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 include a mechanism for transporting toner together with a carrier. [Background technology]

[0002] Conventionally, an image forming apparatus is known 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 in the developer container. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-171105 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 the size of the drum unit or the image forming apparatus.

[0005] Therefore, an object of the present disclosure is to prevent the drum unit or image forming apparatus from becoming larger. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, an image forming apparatus according to a first aspect 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 open 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 relative to the main body housing through the opening in a first direction with the toner cartridge mounted to 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 development unit. The photosensitive drum is rotatable about a first axis extending in a second direction. The development unit is positioned between the toner cartridge and the photosensitive drum. The development unit includes a magnetic roller, a developer container, a first auger, and a second auger. The magnetic roller is positioned 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 positioned 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 developer container. The second auger is located in the developer 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 developer 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 conventional toner replenishment device 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 may be the image forming apparatus of the first or second disclosure, wherein the supply port is located on the opposite side of the first auger and the second auger from the magnetic roller.

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

[0011] Furthermore, 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 of 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 may be 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] Furthermore, the ninth disclosure is the image forming apparatus of 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, and that is not in 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] Furthermore, 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] Furthermore, 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 that faces the first side plate in the second direction and has a second hole, and the image forming apparatus may further comprise a tubular member that fits into the second hole and has an opening through which the other end of the developing unit in the second direction fits.

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

[0022] Furthermore, the 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 located on the opposite side of the second side plate from the first side plate.

[0023] With this, the flange is located on the opposite side of the second side plate from the first side plate, so that the cylindrical member can be prevented from coming off the second side plate.

[0024] Further, the 17th disclosure is the image forming apparatus of 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, and therefore, the tubular member can be further prevented from coming off the second side plate.

[0026] Further, the 18th disclosure is the 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] This allows the third and fourth side plates to protect the first and second side plates.

[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, wherein the charger may be a scorotron charger.

[0030] Furthermore, the 21st disclosure is the image forming apparatus of the 18th disclosure, wherein the image forming apparatus may be configured such that after the boss is inserted into the first hole in the 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 the direction from the second side plate toward the first side plate and is attached to the other end of the developing unit, the flange is positioned on the opposite side of the second side plate from the first side plate, the third side plate is attached to the opposite side of the second side plate from the first side plate, and the fourth side plate is attached to the opposite side of the first side plate from 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 containing toner can be attached, and is a drum unit that can move 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 includes a photosensitive drum that can rotate about a first axis that extends in a second direction, and a developing unit located between the toner cartridge and the photosensitive drum, 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 within the developing container toward the magnetic roller.

[0032] This configuration can prevent the drum unit or the image forming apparatus from becoming larger. [Effects of the Invention]

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

[0034] [Figure 1] 1 is a cross-sectional view showing a color printer according to an embodiment of the present invention. [Figure 2] FIG. 4 is a cross-sectional view showing a state in which the drum unit is located at a pulled-out position. [Figure 3] FIG. 2 is a cross-sectional view showing a drum unit with a toner cartridge attached thereto. [Figure 4] 1A and 1B are perspective views showing a developing unit. [Figure 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] FIG. 10 is an exploded perspective view showing the structure of the other end side of the drum unit in the second direction. [Figure 8] FIG. 4 is an exploded perspective view showing the structure of one end side of the drum unit in the second direction. [Figure 9] 10A to 10C are diagrams showing a method for assembling the drum unit. DETAILED DESCRIPTION OF THE INVENTION

[0035] Next, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. 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 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 light emitting unit, a polygon mirror, a lens, a reflecting mirror, etc. (not shown). The scanner unit 40 emits a laser beam to the photosensitive 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 detachably attached to the drum unit 50. More specifically, the toner cartridge TC is detachably attached in a direction perpendicular to a second direction, which will be 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 pulled-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 photosensitive 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 photosensitive 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 located between the toner cartridges TC and the photosensitive drums 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 around 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 apart 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 a toner cartridge TC. The supply port 62A is located on the opposite side of the magnetic roller 61 from 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. 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. 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 the toner supplied from the supply port 62A to the second auger 64.

[0054] The second auger 64 is located inside 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 inside 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 inside 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 drums 51. The sheet guide 54 is aligned with the photosensitive drums 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, which is 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, which is 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 unit 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 drive roller 71 and the driven roller 72 are spaced apart in the first direction. The drive roller 71 and the driven roller 72 support a conveyor belt 73 that is an endless belt. The transfer roller 74 is located inside the conveyor belt 73. The transfer roller 74 and the photosensitive drum 51 sandwich the conveyor belt 73.

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

[0062] In the image forming unit 30, the scorotron charger 52 charges the surface of the photosensitive drum 51. Then, the scanner unit 40 exposes the surface of the photosensitive drum 51 to light. As a result, an electrostatic latent image is formed on the photosensitive 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 photosensitive drum 51. As a result, a toner image is formed on the photosensitive 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 peripheral 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 further in a direction away from the developing container 62 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 separates the first storage chamber 62B from 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 to the second storage chamber 62C. The supply opening 62E allows the toner and carrier to move 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 toner and carrier to move 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 of the photosensitive drums 51 and the developing units 60 in the second direction. 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 bosses 60A, which are one end of the developing unit 60 in the second direction, to be inserted and supported. That is, the bosses 60A fit into the first holes W11. A protrusion 60B located on the outer peripheral surface of the bosses 60A contacts the surface of the first side plate W1 facing the second side plate W2 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 from 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. Each cylindrical member P has a cylindrical portion P1 and a flange P2.

[0080] The tubular portion P1 is a cylindrical portion. The tubular portion P1 is inserted into the second hole W21. The tubular portion P1 has an outer peripheral surface P11 and an opening P12. The shaft 60C shown in FIG. 4(b), 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 from the first side plate W1. The third side plate W3 is located on the opposite side of the second side plate W2 from 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 photosensitive 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 9(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 facing the second side plate W2.

[0085] After the protrusion 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 opposite side of the second side plate W2 from 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. The toner cartridge TC can be attached to the drum unit 50, and toner is supplied to the developing container 62 from the toner cartridge TC attached to the drum unit 50, so that a conventional toner supply device becomes unnecessary and it is possible to prevent the drum unit 50 or the color printer 1 from becoming larger.

[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 used as the charger, but the charger may be, for example, a charging roller.

[0094] In the above embodiment, the present disclosure is applied to a color printer 1, but the present disclosure is not limited to this and may also 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 sheets, but the sheets may also be, for example, overhead projector sheets.

[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-described 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 Photosensitive drum 60 Development unit 61 Magnetic Roller 62 Developer container 62A Refill port 63 First Ogre 64 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; a toner cartridge containing toner; a drum unit into which the toner cartridge can be attached, the drum unit being movable relative to the main body housing between a storage position located within the main body housing and a pulled-out position pulled out from the main body housing when the toner cartridge is attached to the drum unit; The drum unit is A photosensitive drum; a developing unit located between the photosensitive drum and the toner cartridge, capable of supplying the toner supplied from the toner cartridge to the photosensitive drum; The developing unit comprises: a magnetic roller facing the surface of the photosensitive drum; a developer container containing a carrier, the developer container having a supply port for allowing the toner to be supplied from the toner cartridge; a first auger that circulates the carrier and the toner in the developing container; a second auger capable of transporting the carrier and the toner in the developing container toward the magnetic roller, The drum unit is A plurality of the photosensitive drums; and an image forming apparatus comprising a plurality of the developing units.

2. the plurality of photosensitive drums are aligned in a first direction and are each rotatable about an axis extending in a second direction perpendicular to the first direction; The image forming apparatus according to claim 1 , wherein the plurality of development units are aligned in the first direction.

3. The image forming apparatus according to claim 2 , further comprising a first side wall made of metal, positioned at one end of each of the photosensitive drums in the second direction, and supporting the plurality of photosensitive drums.

4. The image forming apparatus according to claim 3 , further comprising a second metal side wall that is located at the other end of the photosensitive drums in the second direction and supports the plurality of photosensitive drums.

5. a third side wall made of resin and located at one end of the photosensitive drum in the second direction; a fourth side wall made of resin and located at the other end of the photosensitive drum in the second direction; Furthermore, 4. The image forming apparatus according to claim 3, wherein the first side wall is located between the third side edge and the fourth side wall.

6. 2. 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.

7. 2. 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.

8. 2. The image forming apparatus according to claim 1, wherein the drum unit includes a sheet guide for guiding the sheet toward the photosensitive drum.

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

10. the supply port is located above the first auger and the second auger; 2. The image forming apparatus according to claim 1, wherein the rotation axis of the magnetic roller is located below the first auger and the second auger.

11. The developing unit comprises:

11. The image forming apparatus according to claim 10, 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.

12. 12. The image forming apparatus according to claim 11, wherein the layer thickness regulating member is located below the first auger and the second auger.

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

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

15. the first auger transports the toner supplied from the supply port to the second auger; the second auger supplies toner to the magnetic roller; 2. The image forming apparatus according to claim 1, wherein the magnetic roller supplies toner to the photosensitive drum.

16. 2. The image forming apparatus according to claim 1, wherein the drum unit further comprises a charger for charging the photosensitive drum.

17. A drum unit to which a toner cartridge containing toner can be attached, and which is movable with respect to a main body housing of an image forming apparatus between an accommodating position located within the main body housing and a drawn-out position drawn out from the main body housing with the toner cartridge attached to the drum unit, A photosensitive drum; a developing unit located between the toner cartridge and the photosensitive drum, capable of supplying the toner supplied from the toner cartridge to the photosensitive drum; The developing unit comprises: a magnetic roller facing the surface of the photosensitive drum; a developer container containing a carrier, the developer container having a supply port for allowing the toner to be supplied from the toner cartridge; a first auger that circulates the carrier and the toner in the developing container; a second auger capable of transporting the carrier and the toner in the developing container toward the magnetic roller, The drum unit is A plurality of the photosensitive drums; a plurality of said developing units; a first side wall made of metal that supports the plurality of photosensitive drums and the plurality of developing units; A drum unit comprising:

18. the plurality of photosensitive drums are aligned in a first direction and are each rotatable about an axis extending in a second direction perpendicular to the first direction; 18. The drum unit according to claim 17, wherein the plurality of development units are aligned in the first direction.

19. A drum unit as described in Claim 18, characterized in that the first side wall is located at one end of the photosensitive drum in the second direction.

20. 20. The drum unit according to claim 19, further comprising a second side wall made of metal, positioned at the other end of the photosensitive drum in the second direction, and supporting the plurality of photosensitive drums and the plurality of developing units.

21. a third side wall made of resin and located at one end of the photosensitive drum in the second direction; a fourth side wall made of resin and located at the other end of the photosensitive drum in the second direction; Furthermore, 20. The drum unit according to claim 19, wherein the first side wall is located between the third side edge and the fourth side wall.

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