Process cartridge

Abstract

This technology provides an increase in the capacity of the space that houses toner in a process cartridge. [Solution] The developing unit 270, which is detachable from the photoreceptor unit 260, includes a developing roller 71 that supplies toner to the photoreceptor drum 61 and collects toner remaining on the surface of the photoreceptor drum 61, a housing 250 having a storage space for storing toner, and a pressure receiving portion that receives the pressing force from the pressing member 200. In its orientation for use, the housing 250 has an arc-shaped first bottom portion that protrudes outward from the storage space, and an arc-shaped second bottom portion that protrudes outward from the storage space. When viewed from a direction along the rotation axis of the developing roller 71, at least a part of the pressure receiving portion is arranged in the space enclosed by the outer wall of the first bottom portion and the tangent line that contacts the outer wall of the second bottom portion, the first bottom portion, and the second bottom portion.

Description

Technical Field

[0001] The present invention relates to a cartridge such as a photoreceptor unit or a developing unit that can be attached to or detached from an image forming apparatus using an electrophotographic method.

Background Art

[0002] In a laser beam printer or a copying machine as an electrophotographic image forming apparatus, a toner image is formed on a photoreceptor drum, and this toner image is transferred onto a sheet as a recording material to form an image on the recording material. In a laser beam printer, a method is widely adopted in which some parts of the image forming apparatus are provided in a cartridge to facilitate maintenance, the cartridge is taken out of the apparatus main body, and maintenance and replacement are performed. Patent Document 1 discloses a process cartridge in which a developing unit for accommodating toner is detachable from a photoreceptor unit having a photoreceptor drum.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a process cartridge having a structure in which a developing unit for accommodating toner is detachable from a photoreceptor unit having a photoreceptor drum, there remains room for further improvement in terms of size, cost, accuracy, usability, lifespan, etc.

[0005] One object of the present invention is to provide a technology capable of increasing the capacity of the space for accommodating toner in a process cartridge.

Means for Solving the Problems

[0006] To achieve the above objective, a process cartridge according to one embodiment of the present invention comprises a photoreceptor unit and a developing unit that is detachable from the photoreceptor unit, The aforementioned photoreceptor unit is A photoreceptor drum in which an electrostatic latent image is formed, A frame that supports the photosensitive drum, It has a pressing member that presses the developing unit toward the photoreceptor unit, The aforementioned developing unit is A developing roller that supplies toner to the photoreceptor drum and collects toner remaining on the surface of the photoreceptor drum, A housing having a storage space for storing toner, It has a pressing receiving portion that receives the pressing force from the pressing member, The aforementioned enclosure is In its orientation during use, it has a first arc-shaped bottom that protrudes outward from the storage space, and a second arc-shaped bottom that protrudes outward from the storage space. When viewed from a direction along the rotation axis of the developing roller, at least a portion of the pressing receiving portion is configured to be located in the space enclosed by the tangent line that contacts the outer wall of the first bottom and the outer wall of the second bottom, the first bottom, and the second bottom. It is characterized by the following:

[0007] To achieve the above objective, the process cartridge according to one embodiment of the present invention includes a photoreceptor The system comprises a unit and a developing unit that is detachable from the photoreceptor unit, The aforementioned photoreceptor unit is A photoreceptor drum in which an electrostatic latent image is formed, A frame that supports the photosensitive drum, It has a pressing member that presses the developing unit toward the photoreceptor unit, The aforementioned developing unit is A developing roller that supplies toner to the photoreceptor drum and collects toner remaining on the surface of the photoreceptor drum, A housing having a storage space for storing toner, It has a pressing receiving portion that receives the pressing force from the pressing member, The aforementioned enclosure is In the position used, the first bottom portion is arc-shaped and protrudes outward from the storage space, A second arc-shaped bottom portion that protrudes outward from the aforementioned storage space, The first top surface and, A second top surface is provided above the first top surface in the direction of gravity, It has a connecting portion that connects the first top surface and the second top surface, The connecting portion is characterized by having an opposing surface that faces the first top surface.

[0008] To achieve the above objective, a process cartridge according to one embodiment of the present invention comprises a photoreceptor unit and a developing unit that is detachable from the photoreceptor unit, The aforementioned photoreceptor unit is A photoreceptor drum in which an electrostatic latent image is formed, It has a frame that supports the photosensitive drum, The aforementioned developing unit is A developing roller that supplies toner to the photoreceptor drum and collects toner remaining on the surface of the photoreceptor drum, A housing having a storage space for storing toner, A first transport member that transports toner toward the developing roller, The device comprises a second transport member that transports toner toward the first transport member, The aforementioned enclosure is In the position used, the first bottom portion is arc-shaped and protrudes outward from the storage space, It has an arc-shaped second bottom portion that protrudes outward from the aforementioned storage space, The first transport member is, It is positioned above the first bottom and has a rotating shaft and a stirring blade inclined with respect to the axis of the rotating shaft, The second transport member is, It is disposed above the second bottom portion and has a stirring sheet provided with a rotation axis and a slit.

[0009] To achieve the above object, a process cartridge according to an embodiment of the present invention includes a photoreceptor unit and a developing unit detachable from the photoreceptor unit. The photoreceptor unit has a photoreceptor drum on which an electrostatic latent image is formed, and a frame that supports the photoreceptor drum. The developing unit has a developing roller that supplies toner to the photoreceptor drum and recovers the toner remaining on the surface of the photoreceptor drum, a housing in which a storage space for storing toner is formed, a first conveying member that conveys the toner in the storage space toward the developing roller, a second conveying member that conveys the toner in the storage space toward the first conveying member, and a third conveying member that conveys the toner in the storage space toward the second conveying member. The housing has a first bottom portion that protrudes outward from the storage space in an arc shape in the posture during use, a second bottom portion that protrudes outward from the storage space in an arc shape, and a third bottom portion that protrudes outward from the storage space in an arc shape. The first conveying member is disposed above the first bottom portion. The second conveying member is disposed above the second bottom portion. The third conveying member is disposed above the third bottom portion. It is characterized by this.

[0010] To achieve the above object, a process cartridge according to an embodiment of the present invention includes a photoreceptor unit and a developing unit detachable from the photoreceptor unit. The photoreceptor unit [[ID=No.]]has a photoreceptor drum on which an electrostatic latent image is formed, It has a frame that supports the photosensitive drum, The aforementioned developing unit is A developing roller that supplies toner to the photoreceptor drum and collects toner remaining on the surface of the photoreceptor drum, A housing having a storage space for storing toner, A rotatable first transport member that transports the toner in the storage space toward the developing roller, A rotatable second transport member that transports the toner in the storage space toward the first transport member, It has a third transport member that transports the toner in the storage space toward the second transport member, The aforementioned enclosure is In the position used, the first bottom portion is arc-shaped and protrudes outward from the storage space, A second arc-shaped bottom portion that protrudes outward from the aforementioned storage space, It has an arc-shaped third bottom portion that protrudes outward from the aforementioned storage space, The first transport member is positioned above the first bottom, The second transport member is positioned above the second bottom portion. The third transport member is positioned above the third bottom, When viewed from a direction along the rotation axis of the first transport member, in the direction in which a straight line passing through the rotation center of the first transport member and the rotation center of the second transport member extends, at least a portion of the third bottom extends in a direction away from the photoreceptor drum than the end on the opposite side of the photoreceptor unit from the side in which the photoreceptor drum is located. It is characterized by the following: [Effects of the Invention]

[0011] According to the present invention, the capacity of the space for storing toner in a process cartridge can be increased. [Brief explanation of the drawing]

[0012] [Figure 1]Cross-sectional view of an image forming apparatus equipped with a process cartridge. [Figure 2] Cross-sectional view of the developing unit [Figure 3] Perspective view of the developing unit [Figure 4] Deconstructed perspective view of the developing unit [Figure 5] Cross-section of a process cartridge [Figure 6] Top view of the developing unit [Figure 7] Perspective view of the process cartridge [Figure 8] Diagram illustrating the detection component. [Figure 9] Perspective view of the developing unit [Figure 10] Perspective view of the process cartridge [Figure 11] Partial perspective view of the photoreceptor unit [Figure 12] Perspective view of the developing unit and photoreceptor unit. [Figure 13] Top view of the developing unit and photoreceptor unit. [Figure 14] Perspective view of the process cartridge [Figure 15] Partial perspective view of the developing unit and lift member. [Figure 16] Diagram showing the positional relationship between the lifting member and the pressing member. [Figure 17] Diagram showing the detachment of the developing unit. [Figure 18] Cross-sectional view of the process cartridge according to Example 1 [Figure 19] Cross-sectional view of the process cartridge according to Example 2 [Figure 20] Top view of the process cartridge according to Example 3 [Figure 21] Top view of the process cartridge according to Example 4 [Figure 22] Cross-sectional view of the process cartridge according to Example 4 [Figure 23] Examples of possible shapes for notches on the stirring sheet according to Example 4 [Figure 24] Examples of possible shapes for holes on the stirring sheet according to Example 4 [Figure 25] Cross-sectional view of the process cartridge according to Example 4 [Figure 26] Explanatory diagram of an image forming apparatus equipped with a process cartridge according to Example 6 [Figure 27] Explanatory diagram of an image forming apparatus equipped with a process cartridge according to Example 6 [Figure 28] Cross-sectional view of the process cartridge according to Example 6 [Figure 29] Cross-sectional view of the process cartridge according to Example 6 [Figure 30] Perspective view of the process cartridge according to Example 6 [Figure 31] Cross-sectional view of the process cartridge according to Example 6 [Figure 32] Cross-sectional view of the process cartridge according to Example 5 [Figure 33] Cross-sectional view of the process cartridge according to Example 5 [Figure 34] Top view of the process cartridge according to Example 5 [Modes for carrying out the invention]

[0013] The embodiments for carrying out this invention will be described in detail below with reference to the drawings, based on examples. However, the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments should be appropriately modified depending on the configuration of the device to which the invention is applied and various conditions. In other words, the scope of this invention is not intended to be limited to the following embodiments.

[0014] First, an image forming apparatus and process cartridge according to one embodiment of the present invention will be described in detail with reference to the drawings as appropriate. Figure 1 is a cross-sectional view of an image forming apparatus 1 equipped with a process cartridge 5.

[0015] In the following description, directions are defined from the perspective of the user operating the image forming apparatus 1. Specifically, the front side of the image forming apparatus 1 is defined as "front," the back side as "rear," the top side as "up," and the bottom side as "down." Furthermore, when viewing the image forming apparatus 1 from the front, the left side is defined as "left," and the right side as "right." The orientation of the image forming apparatus 1 shown in each figure represents its orientation during use. Similarly, the orientation of the process cartridge 5 is defined as being in the same orientation as when mounted on the image forming apparatus 1. Each direction in each drawing is defined by the arrow indicated in the drawing. The front-to-back, up-and-down, and left-to-right directions indicated by these arrows are mutually orthogonal. These directions are shown in the same way in all drawings. The up-and-down direction is parallel to the vertical direction, and the left-to-right and front-to-back directions are parallel to the horizontal direction. The left-to-right direction is the rotation axis direction of the photoreceptor drum 61, and the development direction is parallel to the horizontal direction. The directions of rotation of the rollers 71 are parallel to each other. The integrated development unit 7 mounted on the photoreceptor unit 6 is called the process cartridge 5. This process cartridge 5 is inserted into the main body 2 in the direction of arrow S1 in the diagram (mounting direction) and removed in the direction of arrow S2 in the diagram.

[0016] <Overall configuration of the image forming apparatus> As shown in Figure 1, the image forming apparatus 1 mainly comprises a paper feeding unit 3 for supplying paper S into the apparatus body 2, an exposure apparatus 4, a process cartridge 5 for transferring a toner image onto the paper S, and a fixing apparatus 8 for thermally fixing the toner image transferred onto the paper S. The paper feeding unit 3 is located in the lower part of the apparatus body 2 and mainly comprises a paper feeding tray 31 and a paper feeding mechanism 32. The paper S contained in the paper feeding tray 31 is supplied by the paper feeding mechanism 32 toward the process cartridge 5 (between the photoreceptor drum 61 and the transfer roller 63). The exposure apparatus 4 is located in the upper part of the apparatus body 2 and includes a laser light-emitting unit (not shown), a polygon mirror (with its symbol omitted), a lens, a reflector, etc. In this exposure apparatus 4, laser light based on image data emitted from the laser light-emitting unit is scanned at high speed across the surface of the photoreceptor drum 61, thereby exposing the surface of the photoreceptor drum 61.

[0017] The process cartridge 5 is located below the exposure apparatus 4. It is inserted in the insertion direction S1 into the housing 23 of the apparatus body 2 through the opening created when the door (opening / closing member) 21 on the apparatus body 2 is opened (indicated by a dashed line in Figure 1), and is mounted on the apparatus body 2. To remove the process cartridge 5 from the apparatus body 2, it is moved in the removal direction S2 and removed. This process cartridge 5 mainly consists of a photoreceptor unit 6 and a developer unit 7. The photoreceptor unit 6 mainly consists of a photoreceptor drum 61, a charging device 62, and a transfer roller 63. The developer unit 7 is detachably mounted to the photoreceptor unit 6. The developing unit 7 mainly comprises a developing roller 71, a supply roller 72, a layer thickness regulating blade 73, a toner storage section (developer storage section) 74 for storing toner (developer), and a first agitator 75A and a second agitator 75B provided within the toner storage section 74.

[0018] <Image Formation Process> Next, the image formation process using this process cartridge 5 will be described. The photoreceptor drum 61 is rotated during the execution of the image formation process. First, the surface of the photoreceptor drum 61 is uniformly charged by the charging device 62, and then it is exposed to laser light corresponding to the image data emitted from the exposure device 4, thereby forming an electrostatic latent image corresponding to the image data on the photoreceptor drum 61.

[0019] Meanwhile, the toner in the toner storage section 74 is agitated by the second agitator 75B and the first agitator 75A, and then supplied to the developing roller 71 via the supply roller 72. The toner supplied to the developing roller 71 enters between the developing roller 71 and the layer thickness regulating blade 73 and is supported on the developing roller 71 as a thin layer of a certain thickness. The toner supported on the developing roller 71 is supplied to the electrostatic latent image formed on the photoreceptor drum 61. As a result, the toner adheres to the electrostatic latent image and becomes a visible image, forming a toner image on the photoreceptor drum 61. Subsequently, the paper S is transported between the photoreceptor drum 61 and the transfer roller 63, and the toner image on the photoreceptor drum 61 is transferred to the paper S. At this time, any remaining toner on the photoreceptor drum 61 is collected by the developing roller 71 and returned to the developing unit 7.

[0020] The fuser unit 8 is located behind the process cartridge 5 and mainly comprises a heating roller 92 and a pressure roller 91. The paper S onto which the toner image has been transferred passes through this fuser unit 8, during which time the paper S is heated and pressurized between the heating roller 92 and the pressure roller 91, fixing the toner image onto the paper S. The paper S that has passed through the fuser unit 8 is discharged onto the output tray 22. It will be done.

[0021] <Process Cartridge Configuration> Next, we will describe each unit of the process cartridge 5. As mentioned above, the process cartridge 5 includes a photoreceptor unit 6 and a developer unit 7 that can be attached to or detached from the photoreceptor unit 6.

[0022] <Developing Unit Configuration> First, the configuration of the developing unit 7 will be explained. Figure 2 is a cross-sectional view of the developing unit 7, which is the AA cross-sectional view in Figure 3. Figure 3 is a perspective view of the developing unit 7 seen from above, and Figure 7 is a perspective view of the process cartridge 5 seen from above. Figure 4 is an exploded perspective view of the developing unit 7. Figure 5 is a cross-sectional view of the developing unit 7 mounted on the photoreceptor unit 6, and its cross-section is parallel in the vertical and front-to-back directions. Figure 6 is a top view of the developing unit 7, showing the top surface of the housing 700 and the side holder 719 removed for explanatory purposes.

[0023] As shown in Figure 2, the developing unit 7 has a gripping portion 701 at the front of the housing 700, which serves as the developing frame, for the user to grasp, and a developing roller 71 is rotatably supported at the rear. Hereafter, the configuration of the developing unit 7 will be described with reference to the direction of the rotation axis of the developing roller 71 being referred to as the axial direction.

[0024] As shown in Figures 4 and 6, the developing roller 71, the supply roller 72, the first agitator (first stirring member) 75A, and the second agitator (second stirring member) 75B are rotatably supported at both ends by the left wall 704 and the right wall 705 of the housing 700, respectively. To the left of the left wall 704 of the housing 700 are the developing coupling 710, the developing roller gear 711, the supply roller gear 712, the first agitator gear 713, the second agitator gear 714, and the idler gears 715A, 715B, and 715C. The developing roller gear 711 is fixed to the end of the developing roller 71, and the supply roller gear 712 is fixed to the end of the supply roller 72. Furthermore, the first agitator gear 713 is fixed to the end of the stirring rod 78A (see Figure 5) of the first agitator 75A, and the second agitator gear 714 is fixed to the end of the stirring rod 78B (see Figure 5) of the second agitator 75B.

[0025] As shown in Figure 3, the developing unit 7 is provided with a first electrical contact 720A that is electrically connected to the developing roller 71 and supplies the voltage applied to the developing roller 71, and a second contact 720B that is electrically connected to the supply roller 72 and supplies the voltage applied to the supply roller 72. These electrical contacts come into contact with a power supply contact (not shown) provided on the main body of the device 2, thereby supplying power to the developing roller 71 and the supply roller 72.

[0026] In conjunction with the closing of the door 21 provided on the main body 2 of the device, a developing drive transmission member (not shown) provided on the main body 2 of the device moves to a position for engaging with the developing coupling 710. Conversely, in conjunction with the opening of the door 21 of the device, the developing drive transmission member moves to a position for disengaging from the developing coupling 710.

[0027] After the door 21 is closed, when the main unit 2 of the device is operated, driving force is transmitted (input) from the developing drive transmission member to the developing coupling 710, which acts as a driving force receiving member. This driving force allows the developing roller 71 to rotate via the developing roller gear 711 and the supply roller 72 via the supply roller gear 712, from the gears provided on the circumferential surface of the developing coupling 710. The developing drive transmission member is configured to transmit driving force to the developing coupling 710 while allowing a positional displacement of the developing coupling 710 within a predetermined range. The developing coupling 710, the developing roller gear 711, and the supply roller gear 712 are restricted from axial movement by side holders 719 attached to the housing 700.

[0028] The developing unit 7 employs two agitators, a first agitator 75A and a second agitator 75B, to agitate the toner in the toner storage section 74. The first agitator 75A includes an agitator rod 78A and an agitator sheet 79A. The first agitator 75A is configured to be rotatable by receiving driving force from the first agitator gear 713 via an idler gear 715A from the developing coupling 710. The second agitator 75B includes an agitator rod 78B and an agitator sheet 79B. The second agitator 75B is configured to be rotatable by receiving driving force from the second agitator gear 714 via idler gears 715B and 715C from the first agitator gear 713.

[0029] The second agitator 75B supplies toner from the toner storage section 74 to the first agitator 75A. Toner near the first agitator 75A in the toner storage section 74 is agitated by the first agitator 75A, then supplied to the supply roller 72, and further supplied to the developing roller 71 by the supply roller 72.

[0030] Furthermore, as shown in Figures 4 and 7, a detection unit 80 is provided at the left end of the developing unit 7. The detection unit 80 is equipped so that the state of a detection member 81 located inside it can be detected by a detection mechanism (not shown) provided in the main body of the device 2. Based on the state of this detection member 81, it is possible to determine whether the developing unit 7 is unused or has already been used.

[0031] The operation of the detection member 81 will be explained using Figures 8(a) and 8(b). Figures 8(a) and 8(b) are views of the developing unit 7 from the left side. For illustrative purposes, the side holder 719 has been removed from the view. As shown in Figure 8(a), the detection member 81 is provided with a detection projection 83 and a detection gear 82. As shown in the figure, the detection gear 82 is a gear with missing teeth. The detection member 81 receives driving force from the second agitator gear 714 to the detection gear 82.

[0032] Figure 8(a) shows the developing unit 7 in an unused state. The detection projection 83 is located on the upper front side of the detection member 81. The detection gear 82 is meshed with the second agitator gear 714. When the developing unit 7 is used, the developing coupling 710 receives a driving force from the developing drive transmission member of the device body 2, causing the second agitator gear 714 to rotate in the direction of arrow R3 in the figure. At this time, since the detection gear 82 is meshed with the second agitator gear 714, the detection member 81 rotates in the direction of arrow R4 in the figure.

[0033] Figure 8(b) shows the state after the detection member 81 has rotated. Since the detection gear 82 is a gear with missing teeth, the detection member 81 rotates in the direction of arrow R4 in the figure, and when there are no gear teeth left to mesh with the second agitator gear 714, the detection member 81 stops rotating. At this time, the detection projection 83 is located on the upper rear side of the detection member 81. By detecting the position of the detection projection 83 of the detection member 81 with a detection mechanism (not shown) provided on the main body of the device 2, it is possible to determine whether the developing unit 7 is unused or has already been used.

[0034] Figure 9 is a perspective view of the developing unit 7 from below. As shown in the figure, the bottom surface of the developing unit 7 is provided with a memory 85 and a positioning projection 86. The memory 85 is provided with a memory chip (not shown) that stores information about the developing unit 7 and a memory electrode 85A that is electrically connected to the memory chip. The memory electrode 85A is in contact with an electrode (not shown) provided on the main body of the device 2, and communicates between the memory chip and the main body of the device 2.

[0035] <Configuration of the photoreceptor unit and support for the developing unit> Next, the detailed configuration of the photoconductor unit 6 will be described. Figure 10 is a perspective view of the process cartridge 5. Figure 11(a) is a partial perspective view of the photoconductor unit 6, and Figure 11(b) is Figure 11(a) is a cross-sectional view of BB. Figure 12 is a perspective view of the developing unit 7 and the photoreceptor unit 6. Figure 13 is a top view showing the left-right arrangement of the photoreceptor unit 6, the developing unit 7, and the developing roller 71. Figure 14(a) is a perspective view of the process cartridge 5 seen from below, and Figure 14(b) is a perspective view of the axial positioning section of the photoreceptor drum 61 of the developing unit 7 and the photoreceptor unit 6. In Figure 14(b), for illustrative purposes, only the positioning projection 86 and the memory 85 of the developing unit 7 are shown.

[0036] As shown in Figure 10, the photoreceptor unit 6 mainly comprises a frame 610 having a pair of left-side walls 611 and a right-side wall 612, and a photoreceptor drum 61 rotatably supported at the rear of the frame 610. At the front of the frame 610 are a mounting section 615 (see Figure 12) on which the developing unit 7 can be mounted, a gripping section 617 for the user to grasp the photoreceptor unit 6, a pressing member 640 for pressing the developing unit 7, and a lifting member (moving member) 642 for lifting the developing unit 7. The lifting member 642 presses and moves the developing unit 7 mounted on the mounting section 615. In the left-right direction, the toner storage section 74 of the developing unit 7 mounted on the mounting section 615 is positioned between the left-side wall 611 and the right-side wall 612.

[0037] At the rear of the frame 610, a first positioning projection 660 and a first guide rib 662 are provided, projecting coaxially from the left wall 611 to the photoreceptor drum. Similarly, a second positioning projection 661 and a second guide rib 663 are provided, projecting coaxially from the right wall 612 to the photoreceptor drum (see Figures 10 and 13).

[0038] The lifespan of the developing unit 7, which is determined by the amount of toner stored in it, is set to be shorter than the lifespan of the photoreceptor unit 6, which is determined by the thickness of the photosensitive layer of the photoreceptor drum 61. Therefore, only the developing unit 7 that has reached the end of its lifespan needs to be replaced separately from the photoreceptor unit 6. In this case, the door 21 is opened, the process cartridge 5 is taken out from inside the main unit 2, the developing unit 7 that has reached the end of its lifespan is removed from the photoreceptor unit 6, and another developing unit 7 is attached to the photoreceptor unit 6 as shown in the mounting direction AD in Figure 12. After that, the photoreceptor unit 6 with the developing unit 7 attached is installed into the main unit 2 as the process cartridge 5.

[0039] As shown in Figures 7, 10, and 12, the left wall 611 and right wall 612 of the frame 610 have receiving portions 641 that receive the rotating bearing members 746A and 746B of the developing roller 71, positioned in front of the photoreceptor drum 61. The receiving portion 641 is a roughly U-shaped recess that is open at the front when viewed from the left side, and the rotating shaft 746 of the developing roller 71 is inserted into it during the process of mounting the developing unit 7 onto the photoreceptor unit 6. The receiving portion 641 supports the developing unit 7 on the photoreceptor unit 6 and guides the movement of the developing unit 7 in the mounting direction AD shown in Figure 12.

[0040] Furthermore, as shown in Figure 13, the bottom surface 613 of the frame 610 is provided with upwardly protruding projections 643 at both ends in the left-right direction. These projections 643 abut against the ribs 718 provided on the bottom of the housing 700 of the developing unit 7 shown in Figure 9, thereby supporting the developing unit 7 in a movable manner.

[0041] As shown in Figure 12, the photoreceptor unit 6 has a positioning hole 68 and a contact opening 69 provided on the frame 610, located on one end of the photoreceptor drum 61 in the direction of its rotation axis (left-right direction). Here, "one end" means the same side as the equal division line in the left-right direction of the photoreceptor drum 61. When the developing unit 7 is installed on the photoreceptor unit 6, as shown in Figures 14(a) and 14(b), the positioning projection 86 of the developing unit 7 is inserted into the positioning hole 68 of the photoreceptor unit 6. The positioning projection 86 and the positioning hole 68 are fitted together in the axial direction (left-right direction) of the photoreceptor drum 61, and the developing unit 7 is positioned relative to the photoreceptor unit 6. The left-right position of 7 is determined. Also, the memory 85 of the developing unit 7 is exposed to the bottom of the process cartridge 5 through the contact opening 69 of the photoreceptor drum 61.

[0042] As shown in Figures 11(a) and 14(b), a box-shaped recess 90L is provided on one end of the frame 610 of the photoreceptor unit 6 in the direction of the rotation axis (left-right direction) of the photoreceptor drum 61. The recess 90L is positioned to overlap with the positioning hole 68 when viewed from the direction of the rotation axis (left-right direction) of the photoreceptor drum 61. This recess 90L reinforces the surrounding area, which has reduced strength due to the positioning hole 68, thereby increasing its strength. As shown in Figure 11(b), the depth D2 of the recess 90L is deeper than the depth D1 of the positioning hole 68, thus greatly increasing the reinforcing effect. This configuration increases the strength around the positioning hole 68 of the photoreceptor unit 6, improving the left-right positioning accuracy of both units by the positioning projection 86 of the developing unit 7 and the positioning hole 68 of the photoreceptor unit 6. As a result, the positional accuracy between the memory electrode 85A of the memory 85 and the electrode provided on the device body 2 is improved, enabling reliable contact between electrodes.

[0043] As shown in Figures 11(a) and 14(b), a sheet member 93L is provided on the photoreceptor drum 61 side of the recess 90L. The leading edge 93LA of the sheet member 93L is in contact with the photoreceptor drum 61. This configuration prevents image defects by scraping off unwanted toner, paper dust, and other foreign matter adhering to the surface of the photoreceptor drum 61 during image formation with the leading edge 93LA. In this configuration, the scraped-off unwanted toner, paper dust, and other foreign matter falls into the recess 90L and is collected. Therefore, contamination of the process cartridge 5 due to scattering of foreign matter and the occurrence of image defects due to foreign matter falling onto the paper S can be prevented. By using the recess 90L as both a reinforcing structure and for foreign matter collection, it becomes unnecessary to provide a separate foreign matter collection structure in addition to the recess 90L, enabling miniaturization of the cartridge and simplification of the configuration.

[0044] As shown in Figure 12, a foreign matter box 90R with a box-shaped recess is provided on the left-right opposite side of the positioning hole 68 of the photoreceptor unit 6. A sheet member 93R is provided on the photoreceptor drum 61 side of the foreign matter box 90R. The tip 93RA of the sheet member 93R is in contact with the photoreceptor drum 61. Similar to the sheet member 93L described above, the tip 93RA scrapes off unwanted toner, paper dust, and other foreign matter adhering to the surface of the photoreceptor drum 61 during image formation, preventing image defects. The scraped-off unwanted toner, paper dust, and other foreign matter fall into the foreign matter box 90R and are collected inside the box.

[0045] As shown in Figure 12, the pressing member 640 is located in front of the frame 610 and is provided at both ends of the frame 610 in the left-right direction. The pressing member 640 is biased from front to back by a compression spring 640A acting as a biasing member. As a result, the biasing force of the compression spring 640A causes the pressing member 640 to press the press-to-press ribs 716A and 716B provided on the housing 700 of the developing unit 7, respectively. By pressing the developing unit 7 with the pressing member 640, the developing roller 71 is biased toward the photoreceptor drum 61.

[0046] As shown in Figures 12 and 7, a recess 664 is provided in the left wall 611 of the photoreceptor unit 6, where the detection unit 80 of the developing unit 7 is located. Because the rigidity of the frame 610 is reduced by the recess 664, a portion of the first guide rib 662 is positioned to overlap it at its lower part. This first guide rib 662 acts as a reinforcing member, thereby mitigating the reduction in the rigidity of the frame 610.

[0047] Furthermore, as shown in Figure 11, a photoreceptor gear (first gear) 65 and a transfer gear (second gear) 66 are fixed to the left end of the photoreceptor drum 61, and are configured to rotate integrally with the photoreceptor drum 61. When the process cartridge 5 is mounted in the main body 2, the drive gear (not shown) of the main body 2 and the photoreceptor gear 65 mesh together, causing the photoreceptor drum 61 and the transfer gear 6 The driving force is transmitted to 6, making it rotatable. Furthermore, the transfer gear 66 meshes with the transfer roller gear (third gear) 67 fixed to the left end of the transfer roller 63, making the transfer roller 63 rotatable as well.

[0048] <Lift mechanism of developing unit 7> Figure 15 is a partial perspective view of the developing unit 7 and the lift member 642. Figure 16 is a top view of the photoreceptor unit 6 with the developing unit 7 attached; in Figure 16(a), the lift member 642 is shown transparently, while in Figure 16(b), the lift member 642 is not shown transparently. Figure 17 is a cross-sectional view of the photoreceptor unit 6 and the developing unit 7, the cross-section being parallel in the vertical and front-back directions. Figure 17(a) shows the developing unit 7 attached to the photoreceptor unit 6, and Figure 17(b) shows the developing unit 7 resting on top of the photoreceptor unit 6. The developing unit 7, attached to the photoreceptor unit 6, is moved to a lifted state by the lift mechanism and then removed from the photoreceptor unit 6. This lift mechanism will be described in detail below.

[0049] As shown in Figures 15 and 17, at least a portion of the lift member 642 is positioned in front of the housing 700 of the developing unit 7 and is rotatably supported on the right side wall 612 under the force of the compression spring 650. Also, at least a portion of the lift member 642 is positioned to overlap in the front-rear direction with respect to the right side wall 705 and the pressing member 640 of the housing 700 that houses the toner. The rotation axis 642X of the lift member 642 is parallel to the left-right direction (the axial direction of the photoreceptor drum 61). The lift member 642 is biased to rotate in the R1 direction by the force of the compression spring 650.

[0050] The user presses the operating part 642A of the lift member 642 against the force of the compression spring 650, rotating the lift member 642 in the R2 direction. This causes the lift member 642 to press against the protruding part 751, moving the developing unit 7 in the detachment direction LD, which separates it from the photoreceptor unit 6. As a result, the developing unit 7 can be removed from the photoreceptor unit 6. The operating part 642A is located on the right end side (one end side) of the photoreceptor unit 6.

[0051] As shown in Figure 17(a), when the developing unit 7 is mounted on the photoreceptor unit 6, the pressing member 640 presses the housing 700, causing the developing roller 71 to be pressed toward the photoreceptor drum 61. The pressing member 640 also locks the developing unit 7 in place to prevent it from detaching from the photoreceptor unit 6. As shown in Figure 15, one end of the lifting member 642 moves the contact surface (contact portion) 751A of the protruding portion 751 of the housing 700 upward. This allows the developing unit 7 to be moved from its mounting position on the mounting portion 615 (see Figure 12) toward the detachment direction LD, thereby detaching it from the photoreceptor unit 6.

[0052] As shown in Figure 17(b), when the front of the developing unit 7 detaches from the photoreceptor unit 6, the developing unit 7 is held in a temporary support position where the supported surface 700c of the housing 700 is supported by the holding portion 640B of the pressing member 640. In the temporary support position, the developing unit 7 has the rotating bearing member 746B (746A) of the developing roller 71 supported by the receiving portion 641. This state is called the lift-up state. At this time, the lock (restriction on removing the developing unit 7 from the photoreceptor unit 6) is released. In this lift-up state, if the user grasps the grip portion 701 and lifts the developing unit 7, the developing unit 7 can be removed from the photoreceptor unit 6 without moving any other components. In this way, the user can remove the developing unit 7 from the photoreceptor unit 6 and install a new developing unit 7 into the photoreceptor unit 6.

[0053] [Example 1] Next, Embodiment 1 of the present invention will be described with reference to Figure 18. In this embodiment, the parts that differ from the configuration of the image forming apparatus 1 and process cartridge 5 described above will be explained in detail. Unless otherwise specified, the configuration is the same as that of the image forming apparatus 1 and process cartridge 5 described above, so such parts will be given the same numbers and detailed explanations will be omitted. Figure 18(a) is a cross-sectional view illustrating the pressing configuration of the developing unit 270 by the pressing member 200 when the developing unit 270 is mounted on the photoreceptor unit 260 in Embodiment 1. Figure 18(b) is a detailed view of the first wall surface 212 and the second wall surface 222 in Figure 18(a). The first wall surface 212 and the second wall surface 222 will be described later.

[0054] As shown in Figure 18(a), the photoreceptor unit 260 is provided with a photoreceptor drum 61, a frame 610, and a pressing member 200. The pressing member 200 is a pressing member that presses the developing roller 71 provided on the developing unit 270 toward the photoreceptor drum 61 when the developing unit 270 is mounted on the photoreceptor unit 260.

[0055] The photoreceptor unit 260 is equipped with a paper dust removal roller 64A, a paper dust recovery roller 64B, and a paper dust recovery chamber 64C. The paper dust removal roller 64A is in contact with the photoreceptor drum 61 and is positioned downstream of the transfer roller 63 in the rotational direction of the photoreceptor drum 61 and upstream of the charging device 62 in the rotational direction of the photoreceptor drum 61. The paper dust recovery roller 64B is in contact with the paper dust removal roller 64A and is positioned behind the paper dust removal roller 64A. The paper dust recovery chamber 64C is a closed space formed by the paper dust recovery roller 64B and the frame 610. The paper dust removal roller 64A removes any paper dust remaining on the photoreceptor drum 61 after the toner image on the photoreceptor drum 61 has been transferred onto the paper S (not shown). The paper dust removed by the paper dust removal roller 64A is collected in the paper dust collection chamber 64C by the paper dust collection roller 64B.

[0056] The developing unit 270 is equipped with a first agitator 211 and a second agitator 221. The first agitator 211 is located in a first stirring chamber 210, which is positioned in front of the developing roller 71 and the supply roller 72. The second agitator 221 is located in a second stirring chamber 220, which is positioned in front of the first stirring chamber 210.

[0057] The first stirring chamber 210 is a space for containing toner, formed by the top surface 240 of the stirring chamber located above the first agitator 211 in the direction of gravity, and the first wall surface 212 located below the first agitator 211 in the direction of gravity. The second stirring chamber 220 is a space for containing toner, formed by the top surface 240 of the stirring chamber and the second wall surface 222 located below the second agitator 221 in the direction of gravity. At least a portion of the first wall surface 212 is a convex (arc-shaped) wall surface (bottom) that protrudes downward in the direction of gravity relative to the first agitator 211. Also, at least a portion of the second wall surface 222 is a convex (arc-shaped) wall surface (bottom) that protrudes downward in the direction of gravity relative to the second agitator 221.

[0058] As shown in Figure 18(b), the first wall surface 212 and the second wall surface 222 are convex walls that protrude downward in the direction of gravity, so a common tangent line T203 (dashed line) can be drawn connecting the outer wall surfaces at the bottom of the first wall surface 212 and the second wall surface 222. Here, the region enclosed by the common tangent line T203, the first wall surface 212, and the second wall surface 222 (cross-hatched region consisting of vertical and horizontal lines) is defined as the first recess 231.

[0059] The first recess 231 is formed at the boundary between the first wall surface 212 and the second wall surface 222 in the front-rear direction, and the first wall surface 212 and the second wall surface 222 are connected via the first recess 231. The first recess 231 is positioned between the rotation centers of the first agitator 211 and the second agitator 221 in the front-rear direction. The first recess 231 has a pressure receiving portion that receives pressure from the pressing member 200. A 231A is provided. The pressure receiving portion 231A receives a pressing force from the pressing member 200 in the direction of the first line T201, causing the developing roller 71 to contact the photoreceptor drum 61 with a predetermined contact pressure. Here, the first line T201 is a straight line perpendicular to the rotation axis direction (left-right direction) of the developing roller 71 and passing through the first wall surface 212 and the second wall surface 222.

[0060] Furthermore, the rotation center of the second agitator 221 is located near the second line T202 in the vertical direction. Here, the second line T202 is perpendicular to the rotation axis direction (left-right direction) of the developing roller 71 and is a straight line connecting the rotation center of the developing roller 71 and the rotation center of the first agitator 211. The second line T202 passes through the second stirring chamber 220.

[0061] From the viewpoint of stabilizing the lateral distribution of the contact pressure of the developing roller 71 against the photoreceptor drum 61, it is preferable that the pressing receiving portion 231A and the pressing member 200 be provided at both ends of the frame 610 in the left-right direction. On the other hand, from the viewpoint of cost, it is also possible to reduce the number of parts by providing the pressing receiving portion 231A and the pressing member 200 near the center of the frame 610 in the left-right direction.

[0062] Furthermore, from the viewpoint of further stabilizing the contact pressure, the pressing receiving portion 231A and the pressing member 200 may be provided at both ends and near the center of the frame 610 in the left-right direction. In addition, from the viewpoint of miniaturizing the developing unit 270 in the left-right direction, the pressing receiving portion 231A and the pressing member 200 may be positioned closer to the center of the frame 610 in the left-right direction than the lift member 642, or they may be positioned to overlap in the left-right direction as long as they do not protrude outside the lift member 642.

[0063] As described above, the process cartridge 5 according to Embodiment 1 shown in Figure 18 comprises a photoreceptor unit 260 and a developer unit 270 that is detachable from the photoreceptor unit 260. The photoreceptor unit 260 includes a photoreceptor drum 61 on which an electrostatic latent image is formed, a frame 610 that supports the photoreceptor drum 61, and a pressing member 200 that presses the developer unit 270 toward the photoreceptor unit 260. The developer unit 270 includes a developer roller 71 that supplies toner to the photoreceptor drum 260 and collects toner remaining on the surface of the photoreceptor drum, a housing 250 in which a first stirring chamber 210 and a second stirring chamber 220 (storage space) for accommodating toner are formed, and a pressing receiving part 231A that receives pressure from the pressing member 200.

[0064] The housing 250 has an arc-shaped (downward-convex) first wall surface 212 (first bottom outer wall) that protrudes outward from the first stirring chamber 210, and an arc-shaped (downward-convex) second wall surface 222 (second bottom outer wall) that protrudes outward from the second stirring chamber 220. When viewed from a direction along the rotation axis of the developing roller 71 (vertically above the paper plane), at least a part of the pressure receiving portion 231A is positioned in the first recess 231 surrounded by a common tangent line T203 that is in contact with the first wall surface 212 and the second wall surface 222, and the first wall surface 212 and the second wall surface 222.

[0065] This allows the pressing member 200 to be placed in the first recess 231, which would normally be dead space, thus enabling miniaturization of the developing unit 270. In other words, the capacity of the space for storing toner can be increased without increasing the size of the developing unit.

[0066] Furthermore, the developing unit 270 according to Embodiment 1 includes, as a member for transporting toner within the housing space of the housing 250, a first agitator 211 (first transport member) that rotates so as to contact the inner wall of the first wall surface 212 and transports the toner, and a second agitator 221 (second transport member) that rotates so as to contact the inner wall of the second wall surface 222 and transports the toner. The pressure receiving portion 231A is positioned horizontally between the rotation center of the first agitator 211 and the rotation center of the second agitator 221.

[0067] Furthermore, in the process cartridge 5 according to Embodiment 1, when the extension line parallel to the pressing direction of the pressing member 200, passing through the point where the pressing member 200 contacts the pressing receiving portion 231A, is defined as the first line T201, the first line T201 passes through (crosses) the first wall surface 212 and the second wall surface 222. Also, in the process cartridge 5 according to Embodiment 1, when viewed from a direction along the rotation axis of the developing roller 71, the second line T202, which passes through the rotation center of the developing roller 71 and the rotation center of the first agitator 211, passes through the second stirring chamber 220, which serves as a transport chamber housing the second agitator 221.

[0068] <Effects and Actions of Example 1> In the process cartridge 5 according to this embodiment, by providing a pressing member 200 in the first recess 231, the pressing receiving portion 231A receives a pressing force from the pressing member 200 in the direction of the first line T201. The pressing receiving portion 231A is located on the side closer to the developing roller 71 (rear side) than the second wall surface 222 in the front-rear direction. Therefore, compared to a configuration that presses the second wall surface 222, which is located on the side further from the developing roller 71 (front side) than the first wall surface 212 in the front-rear direction, it is possible to suppress deformation of the housing 250 due to the pressing force. As a result, it is possible to reduce the loss of contact pressure between the developing roller 71 and the photoreceptor drum 61 due to deformation of the housing 250.

[0069] Furthermore, in this embodiment, since the pressing member 200 is provided in the first recess 231, it is possible to save space in the horizontal direction (front-to-back direction) compared to the case where the pressing member 200 is provided on the front side of the second wall surface 222. In addition, compared to a configuration in which the pressing member 200 biases the portion of either the first wall surface 212 or the second wall surface 222 that is below the first recess 231 in the direction of gravity, the process cartridge 5 according to Embodiment 1 is able to save space in the vertical direction.

[0070] Furthermore, in this embodiment, the rotation center of the second agitator 221 is located near the second line T202 in the vertical direction. Since the second line T202 is set to be inclined more towards the horizontal line (front-back direction) than the vertical line (up-down direction), the vertical difference between the first stirring chamber 210 and the second stirring chamber 220 is kept low. Therefore, the vertical (height) size of the developing unit 270 can be reduced, making it possible to miniaturize the process cartridge 5 and the image forming apparatus 1 in the vertical direction (height). In addition, since the toner drop (height) during toner transport from the second stirring chamber 220 to the first stirring chamber 210 by the second agitator 221 is kept low, an increase in powder pressure due to toner accumulation in the vertical direction can be prevented. Therefore, deterioration due to increased toner powder pressure is suppressed, making it possible to further extend the lifespan of the developing unit 270.

[0071] Furthermore, in this embodiment, by positioning the pressing receiving portion 231A and the pressing member 200 closer to the center of the frame 610 in the left-right direction than the lift member 642, the left-right (width) size of the developing unit 270 can be reduced. This makes it possible to miniaturize the left-right (width) dimensions of the process cartridge 5 and the image forming apparatus 1.

[0072] Furthermore, in this embodiment, since a pressing member 200 is provided in the first recess 231, the first recess 231 and the pressing member 200 can be used as engagement grooves to prevent mis-installation between multiple process cartridges with different specifications such as lifespan and speed. Specifically, if the first recess 231 of the developing unit 270 is located in a different position from the pressing member 200 of the photoreceptor unit, when the developing unit 270 is installed on the photoreceptor unit 260, either the first wall surface 212 or the second wall surface 222 will come into contact with the pressing member 200. In such a case, the developing unit 270 cannot be installed to the completed installation position shown in Figure 18(a), making it possible to make the user aware of the mis-installation of the developing unit 270. ru.

[0073] [Example 2] Next, Embodiment 2 of the present invention will be described with reference to Figure 19. In this embodiment, the parts that differ from the previously described embodiment will be described in detail. Unless otherwise specified, the configuration is the same as in the previously described embodiment, so such parts will be given the same numbers and detailed explanations will be omitted. Figure 19 is a cross-sectional view illustrating the pressing configuration of the developing unit 271 by the pressing member 201 when the developing unit 271 is attached to the photoreceptor unit 261 in Embodiment 2.

[0074] As shown in Figure 19, the photoreceptor unit 261 is provided with a photoreceptor drum 61, a frame 610, and a pressing member 201. The pressing member 201 is located in front of the housing 251 of the developing unit 271, and when the developing unit 271 is mounted on the photoreceptor unit 261, it presses the housing 251 in the direction of arrow 201F. Here, arrow 201F is the pressing force vector that presses the developing roller 71 provided on the developing unit 271 toward the photoreceptor drum 61. Also, arrows 201H and 201V are the horizontal component (force in the front-to-back direction) and vertical component (force in the up-and-down direction) of the pressing force vector 201F, respectively. The direction of the horizontal pressing force component 201H is from front to back, and the direction of the vertical pressing force component 201V is from top to bottom.

[0075] The first recess 231 of the developing unit 271 is provided with a rotation stopper 202 as a substitute for the projection 643 shown in Figure 13. The rotation stopper 202 restricts the rotational movement of the developing unit 271 relative to the photoreceptor unit 261. The rotation stopper 202 consists of a rotation stopper roller 202A and a roller support 202B that supports the rotation stopper roller 202A. The rotation stopper roller 202A is rotatably supported relative to the roller support 202B and has a cylindrical or spherical shape. The roller support 202B is fixedly supported relative to the frame 610. The rotation stopper roller 202A supports the developing unit 271 so that it can move relative to the photoreceptor unit 261 by contacting the pressure receiving portion 231A.

[0076] In this case, the pressure receiving portion 231A receives a reaction force from the rotation-stopping roller portion 202A in the direction of arrow 202F. That is, arrow 202F is the vector of the rotation-stopping contact force that restricts the rotational degree of freedom around the developing roller 71 of the developing unit 271. Also, arrows 202H and 202V are the horizontal component (front-to-back direction) and the vertical component (up-down direction) of the rotation-stopping contact force 202F, respectively. The direction of the horizontal component 202H is from front to back, and the direction of the vertical component 202V is from bottom to top.

[0077] From the viewpoint of stabilizing the lateral distribution of the contact pressure of the developing roller 71 against the photoreceptor drum 61, it is preferable to provide the pressure receiving portion 231A and the rotation stopping portion 202 at both ends of the frame 610 in the left-right direction. On the other hand, from the viewpoint of cost, it is also possible to reduce the number of parts by providing the pressure receiving portion 231A and the rotation stopping portion 202 near the center of the frame 610 in the left-right direction.

[0078] Furthermore, from the viewpoint of further stabilizing the contact pressure, the pressing receiving portion 231A and the rotation stopping portion 202 may be provided at both ends and near the center of the frame 610 in the left-right direction. In addition, from the viewpoint of miniaturizing the developing unit 271 in the left-right direction, the pressing receiving portion 231A and the rotation stopping portion 202 may be positioned closer to the center of the frame 610 than the lift member 642 in the left-right direction, or they may be positioned to overlap in the left-right direction as long as they do not protrude outside the lift member 642.

[0079] The first stirring chamber 210 and the second stirring chamber 220 of the developing unit 271 are located at the bottom on the downward side in the direction of gravity. It is composed of a first wall surface 212 and a second wall surface 222 that form a surface, and a first top surface 241 and a second top surface 242 that form the top surface on the upward side in the direction of gravity. The first top surface 241 and the second top surface 242 are connected to the first top surface 241 via an intersection 242A, which is the rear end of the second top surface 242. The intersection 242A has a shape that extends from the front to the rear on the second top surface 242, and is therefore positioned to overlap the first top surface 241 in the front-to-back direction. In other words, the intersection 242A and the first top surface 241 are provided intersecting in the front-to-back direction.

[0080] As described above, the process cartridge 5 according to Embodiment 2 shown in Figure 19 comprises a photoreceptor unit 261 and a developer unit 271 that is detachable from the photoreceptor unit 261. The photoreceptor unit 261 includes a photoreceptor drum 61, a frame 610 that supports the photoreceptor drum 61, and a rotation stopper 202 that presses the developer unit 271 toward the photoreceptor unit 261. The developer unit 271 includes a developer roller 71, a housing 251 in which a first stirring chamber 210 and a second stirring chamber 220 for containing toner are formed, and a pressure receiving portion 231A that receives pressure from the rotation stopper 202.

[0081] The housing 251 has an arc-shaped first wall surface 212 projecting outward toward the first stirring chamber 210, an arc-shaped second wall surface 222 projecting outward toward the second stirring chamber 220, a first top surface 241 located on the upward side in the direction of gravity, a second top surface 242 located further upward in the direction of gravity than the first top surface 241 and positioned to overlap a part of the first top surface 241 when viewed from above, and an intersection 242A (connecting part) connecting the first top surface 241 and the second top surface 242. The intersection 242A has an opposing surface 242B on the lower side of the second top surface 242 that faces the first top surface 241. As a result, as shown in Figure 19, by inserting a finger into the overlapping portion between the first top surface 241 and the second top surface 242 when viewed from above, and supporting the opposing surface 242B from below while grasping the second top surface 242 from above, this portion can be used as a handle when attaching or detaching the developing unit 271.

[0082] Furthermore, the rotation stopper 202 according to Embodiment 2 has a rotation stopper roller 202A that supports the developing unit 271 when the developing unit 271 is attached to the photoreceptor unit 261. When viewed from a direction along the rotation axis of the developing roller 71, the rotation stopper roller 202A is positioned in the first recess 231, similar to Embodiment 1. This allows the rotation stopper 202 to be positioned in the first recess 231, which would normally be dead space, thus enabling miniaturization of the developing unit 271. In other words, the capacity of the space for storing toner can be increased without increasing the size of the developing unit 271.

[0083] <Effects and Actions of Example 2> In this embodiment, by providing a rotation-stopping portion 202 in the first recess 231, the pressure receiving portion 231A receives a rotation-stopping contact force 202F from the rotation-stopping portion 202. Compared to a configuration in which the rotation-stopping portion 202 supports the portion of either the first wall surface 212 or the second wall surface 222 that is below the first recess 231 in the direction of gravity, the process cartridge 5 according to Embodiment 2 makes it possible to save space in the vertical direction.

[0084] Furthermore, in this embodiment, the horizontal component 202H applied to the developing unit 271 by the rotation stopper 202 is oriented in the same direction as the horizontal component 201H of the pressing force, that is, from the front to the rear. Therefore, the horizontal component 202H adds a biasing force to the developing roller 71 against the photoreceptor drum 61, thereby further stabilizing the contact state of the developing roller 71 with respect to the photoreceptor drum 61.

[0085] In addition, since the contact means of the developing roller 71 with respect to the photoreceptor drum 61 is distributed between the pressing member 201 and the rotation stopper 202, the compression spring force of the pressing member 201 can be kept low. By suppressing the compression spring force of the pressing member 201, the process cartridge 5 can be left unused for a long period of time. This suppresses creep deformation of frame 610, thereby reducing the required strength of frame 610. Consequently, it becomes possible to reduce costs by making frame 610 thinner, etc.

[0086] Furthermore, in this embodiment, the intersection 242A intersects the first top surface 241 of the stirring chamber in the front-rear direction. Therefore, when attaching or detaching the developing unit 271 to the photoreceptor unit 261, the intersection 242A can be used as a handle for gripping the developing unit 271 by hooking a finger on it. Thus, compared to a configuration in which the handle of the developing unit 271 is located in front of the second wall surface 222, it is possible to save space in the horizontal direction (front-rear direction). Moreover, compared to a configuration in which the handle of the developing unit 271 is located in front of the second wall surface 222, it is possible to grip the developing unit 271 at a position closer to the center of gravity 251G in the horizontal direction (front-rear direction). Therefore, it is possible to reduce the strain on the wrist when attaching or detaching the developing unit 271 to the photoreceptor unit 261, that is, the moment load around the wrist associated with gripping the developing unit 271.

[0087] Furthermore, in this embodiment, since the first recess 231 is provided with a rotation stopper 202, the first recess 231 and the rotation stopper 202 can be used as engagement grooves to prevent mis-installation between multiple process cartridges with different specifications such as lifespan and speed. Specifically, if the first recess 231 of the developing unit 271 is located in a different position from the rotation stopper 202, when the developing unit 271 is mounted on the photoreceptor unit 261, either the first wall surface 212 or the second wall surface 222 will come into contact with the rotation stopper 202. In such a case, the developing unit 271 cannot be mounted to the completed mounting position shown in Figure 18(a), making it possible to make the user aware of the incorrect mounting of the developing unit 271.

[0088] [Example 3] Next, Embodiment 3 of the present invention will be described with reference to Figure 20. In this embodiment, the parts that differ from the previously described embodiment will be described in detail. Unless otherwise specified, the configuration is the same as in the previously described embodiment, so such parts will be given the same numbers and detailed explanations will be omitted. Figure 20 is a top view illustrating the left-right arrangement of the first stirring chamber 210 and the second stirring chamber 220 when the developing unit 272 is mounted on the photoreceptor unit 262 in Embodiment 3. Note that the top surface 240 of the stirring chambers is omitted in the figure to show the internal structure of the first stirring chamber 210 and the second stirring chamber 220.

[0089] As shown in Figure 20, the first stirring chamber 210, which serves as the first transport chamber, has a longitudinal width 213H in the left-right direction, from the left wall 704 of the developing unit 272 to the side wall 213 of the first stirring chamber. Similarly, the second stirring chamber 220, which serves as the second transport chamber, has a longitudinal width 223H in the left-right direction, from the left wall 704 to the side wall 223 of the second stirring chamber. The longitudinal width 223H of the second stirring chamber is longer than the longitudinal width 213H of the first stirring chamber.

[0090] At least a portion of the pressing member 200 or the lifting member 642 is positioned to overlap in the left-right direction between the first stirring chamber side wall 213 and the second stirring chamber side wall 223. In other words, the pressing member 200 and the lifting member 642 are positioned in the left-right direction further away from the left-right center of the developing unit 272 than the first stirring chamber side wall 213. In addition, at least a portion of the pressing member 200 or the lifting member 642 is positioned in the left-right direction closer to the left-right center of the developing unit 272 than the second stirring chamber side wall 223.

[0091] The pressing member 200 or the lifting member 642 is positioned in the front-rear direction behind the second stirring chamber 220 and in front of the developing roller 71.

[0092] In this embodiment, the pressing member 200 is provided on the left side relative to the lift member 642, but developing From the perspective of usability when removing the unit, it is also possible to reverse the left-right arrangement, that is, to place the pressing member 200 to the right of the lift member 642. In this embodiment, the pressing member 200 and the lift member 642 are arranged so that at least a portion of them overlap between the first stirring chamber side wall 213 and the second stirring chamber side wall 223 in the left-right direction, but the pressing member 200 may also be placed in the first recess 231 described in Embodiment 2.

[0093] Thus, the developing unit 272 according to Embodiment 3 shown in Figure 20, similar to the previously described embodiment, includes a first agitator 211 for transporting toner, a second agitator 221 for transporting toner, a first stirring chamber 210 housing the first agitator 211, and a second stirring chamber 220 housing the second agitator 221. The longitudinal width 223H of the second stirring chamber 220 in the direction along the rotation axis of the developing roller is larger than the longitudinal width 213H of the first stirring chamber 210 in the direction along the rotation axis of the developing roller.

[0094] <Effects and Actions of Example 3> The lift member 642 is located on the side further from the left-right center of the developing unit 272 than the side wall 213 of the first stirring chamber in the left-right direction, and is positioned between the second stirring chamber 220 and the developing roller 71 in the front-back direction. Therefore, it can be seen from the top view shown in Figure 20, i.e., from the top surface of the developing unit 272, thus ensuring visibility of the lift member 642 when removing the developing unit 272 from the photoreceptor unit 262.

[0095] Since the longitudinal width 223H of the second stirring chamber is longer than the longitudinal width 213H of the first stirring chamber, the capacity of the toner contained in the second stirring chamber 220 can be increased by the difference between the longitudinal width 223H of the second stirring chamber and the longitudinal width 213H of the first stirring chamber. As a result, it becomes possible to further extend the lifespan of the developing unit 272.

[0096] [Example 4] Next, Embodiment 4 of the present invention will be described using Figures 21 to 24. In this embodiment, the parts that differ from the previously described embodiment will be described in detail. Unless otherwise specified, the configuration is the same as in the previously described embodiment, so such parts will be given the same numbers and detailed explanations will be omitted. Figures 21 and 22 are a top view and a cross-sectional view illustrating the developer transport configuration when the developing unit 372 is attached to the photoreceptor unit 362 in Embodiment 4. Note that the top surface 240 of the stirring chamber is omitted in the illustration to show the internal structure of the first stirring chamber 210 and the second stirring chamber 220.

[0097] As shown in Figures 21 and 22, the first stirring chamber 210 is equipped with a rotatable first agitator 311. The first agitator 311 has a first stirring rod 311S, a first rotating shaft 311A ​​extending in the left-right direction, a first stirring sheet 312 made of a flexible sheet material, and a plurality of stirring blades 313, and supplies toner to the supply roller 72 by rotating around the first rotating shaft 311A. In order to adjust the toner supply force, the first stirring sheet 312 has multiple holes 312H provided at intervals along the longitudinal side of the first stirring sheet 312.

[0098] The first stirring rod 311S is equipped with stirring blades 313 to transport the toner in the first stirring chamber 210 to the central part. The toner stored in the supply roller 72 is discharged back into the first stirring chamber 210 by friction with the developing roller 71. A portion of the discharged toner is transported to both ends in the axial direction of the supply roller 72. The stirring blades 313 are provided on the first stirring rod 311S to return the toner transported to these ends back to the central part in the left-right direction of the first stirring chamber 210.

[0099] Multiple stirring blades 313 are provided on the first stirring rod 311S at intervals along the left-right direction of the first stirring rod 311S. In this embodiment, six stirring blades 313 are provided. In this embodiment, the stirring blade 313 is a semi-oval, flat plate-shaped member, configured such that the normal to the first rotation axis 311A ​​at the intersection point 311P has an angle 313θ that intersects the first rotation axis 311A. Of the multiple stirring blades 313, the three on the right are positioned so that the angle 313θ is counterclockwise with respect to the first rotation axis 311A, while the three on the left are positioned so that the angle 313θ is clockwise with respect to the first rotation axis 311A. In other words, the six stirring blades 313 are arranged symmetrically. Therefore, as the first stirring rod 311S rotates, the toner at the left and right ends of the first stirring chamber 210 receives a conveying force from the stirring blades 313 toward the center in the left and right directions.

[0100] Furthermore, the second stirring chamber 220 is equipped with a rotatable second agitator 321. The second agitator 321 has a second rotation shaft 321A extending in the left-right direction and a second stirring sheet 322 made of a flexible sheet material, and conveys toner from the second stirring chamber 220 toward the second stirring chamber 220 by rotating around the second rotation shaft 321A. The second stirring sheet 322 has a linear notch 322C that extends in a direction having a certain angle 322θ with the second rotation shaft 321A.

[0101] In this embodiment, six notches 322C are provided, and each notch 322C is located between the intersection point 311P of the stirring blade 313 and the first rotation axis 311A ​​in the left-right direction. The amount of toner transported by the second agitator is less than the amount of toner transported by the first agitator 311. Of the multiple notches 322C, the three on the right are provided so that the angle 322θ is counterclockwise with respect to the second rotation axis 321A, and the three on the left are provided so that the angle 322θ is clockwise with respect to the second rotation axis 321A. In other words, the six notches 322C are provided symmetrically.

[0102] The stirring blade 313 shown in this embodiment is just one example, and the shape and number of blades can be freely determined from the viewpoint of adjusting the stirring performance. For example, the stirring blade 313 in this embodiment has a semi-oval flat plate shape, but it may also have a helical shape with a twist angle with respect to the first rotation axis 311A, or a shape with irregularities on its edges or surfaces. Furthermore, from the viewpoint of changing the circulation performance at each position in the left-right direction, it is possible for multiple stirring blades 313 to have different shapes, sizes, thicknesses, and angles of orientation of their surfaces. In addition, the spacing between multiple stirring blades 313 does not necessarily have to be equal, and the direction of the normal to the surface at each intersection point 311P does not necessarily have to be the same.

[0103] Furthermore, in this embodiment, the shape of the notch 322C is a line having a constant angle 322θ with respect to the second rotation axis 321A, but this constant angle 322θ may be any angle other than 0 degrees and 180 degrees, and the width of the line may also be freely determined from the viewpoint of machinability. In addition, the shape, number, and spacing of the notches 322C shown in this embodiment are just examples, and these can be freely determined from the viewpoint of adjusting the transport capacity. Furthermore, from the viewpoint of changing the transport capacity according to the position in the left-right direction, it is also possible to have multiple notches 322C with different shapes, sizes, and spacings.

[0104] Figure 23 shows examples of possible shapes for the notches on the stirring sheet according to Example 4. The examples shown in Figure 23 include a shape in which a circle is connected to the end of a rectangle extending perpendicular to the second rotation axis 321A (Figure 23(a)), a shape in which multiple lines are connected at the end or in the middle of the lines (Figures 23(b), 23(c)), an arc shape (Figure 23(d)), and a triangular shape (Figure 23(e)). It is also possible to combine these shapes within a single second stirring sheet 322 (Figure 23(f)).

[0105] Figure 24 also shows examples of possible shapes for the holes on the stirring sheet according to Embodiment 4. As shown in Figure 24, it is also possible to provide a second hole portion 322H on the surface of the second stirring sheet 322 instead of the notch 322C in this embodiment. In this case, the shape of the second hole portion 322H The shape can be freely determined from the viewpoint of adjusting the transport capacity. In the example shown in Figure 24, shapes such as rectangle (Figure 24(a), Figure 24(e)), ellipse (Figure 24(b)), triangle (Figure 24(c)), and circle (Figure 24(d)) are used. Furthermore, the shape of the second hole portion 322H may be different in the left-right direction (Figure 24(f)), and the number and spacing may be freely determined.

[0106] As described above, the developing unit 372 according to Embodiment 4 shown in Figure 21 includes a first agitator 311 that transports toner toward the developing roller and a second agitator 321 that transports toner toward the first agitator 311. The first agitator 311 includes a first rotating shaft 311A ​​and a plurality of stirring blades 313 inclined with respect to the axis of the first rotating shaft 311A. The second agitator 321 includes a second stirring sheet 322. The second stirring sheet 322 has a plurality of notches 322C (slits) formed at an angle with respect to the second rotating shaft 321A. This allows for appropriate adjustment of the amount of toner transported by the first agitator 311 and the second agitator 321.

[0107] Furthermore, the first agitator 311 has multiple stirring blades 313. Also, at least a portion of the notch 322C is located between two adjacent stirring blades 313 in the axial direction when viewed from a direction perpendicular to the first rotation axis 311A. The notch 322C has a first end 322A located on the free end side of the second stirring sheet 322 and a second end 322B on the opposite side of the first end 322A. The notch 322C extends from the second end 322B to the first end 322A, from the center outward in the direction along the second rotation axis 321A of the second stirring sheet 322. This allows the toner in the first stirring chamber 210 and the second stirring chamber 220 to be conveyed in a circulating manner.

[0108] Furthermore, the developing unit 500 according to Embodiment 4 shown in Figure 25 includes a rotatable first agitator 211 (first transport member) that transports toner in the first stirring chamber 210 toward the developing roller 71, a rotatable second agitator 221 (second transport member) that transports toner in the second stirring chamber 220 toward the first agitator 211, and a third agitator 501 (third transport member) that transports toner in the third stirring chamber 503 toward the second agitator 221. The housing has an arc-shaped first wall surface 212 that protrudes toward the outside of the first stirring chamber 210, an arc-shaped second wall surface 222 that protrudes toward the outside of the second stirring chamber 220, and an arc-shaped third wall surface 505 that protrudes toward the outside of the third stirring chamber 503.

[0109] The first agitator 211 is positioned above the first wall surface 212, the second agitator 221 is positioned above the second wall surface 222, and the third agitator 501 is positioned above the third wall surface 505. As shown in Figure 25, when viewed from a direction along the rotation axis of the first agitator 211, at least a portion of the third wall surface 505 extends away from the photoreceptor drum 61 from the end opposite to the end on which the photoreceptor drum 61 is positioned, in the direction connecting the rotation center of the first agitator 211 and the rotation center of the second agitator 221.

[0110] Furthermore, the third agitator 501 is rotatable, and its rotation center may be positioned above the line L1 connecting the rotation center of the first agitator 211 and the rotation center of the second agitator 221 in the direction of gravity.

[0111] <Effects and Actions of Example 4> In this embodiment, the notches 322C of the second stirring sheet 322 are provided between multiple intersections 311P between the stirring blades 313 and the first rotation axis 311A ​​in the left-right direction. Furthermore, the amount of toner transported by the second agitator 321 is less than the amount of toner transported by the first agitator 311. This prevents excessive toner supply to the stirring blades 313 provided on the first agitator 311, thereby suppressing toner deterioration in the developing chamber.

[0112] [Example 5] Next, Embodiment 5 of the present invention will be described using Figures 32, 33, and 34. In this embodiment, the parts that differ from the previously described embodiment will be described in detail. Unless otherwise specified, the configuration is the same as in the previously described embodiment, so such parts will be given the same numbers and detailed explanations will be omitted. Figures 32 and 33 are cross-sectional views of Embodiment 5 when the developing unit 470 is attached to the photoreceptor unit. Figure 34 is a top view illustrating the developer transport configuration when the developing unit is attached to the photoreceptor unit.

[0113] The first agitator 311 has a first stirring rod 311S, a first rotating shaft 311A ​​extending in the left-right direction, a first stirring sheet 312 made of a flexible sheet material, and a plurality of stirring blades 313, and supplies toner to the supply roller 72 by rotating around the first rotating shaft 311A. The first stirring rod 311S is equipped with stirring blades 313 to transport the toner in the first stirring chamber 210 (first toner storage chamber) to the central part. The toner stored in the supply roller 72 is discharged back into the first stirring chamber 210 by friction with the developing roller 71. A portion of the discharged toner is transported to both ends in the axial direction of the supply roller 72.

[0114] The stirring blades 313 described above are provided on the first stirring rod 311S in order to return the toner that has been transported to both ends back to the central part in the left-right direction within the first stirring chamber 210. Furthermore, the stirring blades 313 at both ends of the longitudinal axis reduce the toner pressure at both ends, thereby reducing toner leakage from the toner seal portion (not shown) that fills the gap between both ends of the longitudinal axis of the developing roller 71 and the housing 700, thereby preventing toner leakage.

[0115] Multiple stirring blades 313 are provided at intervals along the left-right direction of the first stirring rod 311S. In this embodiment, six stirring blades 313 are provided. The stirring blades 313 have a semi-oval flat plate shape, and the normal vector at the intersection point 311P with the first rotation axis 311A ​​has an angle 313θ at which it intersects with the first rotation axis 311A. In addition, a rotatable second agitator 321 is provided in the second stirring chamber 220 (second toner storage chamber).

[0116] The second agitator 321 has a second stirring rod 321S, a second rotating shaft 321A extending in the left-right direction, and a second stirring sheet 322 made of a flexible sheet material. By rotating around the second rotating shaft 321A, it conveys toner from the second stirring chamber 220 to the first stirring chamber 210. The amount of toner conveyed by the second agitator 321 is less than the amount of toner conveyed by the first agitator 311.

[0117] Furthermore, the third stirring chamber 403 (third toner storage chamber) is equipped with a rotatable third agitator 401. The third agitator 401 has a third stirring rod 401S, a third rotating shaft 401A extending in the left-right direction, and a third stirring sheet 402 made of a flexible sheet material. By rotating around the third rotating shaft 401A, it transports toner from the third stirring chamber 403 toward the second stirring chamber 220. The amount of toner transported by the third agitator 401 is set to be less than the amount of toner transported by the second agitator 321. This prevents excessive toner from clogging the second stirring chamber 220 and the first stirring chamber 210 in the backward direction.

[0118] Furthermore, the rotation center of the third agitator 401 is located near the second line T302 in the vertical direction, as shown in Figure 32, that is, within the rotation radius of the tip of the third stirring sheet 402. Here, the second line T302 is perpendicular to the rotation axis direction (left-right direction) of the developing roller 71 and is a straight line connecting the rotation center of the developing roller 71 and the rotation center of the first agitator 311. The second line T302 also passes through the second stirring chamber 220 and the third stirring chamber 403.

[0119] The rotation center of the third agitator 401 is located near the second line T302 in the vertical direction. Since the second line T302 is set to be inclined more towards the horizontal line (front-to-back direction) than the vertical line (up-down direction), the vertical difference between the first stirring chamber 210, the second stirring chamber 220, and the third stirring chamber 403 is kept low. Therefore, the vertical (height) size of the developing unit 470 can be reduced, making it possible to miniaturize the vertical (height) of the process cartridge 5 and the image forming apparatus 1.

[0120] In addition, because the toner falls (height) from the third stirring chamber 403 to the second stirring chamber 220 by the third agitator 401 is kept low, an increase in powder pressure due to the accumulation of toner in the vertical direction can be prevented. As a result, deterioration due to increased toner powder pressure is suppressed, making it possible to further extend the lifespan of the developing unit 270.

[0121] As mentioned above, the third agitator 401 is said to consist of a third rotating shaft 401A and a third stirring sheet 402, but it is not necessarily limited to this configuration. For example, as shown in Figures 33 and 34, the third agitator 450 may have a third stirring rod 451S, a plurality of stirring blades 452 and a third stirring sheet 455, and may rotate around the third rotating shaft 451A to transport toner from the third stirring chamber 403 to the second stirring chamber 220.

[0122] The third stirring rod 451S is equipped with stirring blades 452 to transport the toner in the third stirring chamber 403 toward the axially outward direction of the third stirring rod 451S. Multiple stirring blades 452 are provided on the third stirring rod 451S at intervals along the left-right direction of the third stirring rod 451. In this embodiment, six stirring blades 452 are provided. The stirring blades 452 in this embodiment have a semi-oval flat plate shape and are configured such that the normal to the third rotation axis 451A at the intersection point 451P has an angle 453θ where it intersects with the third rotation axis 451A.

[0123] As the first to third agitators rotate, the toner in the third stirring chamber 403 is transported axially outward by the third stirring rod 451S and also transported from the third stirring chamber 403 toward the second stirring chamber 220 by the third stirring sheet 455. Furthermore, as the second agitator 321 rotates, the toner in the second stirring chamber 220 is transported from the second stirring chamber 220 toward the first stirring chamber 210. The first stirring rod 311S of the first agitator 311 is equipped with stirring blades 313 to transport the toner in the first stirring chamber 210 to the central part, so the first, second, and third agitators create the toner circulation indicated by arrows 480 and 481 in Figure 34. This large toner circulation makes it possible to suppress toner deterioration and further extend the lifespan of the developing unit 270.

[0124] The amount of toner transported by the third agitator 450 is set to be equal to or less than the amount of toner transported by the first agitator 311. This prevents excessive toner from clogging the second stirring chamber 220 and the first stirring chamber 210 in the backward direction. In this embodiment, the third agitator is provided with multiple stirring blades, but the second agitator may be provided with multiple stirring blades and transported in the axial direction outward of the stirring rod, and the third agitator may be configured to simply have a stirring sheet fixed to the rotating shaft.

[0125] Furthermore, as shown in Figure 34, in this embodiment, there are no lift members 642, etc., around the third stirring chamber 403, which is located away from the developing roller. As a result, space is created in the axial direction of the stirring rod, and the side wall surface 490 of the third stirring chamber 403 in the left-right direction (axial direction of the third stirring rod 451S) can be positioned further outward in the left-right direction than the side wall surface 491 of the second stirring chamber 220 in the left-right direction (axial direction of the second stirring rod 321S). This allows for an increase in the toner container capacity, making it possible to further extend the lifespan of the developing unit 270.

[0126] Thus, the developing unit 470 according to Embodiment 5 shown in Figure 32 includes a developing roller 71 and The device comprises a housing 700 having a first stirring chamber 210, a second stirring chamber 220, and a third stirring chamber 403 for containing toner; a first agitator 311 for transporting the toner inside the housing 700 toward the developing roller 71; a second agitator 321 for transporting the toner inside the housing 700 toward the first agitator 311; and a third agitator 401 for transporting the toner inside the housing 700 toward the second agitator 321.

[0127] The housing 700 has an arc-shaped first wall surface 212 that protrudes outward toward the first stirring chamber 210, an arc-shaped second wall surface 222 that protrudes outward toward the second stirring chamber 220, and an arc-shaped third wall surface 505 that protrudes outward toward the third stirring chamber 403. The first agitator 311 is positioned above the first wall surface 212, the second agitator 321 is positioned above the second wall surface 222, and the third agitator 401 is positioned above the third wall surface 505.

[0128] Furthermore, as shown in Figure 34, the first agitator 211 includes a first rotating shaft 311A ​​and a plurality of stirring blades 313 fixed to the first rotating shaft 311A. The stirring blades 313 are positioned at an inclination with respect to the axis of the first rotating shaft 311A ​​such that when the first rotating shaft 311A ​​rotates, a force is generated that transports toner inward in the axial direction of the first rotating shaft 311A.

[0129] Furthermore, the third agitator 450 shown in Figures 33 and 34 comprises a third rotating shaft 451A and a plurality of stirring blades 452 fixed to the third rotating shaft 451A. The stirring blades 452 are positioned at an inclination with respect to the axis of the third rotating shaft 451A such that when the third rotating shaft 401A rotates, a force is generated that transports toner outward in the axial direction of the third rotating shaft 451A. Note that the stirring blades 313 and 452 may have shapes such as helical surfaces or flat plates.

[0130] Furthermore, as shown in Figures 33 and 34, the developing unit 470 includes a first stirring chamber 210 housing the first agitator 311, a second stirring chamber 220 housing the second agitator 321, and a third stirring chamber 403 housing the third agitator 450. The width of the third stirring chamber 403, which serves as the third transport chamber, in the direction along the second rotation axis 321A of the second agitator 321 is greater than the width of the second stirring chamber 220, which serves as the second transport chamber, in the direction along the rotation axis of the second agitator 321.

[0131] <Effects and Actions of Example 5> By having the third agitator 401 in the third stirring chamber 403, the toner storage chamber can be made larger. Also, since the rotation center of the third agitator 401 is located near the second line T302 in the vertical direction, that is, within the rotation radius of the tip of the third stirring sheet 402, the vertical (height) size of the developing unit 270 can be reduced. In addition, the stirring blades 313 of the first agitator 311 reduce the toner pressure at both ends, preventing toner leakage from the toner seal portion at the end of the developing roller 71. Furthermore, since the third stirring rod 451S has stirring blades 452 for conveying in the axial direction outward, it is possible to suppress toner deterioration and further extend the lifespan of the developing unit 270. In addition, since the side walls of the third stirring chamber 403 can be made outward in the left-right direction, the toner container capacity can be increased.

[0132] [Example 6] Next, Embodiment 6 of the present invention will be described with reference to Figures 25 to 31. In this embodiment, the parts that differ from the previously described embodiment will be explained in detail. Unless otherwise specified, the configuration is the same as in the previously described embodiment, so such parts will be assigned the same numbers and detailed explanations will be omitted.

[0133] Figures 25 and 29 show that in Example 6, the developing unit 500 is connected to the photoreceptor unit 260. Figure 26(a), Figure 27(a), and Figure 28 are cross-sectional views of the developing unit 500 mounted on the photoconductor unit 260 when it is mounted on the main body 2 of the device. Figures 26(b) and 27(b) are perspective views of the developing unit 500 mounted on the photoconductor unit 260, as seen from the cartridge door 520 side, after it has been mounted on the main body 2 of the device. Figure 30 is a perspective view of the developing unit 500 mounted on the photoconductor unit 260. Figure 31 is a cross-sectional view of the developing unit 500.

[0134] As shown in Figure 25, the developing unit 500 is provided with a third agitator 501 in addition to the configuration of the developing unit 270 described in Example 1. The third agitator 501 is located in a third stirring chamber 503, which is located in front of the second stirring chamber 220. The third stirring chamber 503 is a space for containing toner, formed by a third stirring chamber top surface 504 located above the third agitator 501 in the direction of gravity, and a third wall surface 505 located below the third agitator 501 in the direction of gravity. The third wall surface 505 is a convex wall surface that protrudes downward in the direction of gravity relative to the third agitator 501. A third recess 506 is formed at the boundary between the second wall surface 222 and the third wall surface 505 in the front-rear direction, and the second wall surface 222 and the third wall surface 505 are connected via the third recess 506.

[0135] Furthermore, in this embodiment, when the developing unit 500 is attached to the photoreceptor unit 260, the process cartridge is configured such that the third stirring chamber 503 of the developing unit 500 protrudes forward from the frame 610 of the photoreceptor unit 260.

[0136] Furthermore, the rotation center of the third agitator 501 is positioned above the straight line L1 connecting the rotation center of the first agitator 211 and the rotation center of the second agitator 221.

[0137] As shown in Figure 26(a), the developing unit 500 is attached to the photoreceptor unit 260 and then attached to and detached from the main body of the device. At this time, a first engaging portion 507 is provided on the lower side of the third wall surface 505 in the direction of gravity, as an engagement groove and protrusion shape to prevent mis-attachment between multiple process cartridges with different specifications such as lifespan and speed and the main body. A second engaging portion 508 is also provided on the main body of the device 2 as an engagement groove and protrusion shape corresponding to the first engaging portion 507.

[0138] As shown in Figure 26(b), when a corresponding (matching specification) developing unit 500 is attached to the device body 2, the protrusions and indentations on the first engaging portion 507 and the second engaging portion 508 do not come into contact, and the developing unit 500 can be attached to the device body 2. However, as shown in Figure 27(b), when an incompatible (different specification) developing unit 500 is attached to the device body 2, the protrusions and indentations on the first engaging portion 507 and the second engaging portion 508 interfere with each other. In that case, as shown in Figure 27(a), the developing unit 500 cannot be attached to the device body 2 to the complete mounting position.

[0139] Next, as shown in Figure 28, the photoreceptor unit 260 is provided with a photoreceptor drum 61, a frame 610, and a pressing member 509. The pressing member 509 is located behind the third stirring chamber 503 of the developing unit 500. When the developing unit 500 is mounted on the photoreceptor unit 260, the pressing member 509 presses the developing unit 500 in the direction of arrow 201F, pressing the developing roller 71 provided on the developing unit 500 toward the photoreceptor drum 61. The rotation-stopping roller portion 202 described above may also be provided in the third recess 506. Alternatively, the rotation-stopping roller portion 202 described above may be provided in the first recess 231 instead of the third recess 506. Furthermore, the developing unit 500 may be provided with a roller receiving portion 514 having a surface parallel to the direction of arrow 201F at the location where it contacts the rotation-stopping roller portion 202.

[0140] As shown in Figure 29, the photoreceptor unit 260 is provided with a photoreceptor drum 61, a frame 610, and a pressing member 509. The pressing member 509 is located behind the second stirring chamber 220 of the developing unit 500. When the developing unit 500 is mounted on the photoreceptor unit 260, the pressing member 509 presses the developing unit 500 in the direction of arrow 201F, pressing the developing roller 71 provided on the developing unit 500 toward the photoreceptor drum 61. The pressing member 509 may be located in the first recess 231. Furthermore, a roller receiving portion 514 may be provided in the third recess 506, in which the rotation stopper roller portion 202 contacts. The roller receiving portion 514 may also have a surface parallel to the direction of arrow 201F.

[0141] As shown in Figure 30, the handle 510 is positioned on the upper side in the direction of gravity of the second stirring chamber 220. The handle 510 is rotatably fixed to a handle support 511 provided on the second top surface 242 of the stirring chamber.

[0142] A new product detection mechanism (see Figure 8) using the aforementioned detection member 81 and detection projection 83 may be provided on a surface including the cross-section of the third stirring chamber 503 of the developing unit 500.

[0143] As shown in Figure 31, the developing unit 500 is provided with a first filling port 512 and a second filling port 513. The first filling port 512 is provided between the first agitator 211 and the second agitator 221, and the second filling port 513 is provided between the second agitator 221 and the third agitator 501. Alternatively, the first filling port 512 and the second filling port 513 may be sealed with a sealing member having a shaft portion that rotatably supports an idler gear (not shown) for transmitting drive to the first agitator gear 713, the second agitator gear 714, and the third agitator gear (not shown), as shown in Figure 4.

[0144] Thus, the main body 2 of the image forming apparatus according to Embodiment 6 shown in Figure 27 has a configuration that allows the process cartridge to be attached and detached. The third wall surface 505 of the developing unit 500 may have a first engaging portion 507 that can engage with a second engaging portion 508 (main body engaging portion) provided on the main body 2.

[0145] Furthermore, the photoreceptor unit 260 according to Embodiment 6 has a pressing member 509. The developing unit 500 has a pressing receiving portion that is pressed by the pressing member 509. When viewed from a direction along the rotation axis of the developing roller 71, at least a part of the pressing receiving portion 514 is positioned in the third recess 506, which is enclosed by the tangent line that contacts the second wall surface 222 and the third wall surface 505, the second wall surface 222, and the third wall surface 505. Alternatively, as shown in Figure 29, at least a part of the pressing receiving portion may be positioned in the first recess 231.

[0146] <Effects and Actions of Example 6> In this embodiment, when the developing unit 500 is mounted on the photoreceptor unit 260, the third stirring chamber 503 of the developing unit 500 protrudes forward relative to the frame 610 of the photoreceptor unit 260. In this configuration, the support configuration of the developing unit 500 for the photoreceptor unit 260 is made common with that of the developing unit 270. This makes it possible to mount multiple developing units with different lifespans (toner capacities) without changing the photoreceptor unit 260. Therefore, the number of types of photoreceptor units to be incorporated when manufacturing process cartridges is reduced. As a result, the number of molding dies required for each type of photoreceptor unit can be reduced. In addition, since the assembly equipment only needs to be able to handle a relatively small number of types of photoreceptor units, manufacturing costs can be reduced by simplifying the assembly equipment.

[0147] In this embodiment, the rotation center of the third agitator 501 is positioned above the straight line L1 connecting the rotation center of the first agitator 211 and the rotation center of the second agitator 221. Therefore, gravity is used to transfer toner from the third agitator 501 to the second agitator 221. This makes it possible to transport the toner. As a result, the third recess 506 can be eliminated, and the third wall surface 505 and the second wall surface 222 can be connected by an inclined surface that slopes downward in the direction of gravity from the third wall surface 505 to the second wall surface 222, allowing the toner to be transported by sliding it down the inclined surface. Furthermore, by eliminating the third recess 506, it becomes possible to increase the amount of toner that can be filled.

[0148] Furthermore, as shown in Figure 28, the first engaging portion 507 provided on the developing unit 500 and the second engaging portion 508 provided on the device body 2 make it possible to determine compatibility between the combination of the device body 2 and the developing unit 500. An example of when compatibility is necessary is when the number of product types is increased by changing the toner, resulting in multiple combinations of the main device 2 and the developing unit 500. In such cases, if a developing unit 500 that is not compatible with the main device 2 is installed, there is a risk that the main device 2 will malfunction.

[0149] To prevent such a situation, when attaching the developing unit to the main body 2 of the device, the first engaging portion 507 and the second engaging portion 508 are made to interfere with each other, preventing the developing unit 500 from being attached to the main body 2 of the device. Furthermore, in this embodiment, since the first engaging portion 507 is provided on the developing unit 500 rather than the photoreceptor unit 260, the photoreceptor unit 260 can be standardized even when providing developing units with multiple different specifications as products. In this embodiment, compatibility is achieved through the concave and concave relationship between the first engaging portion 507 and the second engaging portion 508, but this is not the only way to achieve compatibility; various means such as positional relationship and size relationship are possible.

[0150] Furthermore, in this embodiment, by efficiently arranging the pressing member 509 in the space formed by the frame 610 of the photoreceptor unit 260 and the third recess 506 or first recess 231 of the developing unit 500, it becomes possible to press the developing roller 71 toward the photoreceptor drum 61 without affecting the size of the main body 2 of the device. Also, by arranging the rotation-stopping roller 202 in the space formed by the frame 610 and the second recess 232 or first recess 231 of the stirring chamber, the posture of the developing unit 500 can be stabilized. Furthermore, in this embodiment, it becomes possible to stably press the developing roller 71 toward the photoreceptor drum 61. Note that the number of pressing members 509 and rotation-stopping rollers 202 does not need to be limited to one.

[0151] Furthermore, by positioning the handle 510 on the upper side in the direction of gravity of the second stirring chamber 220, which is close to the center of gravity position 500G of the developing unit 500, it is possible to reduce the load on the user when gripping the developing unit 500.

[0152] Furthermore, in this embodiment, since a pressing member 509 is provided in the third recess 506, the third recess 506 and the pressing member 509 can be used as engagement grooves to prevent mis-insertion between multiple process cartridges with different specifications such as lifespan and speed. Specifically, if the third recess 506 of the developing unit 500 is located in a different position from the pressing member 509, when the developing unit 500 is mounted on the photoreceptor unit 260, either the second wall surface 222 or the third wall surface 505 will abut against the pressing member 509. As a result, it is not possible to mount the cartridge to the completed mounting position as shown in Figure 18. By configuring the process cartridge as in this embodiment, it is possible to make the user aware of mis-insertion of the process cartridge into the device body.

[0153] Furthermore, it is possible to combine the configurations described in each of the above embodiments as appropriate, within the bounds of consistency. [Explanation of symbols]

[0154] 5…Process cartridge, 61…Photoconductor drum, 71…Developing roller, 200…Pressing unit Material, 212...First wall surface, 222...Second wall surface, 231...First recess, 250...Housing, 260...Photoconductor unit, 270...Developing unit, 610...Frame

Claims

1. A process cartridge comprising a photoreceptor unit and a developing unit detachable from the photoreceptor unit, The aforementioned photoreceptor unit is A photoreceptor drum in which an electrostatic latent image is formed, A frame that supports the photosensitive drum, It has a pressing member that presses the developing unit toward the photoreceptor unit, The aforementioned developing unit is A developing roller that supplies toner to the photoreceptor drum and collects toner remaining on the surface of the photoreceptor drum, A housing having a storage space for storing toner, It has a pressing receiving portion that receives the pressing force from the pressing member, The aforementioned enclosure is In its orientation during use, it has a first arc-shaped bottom that protrudes outward from the storage space, and a second arc-shaped bottom that protrudes outward from the storage space. When viewed from a direction along the rotation axis of the developing roller, at least a portion of the pressing receiving portion is configured to be located in the space enclosed by the tangent line that contacts the outer wall of the first bottom and the outer wall of the second bottom, the first bottom, and the second bottom. A process cartridge characterized by the following features.

2. The aforementioned developing unit is A first transport member rotates so as to contact the inner wall of the first bottom and transports toner, The device further includes a second transport member that rotates to contact the inner wall of the second bottom and transports toner, When viewed from a direction along the rotation axis of the developing roller, the pressing receiving portion is positioned horizontally between the rotation center of the first conveying member and the rotation center of the second conveying member. The process cartridge according to feature 1.

3. The process cartridge according to claim 1 or 2, characterized in that, when viewed from a direction along the rotation axis of the developing roller, the first straight line extending along the pressing direction of the pressing member against the pressing receiving portion passes through the first bottom and the second bottom.

4. The process cartridge according to claim 2, characterized in that, when viewed from a direction along the rotation axis of the developing roller, a second straight line passing through the rotation center of the developing roller and the rotation center of the first transport member passes through a transport chamber housing the second transport member.

5. The photoreceptor unit has a lifting member that presses and moves the developing unit, The process cartridge according to any one of claims 1 to 4, characterized in that the pressing member is positioned on the central side of the frame than the lift member in the rotation axis direction of the photoreceptor drum.

6. A process cartridge comprising a photoreceptor unit and a developing unit detachable from the photoreceptor unit, The aforementioned photoreceptor unit is A photoreceptor drum in which an electrostatic latent image is formed, A frame that supports the photosensitive drum, It has a pressing member that presses the developing unit toward the photoreceptor unit, The aforementioned developing unit is A developing roller that supplies toner to the photoreceptor drum and collects toner remaining on the surface of the photoreceptor drum, A housing having a storage space for storing toner, It has a pressing receiving portion that receives the pressing force from the pressing member, The aforementioned enclosure is In the position used, the first bottom portion is arc-shaped and protrudes outward from the storage space, A second arc-shaped bottom portion that protrudes outward from the aforementioned storage space, The first top surface and, A second top surface is provided above the first top surface in the direction of gravity, It has a connecting portion that connects the first top surface and the second top surface, The process cartridge is characterized in that the connecting portion has an opposing surface that faces the first top surface.

7. The photoreceptor unit has a rotation-stopping roller that supports the developing unit when the developing unit is attached to the photoreceptor unit. The process cartridge according to claim 6, characterized in that at least a portion of the rotation-stopping roller portion is arranged in the space enclosed by the tangent line that contacts the outer wall of the first bottom portion and the outer wall of the second bottom portion, the first bottom portion, and the second bottom portion, when viewed from a direction along the rotation axis of the developing roller.

8. The aforementioned developing unit is A first transport member rotates so as to contact the inner wall of the first bottom and transports toner, A second transport member rotates to contact the inner wall of the second bottom and transports toner, A first transport chamber for housing the first transport member, It has a second transport chamber for housing the second transport member, The process cartridge according to claim 6 or 7, characterized in that the width of the second transport chamber in the direction along the rotation axis of the developing roller is greater than the width of the first transport chamber.

9. A process cartridge comprising a photoreceptor unit and a developing unit detachable from the photoreceptor unit, The aforementioned photoreceptor unit is A photoreceptor drum in which an electrostatic latent image is formed, It has a frame that supports the photosensitive drum, The aforementioned developing unit is A developing roller that supplies toner to the photoreceptor drum and collects toner remaining on the surface of the photoreceptor drum, A housing having a storage space for storing toner, A first transport member that transports toner toward the developing roller, It has a second transport member that transports toner toward the first transport member, The aforementioned enclosure is In the position used, the first bottom portion is arc-shaped and protrudes outward from the storage space, It has an arc-shaped second bottom portion that protrudes outward from the aforementioned storage space, The first transport member is, It is positioned above the first bottom and has a rotating shaft and a stirring blade inclined with respect to the axis of the rotating shaft, The second transport member is, A process cartridge characterized by having a rotating shaft and a stirring sheet with slits, positioned above the second bottom portion.

10. The first conveying member has a plurality of stirring blades, The process cartridge according to claim 9, characterized in that, when viewed from a direction perpendicular to the axial direction of the rotation axis, at least a portion of the slit is located between two adjacent stirring blades in the axial direction.

11. The aforementioned slit is The stirring sheet has a first end located on the free end side and a second end on the opposite side of the first end, The process cartridge according to claim 9 or 10, characterized in that it extends outward from the center in the axial direction of the rotating shaft from the second end to the first end.

12. A process cartridge comprising a photoreceptor unit and a developing unit detachable from the photoreceptor unit, The aforementioned photoreceptor unit is A photoreceptor drum in which an electrostatic latent image is formed, It has a frame that supports the photosensitive drum, The aforementioned developing unit is A developing roller that supplies toner to the photoreceptor drum and collects toner remaining on the surface of the photoreceptor drum, A housing having a storage space for storing toner, A first transport member that transports the toner in the storage space toward the developing roller, A second transport member transports the toner in the storage space toward the first transport member, It has a third transport member that transports the toner in the storage space toward the second transport member, The aforementioned enclosure is In the position used, the first bottom portion is arc-shaped and protrudes outward from the storage space, A second arc-shaped bottom portion that protrudes outward from the aforementioned storage space, It has an arc-shaped third bottom portion that protrudes outward from the aforementioned storage space, The first transport member is positioned above the first bottom portion, The second transport member is positioned above the second bottom portion. The third transport member is positioned above the bottom of the third, A process cartridge characterized by the following features.

13. The first conveying member comprises a first rotating shaft and a first stirring blade fixed to the first rotating shaft, The process cartridge according to claim 12, characterized in that the first stirring blade is positioned at an inclination with respect to the axis of the first rotating shaft such that when the first rotating shaft rotates, a force is generated that transports toner inward in the axial direction of the first rotating shaft.

14. At least one of the second conveying member and the third conveying member comprises a second rotating shaft and a second stirring blade fixed to the second rotating shaft, The process cartridge according to claim 12 or 13, characterized in that the second stirring blade is positioned at an inclination with respect to the axis of the second rotating shaft such that when the second rotating shaft rotates, a force is generated that transports toner outward in the axial direction of the second rotating shaft.

15. The process cartridge according to claim 13 or 14, characterized in that the stirring blade is flat.

16. A first transport chamber for housing the first transport member, A second transport chamber for housing the second transport member, It has a third transport chamber for housing the third transport member, The process cartridge according to any one of claims 12 to 15, characterized in that the width of the third transport chamber in the direction along the rotation axis of the second transport member is greater than the width of the second transport chamber.

17. A process cartridge comprising a photoreceptor unit and a developing unit detachable from the photoreceptor unit, The aforementioned photoreceptor unit is A photoreceptor drum in which an electrostatic latent image is formed, It has a frame that supports the photosensitive drum, The aforementioned developing unit is A developing roller that supplies toner to the photoreceptor drum and collects toner remaining on the surface of the photoreceptor drum, A housing having a storage space for storing toner, A rotatable first transport member that transports the toner in the storage space toward the developing roller, A rotatable second transport member that transports the toner in the storage space toward the first transport member, It has a third transport member that transports the toner in the storage space toward the second transport member, The aforementioned enclosure is In the position used, the first bottom portion is arc-shaped and protrudes outward from the storage space, A second arc-shaped bottom portion that protrudes outward from the aforementioned storage space, It has an arc-shaped third bottom portion that protrudes outward from the aforementioned storage space, The first transport member is positioned above the first bottom portion, The second transport member is positioned above the second bottom portion. The third transport member is positioned above the third bottom, When viewed from a direction along the rotation axis of the first transport member, in the direction in which the straight line passing through the rotation center of the first transport member and the rotation center of the second transport member extends, at least a portion of the third bottom extends in a direction away from the photoreceptor drum than the end on the opposite side of the photoreceptor unit from the side on which the photoreceptor drum is located. A process cartridge characterized by the following features.

18. The third transport member is rotatable, The process cartridge according to claim 17, characterized in that, when viewed from a direction along the rotation axis of the first conveying member, the rotation center of the third conveying member is positioned above the line connecting the rotation center of the first conveying member and the rotation center of the second conveying member in the direction of gravity.

19. The process cartridge is detachable from the main body of the image forming apparatus. The process cartridge according to claim 17 or 18, characterized in that the third bottom portion has an engagement portion that can engage with a main body engagement portion provided on the main body of the device.

20. The photoreceptor unit has a pressing member, The developing unit has a pressing receiving portion that is pressed by the pressing member, When viewed from a direction along the rotation axis of the developing roller, at least a portion of the pressing receiving portion is positioned in the space enclosed by the tangent line that contacts the outer wall of the second bottom and the outer wall of the third bottom, the second bottom, and the third bottom. A process cartridge according to any one of claims 17 to 19.

21. The photoreceptor unit has a pressing member, The developing unit has a pressing receiving portion that is pressed by the pressing member, When viewed from a direction along the rotation axis of the developing roller, at least a part of the pressing receiving portion is positioned in the space enclosed by the tangent line that contacts the first bottom and the second bottom, the first bottom, and the second bottom. A process cartridge according to any one of claims 17 to 19.

Images