of, for example, metal.

[0078] The first side plate W1 has four first holes W11. The first holes W11 allow the boss 60A, which is one end of the developing unit 60 in the second direction, to be inserted and supported. In other words, the boss 60A fits into the first hole W11. A protrusion 60B located on the outer circumferential surface of the boss 60A contacts the surface of the first side plate W1 on the second side plate W2 side to position the developing unit 60 in the second direction. The fourth side plate W4 is located on the opposite side of the first side plate W1 to the second side plate W2.

[0079] The second side plate W2 faces the first side plate W1 in the second direction. The second side plate W2 has four second holes W21. The drum unit 50 has four cylindrical members P. The cylindrical members P have a cylinder portion P1 and a flange P2.

[0080] The tube portion P1 is a cylindrical portion. The tube portion P1 is inserted into the second hole W21. The tube portion P1 has an outer peripheral surface P11 and an opening P12. The shaft 60C shown in FIG. 4B, which is the other end of the developing unit 60 in the second direction, is inserted into the opening P12 of the tubular member P.

[0081] The flange P2 protrudes from the outer peripheral surface P11 of the cylindrical portion P1. The flange P2 is located on the opposite side of the second side plate W2 to the first side plate W1. The third side plate W3 is located on the opposite side of the second side plate W2 to the first side plate W1.

[0082] 9(c), the flange P2 is located between the second side plate W2 and the third side plate W3. The first side plate W1 and the second side plate W2 are sandwiched between the third side plate W3 and the fourth side plate W4 in the second direction.

[0083] Next, a method for assembling the drum unit 50 will be described. 9(a), each photoconductor drum 51 is attached to a first side plate W1 and a second side plate W2. Although not shown, a unit having a scorotron charger 52 and a cleaning roller 53 is also attached to the first side plate W1 and the second side plate W2.

[0084] 9(a) and (b), the shaft 60C of the developing unit 60 is inserted into the second hole W21 of the second side plate W2. Then, the boss 60A of the developing unit 60 is inserted into the first hole W11 in the direction from the second side plate W2 toward the first side plate W1, and then the protrusion 60B comes into contact with the surface W12 of the first side plate W1 on the second side plate W2 side.

[0085] After the projection 60B comes into contact with the surface W12 of the first side plate W1 facing the second side plate W2, the cylindrical member P is inserted into the second hole W21 in the direction from the second side plate W2 toward the first side plate W1 and attached to the shaft 60C of the developing unit 60. As a result, the flange P2 is positioned on the side of the second side plate W2 opposite to the first side plate W1.

[0086] 9(c), the third side plate W3 is attached to the second side plate W2 on the side opposite the first side plate W1, and the fourth side plate W4 is attached to the first side plate W1 on the side opposite the second side plate W2.

[0087] As described above, the following effects can be obtained in this embodiment. Since the toner cartridge TC can be mounted on the drum unit 50 and toner is supplied from the toner cartridge TC mounted on the drum unit 50 to the developing container 62, a conventional toner supply device becomes unnecessary and it is possible to prevent the drum unit 50 or the color printer 1 from becoming large.

[0088] Since the flange P2 of the cylindrical member P is located on the opposite side of the second side plate W2 from the first side plate W1, it is possible to prevent the cylindrical member P from coming off the second side plate W2.

[0089] Since the flange P2 is sandwiched between the second side plate W2 and the third side plate W3, it is possible to further prevent the tubular member P from coming off the second side plate W2.

[0090] Since the first side plate W1 and the second side plate W2 are sandwiched between the third side plate W3 and the fourth side plate W4 in the second direction, the first side plate W1 and the second side plate W2 can be protected by the third side plate W3 and the fourth side plate W4.

[0091] The present disclosure is not limited to the above-described embodiment, but can be used in various forms as exemplified below.

[0092] In the above embodiment, the first direction is a direction perpendicular to the second direction, but the first direction may be, for example, the same direction as the second direction.

[0093] In the above embodiment, the scorotron charger 52 is exemplified as the charger, but the charger may be, for example, a charging roller.

[0094] In the embodiment described above, the present disclosure is applied to a color printer 1, but the present disclosure is not limited to this and may be applied to other image forming devices, such as monochrome printers, copiers, and multifunction devices.

[0095] In the above embodiment, sheets S such as cardboard, postcards, and thin paper are given as examples of the sheet, but the sheet may be, for example, an OHP sheet.

[0096] In the above embodiment, the transfer member 70 including the conveyor belt 73 is exemplified as the transfer member, but the present disclosure is not limited to this. For example, the transfer member may be a transfer roller that contacts the photosensitive drum.

[0097] The elements described in the above-mentioned embodiment and modified examples may be implemented in any combination. [Explanation of symbols]

[0098] 1. Color printer 10 Main unit housing 10A aperture 11 Front cover 50 Drum Unit 51 Photoconductor drum 60 Development unit 61 Magnetic Roller 62 Developer container 62A Supply port 63 First Ogre 64 The Second Ogre TC Toner Cartridge X1 1st axis X2 2nd axis X3 3rd axis X4 4th axis

Claims

1. An image forming apparatus, a main body housing having an opening, the main body housing having a front cover movable between an open position where the opening is opened and a closed position where the opening is closed; a toner cartridge that contains toner; a drum unit into which the toner cartridge can be attached, the drum unit being movable in a first direction through the opening with respect to the main body housing with the toner cartridge attached to the drum unit, the drum unit being movable between a storage position in which the drum unit is located within the main body housing and a pull-out position in which the drum unit is pulled out from the main body housing, a photoconductor drum rotatable about a first axis extending in a second direction; A developing unit located between the toner cartridge and the photosensitive drum, a magnetic roller located between the toner cartridge and the photosensitive drum and rotatable about a second axis extending in the second direction, the magnetic roller facing a surface of the photosensitive drum; a developing container that contains a carrier and has a supply port that allows the toner to be supplied from the toner cartridge; a first auger located within the developing container and rotatable about a third axis extending in the second direction, the first auger circulating the carrier and the toner within the developing container; a second auger located within the developing container and rotatable about a fourth axis extending in the second direction, the second auger being capable of transporting the carrier and the toner within the developing container toward the magnetic roller; A developing unit comprising: A drum unit having An image forming apparatus comprising:

2. 2. The image forming apparatus according to claim 1, wherein the first direction intersects with the second direction.

3. 3. The image forming apparatus according to claim 1, wherein the supply port is located on an opposite side of the magnetic roller with respect to the first auger and the second auger.

4. The drum unit includes: A plurality of the photoconductor drums arranged in the first direction; The image forming apparatus according to claim 1 , further comprising: a plurality of the developing units arranged in the first direction.

5. 5. The image forming apparatus according to claim 1, further comprising a transfer member for transferring the toner image on the photosensitive drum onto a sheet.

6. 6. The image forming apparatus according to claim 1, wherein the drum unit includes a sheet guide that guides a sheet toward the photosensitive drum.

7. 7. The image forming apparatus according to claim 1, wherein the drum unit includes a cleaning roller for cleaning the photosensitive drum.

8. the supply port is located above the first auger and the second auger, 8. The image forming apparatus according to claim 1, wherein the second shaft is positioned below the first auger and the second auger.

9. The developing unit comprises:

9. The image forming apparatus according to claim 8, further comprising a layer thickness regulating member for regulating the thickness of the toner layer on the magnetic roller, the layer thickness regulating member being out of contact with the magnetic roller.

10. 10. The image forming apparatus according to claim 9, wherein the layer thickness regulating member is located below the first auger and the second auger.

11. 11. The image forming apparatus according to claim 1, wherein the magnetic roller is spaced apart from the surface of the photosensitive drum.

12. 12. The image forming apparatus according to claim 1, wherein the first auger is positioned closer to the supply port than the second auger.

13. the first auger transports the toner supplied from the supply port to the second auger; the second auger supplies toner to the magnetic roller; 13. The image forming apparatus according to claim 1, wherein the magnetic roller supplies toner to the photosensitive drum.

14. The drum unit includes: a first side plate having a first hole for allowing one end of the developing unit in the second direction to be inserted and supported; a second side plate facing the first side plate in the second direction, the second side plate having a second hole; 14. The image forming apparatus according to claim 1, further comprising a cylindrical member that fits into the second hole and has an opening into which the other end of the developing unit in the second direction fits.

15. The developing unit includes at the one end: a boss extending in the second direction and adapted to enter the first hole; 15. The image forming apparatus according to claim 14, further comprising a protrusion protruding from the boss in a direction perpendicular to the second direction, the protrusion contacting a surface of the first side plate facing the second side plate to position the developing unit in the second direction.

16. The cylindrical member is The outer periphery and 16. The image forming apparatus according to claim 15, further comprising a flange protruding from the outer circumferential surface, the flange being located on the opposite side of the second side plate from the first side plate.

17. the drum unit has a third side plate located on the opposite side of the second side plate from the first side plate, 17. The image forming apparatus according to claim 16, wherein the flange is located between the second side plate and the third side plate.

18. the drum unit has a fourth side plate located on the opposite side of the first side plate from the second side plate, 18. The image forming apparatus according to claim 17, wherein the first side plate and the second side plate are sandwiched between the third side plate and the fourth side plate in the second direction.

19. 19. The image forming apparatus according to claim 1, wherein the drum unit further comprises a charger that charges the photosensitive drum.

20. 20. The image forming apparatus according to claim 19, wherein the charger is a scorotron charger.

21. 20. The image forming apparatus according to claim 18, After the boss is inserted into the first hole in a direction from the second side plate toward the first side plate, the protrusion is brought into contact with a surface of the first side plate facing the second side plate, after the protrusion comes into contact with the surface of the first side plate facing the second side plate, the cylindrical member is inserted into the second hole in a direction from the second side plate toward the first side plate and is attached to the other end of the developing unit, and the flange is positioned on a side of the second side plate opposite to the first side plate, the third side plate is attached to the second side plate on the opposite side to the first side plate, an image forming apparatus, wherein the fourth side plate is attached to the first side plate on an opposite side to the second side plate;

22. A drum unit to which a toner cartridge that contains toner can be attached, and the drum unit is movable in a first direction with respect to a main body housing of an image forming apparatus while the toner cartridge is attached to the drum unit, a photoconductor drum rotatable about a first axis extending in a second direction; A developing unit located between the toner cartridge and the photosensitive drum, a magnetic roller located between the toner cartridge and the photosensitive drum and rotatable about a second axis extending in the second direction, the magnetic roller facing a surface of the photosensitive drum; a developing container that contains a carrier and has a supply port that allows the toner to be supplied from the toner cartridge; a first auger located within the developing container and rotatable about a third axis extending in the second direction, the first auger circulating the carrier and the toner within the developing container; a second auger located within the developing container and rotatable about a fourth axis extending in the second direction, the second auger being capable of transporting the carrier and the toner within the developing container toward the magnetic roller; A developing unit comprising: A drum unit comprising:

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