Developing device and image forming apparatus

Abstract

To properly circulate developer in a developing unit.SOLUTION: A developing device comprises a developing chamber that includes a developer carrier and a supply member, a developer storage chamber above the developing chamber, and a stirring member that stirs developer through rotation of a sheet member. The developer carrier, supply member, and stirring member are rotatable along a longitudinal direction. An opening along the longitudinal direction is provided in a wall surface part of the developer storage chamber and the developing chamber. On a cross section in the longitudinal direction, the opening has an upstream side end and a downstream side end in the direction of rotation of the stirring member, and when the upstream side end in a center part in the longitudinal direction is defined as a first end, and the upstream end at an end in the longitudinal direction as a second end, the distance between the first end and a contact part of the developer carrier and the supply member is shorter than the distance between the second end and the contact part.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention relates to a developing device and an image forming apparatus. [Background technology]

[0002] Image forming apparatuses that form images on recording media using an electrophotographic image forming method are known, including electrophotographic copying machines, electrophotographic printers (LED printers, laser beam printers, etc.), facsimile machines, and word processors.

[0003] Patent Document 1 discloses a development unit configuration having a development chamber in which a development roller and a supply roller are installed, and a developer storage chamber in which developer (toner) is stored. In Patent Document 1, an agitating member for agitating the developer is installed in the developer storage chamber provided above the development chamber.

[0004] In a developing unit such as that described in Patent Document 1, or a process cartridge containing such a unit, if a large capacity developer is used, resulting in a large amount of developer or a developer with a heavy specific gravity, the developer in the developer storage chamber tends to be pushed into the lower developing chamber due to the weight of the developer and the movement of the agitating member, causing the developer in the developing chamber to become densely packed. This can result in poor circulation of the developer in the developing chamber, impairing the function of the developing roller and supply roller, and causing image defects such as toner leakage. To address this issue, conventionally, the developer storage chamber has been installed horizontally relative to the developing chamber in a horizontal position to prevent the developer's weight from being applied. However, installing the developer storage chamber in a horizontal position can result in an increase in the size of the device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-194883 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to properly circulate developer in a developing unit. [Means for solving the problem]

[0007] The present invention employs the following configuration: a developer carrier that carries a developer; a supply member that contacts the developer carrier to form a contact portion and supplies the developer to the surface of the developer carrier at the contact portion; a developing chamber in which the developer carrier and the supply member are disposed; a developer storage chamber disposed above the developing chamber in the direction of gravity and configured to store the developer; an agitating member having a shaft and a sheet member held by the shaft, the sheet member agitating the developer contained in the developer containing chamber as the shaft rotates; A developing device comprising: the developer storage chamber is disposed above the developing chamber in a direction of gravity when the developing device is attached to the image forming apparatus; the developer carrier, the supply member, and the stirring member are each rotatable about a rotation axis extending along a longitudinal direction of the developing device; an opening that allows the developer to move from the developer storage chamber to the developing chamber is provided along the longitudinal direction in a wall portion that separates the developer storage chamber from the developing chamber; In the cross section in the longitudinal direction, the opening has an upstream end and a downstream end in the rotation direction of the agitating member, and when the upstream end in the central portion in the longitudinal direction is defined as a first end and the upstream end in the longitudinal direction is defined as a second end, the distance between the first end and the abutting portion of the developer carrier and the supply member is shorter than the distance between the second end and the abutting portion. The developing device is characterized by the above. The present invention also employs the following configuration: a developer carrier that carries a developer; a supply member that contacts the developer carrier to form a contact portion and supplies the developer to the surface of the developer carrier at the contact portion; a developing chamber in which the developer carrier and the supply member are disposed; a developer storage chamber that stores the developer; an agitating member having a shaft and a sheet member held by the shaft, the sheet member agitating the developer contained in the developer containing chamber as the shaft rotates; an image carrier on which an electrostatic latent image formed on a surface thereof is developed when the developer is supplied from the developer carrier; An image forming apparatus comprising: the developer storage chamber is disposed above the developing chamber in the direction of gravity, the developer carrier, the supply member, and the stirring member are each rotatable about a rotation axis extending along a longitudinal direction; an opening that allows the developer to move from the developer storage chamber to the developing chamber is provided along the longitudinal direction in a wall portion that separates the developer storage chamber from the developing chamber; In the cross section in the longitudinal direction, the opening has an upstream end and a downstream end in a direction in which the sheet member passes in response to rotation of the agitating member, and when the upstream end in the center of the longitudinal direction is defined as a first end and the upstream end in the longitudinal direction is defined as a second end, the distance between the first end and a contact portion of the developer carrier and the supply member is shorter than the distance between the second end and the contact portion. The image forming apparatus is characterized by the above. The present invention also employs the following configuration: a developer carrier that carries a developer; a supply member that contacts the developer carrier to form a contact portion and supplies the developer to the surface of the developer carrier at the contact portion; a developing chamber in which the developer carrier and the supply member are disposed; a developer storage chamber that stores the developer; an agitating member having a shaft and a sheet member held by the shaft, the sheet member agitating the developer contained in the developer containing chamber as the shaft rotates; A developing device comprising: the developer storage chamber is disposed above the developing chamber in a direction of gravity when the developing device is attached to the image forming apparatus; the developer carrier, the supply member, and the stirring member are each rotatable about a rotation axis extending along a longitudinal direction of the developing device; an opening that allows the developer to move from the developer storage chamber to the developing chamber is provided along the longitudinal direction in a wall portion that separates the developer storage chamber from the developing chamber; In the cross section in the longitudinal direction, the opening has an upstream end and a downstream end in a direction in which the sheet member passes in response to the rotation of the agitating member, and the width of the upstream end and the downstream end at the center in the longitudinal direction is narrower than the width of the upstream end and the downstream end at the ends in the longitudinal direction. The developing device is characterized by the above. [Effects of the Invention]

[0008] According to the configuration of the present invention, the developer in the developing unit can be circulated appropriately. [Brief explanation of the drawings]

[0009] [Figure 1A] Cross-sectional view showing the shape of the opening of the development unit [Figure 1B] Cross-sectional view showing the shape of the opening of the development unit [Figure 2] Schematic cross-sectional view showing the printer configuration [Figure 3] A perspective view of a process cartridge and a toner cartridge [Figure 4] A perspective view of a process cartridge and a toner cartridge [Figure 5] Side view of the process cartridge and toner cartridge [Figure 6] Side view of the process cartridge and toner cartridge [Figure 7] Cross-sectional view of a process cartridge and a toner cartridge [Figure 8] Cross-sectional view of a process cartridge and a toner cartridge [Figure 9] FIG. 10 is a side view illustrating a drive transmission path of the process cartridge; [Figure 10] Diagram of the process cartridge and toner cartridge viewed from the direction of removal [Figure 11A] Perspective view of the toner cartridge [Figure 11B] Perspective view of the toner cartridge [Figure 12A] Perspective view of the toner cartridge [Figure 12B] Perspective view of the toner cartridge [Figure 13] Toner cartridge viewed from the removal direction [Figure 14] Diagram showing the internal structure of the toner cartridge [Figure 15] Cross section of a toner cartridge [Figure 16A] Toner cartridge side view [Figure 16B] Toner cartridge side view [Figure 17] Toner cartridge side view [Figure 18A] Cross-sectional view showing the position and shape of the opening of the development unit [Figure 18B] Cross-sectional view showing the position and shape of the opening of the development unit [Figure 19A] Cross-sectional view showing the movement of developer inside the process cartridge [Figure 19B] Cross-sectional view showing the movement of developer inside the process cartridge [Figure 20] Cross-sectional view showing the shape of the opening of the development unit [Figure 21A] 10 is a cross-sectional view showing the shape of an opening of a developing unit according to another embodiment; [Figure 21B]10 is a cross-sectional view showing the shape of an opening of a developing unit according to another embodiment; [Figure 22A] Cross-sectional view showing the shape of the opening of the development unit [Figure 22B] Cross-sectional view showing the shape of the opening of the development unit [Figure 23] Block diagram showing the control configuration of the image forming apparatus DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the following embodiments may be changed as appropriate depending on the configuration of the device to which the present invention is applied and various conditions. Therefore, unless otherwise specified, the scope of the present invention is not intended to be limited to these.

[0011] [Example 1] <Overall printer overview> The basic configuration and operation of a printer 100 as an image forming apparatus according to this embodiment will be described with reference to Fig. 2. Fig. 2 is a schematic cross-sectional view showing the configuration of the printer 100 according to this embodiment. Arrow Z indicates the vertical direction, and arrow H indicates the horizontal direction. As shown in Fig. 2, the printer 100 has a device main body 100A, a process cartridge P as a cartridge removably mounted in the device main body 100A, and a toner cartridge T.

[0012] The apparatus main body 100A has a scanner 101 as an exposure device, a stacking tray 102 on which sheets S are stacked, a paper feed roller 103, a transfer roller 104, a fixing unit 105, a discharge tray 106, and a control unit 107. In addition, a process cartridge P and a toner cartridge T (developer cartridge) are removably mounted in the apparatus main body 100A.

[0013] The process cartridge P has a photosensitive drum 12, a charging roller 13 (charging member), a cleaning blade 14 (cleaning member), a drum unit 10, and a developing unit 30 (developing device) having a developing roller 32, a supply roller 33, and a developing frame 31. Further configuration of the process cartridge P will be described later. The drum unit 10 has a drum frame 11, which will be described later. The photosensitive drum 12 is rotatably supported by the drum frame 11. The developing roller 32 is rotatably supported by the developing frame 31. Note that instead of a configuration in which the process cartridge P includes the drum unit 10 and the developing unit 30, a drum cartridge corresponding to the drum unit 10 and a developing cartridge corresponding to the developing unit 30 may be configured to be detachably mountable to the image forming apparatus main body.

[0014] The toner cartridge T can be attached to the process cartridge P. The toner cartridge T contains toner as a developer and is configured to supply the toner to the developing unit 30 of the process cartridge P. As will be described later with reference to the drawings, the toner cartridge T has a toner transport member 62, a toner transport screw 63, and a toner frame 55. The toner transport member 62 and the toner transport screw 63 are rotatably supported by the toner frame 55.

[0015] The image forming operation on the sheet S will be described. The control unit 107 of the printer 100 starts the image forming operation on the sheet S based on a signal received from the external device 200 shown in FIG. 23. The control unit 107 is composed of an information processing device having computational resources such as a processor and memory, a processing circuit, etc. As shown in the block diagram of FIG. 23, the control unit 107 acquires information from each component of the printer 100 in accordance with a program stored in memory or a user instruction using the external device 200, and performs control using control signals. The printer 100 is equipped with a drive source 160 equipped with a motor, etc., and a power supply unit 170 that supplies power such as a drive voltage to each component.

[0016] First, the photosensitive drum 12 is rotated by the drive source 160 of the apparatus main body 100A. With a charging voltage applied to the charging roller 13 by the power supply unit 170, the charging roller 13 is rotated by the photosensitive drum 12. As a result, the surface of the photosensitive drum 12 is uniformly charged. Based on image information, the scanner 101 irradiates a laser beam toward the charged surface of the photosensitive drum 12, and an electrostatic latent image is formed on the surface of the photosensitive drum 12.

[0017] When a development voltage is applied to the development roller 32 by the power supply unit 170, toner is supplied from the development roller 32 to the photosensitive drum 12, and the electrostatic latent image is developed into a toner image. Subsequently, as the photosensitive drum 12 rotates, the toner image formed on the photosensitive drum 12 is transported toward a transfer unit formed between the transfer roller 104 and the photosensitive drum 12.

[0018] Meanwhile, a sheet S is fed from a stacking tray 102 by a sheet feed roller 103. The sheet S is transported to the transfer section in synchronization with the timing at which the toner image formed on the photosensitive drum 12 reaches the transfer section.

[0019] A transfer voltage is applied from a power supply unit 170 to the transfer roller 104, and the toner image is transferred from the photosensitive drum 12 to the sheet S. Residual toner that has not been transferred to the sheet S is removed from the surface of the photosensitive drum 12 by a cleaning blade 14.

[0020] The sheet S onto which the toner image has been transferred is transported toward the fixing unit 105. When the sheet S passes through the fixing unit 105, the toner image is heated and pressurized by the fixing unit 105, and is fixed to the sheet S.

[0021] The printer 100 according to this embodiment can perform double-sided printing, which involves forming an image on both the front and back sides of a sheet S. When an image is formed only on the front side of the sheet S, the sheet S passes through the fixing unit 105 and is discharged to a discharge tray 106. On the other hand, when double-sided printing is performed, the sheet S, on which a toner image has been fixed on its front side, is conveyed in the direction of arrow M through the double-sided conveying path 81 and reaches the transfer unit again, where a toner image is formed on the back side of the sheet S. Thereafter, the sheet S passes through the fixing unit 105 and is discharged to a discharge tray 106.

[0022] <Installing and removing the process cartridge and toner cartridge> 2, 3, 4, 5, 6 and 10, the attachment and detachment of the process cartridge P and the toner cartridge T to and from the apparatus main body 100A according to this embodiment will be described.

[0023] 3 and 4 are perspective views of the process cartridge P and the toner cartridge T. FIGS. 5 and 6 are side views of the process cartridge P and the toner cartridge T. The photosensitive drum 12 is rotatable around a rotation axis (first axis) 12a shown in FIG. 6. The direction in which the rotation axis 12a extends is called the rotation axis direction (axial direction) of the photosensitive drum 12.

[0024] Fig. 3 is a perspective view of the process cartridge P and toner cartridge T as seen from the drive side. Fig. 4 is a perspective view of the process cartridge P and toner cartridge T as seen from the non-drive side. Fig. 5 is a side view of the drive side of the process cartridge P and toner cartridge T as seen in the direction of the rotation axis of the photosensitive drum 12. Fig. 6 is a side view of the non-drive side of the process cartridge P and toner cartridge T as seen in the direction of the rotation axis of the photosensitive drum 12.

[0025] As shown in Figure 2, the printer 100 has a door (opening / closing member) 100B that covers an opening 100C in the device main body 100A. The door 100B is attached to the device main body 100A so as to be rotatable about a rotation axis 100D. The door 100B is configured to be movable in the direction of arrow J from a closed position that covers the opening 100C to an open position that exposes the opening 100C. With the door 100B in the open position, the process cartridge P and toner cartridge T can be installed in and removed from the device main body 100A through the opening 100C.

[0026] FIG. 10 is a diagram of the process cartridge P and toner cartridge T as viewed in the removal direction PDD. As shown in FIG. 10, the drum frame 11 has a process driving end (first end of the drum frame 11) 11f1 and a process non-driving end (second end of the drum frame 11) 11f2 opposite the process driving end 11f1 in the rotational axis direction 12a of the photosensitive drum 12. The process driving end 11f1 and the process non-driving end 11f2 are the outermost portions (ends) of the drum frame 11 in the rotational axis direction of the photosensitive drum 12. There may be multiple process driving ends 11f1 and multiple process non-driving ends 11f2. The center of the drum frame 11 in the rotational axis direction of the photosensitive drum 12 is referred to as the center 11f3. The distance from the center 11f3 of the drum frame 11 to the process driving end 11f1 is equal to the distance from the center 11f3 to the process non-driving end 11f2.

[0027] In this embodiment, the process driving end 11f1 and the process non-driving end 11f2 are the outermost portions (ends) of the process cartridge P in the direction of the rotation axis of the photosensitive drum 12. In other words, in the direction of the rotation axis of the photosensitive drum 12, the process driving end 11f1 and the process non-driving end 11f2 are the driving ends of the process cartridge P (the first end of the process cartridge P). The "drive side" of the drum frame 11 or the process cartridge P is located opposite the "non-drive side" of the drum frame 11 or the process cartridge P in the direction of the rotation axis of the photosensitive drum 12.

[0028] In the direction of the rotation axis of the photosensitive drum 12, the side on which the process driving end 11f1 is located relative to the center 11f3 of the drum frame 11 is the driving side of the drum frame 11 or the driving side of the process cartridge P. In the direction of the rotation axis of the photosensitive drum 12, the side on which the process non-driving end 11f2 is located relative to the center 11f3 of the drum frame 11 is the non-driving side of the drum frame 11 or the non-driving side of the process cartridge P. In this embodiment, in the direction of the rotation axis of the photosensitive drum 12, the center 11f3 of the drum frame 11 is the same as the center of the process cartridge P.

[0029] As will be described later, the toner conveying member 62 shown in Fig. 14 is rotatable around a rotation axis 62a. The direction in which the rotation axis 62a extends is referred to as the rotation axis direction (axial direction) of the toner conveying member 62. The toner conveying screw 63 shown in Fig. 14 is rotatable around a rotation axis 63a. The direction in which the rotation axis 63a extends is referred to as the rotation axis direction (axial direction) of the toner conveying screw 63.

[0030] As shown in FIG. 10 , the toner frame 55 has a toner driving end (first end of the toner frame 55) 55a1 and a toner non-driving end 55a2 (second end of the toner frame 55) opposite the toner driving end 55a1 in the rotational axis direction LD of the toner transport screw 63. The toner driving end 55a1 and the toner non-driving end 55a2 are the outermost portions (ends) of the toner frame 55 in the rotational axis direction of the toner transport screw 63. There may be multiple toner driving ends 55a1 and multiple toner non-driving ends 55a2. The center of the toner frame 55 in the rotational axis direction of the toner transport screw 63 is referred to as the center 55a3. The distance from the center 55a3 of the toner frame 55 to the toner driving end 55a1 is equal to the distance from the center 11f3 to the toner non-driving end 55a2.

[0031] In this embodiment, the toner driving end 55a1 and the toner non-driving end 55a2 are the outermost portions (ends) of the toner cartridge T in the direction of the rotation axis of the toner transport screw 63. In other words, the toner driving end 55a1 and the toner non-driving end 55a2 coincide with the driving end (first end of the toner cartridge T) and the non-driving end (second end of the toner cartridge T) of the toner cartridge T in the direction of the rotation axis of the toner transport screw 63.

[0032] In the direction of the rotation axis of the toner transport screw 63, the side on which the toner driving end 55a1 is located relative to the center 55a3 of the toner frame 55 is the driving side of the toner frame 55 or the driving side of the toner cartridge T. In the direction of the rotation axis of the toner transport screw 63, the side on which the toner non-driving end 55a2 is located relative to the center 55a3 of the toner frame 55 is the non-driving side of the toner frame 55 or the non-driving side of the toner cartridge T. In this embodiment, in the direction of the rotation axis of the toner transport screw 63, the center 55a3 of the toner frame 55 is the same as the toner cartridge T.

[0033] In the direction of the rotation axis of the toner transport screw 63, the drive side of the toner frame 55 or the drive side of the toner cartridge T is located opposite to the non-drive side of the toner frame 55 or the non-drive side of the toner cartridge T.

[0034] In this embodiment, the rotational axis direction of the photosensitive drum 12, the rotational axis direction of the toner transport member 62, and the rotational axis direction of the toner transport screw 63 are parallel to one another. Therefore, the rotational axis direction of the photosensitive drum 12, the rotational axis direction of the toner transport member 62, and the rotational axis direction of the toner transport screw 63 are also simply referred to as the axial direction (first direction) LD.

[0035] In this embodiment, in the axial direction LD, the position of the center 55a3 of the toner frame 55 is the same as the position of the center 11f3 of the drum frame 11. However, the position of the center 55a3 of the toner frame 55 and the position of the center 11f3 of the drum frame 11 may be different.

[0036] As shown in Figures 3 and 5, the process cartridge P has a drive-side process guide 22 on the drive side of the drum frame 11. The toner cartridge T has a drive-side toner guide 51 on the drive side of the toner frame 55. As shown in Figures 4 and 6, the process cartridge P has a non-drive-side process guide 23 on the non-drive side of the drum frame 11. The toner cartridge T has a non-drive-side toner guide 52 on the non-drive side of the toner frame 55.

[0037] The direction in which the process cartridge P is attached to the apparatus main body 100A is called the attachment direction PDA. The direction in which the process cartridge P is removed from the apparatus main body 100A is called the removal direction PDD. The attachment direction PDA and the removal direction PDD are collectively called the attachment / detachment direction PD of the process cartridge P. The drive side process guide 22 and the non-drive side process guide 23 are formed along the attachment / detachment direction PD. The drive side process guide 22 and the non-drive side process guide 23 are guided by guide portions of the apparatus main body 100A, and the process cartridge P moves in the attachment / detachment direction PD relative to the apparatus main body 100A.

[0038] The direction in which the toner cartridge T is attached to the apparatus main body 100A is called the attachment direction TDA. The direction in which the toner cartridge T is removed from the apparatus main body 100A is called the removal direction TDD. The attachment direction TDA and the removal direction TDD are collectively called the attachment / detachment direction TD of the toner cartridge T. The drive side toner guide 51 and the non-drive side toner guide 52 are formed along the attachment / detachment direction TD. The drive side toner guide 51 and the non-drive side toner guide 52 are guided by guide portions of the apparatus main body 100A, and the toner cartridge T moves in the attachment / detachment direction TD relative to the apparatus main body 100A.

[0039] In this embodiment, the mounting / removal direction PD of the process cartridge P is a direction that intersects with the axial direction LD. It is preferable that the angle between the mounting / removal direction PD and the direction perpendicular to the axial direction LD is smaller than the angle between the axial direction LD and the mounting / removal direction PD, and it is more preferable that the mounting / removal direction PD is a direction that is perpendicular to the axial direction LD.

[0040] In this embodiment, the mounting / removal direction TD of the toner cartridge T is a direction that intersects with the axial direction LD. It is preferable that the angle between the mounting / removal direction TD and the direction perpendicular to the axial direction LD is smaller than the angle between the axial direction LD and the mounting / removal direction TD, and it is more preferable that the mounting / removal direction TD is a direction that intersects with the axial direction LD.

[0041] In this embodiment, the attachment / detachment direction PD and the attachment / detachment direction TD are parallel to each other, but the attachment / detachment direction PD and the attachment / detachment direction TD may be different from each other.

[0042] In this embodiment, the process cartridge P is attached to and detached from the apparatus main body 100A without the toner cartridge T attached thereto. In other words, the process cartridge P is attached to and detached from the apparatus main body 100A before the toner cartridge T is attached to and detached therefrom.

[0043] With the toner cartridge T not yet attached to the apparatus main body 100A, the process cartridge P is attached to the apparatus main body 100A through the opening 100C. Furthermore, with the process cartridge P attached to the apparatus main body 100A, the toner cartridge T is attached to the apparatus main body 100A and the process cartridge P through the opening 100C.

[0044] When the toner cartridge T and the process cartridge P are attached to the device main body 100A, the process cartridge P is located downstream of the toner cartridge T and the toner cartridge T is located upstream of the process cartridge P in the attachment direction PDA and the attachment direction TDA.

[0045] When the toner cartridge T and the process cartridge P are removed from the apparatus main body 100A, the toner cartridge T is removed from the apparatus main body 100A and the process cartridge P through the opening 100C. Thereafter, the process cartridge P is removed from the apparatus main body 100A through the opening 100C.

[0046] <Toner cartridge> The configuration of the toner cartridge T according to this embodiment will be described in more detail with reference to FIGS. 7, 8, and 11A to 17.

[0047] 11A to 12B are perspective views of the toner cartridge T. Specifically, FIGS. 11A and 11B are perspective views of the toner cartridge T as viewed from the drive side. Part of the toner cartridge T is omitted in FIG. 11B. FIGS. 12A and 12B are perspective views of the toner cartridge T as viewed from the non-drive side. Part of the toner cartridge T is omitted in FIG. 12B.

[0048] Fig. 13 is a view of the toner cartridge T as seen in the removal direction TDD. Fig. 14 is a view showing the internal structure of the toner cartridge T. Fig. 15 is a cross-sectional view of the toner cartridge T taken along a direction perpendicular to the axial direction LD.

[0049] 16A, 16B, and 17 are side views of the toner cartridge T. Specifically, Fig. 16A and 16B are side views of the drive side of the toner cartridge T as viewed in the axial direction LD. Fig. 17 is a side view of the non-drive side of the toner cartridge T as viewed in the axial direction LD.

[0050] 7 and 14, a toner frame 55 of the toner cartridge T is provided with a toner storage chamber 53 (first chamber) and a toner recovery chamber 54 (second chamber). The toner storage chamber 53 stores toner to be supplied to the process cartridge P. The toner recovery chamber 54 stores toner returned from the process cartridge P by the return screw 18 shown in FIG.

[0051] The toner recovery chamber 54 and the toner storage chamber 53 are separated (isolated) from each other. Specifically, the toner frame 55 has a partition wall 55b, and the toner recovery chamber 54 and the toner storage chamber 53 are completely separated by the partition wall 55b. This prevents toner from moving between the toner recovery chamber 54 and the toner storage chamber 53, and prevents the toner stored in the toner recovery chamber 54 and the toner stored in the toner storage chamber 53 from mixing with each other.

[0052] The volume of the toner storage chamber 53 is larger than the volume of the toner recovery chamber 54. In this embodiment, the distance between the partition wall 55b and the toner non-driving end 55a2 in the axial direction LD is shorter than the distance between the partition wall 55b and the toner driving end 55a1.

[0053] In the axial direction, the toner storage chamber 53 is disposed so as to overlap with the center 55a3 of the toner frame 55. On the other hand, in the axial direction LD, the toner recovery chamber 54 is disposed on the non-drive side of the toner frame 55. In the axial direction LD, the distance between the toner recovery chamber 54 and the toner non-drive end 55a2 is shorter than the distance between the toner recovery chamber 54 and the toner drive end 55a1. In addition, in the axial direction LD, the toner recovery chamber 54 is disposed so as to overlap with the center 55a2 of the toner storage chamber 53. is placed between.

[0054] As shown in Figures 13 and 14, the toner frame 55 has a container portion 56 equipped with a toner storage chamber 53 and a toner recovery chamber 54, a drive end cover 57 arranged on the drive side of the toner cartridge T, and a non-drive end cover 58 arranged on the non-drive side of the toner cartridge T.

[0055] The container unit 56 includes a first container 56a having a toner storage chamber 53 and a second container 56b having a toner recovery chamber 54. In this embodiment, the second container 56b is fixed to the first container 56a, and the side walls of the first container 56a and the second container 56b face each other and function as a partition wall 55b.

[0056] 11A and 11B, the toner frame 55 has a toner discharge port (first opening) 61 for discharging the toner contained in the toner storage chamber 53 toward the developing unit 30 of the process cartridge P. The toner discharge port 61 connects the outside of the toner frame 55 with the toner storage chamber 53, and the toner contained in the toner storage chamber 53 is discharged to the outside of the toner frame 55 through the toner discharge port 61. The toner discharge port 61 is provided in the first container 56a.

[0057] In the axial direction LD, the toner discharge port 61 is disposed closer to the driving side of the toner frame 55. In the axial direction LD, the distance between the toner discharge port 61 and the toner driving end 55a1 is shorter than the distance between the toner discharge port 61 and the toner non-driving end 55a2.

[0058] The toner discharge port 61 is covered by a discharge port shutter (not shown). The discharge port shutter opens and closes in conjunction with the installation and removal of the toner cartridge T relative to the process cartridge P. When the toner cartridge T is installed in the process cartridge P, toner is allowed to be discharged from the toner discharge port 61. As described above, the developing roller 32 of the process cartridge P develops the electrostatic latent image formed on the photosensitive drum 12 with toner discharged from the toner discharge port 61.

[0059] 7 and 14, a toner transport member 62 and a toner transport screw 63 are housed inside the toner storage chamber 53. The toner transport member 62 and the toner transport screw 63 can be called the first rotating member of the toner cartridge T.

[0060] 14 and 15, the toner cartridge T has a toner discharging device 64 for discharging toner from the toner discharging port 61. The toner discharging device 64 has a pump unit 65 that discharges air by being compressed, an air guide 66 that guides the air discharged by the pump unit 65 toward the toner discharging port 61, a compression unit 67 that compresses the pump unit 65, and an operating gear 68 that moves the compression unit 67. The operating gear 68 has an operating groove 68a for moving the compression unit 67.

[0061] Toner transport member 62 has flexible fins 62b and a shaft 62c to which fins 62b are attached, and rotates around rotation axis 62a to transport toner toward toner transport screw 63. As shown in FIG. 15, fins 62b come into contact with the inner wall of toner storage chamber 53 and deform from its natural state shown by solid lines to the state shown by dashed lines to transport toner. Toner transport screw 63 has spiral fins 63b1 and a screw shaft 63b2, and rotates around rotation axis 63a to transport toner toward toner discharge port 61. Spiral fins 63b1 and screw shaft 63b2 are integrally formed.

[0062] On the other hand, when the operating gear 68 rotates, the compression portion 67 that engages with the operating groove 68a moves in the direction of the operating gear 68. The pump portion 65 is compressed by the movement of the compression portion 67, and the pump portion 65 sends out air toward the toner-accommodating chamber 53.

[0063] The sent-out air is guided by air guide 66 toward toner discharge port 61. A cover member is disposed near toner discharge port 61, and the cover member covers a portion of toner transport screw 63. This prevents toner transported by toner transport member 62 from being directly discharged from toner discharge port 61, and also allows air released from air guide 66 to efficiently flow toward toner discharge port 61.

[0064] 11A and 11B, the toner frame 55 is provided with a toner receiving port (second opening) 84 that receives toner returned from the process cartridge P. The toner receiving port 84 connects the outside of the toner frame 55 with the toner recovery chamber 54. The toner recovery chamber 54 stores toner (recovered toner) that is discharged from the toner return opening 20 shown in FIG. 8 and passes through the toner receiving port 84.

[0065] In the axial direction LD, the toner receiving opening 84 is disposed closer to the non-drive side of the toner frame 55. That is, in the axial direction LD, the distance between the toner receiving opening 84 and the toner non-driven end 55a2 is shorter than the distance between the toner receiving opening 84 and the toner driven end 55a1. Also, in the axial direction LD, the distance between the toner receiving opening 84 and the toner non-driven end 55a2 is shorter than the distance between the toner receiving opening 84 and the center 55a3 of the toner frame 55.

[0066] The toner receiving opening 84 is covered by a receiving opening shutter 85. The receiving opening shutter 85 is opened and closed in conjunction with the attachment and detachment of the toner cartridge T to and from the process cartridge P.

[0067] More specifically, the receiving port shutter 85 is movable between a closed position that covers the toner receiving port 84 and an open position that exposes the toner receiving port 84. As shown in Figure 8, when the toner cartridge T is attached to the process cartridge P, the receiving port shutter 85 comes into contact with the process cartridge P and moves to the open position. With the toner cartridge T attached to the process cartridge P, the toner receiving port 84 and the toner return opening 20 face each other.

[0068] 14, the toner recovery chamber 54 includes a first recovery chamber 69, a second recovery chamber 70, and a third recovery chamber 71. The toner cartridge T has a first recovery screw 72 that transports toner from the first recovery chamber 69 to the second recovery chamber 70, and a second recovery screw (second rotating member) 73 that transports toner from the second recovery chamber 70 to the third recovery chamber 71. The first recovery screw 72 and the second recovery screw 73 are housed in the toner recovery chamber 54.

[0069] 8, the first recovery screw 72 is rotatable about a rotation axis 72a, and the second recovery screw 73 is rotatable about a rotation axis 73a. The direction of the rotation axis 72a is parallel to the axial direction LD, and the direction of the rotation axis 73a is a direction intersecting the axial direction LD. It is preferable that the angle formed between the direction perpendicular to the axial direction LD and the direction of the rotation axis 73a is smaller than the angle formed between the axial direction LD and the direction of the rotation axis 73a, and it is more preferable that the direction of the rotation axis 73a is a direction perpendicular to the axial direction LD.

[0070] The toner received through the toner receiving port 84 is accumulated in the first recovery chamber 69 and is transported from the first recovery chamber 69 to the second recovery chamber 70 by the first recovery screw 72. The toner transported to the second recovery chamber 70 is transported vertically upward by the second recovery screw 73, and is transported from the second recovery chamber 70 to the third recovery chamber 71.

[0071] As shown in FIGS. 16A and 16B, the toner cartridge T includes a second toner coupling 74, a first toner coupling 75, a conveying gear 76, and a discharge gear 77.

[0072] The operating gear 68, the second toner coupling 74, the first toner coupling 75, the conveying gear 76, and the discharge gear 77 are disposed on the driving side of the toner cartridge T. That is, in the axial direction LD, the distances between the second toner coupling 74 and the first toner coupling 75 and the toner driving end 55a1 are shorter than the distances between the second toner coupling 74 and the first toner coupling 75 and the toner non-driving end 55a2.

[0073] 13 and 16A covers at least a portion of the operating gear 68, the second toner coupling 74, the first toner coupling 75, the conveying gear 76, and the discharge gear 77, and has a driving-side toner guide 51. The driving-end cover 57 covers at least a portion of the pump section 65.

[0074] The conveying gear 76 is connected to the toner conveying member 62, and the discharge gear 77 is connected to the toner conveying screw 63. The second toner coupling 74 receives a driving force (external force) from the apparatus main body 100A and rotates the conveying gear 76. As a result, the toner conveying member 62 is rotated. The first toner coupling 75 meshes with the operating gear 68 via an idler gear, and the operating gear 68 meshes with the discharge gear 77. The first toner coupling 75 receives a driving force (external force) from the apparatus main body 100A and rotates the operating gear 68 and the discharge gear 77. As a result, the pump portion 65 is compressed and the toner conveying screw 63 is rotated.

[0075] That is, the second toner coupling 74 functions as a driving member that drives the toner conveying member 62. The first toner coupling 75 functions as a driving member that drives the toner discharging device 64 and the toner conveying screw 63.

[0076] 17, the toner cartridge T has a detection member 78 for detecting the amount of toner in the toner recovery chamber 54. The non-driving end cover 58 covers the detection member 78 and has the non-driving side toner guide 52.

[0077] The detection member 78 in this embodiment is a pair of light guides that guide light. The detection member 78 includes light guide members 78a1 and 78a2, and is disposed on the non-driven side of the toner cartridge T. That is, in the axial direction LD, the distance between the light guide members 78a1 and 78a2 and the toner non-driven end 55a2 is shorter than the distance between the light guide members 78a1 and 78a2 and the toner driving end 55a1.

[0078] A portion of light-guiding member 78a1 and a portion of light-guiding member 78a2 are exposed to toner recovery chamber 54. One of light-guiding member 78a1 and light-guiding member 78a2 guides light from the outside of toner recovery chamber 54 to the inside of toner recovery chamber 54. The light guided to the inside of toner recovery chamber 54 passes through toner recovery chamber 54. The other of light-guiding member 78a1 and light-guiding member 78a2 guides light from the inside of toner recovery chamber 54 to the outside of toner recovery chamber 54.

[0079] Control unit 107 of apparatus main body 100A can detect the amount of toner based on light that has passed through the interior of toner recovery chamber 54 via light guiding members 78a1 and 78a2. Note that a pair of electrodes facing each other can also be used as detection member 78. In this case, control unit 107 of apparatus main body 100A can detect the amount of toner based on a change in electrostatic capacitance between the pair of electrodes.

[0080] <Process cartridge> 3 to 10, the structure of the process cartridge P according to this embodiment will be further explained. will be explained in detail.

[0081] 7 and 8 are cross-sectional views of the process cartridge P and the toner cartridge T. Specifically, Fig. 7 and Fig. 8 are cross-sectional views of the process cartridge P and the toner cartridge T taken along a direction perpendicular to the axial direction LD. Fig. 8 is a view of the process cartridge P and the toner cartridge T cut along the rotation axis RS of a return screw 18, which will be described later.

[0082] Figure 9 is a side view illustrating the drive transmission path of the process cartridge P. Figure 10 is a view of the process cartridge P and the toner cartridge T as viewed in the removal direction PDD.

[0083] The process cartridge P includes a developing unit 30 and a drum unit 10. The developing unit 30 is movably (rotatably) connected to the drum unit 10. As shown in FIGS. 5 and 6 , the process cartridge P has a drive-side spring 37 and a non-drive-side spring 38, which are attached to the drum unit 10 and the developing unit 30. The drive-side spring 37 and the non-drive-side spring 38 bias the developing unit 30 so that the developing roller 32 is pressed against the photosensitive drum 12.

[0084] 7 and 8, the developing unit 30 has a developing frame 31, a developing roller 32 (developer carrier) that carries toner, a supply roller 33 (supply member) that comes into contact with the developing roller 32 to supply toner, a developing blade 34, and an agitating unit 35 (agitating member). The developing frame 31 supports the developing roller 32, the supply roller 33, the developing blade 34, and the agitating unit 35. The developing frame 31 is provided with a developer storage chamber 31a and a developing chamber 31b.

[0085] The developer storage chamber 31a is disposed above the developing chamber 31b in the direction of gravity via a wall portion 201e, which is the partition plate shown in Fig. 1A. Furthermore, the wall portion 201e is provided with an opening 201 that connects the developer storage chamber 31a and the developing chamber 31b.

[0086] An agitation unit 35 is disposed in the developer storage chamber 31a, and a development roller 32, a supply roller 33, and a development blade 34 are disposed in the development chamber 31b.

[0087] The stirring unit 35 is composed of a rotationally supported stirring shaft 35c and a flexible sheet member 35a fixed to the stirring shaft 35c.

[0088] 7, supply roller 33 rotates in the same direction (arrow K direction) as development roller 32, and stirring unit 35 rotates in the opposite direction (arrow Q direction) to that of supply roller 33. In addition, the longitudinal direction of supply roller 33 in development unit 30 will hereinafter be referred to as the longitudinal direction.

[0089] Toner supplied from the toner cartridge T is contained in the developer containing chamber 31a. The stirring unit 35 transports the toner contained in the developer containing chamber 31a to the developing chamber 31b. The toner transported to the developing chamber 31b is supplied to the developing roller 32 by a supply roller 33 which rotates in contact with the developing roller 32. The toner supplied to the developing roller 32 is regulated by the developing blade 34, and a toner layer is formed on the surface of the developing roller 32. The developing blade 34 functions as a layer thickness regulating member which regulates the thickness of the toner layer.

[0090] As shown in Figures 7 and 8, the drum unit 10 has a drum frame 11, a photosensitive drum 12 (image carrier), a charging roller 13, a cleaning blade 14, an intermediate transport member 15, an intermediate screw 16, a transmission shaft 17, and a return screw 18. The drum frame 11 supports the photosensitive drum 12, the charging roller 13, the cleaning blade 14, the intermediate transport member 15, the intermediate screw 16, the transmission shaft 17, and the return screw 18. The port 10 has a memory tag 90P, which will be described later.

[0091] The drum frame 11 includes a cleaning material recovery chamber 19. In the cleaning material recovery chamber 19, an intermediate conveying member 15, an intermediate screw 16, and a return screw 18 are arranged.

[0092] 8, the drum frame 11 is provided with a return path 45 that houses the return screw 18. The return path 45 can be said to be a part of the cleaning material recovery chamber 19.

[0093] The charging roller 13 is in contact with the photosensitive drum 12 and is rotated by the photosensitive drum 12. The cleaning blade 14 is in contact with the photosensitive drum 12 and collects toner remaining on the surface of the photosensitive drum 12. The collected toner (waste toner, residual toner, collected toner) is stored in a cleaning and collection chamber 19. The collected toner is transported by an intermediate transport member 15 toward an intermediate screw 16, which transports the collected toner toward a return screw 18. The intermediate transport member 15 transports the collected toner in a direction intersecting the axial direction LD. The intermediate screw 16 transports the collected toner along the axial direction LD.

[0094] The return screw (rotating member) 18 rotates around a rotation axis (second axis) RS shown in Fig. 6. The direction in which the rotation axis RS of the return screw 18 extends is called the rotation axis direction of the return screw 18 (second direction).

[0095] The rotational axis direction of the return screw 18 is a direction that intersects with the axial direction LD. It is preferable that the angle between the direction perpendicular to the axial direction LD and the rotational axis direction of the return screw 18 is smaller than the angle between the axial direction LD and the rotational axis direction of the return screw 18, and it is more preferable that the rotational axis direction of the return screw 18 is a direction that intersects with the axial direction LD at right angles.

[0096] 8, the drum frame 11 has a return opening 20. The return opening 20 communicates with the return path 45 of the cleaning and recovery chamber 19 and the outside of the drum frame 11, and faces the return screw 18. The recovered toner delivered from the intermediate screw 16 to the return screw 18 is transported by the return screw 18 toward the return opening 20, discharged from the return opening 20, and passed through a toner receiving port 84, which will be described later, to be received in the toner cartridge T.

[0097] In this way, the return screw 18 functions as a transport member that transports the toner recovered from the photosensitive drum 12 toward the toner receiving port 84. The direction in which the return screw 18 transports the recovered toner is from the process cartridge P toward the toner cartridge T, that is, the upward direction in the vertical direction.

[0098] The return screw 18 has a spiral fin 18b and a screw shaft 18c, and rotates around a rotation axis RS to transport the toner toward the return opening 20. The spiral fin 18b and the screw shaft 18c are integrally formed.

[0099] As shown in FIGS. 3 and 5, the process cartridge P has a process coupling 36 (first input portion, developing drive member) and a drum gear 21 (second input portion, drum drive member). When the process coupling 36 engages with the main body coupling of the apparatus main body 100A, a driving force (external force) is transmitted from the apparatus main body 100A to the process coupling 36. When the drum gear 21 engages with the main body gear of the apparatus main body 100A, a driving force (external force) is transmitted from the apparatus main body 100A to the drum gear 21, causing the drum gear 21 to rotate. When the drum gear 21 rotates, the photosensitive drum 12 is driven to rotate.

[0100] In this embodiment, the process coupling 36 and the drum gear 21 are disposed on the driving side of the process cartridge P. That is, in the axial direction LD, the process driving end 1 The distance between 11f1 and the process coupling 36 is shorter than the distance between the non-process drive end 11f2 and the process coupling 36. Similarly, in the axial direction LD, the distance between the process drive end 11f1 and the drum gear 21 is shorter than the distance between the non-process drive end 11f2 and the drum gear 21.

[0101] 9, the process cartridge P has an agitation gear 39 that drives the agitation unit 35, a development gear 40 that drives the development roller 32, and a supply gear 41 that drives the supply roller 33. The agitation gear 39, the development gear 40, and the supply gear 41 are connected to the process coupling 36 via a plurality of idler gears 42, and when the process coupling 36 rotates, the development roller 32, the supply roller 33, and the agitation unit 35 are driven to rotate.

[0102] The process cartridge P also has an intermediate conveying gear 24 that drives the intermediate conveying member 15, an intermediate screw gear 25 that drives the intermediate screw 16, and a shaft gear 26 that drives the transmission shaft 17. The intermediate conveying gear 24, the intermediate screw gear 25, and the shaft gear 26 are connected to a process coupling 36 via multiple idler gears 27, and when the process coupling 36 rotates, the intermediate conveying member 15, the intermediate screw 16, and the transmission shaft 17 rotate.

[0103] 8, the return path 45 and the return screw 18 are disposed on the non-drive side of the process cartridge P. That is, in the axial direction LD, the distance between the return screw 18 and the non-drive end 11f2 of the process cartridge is shorter than the distance between the return screw 18 and the drive end 11f1 of the process cartridge.

[0104] 10, the distance between the rotation axis RS and the non-drive end 11f2 of the return screw 18 in the axial direction LD is shorter than the distance between the rotation axis RS and the drive end 11f1. Also, the distance between the rotation axis RS and the non-drive end 11f2 in the axial direction LD is shorter than the distance between the rotation axis RS and the center 11f3 of the drum frame 11.

[0105] 8, a transmission gear 28 is attached to the transmission shaft 17, and a return gear 29 that meshes with the transmission gear 28 is attached to the return screw 18. The transmission gear 28 and the return gear 29 are bevel gears, and the rotation of the transmission shaft 17 causes the return screw 18 to rotate. In other words, the driving force transmitted to the process coupling 36 is transmitted by the transmission shaft 17 from the drive side of the process cartridge P to the non-drive side of the process cartridge P, and then transmitted to the return screw 18. In other words, the process coupling 36 is configured to drive the return screw 18.

[0106] As shown in FIG. 10, the transmission shaft 17 is disposed outside the cleaning material collection chamber 19 , and the transmission gear 28 and the return gear 29 mesh with each other outside the cleaning material collection chamber 19 .

[0107] As shown in Figures 4 and 6, the developing roller electrode 32a (developing roller contact), developing blade electrode 34a (developing blade contact), supply roller electrode 33a (supply roller contact), and charging roller electrode 13a (charging contact) are arranged on the non-driven side of the process cartridge P. In other words, the distance between the process non-driven end 11f2 and the charging roller electrode 13a is shorter than the distance between the process driven end 11f1 and the charging roller electrode 13a. Similarly, the distance between the process non-driven end 11f2 and the developing roller electrode 32a, developing blade electrode 34a, and supply roller electrode 33a is shorter than the distance between the process driven end 11f1 and the developing roller electrode 32a, developing blade electrode 34a, and supply roller electrode 33a.

[0108] The developing roller electrode 32a, the developing blade electrode 34a, the supply roller electrode 33a, and the charging roller electrode 13a are connected to the developing roller 32, the developing blade 34, the supply roller 33, and the charging roller 13. When an image forming operation is performed, a predetermined voltage is applied to the developing roller electrode 32a, the developing blade electrode 34a, the supply roller electrode 33a, and the charging roller electrode 13a from the power supply unit 170 of the apparatus main body 100A.

[0109] The material of each of the developing roller electrode 32a, the developing blade electrode 34a, the supply roller electrode 33a, and the charging roller electrode 13a may be metal or a resin having electrical conductivity.

[0110] In this embodiment, the directions of the rotation axes of the developing roller 32, supply roller 33, stirring unit 35, charging roller 13, intermediate conveying member 15, intermediate screw 16, and transmission shaft 17 are parallel to the axial direction LD. The directions of the rotation axes of each gear except for the process coupling 36, drum gear 21, and return gear 29 are also parallel to the axial direction LD.

[0111] <Detailed internal structure of the developing unit 30, which is a feature of the present invention> 1A and 1B, the shape of opening 201 of developing unit 30 according to the present invention will be described. Fig. 1A is a side cross-sectional view of the developing unit showing the shape of opening 201 at an end in the longitudinal direction, and Fig. 1B is a side cross-sectional view of the developing unit showing the shape of opening 201 at the center in the longitudinal direction.

[0112] 1A, in the cross-sectional view of the longitudinal end, the opening 201 is defined by a second end 201b located upstream in the rotation direction Q of the agitation unit 35 and a fourth end 201d located downstream in the rotation direction Q of the agitation unit 35. The second end 201b is the upstream opening end of the longitudinal end, and the fourth end 201d is the downstream opening end of the longitudinal end.

[0113] 1B, in a cross-sectional view of the center portion in the longitudinal direction, the opening 201 is defined by a first end 201a located upstream in the rotation direction Q of the agitation unit 35 and a third end 201c located downstream in the rotation direction Q of the agitation unit 35. The first end 201a is the upstream opening end in the center portion in the longitudinal direction, and the third end 201c is the downstream opening end in the center portion in the longitudinal direction.

[0114] The length of the sheet member 35a of the agitation unit 35 will be described. When the sheet member 35a is not bent, the distance from the center of the rotation axis of the agitation unit 35 to the free leading edge of the sheet is defined as the "free distance of the sheet." The distance from the rotation center of the agitation unit 35 to the first end 201a is defined as the "center-to-end distance at the center." The distance from the rotation center of the agitation unit 35 to the second end 201b is defined as the "center-to-end distance at the end." In this case, the "free distance of the sheet" is longer than the "center-to-end distance at the center" and the "center-to-end distance at the end." Therefore, the sheet member 35a of the agitation unit 35 bends and contacts the wall surface 201e near the opening 201 of the developer storage chamber 31a, stirring the developer in the developer storage chamber 31a and sending the developer into the developing chamber 31b.

[0115] Here, the contact portion of the supply roller 33 with the developing roller 32 is referred to as the contact portion 202. When the supply roller 33 is wedged into the developing roller 32 by a predetermined distance as shown in the cross-sectional view, the contact portion 202 may be located at the center of the wedged area, at an end portion, or at another predetermined position. In this case, the first end 201a of the opening 201 is located closer to the contact portion 202 of the supply roller 33 than the second end 201b of the opening 201. Specifically, the relationship is such that "distance L1 between the first end 201a and the contact portion 202" is smaller than "distance L2 between the second end 201b and the contact portion 202." In this case, distance L1 and distance L2 are not limited to the distance between the end and the contact portion 202, but may also be the distance between the end and the suction portion 202a or the distance between the end and the discharge portion 202b.

[0116] 1, distance L2 is measured by measuring the distance between a line passing through second end 201b and perpendicular to wall surface 201e and a line passing through contact portion 202 and perpendicular to wall surface 201e. Also, in FIG. 2, distance L1 is measured by measuring the distance between a line passing through first end 201a and perpendicular to wall surface 201e and a line passing through contact portion 202 and perpendicular to wall surface 201e. However, for example, instead of a line perpendicular to wall surface 201e, a line connecting second end 201b (or first end 201a) and the center of the rotation axis of stirring unit 35 may be used. Alternatively, the distance between second end 201b (or first end 201a) and contact portion 202 may be measured directly.

[0117] (additional configuration) In addition to the above configuration, in this embodiment, the first end 201a and the second end 201b are each positioned to be more effective. The following explanation will be given using the side cross-sectional views of the developing unit shown in Figures 18A and 18B. Figure 18A shows the shape of the opening 201 at both longitudinal ends, and Figure 18B shows the shape of the opening 201 at the longitudinal center.

[0118] 18A and 18B, a line connecting the center of the agitation shaft and the center of the supply roller is designated as L3. As shown in FIG. 18B, a first end 201a of the opening 201 is located downstream of L3 in the rotation direction Q of the agitation unit 35. On the other hand, as shown in FIG. 18A, a second end 201b of the opening 201 is located upstream of L3 in the rotation direction Q of the agitation unit 35.

[0119] The size of the opening 201 in this embodiment will be described with reference to Figure 20. Figure 20 is a view of the opening 201 as seen from the inside of the developer accommodating chamber 31a in the front direction. In this embodiment, as shown in Figure 20, the opening 201 has a relationship such that "distance L4 between the first end 201a and the third end 201c" is smaller than "distance L5 between the second end 201b and the fourth end 201d."

[0120] Here, the shape of the opening 201 may be a shape as shown in Figures 22A and 22B. Figures 22A and 22B show other shape examples of the opening 201, and are views of the opening 201 viewed from the front direction from inside the developer accommodating chamber 31a.

[0121] As shown in Fig. 22A, opening 201 may have a shape in which there is no partition in the longitudinal direction, or as shown in Fig. 22B, first end 201a and second end 201b of opening 201 may change continuously in the longitudinal direction. Furthermore, the shape of opening 201 is not limited to these examples as long as it satisfies the positional relationship described above.

[0122] <Description of Developer Circulation Inside the Development Unit 30> 19A and 19B, the circulation of developer inside developing unit 30 will be described below. FIG. 19A is a longitudinal cross-sectional view of developing unit 30. FIG. 19B is a longitudinal cross-sectional view showing the movement of developer in developing chamber 31b around supply roller 33 of developing unit 30 in the longitudinal direction.

[0123] As shown in FIG. 19A, the developer contained in the developer storage chamber 31a is subjected to its own weight in the direction of arrow Z, and therefore becomes more compacted as it approaches the developing chamber 31b. Also, the sheet member 35a of the stirring unit 35 rotates in the direction of arrow Q while being bent in contact with the wall surface portion 201e of the opening 201, and the developer in the developer storage chamber 31a is stirred inside the storage chamber and fed in the direction of arrow R. In particular, at the center in the longitudinal direction, there is a tendency for more developer to be sent from the developer storage chamber 31a to the developing chamber 31b than at the ends. In FIG. 19A, the tip of the sheet member 35a (the end not connected to the shaft) moves while contacting the opening 201 as it passes near the opening. However, the length of the sheet member 35a is such that it can stir the developer. The length of the sheet member 35a may be such that the tip does not come into contact with the opening 201 when passing near the opening.

[0124] Meanwhile, the developer in the developing chamber 31b is contained in the supply roller 33 through the suction portion 202a. The developer contained in the supply roller 33 is discharged from the discharge portion 202b, circulating the developer in the developing chamber 31b. This action of the supply roller 33 is called "breathing of the supply roller 33." In this embodiment, in order to illustrate the action of the supply roller 33 and the movement of the developer, the contact portion 202, the suction portion 202a, and the discharge portion 202b have been described separately. However, in reality, the positional relationship between each of these is not clearly distinguishable, and therefore, in describing the positional relationships and directions of action in this invention, these distinctions will not be used to limit the present invention.

[0125] 19B, the movement of the developer in the longitudinal direction of the supply roller in the developing chamber 31b will be described. Of the developer in the developing chamber 31b, the rotation of the supply roller 33 causes the developer that is not caught by the supply roller 33 near the suction portion 202a to be sent to the longitudinal end of the process cartridge (in the direction of the arrow S).

[0126] As explained above, developer circulates, and generally, it is desirable for developer circulation to occur smoothly. However, as the weight of developer in the developer storage chamber 31a increases, the lower portion of the developer storage chamber 31a in the direction of gravity becomes compacted, and the amount of developer sent to the developing chamber 31b increases. This effect tends to be particularly pronounced in the longitudinal center portion. As a result, the developer sent from the previous developer storage chamber 31a compacts the area near the discharge portion 202b in the developing chamber 31b, preventing the "supply roller from breathing." As a result, the amount of developer remaining near the suction portion 202a sent toward the longitudinal end of the process cartridge (in the direction of arrow S) increases as the supply roller 33 rotates.

[0127] As a result, at the longitudinal end portions of the developing chamber 31b, the developer circulates less and becomes compacted, which may result in poor image quality due to toner deterioration.

[0128] <Effects of the present invention> Considering the circulation of the developer described above, by making the relationship of distance L1<distance L2 as shown in FIGS. 1A and 1B, the amount of developer transported from developer storage chamber 31a to developing chamber 31b in the longitudinal center can be reduced. As a result, the amount of developer remaining near suction portion 202a of supply roller 33 in developing chamber 31b can be optimized. Therefore, the amount of developer transported to the longitudinal end of supply roller 33 in developing chamber 31b (in the direction of arrow S (see FIGS. 19A and 19B)) by rotation of supply roller 33 can be reduced.

[0129] 18B, the position of the first end 201a is located downstream of the line L3 in the rotation direction at the longitudinal center portion. This allows the direction in which the developer transport force F1 of the sheet member 35a of the agitating unit 35 acts to be shifted from the direction toward the discharge portion 202b at the longitudinal center portion. This makes it possible to more effectively reduce the amount of developer transported from the developer storage chamber 31a to the developing chamber 31b by the transport force of the agitating unit 35 at the longitudinal center portion of the supply roller.

[0130] On the other hand, as shown in FIG. 18A, at both longitudinal ends, the second end 201b is positioned upstream of the line L3 in the rotation direction. This allows the direction in which the conveying force F2 of the leading end 35b of the bent sheet member 35a acts to be directed toward the discharge portion 202b of the supply roller. Furthermore, the leading end 35b of the sheet member 35a can enter the developing chamber 31b. As a result, the developing chamber 31b at both longitudinal ends is effectively developed. The imaging agent can be circulated.

[0131] 20, by setting the size of the opening 201 so that distance L4 is smaller than distance L5, the amount of developer transported from the developer storage chamber 31a to the developing chamber 31b can be reduced in the longitudinal center portion, where a large amount of developer tends to be transported. This allows for optimization of the circulation of the entire developing unit.

[0132] As described above, by adopting the configuration of this embodiment, it is possible to optimize the circulation balance of the developer in the developing unit, and to provide a developing unit that does not cause image defects due to developer leakage or poor circulation.

[0133] The present invention is not limited to the aforementioned supply configuration consisting of a process cartridge and a toner cartridge. Similar effects can be expected from an all-in-one cartridge in which a process cartridge and a toner cartridge are integrated, as shown in Figures 21A and 21B. Figures 21A and 21B are cross-sectional views showing the shape of the opening 201 of an all-in-one cartridge configuration incorporating a configuration similar to this embodiment, in which a large volume of developer is filled in the developer storage chamber 31a. Even with this all-in-one configuration, the effect of optimizing developer circulation can be obtained.

[0134] As described above, the configuration described in this specification allows proper circulation of developer even when the weight of developer increases in a development unit configuration in which a developer storage chamber having an agitator unit is installed above the development chamber in the direction of gravity. Specifically, the opening connecting the developer storage chamber and the development chamber is shaped so that the longitudinal ends allow developer to pass through more easily than the central portion. By changing the position and shape of the opening between the longitudinal ends and the central portion, proper circulation of developer can be achieved. Typically, as shown in Figures 20, 22A, and 22B, the longitudinal ends are configured to have a wider opening than the central portion. However, the shape of the opening may be such that the longitudinal ends allow developer to pass through more easily than the central portion. For example, it may be sufficient if some of the ends have a wider opening than the central portion.

[0135] [Configuration 1] a developer carrier that carries a developer; a supply member that contacts the developer carrier to form a contact portion and supplies the developer to the surface of the developer carrier at the contact portion; a developing chamber in which the developer carrier and the supply member are disposed; a developer storage chamber that stores the developer; an agitating member having a shaft and a sheet member held by the shaft, the sheet member agitating the developer contained in the developer containing chamber as the shaft rotates; A developing device comprising: the developer storage chamber is disposed above the developing chamber in a direction of gravity when the developing device is attached to the image forming apparatus; the developer carrier, the supply member, and the stirring member are each rotatable about a rotation axis extending along a longitudinal direction of the developing device; an opening that allows the developer to move from the developer storage chamber to the developing chamber is provided along the longitudinal direction in a wall portion that separates the developer storage chamber from the developing chamber; In the cross section in the longitudinal direction, the opening has an upstream end and a downstream end in a direction in which the sheet member passes in response to rotation of the agitating member, and when the upstream end in the center of the longitudinal direction is defined as a first end and the upstream end in the longitudinal direction is defined as a second end, the distance between the first end and a contact portion of the developer carrier and the supply member is shorter than the distance between the second end and the contact portion. A developing device characterized by: [Configuration 2] In the cross section in the longitudinal direction, the first end is located downstream of a line connecting a rotation center of the shaft and a rotation center of the supply member in a rotation direction of the stirring member, The second end is located upstream of a line connecting the rotation center of the shaft and the rotation center of the supply member in the rotation direction of the agitating member. 2. The developing device according to claim 1, [Configuration 3] the sheet member of the stirring member is flexible, When the sheet member is not deflected, the distance from the rotation center of the shaft to the free tip end of the sheet member is longer than the distance from the rotation center to the wall surface portion, The sheet member rotates while contacting the wall surface portion. 3. The developing device according to configuration 1 or 2. [Configuration 4] The sheet member can enter the opening at the end portions in the longitudinal direction, but cannot enter the opening at the center portion in the longitudinal direction. 4. The developing device according to configuration 3. [Configuration 5] In the cross section in the longitudinal direction, when the downstream end of the opening in the central portion in the longitudinal direction is defined as a third end, and the downstream end of the end in the longitudinal direction is defined as a fourth end, the distance from the first end to the third end in the central portion in the longitudinal direction is shorter than the distance from the second end to the fourth end at the end in the longitudinal direction. 5. The developing device according to any one of configurations 1 to 4. [Configuration 6] a developer carrier that carries a developer; a supply member that contacts the developer carrier to form a contact portion and supplies the developer to the surface of the developer carrier at the contact portion; a developing chamber in which the developer carrier and the supply member are disposed; a developer storage chamber that stores the developer; an agitating member having a shaft and a sheet member held by the shaft, the sheet member agitating the developer contained in the developer containing chamber as the shaft rotates; an image carrier on which an electrostatic latent image formed on a surface thereof is developed when the developer is supplied from the developer carrier; An image forming apparatus comprising: the developer storage chamber is disposed above the developing chamber in the direction of gravity, the developer carrier, the supply member, and the stirring member are each rotatable about a rotation axis extending along a longitudinal direction; an opening that allows the developer to move from the developer storage chamber to the developing chamber is provided along the longitudinal direction in a wall portion that separates the developer storage chamber from the developing chamber; In the cross section in the longitudinal direction, the opening has an upstream end and a downstream end in a direction in which the sheet member passes in response to rotation of the agitating member, and when the upstream end in the center of the longitudinal direction is defined as a first end and the upstream end in the longitudinal direction is defined as a second end, the distance between the first end and a contact portion of the developer carrier and the supply member is shorter than the distance between the second end and the contact portion. An image forming apparatus characterized by: [Configuration 7] a developer carrier that carries a developer; a supply member that contacts the developer carrier to form a contact portion and supplies the developer to the surface of the developer carrier at the contact portion; a developing chamber in which the developer carrier and the supply member are disposed; a developer storage chamber that stores the developer; an agitating member having a shaft and a sheet member held by the shaft, the sheet member agitating the developer contained in the developer containing chamber as the shaft rotates; A developing device comprising: the developer storage chamber is disposed above the developing chamber in a direction of gravity when the developing device is attached to the image forming apparatus; the developer carrier, the supply member, and the stirring member are each rotatable about a rotation axis extending along a longitudinal direction of the developing device; an opening that allows the developer to move from the developer storage chamber to the developing chamber is provided along the longitudinal direction in a wall portion that separates the developer storage chamber from the developing chamber; In the cross section in the longitudinal direction, the opening has an upstream end and a downstream end in a direction in which the sheet member passes in response to the rotation of the agitating member, and the width of the upstream end and the downstream end at the center in the longitudinal direction is narrower than the width of the upstream end and the downstream end at the ends in the longitudinal direction. A developing device characterized by: [Explanation of symbols]

[0136] 31a: developer storage chamber, 31b: development chamber, 32: development roller, 33: supply roller, 35: stirring unit, 35a: sheet member, 35c: shaft member, 201: opening, 201a: first end, 201b: second end, 201e: wall portion, 202: contact portion

Claims

1. a developer carrier that carries a developer; a supply member that contacts the developer carrier to form a contact portion and supplies the developer to the surface of the developer carrier at the contact portion; a developing chamber in which the developer carrier and the supply member are disposed; a developer storage chamber that stores the developer; an agitating member having a shaft and a sheet member held by the shaft, the sheet member agitating the developer contained in the developer containing chamber as the shaft rotates; A developing device comprising: the developer storage chamber is disposed above the developing chamber in a direction of gravity when the developing device is attached to the image forming apparatus; the developer carrier, the supply member, and the stirring member are each rotatable about a rotation axis extending along a longitudinal direction of the developing device; an opening that allows the developer to move from the developer storage chamber to the developing chamber is provided along the longitudinal direction in a wall portion that separates the developer storage chamber from the developing chamber; In the cross section in the longitudinal direction, the opening has an upstream end and a downstream end in a direction in which the sheet member passes in response to rotation of the stirring member, and when the upstream end in the center of the longitudinal direction is defined as a first end and the upstream end in the longitudinal direction is defined as a second end, the distance between the first end and a contact portion of the developer carrier and the supply member is shorter than the distance between the second end and the contact portion. A developing device characterized by:

2. In the cross section in the longitudinal direction, the first end is located downstream of a line connecting a rotation center of the shaft and a rotation center of the supply member in a rotation direction of the stirring member, The second end is located upstream of a line connecting the rotation center of the shaft and the rotation center of the supply member in the rotation direction of the agitating member.

2. The developing device according to claim 1.

3. the sheet member of the stirring member is flexible, When the sheet member is not deflected, the distance from the rotation center of the shaft to the free tip end of the sheet member is longer than the distance from the rotation center to the wall surface portion, The sheet member rotates while contacting the wall surface portion.

3. The developing device according to claim 1, wherein the developing device is a developing unit.

4. The sheet member can enter the opening at the end portions in the longitudinal direction, but cannot enter the opening at the center portion in the longitudinal direction.

4. The developing device according to claim 3.

5. In the cross section in the longitudinal direction, when the downstream end of the opening in the central portion in the longitudinal direction is defined as a third end and the downstream end of the end in the longitudinal direction is defined as a fourth end, the distance from the first end to the third end in the central portion in the longitudinal direction is shorter than the distance from the second end to the fourth end at the end in the longitudinal direction.

3. The developing device according to claim 1, wherein the developing device is a developing unit.

6. a developer carrier that carries a developer; a supply member that contacts the developer carrier to form a contact portion and supplies the developer to the surface of the developer carrier at the contact portion; a developing chamber in which the developer carrier and the supply member are disposed; a developer storage chamber that stores the developer; an agitating member having a shaft and a sheet member held by the shaft, the sheet member agitating the developer contained in the developer containing chamber as the shaft rotates; an image carrier on which an electrostatic latent image formed on a surface thereof is developed when the developer is supplied from the developer carrier; An image forming apparatus comprising: the developer storage chamber is disposed above the developing chamber in the direction of gravity, the developer carrier, the supply member, and the stirring member are each rotatable about a rotation axis extending along a longitudinal direction; an opening that allows the developer to move from the developer storage chamber to the developing chamber is provided along the longitudinal direction in a wall portion that separates the developer storage chamber from the developing chamber; In the cross section in the longitudinal direction, the opening has an upstream end and a downstream end in a direction in which the sheet member passes in response to rotation of the stirring member, and when the upstream end in the center of the longitudinal direction is defined as a first end and the upstream end in the longitudinal direction is defined as a second end, the distance between the first end and a contact portion of the developer carrier and the supply member is shorter than the distance between the second end and the contact portion. An image forming apparatus characterized by:

7. a developer carrier that carries a developer; a supply member that contacts the developer carrier to form a contact portion and supplies the developer to the surface of the developer carrier at the contact portion; a developing chamber in which the developer carrier and the supply member are disposed; a developer storage chamber that stores the developer; an agitating member having a shaft and a sheet member held by the shaft, the sheet member agitating the developer contained in the developer containing chamber as the shaft rotates; A developing device comprising: the developer storage chamber is disposed above the developing chamber in a direction of gravity when the developing device is attached to the image forming apparatus; the developer carrier, the supply member, and the stirring member are each rotatable about a rotation axis extending along a longitudinal direction of the developing device; an opening that allows the developer to move from the developer storage chamber to the developing chamber is provided along the longitudinal direction in a wall portion that separates the developer storage chamber from the developing chamber; In the cross section in the longitudinal direction, the opening has an upstream end and a downstream end in a direction in which the sheet member passes in response to the rotation of the agitating member, and the width of the upstream end and the downstream end at the center in the longitudinal direction is narrower than the width of the upstream end and the downstream end at the ends in the longitudinal direction. A developing device characterized by:

Images