Developing cartridge and method for manufacturing the same

Abstract

To suppress toner from leaking from a space between a holder and a plate.SOLUTION: A development cartridge 1 comprises a development roller 10, a blade 30 in contact with the development roller 10, a holder 40, a plate 50 and a film 80. The development roller 10 is rotatable about an axis extending in a first direction. The holder 40 has a first surface 40A to which the blade 30 is attached and a second surface 40B located on the opposite side to the first surface 40A. The plate 50 has a first end face 50A in contact with the second surface 40B, having a center in the first direction projecting toward the holder 40 compared to one end and the other end of the first end face 50A. The film 80 comes in contact with the holder 40 and the plate 50. The film 80 covers a contact portion between the second surface 40B of the holder 40 and the first end face 50A of the plate 50.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a developing cartridge including a blade that contacts a developing roller and a method for manufacturing the same.

Background Art

[0002] Conventionally, as a developing cartridge, one including a developing roller, a developing frame, and a blade is known (Patent Document 1). In this technique, the blade is sandwiched between a plate and a holder and attached to the developing frame. The holder is formed by performing a bending process of bending a metal plate into an L shape.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a demand to miniaturize the developing cartridge. In order to miniaturize the developing cartridge, a configuration in which the holder is not formed in an L shape but pressed against the end surface of the plate can be considered. However, in a configuration in which the holder is pressed against the end surface of the plate, there is a risk that toner may leak from between the holder and the plate.

[0005] Therefore, an object of the present disclosure is to suppress leakage of toner from between the holder and the plate.

Means for Solving the Problems

[0006] A developing cartridge of the present disclosure for solving the aforementioned problems comprises a developing roller, a blade, a holder, a plate, and a film. The developing roller is rotatable about a developing roller axis extending in a first direction. The blade contacts the developing roller. The blade extends in a first direction. The holder is a flat plate extending in a first direction. The holder has a first surface to which the blade is mounted and a second surface located opposite the first surface. The plate is a flat plate extending in a first direction. The plate has a first end surface that contacts the second surface, the first end surface having a center in the first direction that protrudes toward the holder more than one end and the other end of the first end surface in the first direction. The film contacts the holder and the plate. The film covers the contact area between the second surface of the holder and the first end surface of the plate.

[0007] With this configuration, the film covers the contact area between the second surface of the holder and the first end surface of the plate, thus preventing toner from leaking between the holder and the plate.

[0008] Furthermore, in the aforementioned developing cartridge, the film has a first portion that is attached to at least one of the blade and the holder, and a second portion that is attached to the plate.

[0009] According to this design, the film is bonded to the blade or holder and the plate, which prevents toner from leaking between the holder and the plate.

[0010] Furthermore, in the aforementioned developing cartridge, the film may further have a third portion that is not adhered, and the third portion may be located between the first portion and the second portion and be curved.

[0011] According to this, it is possible to suppress the formation of wrinkles in the third section.

[0012] Furthermore, in the aforementioned developing cartridge, the film may be attached to at least one of the blade and the holder by double-sided tape.

[0013] Furthermore, in the aforementioned developing cartridge, the film may be attached to the blade with double-sided tape.

[0014] Furthermore, in the aforementioned developing cartridge, the film may be attached to the plate with double-sided tape.

[0015] Furthermore, the developing cartridge may also further include a developing frame to which developing rollers, a holder, and a plate are attached, wherein the plate is fixed to the developing frame by screws, and the screws are located between one end and the other end of the film in the first direction.

[0016] According to this method, toner leakage can be suppressed over an area wider than the area where the screws that secure the developing frame are located.

[0017] Furthermore, the developing cartridge may further include a developing frame to which developing rollers, a holder, and a plate are attached, and the plate may be fixed to the developing frame by a plurality of screws arranged in a first direction, with the plurality of screws positioned between one end and the other end of the film in the first direction.

[0018] According to this method, toner leakage can be suppressed over an area wider than the range in which multiple screws are located.

[0019] Furthermore, the developing cartridge described above may further include a developing frame on which developing rollers, a holder, and a plate are attached, and a seal located between the second surface of the holder and the developing frame, the seal extending in the first direction.

[0020] Furthermore, in the aforementioned developing cartridge, the holder may be configured to be located between the seal and the film.

[0021] Also, in the above-described developing cartridge, a developing frame to which a developing roller, a holder, and a plate are attached, and a seal located between the second surface of the holder and the developing frame, the seal extending in a first direction, are further provided, and the holder may be configured to be located between the seal and a first portion.

[0022] Also, in the above-described developing cartridge, a developing frame to which a developing roller, a holder, and a plate are attached, and a seal located between the second surface of the holder and the developing frame, the seal extending in a first direction, are further provided, and the plate may be configured to be located between a second portion and the seal.

[0023] Further, the method for manufacturing the above-described developing cartridge may include a first step of fixing a plate to a developing frame, a second step of adhering a film to at least one of the blade of the holder to which the blade is attached and the holder after the first step, a third step of fixing the holder to which the blade is attached to the developing frame after the second step, and a fourth step of adhering the film to the plate after the third step.

[0024] According to this, since the method for manufacturing the developing cartridge includes the first step, the second step, the third step, and the fourth step, the developing cartridge can be manufactured efficiently.

Advantages of the Invention

[0025] According to the present disclosure, it is possible to suppress toner from leaking between the holder and the plate.

Brief Description of the Drawings

[0026] [Figure 1] It is a perspective view of a developing cartridge. [Figure 2] It is an exploded perspective view of a developing cartridge. [Figure 3] It is a cross-sectional view of a developing cartridge. [Figure 4] It is an exploded perspective view of a blade unit. [Figure 5]This is a front view of the blade unit. [Figure 6] This is a plan view of the plate. [Figure 7] This is an enlarged view of Figure 3, illustrating the area where the film is bonded. [Figure 8] This is a diagram of the film before it is attached to the developing cartridge. [Figure 9] Figures (a) to (c) illustrate the process of attaching the film to the developing cartridge. [Modes for carrying out the invention]

[0027] Next, embodiments of the present disclosure will be described with reference to the drawings as appropriate. As shown in Figure 1, the developing cartridge 1 is used in an electrophotographic image forming apparatus such as a laser printer. The developing cartridge 1 is detachably mounted in the image forming apparatus.

[0028] As shown in Figures 1 and 2, the developing cartridge 1 comprises a developing roller 10, a supply roller 20, a blade unit BL, a plate 50, a developing frame 60, a film 80, and a seal 90. The developing cartridge 1 also further comprises a first screw 71, a second screw 72, and a third screw 73 for attaching the plate 50 to the developing frame 60, and a first fixing screw 74 and a second fixing screw 75 for attaching the blade unit BL to the developing frame 60.

[0029] The developing roller 10 is a roller having a surface for carrying toner. As shown in Figure 2, the developing roller 10 is rotatable about a developing roller shaft 10X extending in a first direction. The developing roller 10 has a metal developing roller shaft 11 that is rotatably supported on the developing frame 60, and a developing roller body 12 that covers the developing roller shaft 11. The developing roller body 12 is made of conductive rubber or the like.

[0030] Here, the first direction is the same as the longitudinal direction of the developing roller 10, blade unit BL, and plate 50. The second direction is the direction intersecting the first direction. Preferably, the second direction is perpendicular to the first direction. The second direction is the same as the short direction of the plate 50. The third direction is the direction intersecting the first and second directions. Preferably, the third direction is perpendicular to the first and second directions. The third direction is the same as the short direction of the blade unit BL.

[0031] As shown in Figure 3, the supply roller 20 is a roller that supplies toner to the developing roller 10. The supply roller 20 is rotatable about a supply roller shaft 20X that extends in a first direction. The supply roller 20 has a supply roller shaft 21 that is rotatably supported on the developing frame 60 and a supply roller body 22 that covers the supply roller shaft 21. The supply roller body 22 is made of a sponge or the like.

[0032] The blade unit BL is a component that restricts the toner supplied to the developing roller 10 to a thin layer of a certain thickness. The blade unit BL comprises a blade 30 that contacts the developing roller 10 and a holder 40 that supports the blade 30.

[0033] As shown in Figure 4, the blade 30 extends in a first direction. The blade 30 has a blade sheet metal 31 and a rubber portion 32. The blade 30 also has a front surface 30A and a back surface 30B located opposite the front surface 30A. More specifically, the blade 30 has a front surface 30A and a back surface 30B located opposite the front surface 30A in a second direction. More specifically, the blade sheet metal 31 has a front surface 30A and a back surface 30B.

[0034] One end of the blade sheet metal 31 in the third direction is attached to the holder 40. The rubber part 32 is attached to the other end of the blade sheet metal 31 in the third direction. More specifically, the rubber part 32 is fixed to the other end of the blade sheet metal 31 in the third direction with adhesive. The rubber part 32 is the part that contacts the circumferential surface of the developing roller 10. The rubber part 32 is attached to the front surface 30A of the blade sheet metal 31. More specifically, the rubber part 32 is fixed to the front surface 30A of the blade sheet metal 31 with adhesive.

[0035] The blade 30 has a first hole 34 and a second hole 35. More specifically, the blade sheet metal 31 has a first hole 34 and a second hole 35. The first hole 34 is a round hole, and the second hole 35 is an elongated hole that is long in the first direction. The second hole 35 is located away from the first hole 34 in the first direction. Specifically, the first hole 34 is located at one end of the blade sheet metal 31 in the first direction, and the second hole 35 is located at the other end of the blade sheet metal 31 in the first direction. In addition, the first hole 34 and the second hole 35 are located away from the rubber portion 32 in the third direction. Specifically, the first hole 34 and the second hole 35 are located at one end of the blade sheet metal 31 in the third direction, and the rubber portion 32 is located at the other end of the blade sheet metal 31 in the third direction.

[0036] The holder 40 extends in a first direction. The holder 40 is a flat plate-shaped member made of a metal plate. The thickness of the holder 40 in the second direction is greater than the thickness of the blade sheet metal 31 in the second direction. The holder 40 has a first surface 40A and a second surface 40B. The first surface 40A is the surface to which the blade 30 is attached. The second surface 40B is located on the opposite side of the first surface 40A in the second direction.

[0037] The holder 40 has a holder central portion 41, a first holder end portion 42, and a second holder end portion 43.

[0038] The holder central portion 41 is located in the center of the holder 40 in the first direction. The holder central portion 41 has a first holder protrusion 44 and a second holder protrusion 45. The first holder protrusion 44 and the second holder protrusion 45 are substantially cylindrical protrusions that project from the first surface 40A toward the blade 30. The second holder protrusion 45 is located away from the first holder protrusion 44 in the first direction. Specifically, the first holder protrusion 44 is located at one end of the holder central portion 41 in the first direction, and the second holder protrusion 45 is located at the other end of the holder central portion 41 in the first direction.

[0039] With the back surface 30B of the blade 30 and the first surface 40A of the holder 40 in contact, the first holder projection 44 fits into the first hole 34 of the blade 30, and the second holder projection 45 fits into the second hole 35 of the blade 30. The second hole 35 is an elongated hole in the first direction, which allows for the absorption of dimensional errors between the first hole 34 and the second hole 35 in the first direction, as well as the absorption of linear expansion of the blade sheet metal 31 and the holder 40 in the first direction.

[0040] The first holder end 42 is located at one end of the holder 40 in the first direction. The first holder end 42 has a first fixing hole 46 through which the first fixing screw 74 (see Figure 2) passes. The first fixing hole 46 is a round hole. In the first direction, the first fixing hole 46 is located closer to one end of the holder 40 in the first direction than the first holder protrusion 44.

[0041] The second holder end 43 is located at the other end of the holder 40 in the first direction. The second holder end 43 has a second fixing hole 47 through which the second fixing screw 75 (see Figure 2) passes. The second fixing hole 47 is an elongated hole that is longer in the first direction. In the first direction, the second fixing hole 47 is located closer to the other end of the holder 40 in the first direction than the second holder protrusion 45.

[0042] As shown in Figure 5, the length H41 of the holder center portion 41 in the third direction is constant across the first direction. The length H41 of the holder center portion 41 in the third direction is shorter than the length H42 of the first holder end portion 42 and the length H43 of the second holder end portion 43 in the third direction. For example, the length H41 of the holder center portion 41 in the third direction is 5 mm or less. The length H42 of the first holder end portion 42 and the length H43 of the second holder end portion 43 in the third direction are approximately the same.

[0043] The blade 30 is fixed to the holder 40. More specifically, the blade 30 is fixed to the holder 40 by welding the back surface 30B of the blade sheet metal 31 to the first surface 40A of the holder 40 while they are in contact. The back surface 30B of the blade 30 is joined to the first surface 40A of the holder 40 by welding.

[0044] As shown in Figure 6, the plate 50 extends in a first direction. The plate 50 is a flat, plate-shaped member made of metal. The shape of the plate 50 is different from the shape of the holder 40. The thickness of the plate 50 in the third direction is greater than the thickness of the holder 40 in the second direction. The plate 50 has a central plate portion 51, which is the center of the plate 50 in the first direction, a first plate end portion 52, which is one end of the plate 50 in the first direction, and a second plate end portion 53, which is the other end of the plate 50 in the first direction.

[0045] The length of the central portion 51 of the plate in the second direction is longer than the length of the first end portion 52 and the length of the second end portion 53 in the second direction. The central portion 51 of the plate has three boss holes 54 and one plate recess 55.

[0046] As shown in Figure 2, the boss hole 54 is a through hole into which the boss 66 of the developing frame 60, which will be described later, is inserted. The boss hole 54 includes a first boss hole 54A into which the first boss 66A, which will be described later, is inserted, a second boss hole 54B into which the second boss 66B, which will be described later, is inserted, and a third boss hole 54C into which the third boss 66C, which will be described later, is inserted.

[0047] The first boss hole 54A is an elongated hole that is longer in the second direction (see Figure 6). The length of the first boss hole 54A in the second direction, which is its longitudinal direction, is greater than the diameter of the first boss 66A. The length of the first boss hole 54A in the first direction, which is its short direction, is approximately the same as the diameter of the first boss 66A.

[0048] The second boss hole 54B is an elongated hole that is longer in the second direction (see Figure 6). The length of the second boss hole 54B in the second direction, which is its longitudinal direction, is greater than the diameter of the second boss 66B. The length of the second boss hole 54B in the first direction, which is its transverse direction, is greater than the diameter of the second boss 66B. The second boss hole 54B is located away from the first boss hole 54A in the first direction. Specifically, the first boss hole 54A is located at one end of the central portion 51 of the plate in the first direction, and the second boss hole 54B is located at the other end of the central portion 51 of the plate in the first direction.

[0049] The third boss hole 54C is an elongated hole that is longer in the second direction (see Figure 6). The length of the third boss hole 54C in the second direction, which is its longitudinal direction, is greater than the diameter of the third boss 66C. The length of the third boss hole 54C in the first direction, which is its short direction, is greater than the diameter of the third boss 66C. The third boss hole 54C is located away from the first boss hole 54A and the second boss hole 54B in the first direction. More specifically, the third boss hole 54C is located between the first boss hole 54A and the second boss hole 54B in the first direction. In particular, the third boss hole 54C is located in the center of the central portion 51 of the plate in the first direction.

[0050] The plate recess 55 has a shape that is recessed toward the first end face 50A of the plate 50, which will be described later. The plate recess 55 is located at one end of the central portion 51 of the plate in the first direction. More specifically, the plate recess 55 is located between the first boss hole 54A and the first plate end 52 in the first direction. The plate recess 55 is present only at one end of the central portion 51 of the plate in the first direction, and not at the other end of the central portion 51 of the plate in the first direction.

[0051] Returning to Figure 6, the plate 50 has a first end face 50A and a second end face 50B located on the opposite side of the first end face 50A. The first end face 50A is the surface that contacts the second surface 40B of the holder 40 (see Figure 7). In the first direction, the first end face 50A extends across the central portion 51 of the plate, the first plate end portion 52, and the second plate end portion 53.

[0052] In the first direction, the center 50C of the first end face 50A protrudes toward the holder 40 more than one end 50D and the other end 50E of the first end face 50A in the first direction. More specifically, in the second direction, the center 50C of the first end face 50A in the first direction protrudes toward the holder 40 more than one end 50D and the other end 50E of the first end face 50A in the first direction.

[0053] Specifically, the first end face 50A has a first protrusion 56A, a second protrusion 56B, a third protrusion 56C, a fourth protrusion 56D, and a fifth protrusion 56E. The first protrusion 56A, the second protrusion 56B, the third protrusion 56C, the fourth protrusion 56D, and the fifth protrusion 56E protrude toward the holder 40 in the second direction.

[0054] The first protrusion 56A is located at the center 50C of the first end face 50A in the first direction. The second protrusion 56B is located between one end 50D of the first end face 50A and the first protrusion 56A in the first direction. More specifically, the second protrusion 56B is located at one end of the central portion 51 of the plate in the first direction. The third protrusion 56C is located between the other end 50E of the first end face 50A and the first protrusion 56A in the first direction. More specifically, the third protrusion 56C is located at the other end of the central portion 51 of the plate in the first direction. The fourth protrusion 56D is located between the first protrusion 56A and the second protrusion 56B in the first direction. The fifth protrusion 56E is located between the first protrusion 56A and the third protrusion 56C in the first direction.

[0055] The amount of protrusion of the first protrusion 56A is greater than the amount of protrusion of the second protrusion 56B and the amount of protrusion of the third protrusion 56C. Here, the amount of protrusion refers to the amount of protrusion from the plane PL connecting one end 50D and the other end 50E of the first end face 50A. The amount of protrusion of the second protrusion 56B and the amount of protrusion of the third protrusion 56C are approximately the same. The amount of protrusion of the fourth protrusion 56D is greater than the amount of protrusion of the second protrusion 56B and less than the amount of protrusion of the first protrusion 56A. The amount of protrusion of the fifth protrusion 56E is greater than the amount of protrusion of the third protrusion 56C and less than the amount of protrusion of the first protrusion 56A. The amount of protrusion of the fourth protrusion 56D and the amount of protrusion of the fifth protrusion 56E are approximately the same.

[0056] The protrusion amounts of the first protrusion 56A, the second protrusion 56B, and the fourth protrusion 56D increase in the order of the second protrusion 56B, the fourth protrusion 56D, and the first protrusion 56A, from one end 50D of the first end face 50A toward the center 50C in the first direction. Also, the protrusion amounts of the first protrusion 56A, the third protrusion 56C, and the fifth protrusion 56E increase in the order of the third protrusion 56C, the fifth protrusion 56E, and the first protrusion 56A, from the other end 50E of the first end face 50A toward the center 50C in the first direction. The second protrusion 56B, the fourth protrusion 56D, the first protrusion 56A, the fifth protrusion 56E, and the third protrusion 56C are stepped in shape, protruding more towards the center in the first direction.

[0057] The second end face 50B is located on the opposite side of the first end face 50A in the second direction. In the first direction, the second end face 50B extends across the plate center 51, the first plate end 52, and the second plate end 53. In the first direction, the second end face 50B includes the second end face center 51B located in the plate center 51, the second end face one end 52B located in the first plate end 52, and the second end face other end 53B located in the second plate end 53. The second end face one end 52B and the second end face other end 53B are located closer to the first end face 50A than the second end face center 51B in the second direction.

[0058] As shown in Figure 2, the developing frame 60 is a component to which the developing roller 10, supply roller 20, holder 40, and plate 50 are attached. The developing frame 60 rotatably supports the developing roller 10 and the supply roller 20. The developing frame 60 is made of resin or the like. The developing frame 60 has a storage chamber 60A (see Figure 3) and an opening 60B. Toner is stored in the storage chamber 60A. The opening 60B is an opening for supplying the toner in the storage chamber 60A to the developing roller 10.

[0059] As shown in Figure 3, the developing frame 60 further comprises a first frame 61 and a second frame 62. The first frame 61 has a box shape with openings on one side in the second direction and one side in the third direction. The second frame 62 covers the first frame 61 from one side in the third direction. The second frame 62 is fixed to the first frame 61 by welding, adhesive, or the like.

[0060] The first frame 61 is to which the developing roller 10, the supply roller 20, and the blade unit BL are attached. As shown in Figure 2, the first frame 61 has a first support portion 63A and a second support portion 63B, a first fixing portion 64A and a second fixing portion 64B, and two protrusions 65.

[0061] The first support portion 63A and the second support portion 63B are parts that rotatably support the developing roller 10. More specifically, the first support portion 63A and the second support portion 63B rotatably support the developing roller shaft 11 via bearing members. The second support portion 63B is located away from the first support portion 63A in the first direction. Specifically, the first support portion 63A is located on the first side wall 61A at one end of the first frame 61 in the first direction, and the second support portion 63B is located on the second side wall 61B at the other end of the first frame 61 in the first direction.

[0062] The first fixing portion 64A and the second fixing portion 64B are the parts to which the blade unit BL is fixed. The first fixing portion 64A and the second fixing portion 64B are located between the first side wall 61A and the second side wall 61B in the first direction. The second fixing portion 64B is located away from the first fixing portion 64A in the first direction. Specifically, the first fixing portion 64A is located at one end of the first frame 61 in the first direction, and the second fixing portion 64B is located at the other end of the first frame 61 in the first direction. The first fixing portion 64A is located inside the first side wall 61A in the first direction, and the second fixing portion 64B is located inside the second side wall 61B in the first direction.

[0063] The two projections 65 are for positioning the plate 50 relative to the developing frame 60, more specifically, the first frame 61, and protrude in a third direction. The two projections 65 position the plate 50 in a second direction. The two projections 65 include a first projection 65A and a second projection 65B.

[0064] As shown in Figure 1, the first projection 65A contacts the first plate end 52 of the plate 50. The second projection 65B contacts the second plate end 53 of the plate 50.

[0065] As shown in Figure 2, the second frame 62 is the part to which the plate 50 is attached. The plate 50 is attached to the second frame 62 so as not to come off the developing frame 60. The second frame 62 has three bosses 66 and one frame protrusion 67.

[0066] The three bosses 66 protrude in a third direction from the plate mounting surface 62A of the second frame 62. The three bosses 66 are cylindrical and have screw holes into which the first screw 71, the second screw 72, and the third screw 73 are inserted. The first screw 71, the second screw 72, and the third screw 73 are inserted into the screw holes of the three bosses 66 and fixed to the developing frame 60 when the three bosses 66 are inserted into the boss holes 54 of the plate 50.

[0067] As shown in Figure 3, the length H66 of the boss 66 in the third direction is longer than the length T50 of the plate 50 in the third direction. In other words, the amount of protrusion of the boss 66 from the plate mounting surface 62A is greater than the length H66 of the plate 50 in the third direction. Therefore, the tip of the boss 66 protrudes from the plate 50 in the third direction when the boss hole 54 of the plate 50 is inserted into the boss 66. The first screw 71, the second screw 72, and the third screw 73 do not come into contact with the plate 50 when fixed to the developing frame 60. In the third direction, the plate 50 is positioned with a gap between it and the heads of the first screw 71, the second screw 72, and the third screw 73. The tightening force of the first screw 71, the second screw 72, and the third screw 73 does not act on the plate 50.

[0068] Returning to Figure 2, the frame protrusion 67 is the portion that fits into the plate recess 55 of the plate 50. The frame protrusion 67 is located at one end of the developing frame 60 in the first direction. The frame protrusion 67 is present only at one end of the developing frame 60 in the first direction and not at the other end of the developing frame 60 in the first direction.

[0069] As shown in Figure 7, the film 80 is positioned to contact the holder 40 and the plate 50. The film 80 covers the contact area CP between the second surface 40B of the holder 40 and the first end surface 50A of the plate 50. In other words, the film 80 covers the boundary between the second surface 40B of the holder 40 and the first end surface 50A of the plate 50. The film 80 has a first portion 81, a second portion 82, and a third portion 83 (see also Figures 1 and 8).

[0070] The first portion 81 is a portion that is bonded to at least one of the blade 30 and the holder 40. In this embodiment, the first portion 81 is bonded to the blade 30 by double-sided tape D. As shown in Figure 8, the first portion 81 has the first adhesive layer 81P of the double-sided tape D attached to it.

[0071] The second part 82 is the portion that is adhered to the plate 50. In this embodiment, the second part 82 is adhered to the plate 50 by double-sided tape D. As shown in Figure 8, the second adhesive layer 82P of the double-sided tape D is attached to the second part 82.

[0072] The third portion 83 is located between the first portion 81 and the second portion 82. The third portion 83 is the part that is not adhered to the blade 30, the holder 40, or the plate 50. As shown in Figure 7, when the film 80 is attached to the developing cartridge 1, the third portion 83 is bent approximately 90° from the second direction to the third direction. In other words, the third portion 83 is bent when viewed from the first direction. In this embodiment, no adhesive layer is attached to the third portion 83.

[0073] As mentioned above, the plate 50 is fixed to the developing frame 60 by a first screw 71, a second screw 72, and a third screw 73, which are aligned in the first direction. As shown in Figure 1, the first screw 71, the second screw 72, and the third screw 73 are located between one end 80A of the film 80 and the other end 80B of the film 80 in the first direction. In other words, the film 80 is provided over a wider area in the first direction than the area where the first screw 71, the second screw 72, and the third screw 73 are located.

[0074] The seal 90 is made of an elastic material such as a sponge. The seal 90 extends in a first direction (see Figure 2). The seal 90 is located between the second surface 40B of the holder 40 and the developing frame 60. The holder 40 is located between the film 80 and the seal 90. More specifically, in the second direction, the holder 40 is located between the first portion 81 of the film 80 and the seal 90. In the third direction, the plate 50 is located between the second portion 82 of the film 80 and the seal 90.

[0075] Next, a method for manufacturing the developing cartridge 1, specifically a method of attaching the film 80 to the developing cartridge 1, will be described. The manufacturing method for the developing cartridge 1 comprises a first step, a second step, a third step, and a fourth step.

[0076] The first step is to fix the plate 50 to the developing frame 60. Specifically, as shown in Figure 2, the plate 50 is attached to the plate mounting surface 62A of the developing frame 60, and the plate 50 is fixed to the developing frame 60 by inserting the first screw 71, the second screw 72, and the third screw 73 into the screw holes of the three bosses 66.

[0077] The second step, after the first step, is to adhere the film 80 to at least one of the blade 30 and the holder 40 of the holder 40 (blade unit BL) to which the blade 30 is attached. As shown in Figure 9(a), before the film 80 is attached to the developing cartridge 1, the first adhesive layer 81P of the first portion 81 has the first release paper HA1 attached to it. In the third step, the first release paper HA1 is peeled off the first portion 81 of the film 80 and the first portion 81 is adhered to the blade 30.

[0078] The third step, after the second step, is to fix the holder 40 (blade unit BL) to which the blade 30 is attached to the developing frame 60. Specifically, as shown in Figure 2, the first fixing screw 74 is passed through the first fixing hole 46 of the holder 40 and fixed to the first fixing part 64A of the developing frame 60, and the second fixing screw 75 is passed through the second fixing hole 47 of the holder 40 and fixed to the second fixing part 64B of the developing frame 60.

[0079] At this time, the blade unit BL has a second surface 40B of the holder 40 that contacts the first end surface 50A of the plate 50. As a result, the first protrusion 56A, second protrusion 56B, third protrusion 56C, fourth protrusion 56D, and fifth protrusion 56E (see Figure 6) of the first end surface 50A can cause the central part of the blade unit BL in the first direction to protrude toward the developing roller 10 more than both ends of the blade unit BL in the first direction. Specifically, the central parts of the holder 40 and blade 30 in the first direction can protrude toward the developing roller 10 more than both ends of the holder 40 and blade 30 in the first direction.

[0080] The fourth step is to adhere the film 80 to the plate 50 after the third step. As shown in Figure 9(b), before the film 80 is attached to the developing cartridge 1, the second adhesive layer 82P of the second portion 82 has the second release paper HA2 attached to it. In the fourth step, the second release paper HA2 is peeled off the second portion 82 of the film 80. Then, as shown in Figure 9(c), the second portion 82 is adhered to the plate 50 while folding the third portion 83.

[0081] Based on the above, the following effects can be obtained in this embodiment.

[0082] According to the developing cartridge 1 of this embodiment, the first end face 50A of the plate 50 makes it possible to make the central portion of the holder 40 and blade 30 in the first direction protrude toward the developing roller 10 more than the ends of the holder 40 and blade 30 in the first direction. Furthermore, since the holder 40 is flat, or more precisely, a flat plate shape that has not been bent, the holder 40 and the blade 30 attached to the holder 40 can be made smaller.

[0083] As described above, the developing cartridge 1 has a protruding central portion of the plate 50, and the holder 40 is made into a plate shape in order to miniaturize the developing cartridge 1, which means that toner may leak from between the plates 50. However, as shown in Figure 7, in this embodiment, the developing cartridge 1 has the film 80 covering the contact portion CP between the second surface 40B of the holder 40 and the first end surface 50A of the plate 50, so that toner leakage from between the holder 40 and the plate 50 can be suppressed.

[0084] Furthermore, the film 80 has a first portion 81 that is adhered to at least one of the blade 30 and the holder 40, and a second portion 82 that is adhered to the plate 50. As a result, since the film 80 is adhered to the blade 30 or the holder 40 and the plate 50, it is possible to suppress toner leakage from between the holder 40 and the plate 50.

[0085] Furthermore, the film 80 has a third portion 83 that is not adhered to any of the blade 30, holder 40, and plate 50. This unadhered third portion 83 constitutes a folded portion when viewed from the first direction, and since the adhered first portion 81 and second portion 82 are not folded when viewed from the first direction, wrinkles can be suppressed in the third portion 83, making it easy to apply the film 80 without wrinkles.

[0086] Furthermore, the first screw 71, second screw 72, and third screw 73 that fix the plate 50 are located between one end 80A of the film 80 and the other end 80B of the film 80 in the first direction. Therefore, since the film 80 is provided over a wider area in the first direction than the area where the first screw 71, second screw 72, and third screw 73 are located, toner leakage can be suppressed over a wider area than the area where the first screw 71, second screw 72, and third screw 73 are located.

[0087] Furthermore, the developing cartridge 1 is manufactured in the following order: a first step of fixing the plate 50 to the developing frame 60, a second step of bonding the film 80 to the blade unit BL, a third step of fixing the blade unit BL to the developing frame 60, and a fourth step of bonding the film 80 to the plate 50. Therefore, by bonding the first part 81 of the film 80 to the blade unit BL first and then bonding the second part 82 to the plate 50 afterward, failures in bonding the film 80 can be suppressed. As a result, the developing cartridge 1 can be manufactured efficiently.

[0088] Although embodiments have been described above, this disclosure is not limited to the embodiments described above and can be implemented with appropriate modifications as illustrated below.

[0089] In the above-described embodiment, the film 80 was adhered to the blade 30 and plate 50 by double-sided tape, but the method of adhesion is not limited to double-sided tape. For example, the film 80 may be adhered to the blade 30 and plate 50 by adhesive.

[0090] In the above-described embodiment, the film 80 had a first portion 81, a second portion 82, and a third portion 83, but the third portion 83 may be omitted. In other words, the film 80 may have a configuration in which it does not have any portion that is not adhered to the blade 30, the holder 40, or the plate 50.

[0091] In the above-described embodiment, the plate 50 was attached to the developing frame 60 by multiple screws (first screw 71, second screw 72, third screw 73). However, the plate 50 may also be attached to the developing frame by a single screw (for example, any one of the first screw 71, second screw 72, or third screw 73). In this case, the screw is located between one end 80A of the film 80 in the first direction and the other end 80B of the film 80 in the first direction. Even in this configuration, toner leakage can be suppressed over a wider area than the area where the screw fixing the developing frame 60 is located.

[0092] In the above-described embodiment, the third portion 83 was not fitted with an adhesive layer. However, even if an adhesive layer is fitted to the third portion 83, the third portion 83 may not be bonded to the blade 30, holder 40, or plate 50 by not removing the release paper from the portion corresponding to the third portion 83.

[0093] Furthermore, the first end face of the plate may be configured without a fourth or fifth protrusion. In this case, the second and third protrusions may be connected to the first protrusion. Also, the first end face of the plate may be configured having only the first protrusion. Furthermore, the first end face of the plate may not have any protrusions, and the center of the first end face in the first direction may be an arched curved surface that protrudes toward the holder more than one end of the first end face in the first direction and the other end of the first end face in the first direction.

[0094] In the above-described embodiment, the projection 65 of the developing frame 60 was configured to include a first projection 65A and a second projection 65B, but it is not limited to this configuration. For example, the developing frame may have only one projection.

[0095] In the above-described embodiment, the blade 30 had a rubber portion 32, but it is not limited to this. For example, the blade may have no rubber portion. That is, the blade may have a blade sheet metal that is in direct contact with the developing roller.

[0096] In the above-described embodiment, the blade 30 and the holder 40 were fixed by welding, but the invention is not limited to this. For example, the blade and the holder may be fixed by adhesive or other means.

[0097] In the above-described embodiment, the developing cartridge 1 was equipped with a storage chamber 60A in which toner is contained, but it is not limited to this. For example, the developing cartridge may be configured without a storage chamber. In this case, the developing cartridge may be configured such that a toner cartridge in which toner is contained is detachably mounted.

[0098] The elements described in the above embodiments and modifications may be implemented in any combination. [Explanation of Symbols]

[0099] 1. Developing cartridge 10 Developing roller 30 blades 40 holders 40A, Page 1 40B 2nd side 41 Holder center 50 plates 50A 1st end face 50B 2nd end face 50C center 60 developing frames 80 film 81 Part 1 82 Part 2 83 Part 3 90 stickers CP contact part

Claims

1. A developing roller that is rotatable with respect to a developing roller shaft extending in the first direction, A blade that contacts the developing roller, comprising a blade extending in the first direction, A flat plate-shaped holder extending in the first direction, having a first surface to which the blade is attached, and a second surface located opposite the first surface, A plate in the shape of a flat plate extending in the first direction, having a first end face that contacts the second surface, the first end face having a center in the first direction that protrudes toward the holder more than one end and the other end of the first end face in the first direction, A film that contacts the holder and the plate, the film covering the contact portion between the second surface of the holder and the first end surface of the plate, A developing cartridge characterized by having the following features.

2. The developing cartridge according to claim 1, characterized in that the film has a first portion adhered to the blade and a second portion adhered to the plate.

3. The aforementioned film further has a third portion that is not adhered, The developing cartridge according to claim 2, characterized in that the third portion is located between the first and second portions and is curved.

4. The developing cartridge according to claim 3, characterized in that the film is adhered to at least one of the blade and the holder by double-sided tape.

5. The developing cartridge according to claim 4, characterized in that the film is attached to the blade by double-sided tape.

6. The developing cartridge according to any one of claims 1 to 5, characterized in that the film is adhered to the plate by double-sided tape.

7. The developing frame further comprises the developing roller, the holder, and the plate to which the developing roller, the holder, and the plate are attached. The plate is fixed to the developing frame by screws, The developing cartridge according to any one of claims 1 to 5, characterized in that the screw is located between one end of the film in the first direction and the other end of the film in the first direction.

8. The developing frame further comprises the developing roller, the holder, and the plate to which the developing roller, the holder, and the plate are attached. The plate is fixed to the developing frame by a plurality of screws arranged in the first direction, The developing cartridge according to any one of claims 1 to 5, characterized in that the plurality of screws are located between one end of the film in the first direction and the other end of the film in the first direction.

9. A developing frame on which the developing roller, the holder, and the plate are attached, The developing cartridge according to any one of claims 1 to 5, further comprising a seal located between the second surface of the holder and the developing frame, the seal extending in the first direction.

10. The developing cartridge according to claim 9, characterized in that the holder is located between the seal and the film.

11. The developing frame to which the developing roller, the holder, and the plate are attached, and the developing frame further comprises a seal located between the second surface of the holder and the developing frame, the seal extending in the first direction, The developing cartridge according to claim 2, characterized in that the holder is located between the seal and the first portion.

12. The developing frame to which the developing roller, the holder, and the plate are attached, and the developing frame further comprises a seal located between the second surface of the holder and the developing frame, the seal extending in the first direction, The developing cartridge according to claim 2, characterized in that the plate is located between the second portion and the seal.

13. A method for manufacturing a developing cartridge according to claim 1, The developing cartridge further comprises a developing frame on which the developing roller, the holder, and the plate are mounted, The first step is to fix the plate to the developing frame, A second step is to adhere the film to at least one of the blade and the holder to which the blade is attached, After the second step, a third step is to fix the holder to which the blade is attached to the developing frame, After the third step, a fourth step is to adhere the film to the plate, A method for manufacturing a developing cartridge, characterized by comprising the following features.

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