drum cartridge

Abstract

To provide a structure that can correctly detect the toner concentration of a developer in a cartridge that can be attached to and detached from an image forming apparatus and has a developing container that can accommodate the developer. A cartridge (50) that can be attached to and detached from a color printer (1) in a first direction includes a photosensitive drum (51) that can rotate around a first shaft extending in a second direction, a developing container (62) that accommodates a developer including toner and a carrier, a first screw conveyor (63) located inside the developing container (62) and capable of conveying the developer inside the developing container (62) in the second direction, a magnetic roller (61) that can rotate around a second shaft extending in the second direction and can supply the developer inside the developing container (62) to the photosensitive drum (51), and a toner sensor (66) that can detect the toner concentration of the developer.

Description

Technical Field

[0001] This invention relates to a drum housing mounted on an image forming apparatus. Background Technology

[0002] Conventionally, image forming apparatuses have been known to have a structure comprising a main housing and a drum cartridge (Patent Document 1). The drum cartridge includes: a photosensitive drum; a developing container holding a developer containing toner and a carrier; a developing roller supplying the developer from the developing container to the photosensitive drum; a screw conveyor capable of conveying the developer from the developing container; and a toner sensor that detects the concentration of toner relative to the developer in the developing container. The toner sensor is located on the bottom surface of the developing container. Since the developer accumulates on the bottom surface of the developing container, the toner concentration can be easily detected by the toner sensor being located below the screw conveyor, i.e., on the bottom surface of the developing container.

[0003] Additionally, as another image forming apparatus, a structure is known that includes a main housing, a drum cartridge detachable from the main housing, and a toner cartridge detachable from the drum cartridge (Patent Document 2). The drum cartridge is movable between a receiving position within the main housing and a pull-out position pulled out from the main housing. Furthermore, the drum cartridge includes a photosensitive drum, a developing container for containing toner, a developing roller for supplying toner from the developing container to the photosensitive drum, and a screw conveyor for transporting toner from the developing container. The developing container has a replenishment port that allows toner from the toner cartridge to pass through. The replenishment port is located above the screw conveyor.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2005-114827

[0007] Patent Document 1: Japanese Patent Application Publication No. 2011-257488

[0008] The technical problem that the invention aims to solve

[0009] When combining the technology of Patent Document 2 with that of Patent Document 1, consider, for example, that the toner sensor coincides with the replenishment port of the developing container in the vertical direction. In this case, the replenished toner is not sufficiently stirred with the developer present in the developing container, and the toner concentration may not be accurately detected by the toner sensor. Summary of the Invention

[0010] The object of the present invention is to accurately detect the concentration of toner relative to developer in a drum cartridge having a toner sensor for detecting the toner concentration relative to developer and a refill port for allowing toner to flow through the toner cartridge.

[0011] Technical means for solving technical problems

[0012] To achieve the above objectives, the present invention provides a drum cartridge detachable from the main housing of an image forming apparatus along a first direction. The drum cartridge comprises: a photosensitive drum rotatable about a first axis extending along a second direction intersecting the first direction; a frame detachable from a toner cartridge in a third direction intersecting the first and second directions, the toner cartridge containing toner; a developing container containing a developer comprising toner and a carrier; a magnetic roller located within the developing container, rotatable about a second axis extending along the second direction, and capable of supplying toner from the developing container to the photosensitive drum; a first screw conveyor located within the developing container, rotatable about a third axis extending along the second direction, and capable of conveying the developer from the developing container along the second direction, the first screw conveyor being located on the side opposite to the photosensitive drum in the third direction relative to the magnetic roller; and a toner sensor capable of detecting the toner concentration of the developer in the developing container. The developing container has a replenishment port that replenishes toner within the toner cartridge when it is installed in the developing unit. This replenishment port is located on the side opposite to the photosensitive drum in the third direction relative to the first spiral conveyor, and at one end of the developing container in the second direction. A toner sensor is located in the third direction between the photosensitive drum and the first spiral conveyor, and at the other end of the developing container in the second direction.

[0013] Based on this structure, the toner sensor can detect the toner concentration of the developer after the toner supplied from the supply port is thoroughly mixed with the developer present in the developing container.

[0014] Alternatively, the structure could be as follows: the drum box has a second spiral conveyor inside the developing container, the second spiral conveyor being located at a distance from the first spiral conveyor in a first direction, capable of stirring the developer in the developing container in a second direction, and facing the magnetic roller in a third direction, the second spiral conveyor being located between the magnetic roller and the feed port in the third direction.

[0015] According to this structure, by positioning the magnetic roller below the first and second helical conveyors, the size of the drum box in the first direction is smaller compared to a structure in which the magnetic roller is positioned to the side of the first and second helical conveyors.

[0016] Alternatively, the structure could be as follows: the developing container has a partition wall extending in a second direction, located between a first screw conveyor and a second screw conveyor in the first direction. The partition wall has: a recovery opening allowing developer delivered by the second screw conveyor to pass through; and a supply opening allowing developer delivered by the first screw conveyor to pass through, and located separately from the recovery opening in the second direction. The first screw conveyor can deliver developer to the second screw conveyor via the supply opening, and the second screw conveyor can deliver developer to the first screw conveyor via the recovery opening. A toner sensor is located between the supply opening and the recovery opening in the second direction.

[0017] According to this structure, the toner sensor can detect the toner concentration of the developer circulating through the first and second spiral conveyors.

[0018] Alternatively, the colorant sensor can be positioned closer to the first screw conveyor than to the second screw conveyor.

[0019] Based on this structure, the toner concentration of the developer conveyed by the first spiral conveyor can be detected.

[0020] Alternatively, the structure could be as follows: a first spiral conveyor transports developer from the recovery opening toward the supply opening in the second direction, a second spiral conveyor transports developer from the supply opening toward the recovery opening in the second direction, and a toner sensor is located between the supply port and the toner sensor in the third direction.

[0021] Based on this structure, it is possible to detect the toner concentration of the developer being conveyed from the first spiral conveyor to the second spiral conveyor.

[0022] Alternatively, the structure could be such that the supply port is located in the second direction closer to the recovery port than to the supply port.

[0023] According to this structure, since the replenishment port is located close to the recovery opening, it is possible to extend the distance that the developer recovered by the recovery opening and the toner replenished from the replenishment port are stirred until they are toward the supply opening.

[0024] Alternatively, the structure could be as follows: the drum housing has a scraper that limits the thickness of the developer layer on the magnetic roller, and the scraper is positioned in the third-order direction between the photosensitive drum and the toner sensor.

[0025] According to this structure, the colorant sensor and the scraper are both located below the first spiral conveyor in the third direction. Therefore, the size of the drum box in the first direction is smaller compared to the case where the colorant sensor or the scraper is located on the side of the first spiral conveyor.

[0026] Alternatively, the structure may include a drum housing with a scraper mounting component, which mounts a scraper and is mounted on a developing container. The scraper mounting component has: a first portion for mounting the scraper; and a second portion that bends in a third direction from the first portion toward the toner sensor. The length of the first portion in the second direction is longer than the length of the scraper in the second direction, and the length of the second portion in the second direction is shorter than the length of the scraper in the second direction.

[0027] According to this structure, the colorant sensor can be located in a position that does not interfere with the second part of the scraper mounting component.

[0028] Alternatively, the scraper mounting components can be made of metal.

[0029] Based on this structure, the positioning of the scraper relative to the magnetic roller is easy by utilizing the scraper mounting component.

[0030] Alternatively, the structure could be as follows: the drum housing has an insulating sheet that covers the color toner sensor.

[0031] This structure reduces the impact on detection accuracy of the color powder sensor caused by the conductive scraper mounting component.

[0032] Alternatively, the toner sensor can be a permeability sensor. It can have the following structure: the toner sensor has a main body located outside and mounted on the developing container; and a detection unit capable of contacting the developer inside the developing container and detecting permeability.

[0033] Based on this structure, the magnetic permeability is detected by a toner sensor, thereby enabling the image forming apparatus to detect the ratio of toner to carrier in the developing container.

[0034] Alternatively, the structure may include: a connector that is electrically connected to the image forming apparatus when the drum is mounted on it; and a relay board that electrically connects the toner sensor to the connector and communicates the signal detected by the toner sensor to the developing unit.

[0035] According to this structure, the wiring between the main body and the drum unit can be simplified compared to the case where the toner sensor is directly electrically connected to the main body.

[0036] The effects of the invention

[0037] According to the present invention, since the toner sensor is located far from the supply port, the toner sensor can detect the developed image after the supplied toner and the developer present in the developing container are thoroughly mixed. Therefore, the toner concentration of the developer can be accurately detected. Attached Figure Description

[0038] Figure 1 This is a cross-sectional view showing the color printer of this embodiment.

[0039] Figure 2 This is a cross-sectional view showing the drum housing with the toner cartridge installed.

[0040] Figure 3 This is a cross-sectional view showing the drum box in the pulled-out position.

[0041] Figure 4 This is a cross-sectional view of the developing unit viewed from the other end side in the second direction.

[0042] Figure 5 This is a cross-sectional view of the developing unit viewed from one side upwards from a third-party perspective.

[0043] Figure 6 This is a perspective view of the developing unit, showing a portion of the developing container and the second spiral conveyor, but not explicitly shown.

[0044] Figure 7 It is a 3D view of the scraper blade and scraper blade mounting components.

[0045] Figure 8 This is a 3D view of the colorant sensor.

[0046] Figure 9 These are perspective views of the developing unit viewed from the magnetic roller side. (a) shows the toner sensor without the insulating sheet covering it, and (b) shows the toner sensor with the insulating sheet covering it.

[0047] Figure 10 It is a 3D diagram showing the wiring between the color toner sensor, relay board, and connector. Detailed Implementation

[0048] Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the direction in which the drum cartridge 50 is attached or detached relative to the main housing 10 is referred to as the first direction. The axial direction of the photosensitive drum 51 is referred to as the second direction. The first direction intersects the second direction. Preferably, the angle between the first and second directions is in the range of 80° to 100°. More preferably, the first and second directions are orthogonal. The direction in which the toner cartridge TC is attached or detached relative to the developing unit is referred to as the third direction. The third direction intersects the second direction. Preferably, the angle between the third direction and the second direction is in the range of 80° to 100°. More preferably, the third direction is orthogonal to the second direction. The third direction intersects the first direction. Preferably, the angle between the third direction and the first direction is in the range of 80° to 100°. More preferably, the third direction is orthogonal to the first direction. That is, the third direction intersects the first and second directions. More preferably, the third direction is orthogonal to both the first and second directions. Furthermore, in the following description, within the main body housing 10, the side facing upwards will be referred to as "above," and the other side facing upwards will be referred to as "below." For example, in Figure 2 In the middle, the color powder box TC is located above the first screw conveyor 63, and the magnetic roller 61 is located below the second screw conveyor 64.

[0049] (1) Overall description of color printer 1

[0050] like Figure 1 As shown, a color printer 1, which is an example of an image forming apparatus, includes: a main housing 10, a sheet supply unit 20, an image forming unit 30, an ejection unit 90, and a control unit 100.

[0051] The main housing 10 has an opening 10A, a front cover 11, and a main connector 12. The front cover 11 is movable between an open position (opening the opening 10A) and a closed position (closing the opening 10A). Specifically, the front cover 11 is rotatable between the open and closed positions. The main connector 12 is located inside the main housing 10. The main connector 12 is electrically connected to the control unit 100.

[0052] The sheet supply unit 20 includes a supply tray 21 and a sheet conveying mechanism 22. The supply tray 21 holds the sheet S. The sheet conveying mechanism 22 conveys the sheet S from the supply tray 21 to the image forming unit 30.

[0053] The image forming unit 30 includes: a scanning unit 40, a drum 50, four toner cartridges TC, a transfer unit 70, and a fixing device 80.

[0054] The scanning unit 40 includes a laser emitter (not shown), a multi-faceted mirror, a lens, and a reflector. The scanning unit 40 emits laser light into the photosensitive drum 51.

[0055] The drum box 50 can move relative to the main body housing 10 in a first direction via the opening 10A.

[0056] The drum cartridge 50 is movable relative to the main housing 10 in a first direction between a receiving position within the main housing 10 and a pull-out position from the main housing 10. The drum cartridge 50 is supported on the main housing 10 in a manner that allows it to move between the receiving position and the pull-out position. The drum cartridge 50 is detachable from the color printer 1.

[0057] like Figure 2 As shown, the drum cartridge 50 includes: multiple photosensitive drums 51, multiple grid-controlled corona chargers 52, multiple cleaning rollers 53, a frame 59, a handle 501, multiple developing units 60, a film guide 54, and a connector 55. Specifically, the drum cartridge 50 includes: four photosensitive drums 51, four grid-controlled corona chargers 52, four cleaning rollers 53, a frame 59, a handle 501, four developing units 60, a film guide 54, and a connector 55.

[0058] The handle 501 is located at one end in the first direction. The user can hold the handle 501 and pull out the drum box 50.

[0059] Four developing units 60 are arranged along the first direction.

[0060] Multiple photosensitive drums 51, multiple grid-controlled corona chargers 52, multiple cleaning rollers 53, and multiple developing units 60 form images of different colors (e.g., cyan, magenta, yellow, and black). However, in this embodiment, the multiple photosensitive drums 51, multiple grid-controlled corona chargers 52, multiple cleaning rollers 53, and multiple developing units 60 have the same structure except for the color of the developer used for image formation. Therefore, only one of them will be described below.

[0061] The photosensitive drum 51 is capable of rotating about a first axis X1 extending in a second direction.

[0062] The grid-controlled corona charger 52 is an electrical device that charges the photosensitive drum 51. Alternatively, a charging roller can be used instead of the grid-controlled corona charger 52.

[0063] The cleaning roller 53 is used to clean the photosensitive drum 51. Alternatively, a cleaning scraper can be used instead of the cleaning roller 53.

[0064] The developing unit 60 is located in the third-order direction between the toner cartridge TC and the photosensitive drum 51. The developing unit 60 includes: a magnetic roller 61, a developing container 62, a first spiral conveyor 63, a second spiral conveyor 64, and a scraper 65.

[0065] The magnetic roller 61 is a roller that supplies toner to the photosensitive drum 51. The magnetic roller 61 has a magnetic shaft component 61A and a magnetic sleeve 61B. The magnetic shaft component 61A has different magnetic poles arranged in a predetermined pattern along the axial direction. The magnetic shaft component 61A is, for example, a cylindrical component with multiple permanent magnets embedded therein. The magnetic shaft component 61A is fixed to the developing container 62.

[0066] The magnetic sleeve 61B is, for example, a cylindrical component mainly composed of a non-magnetic metallic material. The magnetic sleeve 61B is rotatable about the magnetic shaft component 61A. The magnetic sleeve 61B uses the magnetic force of the magnetic shaft component 61A to hold the developer. In addition, a developing voltage is applied to the magnetic sleeve 61B from the main housing 10.

[0067] The magnetic roller 61 is located below the first spiral conveyor 63 and the second spiral conveyor 64, described later, in a third-order direction. The magnetic roller 61 is positioned between the toner cartridge TC and the photosensitive drum 51. The magnetic sleeve 61B is rotatable about a second axis X2 extending in a second direction. That is, the magnetic roller 61 is rotatable about the second axis X2 extending in a second direction. The magnetic roller 61 faces the surface of the photosensitive drum 51. The magnetic roller 61 is separated from the surface of the photosensitive drum 51.

[0068] The developing container 62 is a container for holding toner as a non-magnetic material and a carrier as a magnetic material. The carrier is, for example, iron powder. The developing container 62 has a replenishment port 62A. The replenishment port 62A allows toner to be replenished from the toner cartridge TC. The replenishment port 62A is located on the opposite side of the magnetic roller 61 in the third-order direction relative to the first screw conveyor 63 and the second screw conveyor 64.

[0069] In the third direction, the replenishment port 62A is located above the first screw conveyor 63 and the second screw conveyor 64. Specifically, the replenishment port 62A is located above the first screw conveyor 63. The second shaft X2 is located below the first screw conveyor 63 and the second screw conveyor 64. Specifically, the second shaft X2 is located below the second screw conveyor 64. When the toner cartridge TC is installed in the developing container 62, toner can be replenished to the developing container 62 through the replenishment port 62A. Additionally, as... Figure 6 As shown, the supply port 62A is located at one end of the developing container 62 in the second direction.

[0070] like Figure 2 As shown, a first spiral conveyor 63 and a second spiral conveyor 64 are located within the developing container 62. The first spiral conveyor 63 is rotatable about a third axis X3 extending in a second direction. The second spiral conveyor 64 is rotatable about a fourth axis X4 extending in a first direction. The first spiral conveyor 63 is located at a distance from the second spiral conveyor 64 in the first direction. The first spiral conveyor 63 is located closer to the feed port 62A than the second spiral conveyor 64.

[0071] The scraper blade 65 is a component that limits the thickness of the toner layer on the magnetic roller 61. The scraper blade 65 is not in contact with the magnetic roller 61. The scraper blade 65 is parallel to the magnetic roller 61 in a first direction. The second shaft X2 is located between the scraper blade 65 and the first shaft X1 in a second direction.

[0072] The sheet guide 54 is a guide that guides the sheet S toward the photosensitive drum 51. The sheet guide 54 is parallel to the photosensitive drum 51 in a first direction. The sheet guide 54 is located upstream of the four photosensitive drums 51 in the conveying direction of the sheet S.

[0073] The magnetic roller 61, located at the uppermost point in the conveying direction of sheet S, is positioned between the sheet guide 54 and the second screw conveyor 64 in the third direction. The scraper 65, located at the uppermost point in the conveying direction of sheet S, is positioned between the sheet guide 54 and the first screw conveyor 63 in the third direction.

[0074] Connector 55 is located on the outer surface of drum cassette 50. More specifically, connector 55 is located on the outer surface of the frame supporting the developing unit 60.

[0075] Frame 59 allows for the loading and unloading of a toner cartridge in a third-party upward manner, the toner cartridge being capable of holding toner. Frame 59 has a developing container 62, described later, capable of holding a developer containing toner and a carrier.

[0076] The four toner cartridges TC are identical in structure except for the color of the developer they contain. Therefore, only one of them will be described below.

[0077] The toner cartridge TC houses toner that is a non-magnetic material. For example... Figure 3 As shown, the toner cartridge TC can be installed or removed relative to the frame 59 of the drum cartridge 50. Specifically, the toner cartridge TC can be installed and removed relative to the frame 59 of the drum cartridge 50 in a third direction.

[0078] The toner cartridge TC has a toner memory TM. The toner memory TM has a storage element capable of storing information and a contact capable of contacting the first electrical contact 56 described later. The toner memory TM stores toner cartridge information related to the toner cartridge TC. The toner cartridge information is at least one of identification information capable of identifying each toner cartridge TC and toner life information for each toner cartridge TC. The identification information is, for example, a serial number. The toner life information is, for example, at least one of the following: the cumulative number of rotations of the magnetic roller 61 or the first screw conveyor 63, the number of points used, and the remaining toner level.

[0079] like Figure 1 As shown, the transfer unit 70 is a component that transfers the toner image on the photosensitive drum 51 onto the sheet S. The transfer unit 70 is located between the sheet supply section 20 and the drum cassette 50. The transfer unit 70 includes a drive roller 71, a driven roller 72, a conveyor belt 73, and a transfer roller 74.

[0080] The drive roller 71 and the driven roller 72 are separated in a first direction. The drive roller 71 and the driven roller 72 support a conveyor belt 73 made of an annular belt. The transfer roller 74 is located inside the conveyor belt 73. The conveyor belt 73 is held between the transfer roller 74 and the photosensitive drum 51.

[0081] The fixing device 80 includes a heating roller 81 and a pressure roller 82. A sheet S is sandwiched between the pressure roller 82 and the heating roller 81.

[0082] The image forming unit 30 performs the following series of actions when forming an image.

[0083] In the image forming unit 30, the grid-controlled corona charger 52 charges the surface of the photosensitive drum 51. Then, the scanning unit 40 forms an electrostatic latent image on the photosensitive drum 51 by exposing the surface of the photosensitive drum 51.

[0084] The magnetic roller 61 forms a developer image on the photosensitive drum 51 by supplying developer to the electrostatic latent image formed on the photosensitive drum 51. Then, the conveyor belt 73 transports the sheet S from the sheet supply section 20 toward the photosensitive drum 51. The transfer roller 74 transfers the developer image from the photosensitive drum 51 to the sheet S by pushing the sheet S, which is sandwiched between the conveyor belt 73 and the photosensitive drum 51, from the inside of the conveyor belt 73 toward the photosensitive drum 51. The fixing device 80 fixes the developer image onto the sheet S by clamping the transferred developer image onto the sheet S using a heating roller 81 and a pressure roller 82.

[0085] The discharge section 90 is equipped with multiple conveying rollers 91. The conveying rollers 91 discharge the sheet S that has passed through the fuser to the outside of the main housing 10.

[0086] The control unit 100 includes, for example, a CPU, RAM, ROM, and input / output circuits. It performs calculations based on information from the installed cartridge, programs or data stored in the ROM, and so on, thereby controlling the color printer 1.

[0087] like Figure 1 As shown, connector 55 is electrically connected to color printer 1 when drum cartridge 50 is installed in color printer 1. Specifically, connector 55 contacts and is electrically connected to main connector 12 when drum cartridge 50 is installed in main housing 10. When toner cartridge TC is installed in drum cartridge 50 and connector 55 is electrically connected to main connector 12, control unit 100 can obtain toner cartridge information from toner memory TM or write information to toner memory TM.

[0088] (2) Structure of the developing unit

[0089] (2-1) Structure of the developing container 62

[0090] like Figure 5 As shown, the developing container 62 has a first receiving chamber 62B, a second receiving chamber 62C, a partition wall 62D, a supply opening 62E, and a recovery opening 62F. The first receiving chamber 62B is the space that houses the first screw conveyor 63. The second receiving chamber 62C is the space that houses the second screw conveyor 64. The first receiving chamber 62B and the second receiving chamber 62C house toner and carrier inside them.

[0091] The partition wall 62D is the wall that separates the first containment chamber 62B and the second containment chamber 62C. The partition wall 62D extends along a second direction. The partition wall 62D is located between the first screw conveyor 63 and the second screw conveyor 64.

[0092] The supply opening 62E is located at the other end of the partition wall 62D in a second direction. The supply opening 62E is connected to the first containment chamber 62B and the second containment chamber 62C. The supply opening 62E allows the toner and carrier to move from the first containment chamber 62B to the second containment chamber 62C.

[0093] The recovery opening 62F is located at one end of the partition wall 62D in a second direction. The recovery opening 62F is connected to the first containment chamber 62B and the second containment chamber 62C. The recovery opening 62F allows the toner and carrier to move from the second containment chamber 62C to the first containment chamber 62B.

[0094] Supply port 62A is connected to the first containment chamber 62B. Supply port 62A is located closer to recovery port 62F than to supply port 62E. Specifically, the distance from supply port 62A to supply port 62E is greater than the distance from supply port 62A to recovery port 62F.

[0095] (2-2) Structure of the first screw conveyor 63 and the second screw conveyor 64

[0096] The first screw conveyor 63 conveys toner and carrier from one end 60A of the developing container 62 in the second direction to the other end 60B. In other words, the first screw conveyor 63 conveys toner and carrier from the recovery opening 62F to the supply opening 62E. Specifically, the first screw conveyor 63 conveys toner and carrier, which are replenished from the supply port 62A to the first receiving chamber 62B, together with the carrier, to the supply opening 62E. Additionally, the first screw conveyor 63 conveys toner and carrier, which are replenished from the recovery opening 62F to the first receiving chamber 62B, to the supply opening 62E. The developer conveyed to the supply opening 62E is then conveyed from the first receiving chamber 62B to the second receiving chamber 62C via the supply opening 62E. In other words, the supply opening 62E allows the developer conveyed by the first screw conveyor 63 to move toward the second screw conveyor 64.

[0097] The first spiral conveyor 63 does not contact the detection section 66B of the toner sensor 66, which will be described later. More specifically, the diameter of the first spiral conveyor 63 at the first blade 63A is smaller than the diameter of the other parts of the first spiral conveyor 63, and the first blade 63A is a blade located near the detection section 66B of the first spiral conveyor 63.

[0098] The second screw conveyor 64 conveys toner and carrier from one end 60B of the developing container 62 in the second direction toward one end 60A. In other words, the second screw conveyor 64 conveys toner and carrier from the supply opening 62E toward the recovery opening 62F. Specifically, the second screw conveyor 64 conveys the toner and carrier supplied from the supply opening 62E to the second receiving chamber 62C together toward the other end in the second direction. The developer conveyed by the second screw conveyor 64 in the second direction adheres to the surface of the magnetic roller 61 using the magnetic force of the magnetic roller 61. The developer conveyed to the recovery opening 62F is conveyed from the second receiving chamber 62C to the first receiving chamber 62B via the recovery opening 62F. In other words, the recovery opening 62F allows the developer conveyed by the second screw conveyor 64 to move toward the first screw conveyor 63.

[0099] The first spiral conveyor 63 and the second spiral conveyor agitate the developer within the developing container 62 while conveying it. The agitation of the developer by the first spiral conveyor 63 and the second spiral conveyor 64 causes the developer to become triboelectrically charged.

[0100] In this way, the first screw conveyor 63 and the second screw conveyor 64 can convey toner and carrier from the feed port 62A toward the magnetic roller 61. In addition, the first screw conveyor 63 and the second screw conveyor 64 circulate the carrier and toner within the developing container 62.

[0101] (2-3) Structure of scraper 65

[0102] The scraper blade 65 is made of metal. In this embodiment, the scraper blade 65 is made of stainless steel.

[0103] like Figure 7 , Figure 9 As shown, the scraper blade 65 is integrally mounted to the developing container 62 with the scraper blade mounting member 67. More specifically, the scraper blade 65 is threadedly fixed to the developing container 62 while in contact with the first portion 67A of the scraper blade mounting member 67. Thus, the scraper blade 65 is mounted to the developing container 62 while supported by the scraper blade mounting member 67.

[0104] The scraper 65 is located below the first spiral conveyor 63. In the third-order direction, the scraper 65 is located below the second spiral conveyor 64. The scraper 65 is located below the toner sensor 66. In other words, the scraper 65 is located between the photosensitive drum 51 and the toner sensor 66 in the third-order direction.

[0105] The scraper mounting component 67 is located in the third-order direction between the scraper 65 and the developing container 62. The scraper mounting component 67 is made of metal. In this embodiment, the scraper mounting component 67 is made of stainless steel.

[0106] The scraper mounting member 67 has a first portion 67A and a second portion 67B bent from the first portion 67A. The first portion 67A supports the scraper 65. The length of the first portion 67A in the second direction is longer than the length of the scraper 65 in the second direction. Thus, the scraper mounting member 67 can make integral contact with the scraper 65 in the second direction and support the scraper 65. The second portion 67B is located between the scraper 65 and the developing container 62 when the scraper mounting member 67 is installed in the developing container 62. The second portion 67B covers the space between the scraper 65 and the developing container 62. The length of the second portion 67B in the second direction is shorter than the length of the scraper 65 in the second direction. Thus, when the scraper mounting member 67 is installed in the developing container 62, the toner sensor 66 is exposed in the first direction.

[0107] (2-4) Structure of the colorant sensor 66

[0108] like Figure 4 As shown, the developing unit 60 has a toner sensor 66.

[0109] The toner sensor 66 can detect the toner concentration within the developing container 62. The signal detected by the toner sensor 66 is transmitted to the control unit 100. Therefore, the control unit 100 can determine the amount of toner in the developing container 62 based on the signal transmitted from the toner sensor 66. In this embodiment, the toner sensor 66 is a permeability sensor capable of detecting permeability. When a power supply voltage and a control voltage are applied, the permeability sensor outputs a voltage corresponding to the permeability of the detected object. In this embodiment, the voltage value output by the toner sensor 66 changes according to the toner concentration in the developer.

[0110] like Figure 8 As shown, the color powder sensor 66 has a main body 66A, a detection part 66B, and a sensor connector 66C.

[0111] The main body 66A is located outside the developing container. For example... Figure 9As shown in (a), the main body 66A is mounted to the developing container 62. More specifically, the main body 66A is attached to the developing container 62 by double-sided tape. Thus, the toner sensor 66 is mounted to the developing container 62. Alternatively, the toner sensor 66 can also be mounted to the developing container 62 by threaded fastening, adhesive, or the like.

[0112] like Figure 9 As shown in (b), an insulating sheet 68 is attached to the main body 66A. The insulating sheet 68 covers the entire main body 66A in a manner that does not expose the main body 66A. Specifically, the end of the insulating sheet 68 is attached to the developing container, covering the entire side of the main body 66A facing the second direction and the entire bottom surface of the main body 66A facing the third direction. In addition, a seal (not shown) for preventing leakage of developer is attached to the insulating sheet 68.

[0113] The detection section 66B protrudes from the main body 66A. The detection section 66B is cylindrical in shape. Figure 6 As shown, the detection unit 66B enters the hole in the developing container 62 and comes into contact with the developer inside the developing container 62. More specifically, the detection unit 66B comes into contact with the developer inside the first receiving chamber 62B. Therefore, the toner sensor 66 can detect the toner concentration of the developer conveyed in the first receiving chamber 62B. In other words, the toner sensor 66 can detect the toner concentration of the developer conveyed by the first screw conveyor 63.

[0114] Furthermore, since the detection section 66B of the toner sensor 66 detects toner concentration while in contact with the developer, it is preferable that there is a sufficient amount of developer near the detection section 66B. If there is insufficient developer near the detection section 66B, the toner sensor 66 may sometimes fail to accurately detect the toner concentration of the developer. Specifically, in this embodiment, if the developer is not present at least 6 mm away in the direction perpendicular to the detection surface of the detection section 66B, the toner sensor 66 may fail to accurately detect the toner concentration of the developer. Additionally, in this embodiment, the developer in the developing container 62 is filled above the rotation axis of the first screw conveyor 63. Therefore, as long as there is a sufficient amount of developer near the detection section 66B, the toner sensor 66 can also be positioned diagonally below the first screw conveyor 63, etc.

[0115] Sensor connector 66C is electrically connected to toner sensor 66 and the second electrical contact 57 (described later). The voltage applied to sensor connector 66C is applied to the circuitry of main body 66A and detection unit 66B. Additionally, the signal detected by toner sensor 66 is transmitted to control unit 100 via sensor connector 66C.

[0116] Toner sensor 66 is located below the first spiral conveyor 63. In the third-order direction, toner sensor 66 is positioned between the photosensitive drum 51 and the first spiral conveyor 63. In the third-order direction, toner sensor 66 is located on the side opposite to the feed port 62A relative to the first spiral conveyor 63. Toner sensor 66 is located below the developing container 62. Toner sensor 66 is located below the second spiral conveyor 64. Toner sensor 66 is located closer to the first spiral conveyor 63 than closer to the second spiral conveyor 64.

[0117] With the toner cartridge TC installed in the developing unit 60, the toner sensor 66 is located at the same end as the toner memory TM in the second direction. Specifically, both the toner sensor 66 and the toner memory TM are located on the opposite side of the supply port 62A in the second direction. Thus, the first electrical contact 56 and the second electrical contact 57, described later, can be located at the same end.

[0118] The toner sensor 66 is located in the second direction between the supply opening 62E and the recovery opening 62F. The toner sensor 66 detects the toner concentration of the developer conveyed by the first screw conveyor from the recovery opening 62F toward the supply opening 62E.

[0119] The toner sensor 66 is located on the opposite end of the developing container 62 in a second direction. More specifically, the toner sensor 66 is located closer to the other end 60B than to one end 60A. Therefore, the detection unit 66B is located on the opposite end in the second direction. In other words, the toner sensor 66 is located closer to the supply opening 62E than to the recovery opening 62F.

[0120] Furthermore, the toner sensor 66 is located in the second direction at a position away from the replenishment port 62A. Specifically, the replenishment port 62A is located closer to the recovery port 62F than to the supply port 62E, while the toner sensor 66 is located closer to the supply port 62E than to the recovery port 62F. Thus, the toner sensor 66 can detect the toner concentration of the toner replenished by the replenishment port 62A and the developer present in the developing container 62 after thorough mixing.

[0121] Furthermore, when the scraper mounting member 67, which is a conductor, is brought extremely close to the toner sensor 66, the toner sensor 66 sometimes fails to accurately detect the toner concentration of the developer in the developer container 62. Therefore, in the color printer 1 of this embodiment, the distance between the scraper mounting member 67 and the toner sensor 66 is 5 mm or more.

[0122] Furthermore, when the scraper 65, which is a conductor, is brought extremely close to the toner sensor 66, the toner sensor 66 sometimes fails to accurately detect the toner concentration of the developer in the developing container 62. Therefore, in the color printer 1 of this embodiment, the distance between the scraper 65 and the toner sensor 66 is 5 mm or more.

[0123] (3) Structure of the relay circuit between color printer 1 and toner sensor 66

[0124] (3-1)Frame 59

[0125] like Figure 10 As shown, the drum box 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 examples of a frame 59 capable of mounting and dismounting the toner cartridge TC. The third side plate W3, the fourth side plate W4, the front plate W5, and the rear plate W6 are made of resin.

[0126] 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.

[0127] (3-2) Structure of relay substrate 58

[0128] The drum box 50 also includes a first electrical contact 56, a second electrical contact 57, a relay board 58, wiring CA1, and wiring CA2.

[0129] More specifically, the drum housing 50 has a plurality of first electrical contacts 56. Each first electrical contact 56 corresponds to a plurality of toner memories TM. The first electrical contacts 56 are located on the inner side of the fourth side plate W4 and arranged along the second direction. When the toner cartridge TC is mounted on the drum housing 50 and the drum housing 50 is mounted on the main body housing 10, the first electrical contacts 56 contact the toner memories TM, thereby electrically connecting to the toner memories TM.

[0130] Additionally, the drum housing 50 has multiple second electrical contacts 57. Each second electrical contact 57 corresponds to a plurality of toner sensors 66. The second electrical contacts 57 are located on the inner side of the fourth side plate W4, arranged along the second direction. When the drum housing 50 is mounted on the main body housing 10, the second electrical contacts 57 contact the output contacts of the toner sensors 66, thereby electrically connecting to the toner sensors 66.

[0131] The relay board 58 is located on the inner surface of the rear plate W6 of the drum housing 50. The relay board 58 has a drum memory 58M that stores drum housing information related to the drum housing 50. Specifically, the drum memory 58M is located on the relay board. The relay board 58 is electrically connected to the first electrical contact 56 and the second electrical contact 57 via wiring CA1. Additionally, the relay board 58 is electrically connected to the connector 55 via wiring CA2. The relay board 58 electrically connects each toner sensor 66 to the connector 55. The relay board 58 electrically connects each toner memory TM to the connector 55. The drum memory 58M is electrically connected to the connector 55 via wiring CA2.

[0132] The drum box information is at least one of identification information that can identify the drum box 50 and drum life information of the photosensitive drum 51. The identification information is, for example, a serial number. The drum life information is, for example, at least one of the cumulative number of rotations of the photosensitive drum 51, the cumulative number of printed sheets using the photosensitive drum 51, and the cumulative dot count using the photosensitive drum 51.

[0133] The signal detected by the toner sensor 66 is communicated to the control unit 100 of the color printer 1 via the relay board 58.

[0134] The toner cartridge information stored in the toner memory TM is communicated to the control unit 100 of the color printer 1 via the relay board 58.

[0135] The information stored in the drum memory 58M is communicated to the control unit 100 of the color printer 1.

[0136] (4) Effects

[0137] According to one embodiment of the present invention described above, the toner sensor 66 is located on the side opposite to the supply port 62A in the second direction. Therefore, the toner supplied by the supply port 62A is stirred with the developer in the developing container 62 during delivery to the toner sensor 66. As a result, the toner concentration of the developer with minimal deviation in toner concentration can be detected in the toner sensor 66, thus achieving good detection accuracy.

[0138] Furthermore, since the magnetic roller 61 is located below the first screw conveyor 63 and the second screw conveyor 64, the size of the drum box 50 in the first direction can be further reduced compared to a structure located to the side of the first screw conveyor 63 and the second screw conveyor 64. As a result, the length that the user must pull out when pulling out the drum box 50 in the first direction is reduced, making it easier to handle.

[0139] In addition, since the toner sensor 66 is located between the supply opening 62E and the recovery opening 62F, it is possible to detect the toner concentration of the developer circulating in the developing container 62.

[0140] Furthermore, since the toner sensor 66 is located closer to the first screw conveyor 63 than to the second screw conveyor 64, it can detect the toner concentration of the developer in the first receiving chamber 62B, which is not adjacent to the magnetic roller 61. Therefore, compared to detecting the toner concentration of the developer in the second receiving chamber 62C, the toner sensor 66 is less affected by the magnetic roller 61, resulting in better detection accuracy.

[0141] Because the toner sensor 66 is located below the first screw conveyor 63, and the scraper 65 is located below the toner sensor 66, the drum box 50 is smaller in the first direction compared to when the scraper 65 or the toner sensor 66 is located on the side. Therefore, the length that the user must pull out when pulling out the drum box 50 in the first direction is reduced.

[0142] Furthermore, by making the second portion 67B of the scraper mounting member 67 shorter than the scraper 65, the toner sensor 66 can be positioned between the scraper mounting member 67 and the scraper 65. Thus, the bending of the second portion 67B can maintain the strength of the scraper mounting member 67 and position the toner sensor 66 in a position where it does not interfere with the scraper mounting member 67.

[0143] Furthermore, since the scraper mounting component 67 is made of metal, it has good strength and machinability, resulting in good positioning accuracy relative to the developing container 62. Consequently, its positioning accuracy relative to the magnetic roller 61 is also good, and the distance between the scraper 65 and the magnetic roller 61 is such that the thickness of the developer on the magnetic roller 61 is appropriate.

[0144] Furthermore, the toner sensor 66 is covered by an insulating sheet 68, which reduces the influence of the scraper mounting member 67, which is a conductive component, on the toner sensor 66. Therefore, even though the toner sensor 66 is located between the scraper mounting member 67 and the developing container 62, the toner sensor 66 can accurately detect the toner concentration of the developer.

[0145] Furthermore, since the toner sensor 66 is a permeability sensor, it can detect the permeability of the developer. Therefore, even if the amount of carrier in the developing container 62 of the color printer 1 decreases during use, toner can be replenished from the toner cartridge TC in a manner that optimizes the toner-to-carrier ratio in the developing container 62. Thus, by maintaining a constant toner-to-carrier ratio in the developing container 62, the amount of developer flowing from the magnetic roller 61 to the photosensitive drum 51 can be kept relatively constant.

[0146] In addition, by attaching a seal to the insulating sheet 68, it is possible to prevent developer from leaking between the developing container 62 and the scraper mounting component 67.

[0147] (5) Variations

[0148] The above describes one embodiment of the present invention, but the present invention is not limited to the above embodiment and can be implemented with appropriate modifications.

[0149] In one of the above embodiments, the pigment sensor is a magnetic sensor capable of detecting permeability, but it can also be a physical sensor that detects the amount of pigment or stirring torque, or an optical sensor that detects the transmittance or reflectivity of the pigment.

[0150] In one embodiment described above, the scraper is made of metal, but it can also be made of resin.

[0151] In one embodiment described above, the drum housing has four developing units, which can be more or less than four. For example, there can also be only one developing unit. In this case, the photosensitive drum can also be a single unit.

[0152] In one embodiment described above, the drum memory is configured to store drum box information, but it can also store information detected by the toner sensor. Additionally, the drum memory can also store calibration-related values.

[0153] Furthermore, the elements described in the above-described embodiment and its variations can be appropriately combined and implemented.

[0154] Symbol Explanation

[0155] 10 Main body shell

[0156] 50 drum boxes

[0157] 51 photosensitive drum

[0158] 55 connector

[0159] 59 Frames

[0160] 60 developing units

[0161] 61 magnetic rollers

[0162] 62 developing containers

[0163] 62A supply port

[0164] 62B First Containment Chamber

[0165] 62C Second Containment Chamber

[0166] 62D partition wall

[0167] 62E Supply Opening

[0168] 62F Recycling Opening

[0169] 63 First Screw Conveyor

[0170] 64 Second Screw Conveyor

[0171] 65 scraper

[0172] 66-color toner sensor

[0173] 67 Scraper Blade Mounting Components

[0174] 68 Insulating Sheet

[0175] TC Powder Box

Claims

1. A drum housing, detachable relative to the main body housing of an image forming apparatus along a first direction, characterized in that, have: A photosensitive drum capable of rotating about a first axis extending along a second direction intersecting the first direction; A frame that allows a toner cartridge to be loaded and unloaded in a third-party upward direction intersecting the first and second directions, the toner cartridge being able to contain toner, and the frame having a developing container capable of containing a developer containing toner and a carrier. A magnetic roller, located inside the developing container, is rotatable about a second axis extending in the second direction and is capable of supplying toner from the developing container to the photosensitive drum; A first spiral conveyor, located inside the developing container, is rotatable about a third axis extending in the second direction and is capable of conveying developer within the developing container in the second direction. The first spiral conveyor is located on the opposite side of the photosensitive drum relative to the magnetic roller in the third direction. as well as A toner sensor is included, which can detect the toner concentration of the developer in the developing container. The developing container has a refill port that, when the toner cartridge is mounted on the frame, allows for the replenishment of toner within the cartridge. This refill port is located on the side opposite to the photosensitive drum in the third direction relative to the first spiral conveyor, and at one end of the developing container in the second direction. The toner sensor is located in the third direction between the photosensitive drum and the first spiral conveyor, and at the other end of the developing container in the second direction.

2. The drum box according to claim 1, characterized in that, The drum cassette includes a second spiral conveyor located separately from the first spiral conveyor in a first direction, capable of conveying the developer within the developing container along the second direction, and facing the magnetic roller in the third direction. The second screw conveyor is located in the third direction between the magnetic roller and the feed port.

3. The drum box according to claim 2, characterized in that, The developing container has a partition wall extending along the second direction, which is located between the first screw conveyor and the second screw conveyor in the first direction. The partition wall has: A supply opening that allows developer conveyed by the first screw conveyor to move toward the second screw conveyor; and A recovery opening allows the developer conveyed by the second screw conveyor to move toward the first screw conveyor, and is located in the second direction at a position separate from the supply opening. The colorant sensor is located in the second direction between the supply opening and the recycling opening.

4. The drum box according to claim 3, characterized in that, The colorant sensor is located closer to the first screw conveyor than to the second screw conveyor.

5. The drum box according to claim 4, characterized in that, The colorant sensor is located in the second direction closer to the supply opening than to the recycling opening.

6. The drum box according to any one of claims 3 to 5, characterized in that, The replenishment port is located in the second direction closer to the recovery opening than to the supply opening.

7. The drum box according to claim 6, characterized in that, The magnetic roller is located on the opposite side of the feed port relative to the second screw conveyor in the third direction.

8. The drum box according to any one of claims 1 to 5, characterized in that, It includes a scraper that limits the thickness of the developer layer on the magnetic roller. The scraper is positioned in the third-party direction between the photosensitive drum and the toner sensor.

9. The drum box according to claim 8, characterized in that, It includes a scraper mounting component, on which the scraper is mounted and installed in the developing container. The scraper mounting component has: The first part is for installing the scraper blade; as well as The second part bends upward from the first part toward the colorant sensor in the direction of the third party. The length of the first portion in the second direction is longer than the length of the scraper in the second direction. The length of the second part in the second direction is shorter than the length of the scraper in the second direction.

10. The drum box according to claim 9, characterized in that, The scraper mounting component is made of metal.

11. The drum box according to claim 10, characterized in that, It includes an insulating sheet that covers the colorant sensor.

12. The drum box according to any one of claims 1 to 5, characterized in that, The pigment sensor is a permeability sensor.

13. The drum box according to claim 12, characterized in that, The colorant sensor has the following features: The main body is located outside the developing container and is mounted on the developing container; as well as The detection unit is capable of contacting the developer in the developing container and detecting the magnetic permeability.

14. The drum box according to any one of claims 1 to 5, characterized in that, have: A connector that is electrically connected to the image forming apparatus when the drum housing is mounted on the image forming apparatus; as well as A relay substrate electrically connects the toner sensor to the connector and communicates the signal detected by the toner sensor to the connector.

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