Development cartridge

Abstract

To prevent a development roller from warping when a development cartridge has dropped.SOLUTION: A development cartridge 10 includes a housing 11, a development roller 12 and a protective covering 20. The housing 11 is configured to house toner therein. The development roller 12 is rotatably supported by the housing 11, centering a first shaft X1 extending in an axial direction. The protective covering 20 is detachable from the housing 11 and covers the development roller 12. The protective covering 20 includes a first face 21 and a second face 22. The first face 21 opposes a peripheral surface of the development roller 12 in a state in which the protective covering 20 is attached to the housing 11. The first face 21 has an arc surface 21A along the peripheral surface of the development roller 12. The second face 22 protrudes from the arc surface 21A toward the development roller 12. The second face 22 is alienated from the peripheral surface of the development roller 12 in a state in which the protective covering 20 is attached to the housing 11.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to a developer cartridge having a developer roller. [Background technology]

[0002] To prevent damage caused by dropping the developing cartridge, the developing cartridge is transported in a packaged state such as a cardboard box. In this case, a protective cover is attached to cover the developing roller in the developing cartridge to protect the developing roller (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-069953 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the developer cartridge is dropped, the developer roller may bend due to the impact of the drop. The protective cover of Patent Document 1 has a sufficient gap between the developer roller and the protective cover, so that the protective cover does not come into contact with the developer roller even if the developer roller is bent due to the drop. As a result, the developer roller is bent significantly, creating a gap between the developer roller and the housing, which may cause toner to leak from the gap.

[0005] Therefore, an object of the present disclosure is to prevent the developing roller from bending when the developing cartridge is dropped. [Means for solving the problem]

[0006] A developing cartridge according to the present disclosure, which is intended to solve the above-mentioned problems, includes a housing, a developing roller, and a protective cover. The housing contains toner therein. The developing roller is supported by the housing so as to be rotatable about a rotation axis extending in the axial direction. The protective cover is detachable from the housing and covers the developing roller. The protective cover has a first surface and a second surface. The first surface faces the circumferential surface of the developing roller when the protective cover is attached to the housing. The first surface has an arcuate surface that follows the circumferential surface of the developing roller. The second surface protrudes from the arcuate surface toward the developing roller. The second surface is spaced apart from the circumferential surface of the developing roller when the protective cover is attached to the housing.

[0007] When the protective cover is attached to the housing, the second surface of the protective cover is separated from the peripheral surface of the developing roller, so that the protective cover does not come into contact with the developing roller unless it is subjected to an impact such as being dropped, thereby preventing damage to the developing roller. When the protective cover is attached to the housing, the second surface of the protective cover protrudes from the arc surface toward the developing roller, so that the protective cover can come into contact with the developing roller if the developing cartridge is dropped. By bringing the second surface into contact with the developing roller, it is possible to prevent the developing roller from being bent due to the developing cartridge being dropped.

[0008] The protective cover may further include a film disposed between the housing and the peripheral surface of the developing roller, contacting the developing roller from one end to the other end in the axial direction. The housing may have an attachment portion to which the film is attached, the attachment portion protruding in a direction away from the developing roller, and the distance from the peripheral surface of the developing roller to the second surface may be smaller than the distance from the peripheral surface of the developing roller to the tip of the attachment portion when the protective cover is attached to the housing.

[0009] Since the distance from the peripheral surface of the developing roller to the second surface is smaller than the distance from the peripheral surface of the developing roller to the tip of the affixed portion, the second surface is likely to come into contact with the developing roller if the developing cartridge is dropped. By having the second surface come into contact with the developing roller, it is possible to prevent the developing roller from being bent due to the developing cartridge being dropped.

[0010] Furthermore, with the protective cover attached to the housing, the distance from the circumferential surface of the developing roller to the second surface may be less than 2 mm.

[0011] When the distance from the peripheral surface of the developing roller to the second surface is less than 2 mm, the second surface is likely to come into contact with the developing roller if the developing cartridge is dropped. When the second surface comes into contact with the developing roller, bending of the developing roller due to the dropping of the developing cartridge can be suppressed.

[0012] Furthermore, with the protective cover attached to the housing, the distance from the circumferential surface of the developing roller to the second surface may be less than 1 mm.

[0013] When the distance from the peripheral surface of the developing roller to the second surface is less than 1 mm, the second surface is likely to come into contact with the developing roller if the developing cartridge is dropped. When the second surface comes into contact with the developing roller, bending of the developing roller due to the dropping of the developing cartridge can be suppressed.

[0014] Furthermore, with the protective cover attached to the developing cartridge, the distance from the circumferential surface of the developing roller to the second surface may be 0.3 mm or more.

[0015] By setting the distance from the peripheral surface of the developing roller to the second surface at 0.3 mm or more, the second surface will not come into contact with the developing roller unless the developing cartridge is dropped, thereby preventing the developing roller from being scratched.

[0016] The protective cover may extend in the axial direction, and the second surface may be located at the center of the protective cover in the axial direction.

[0017] Since the second surface is located at the center in the axial direction of the protective cover, the developing roller is likely to come into contact with the second surface when it is bent.

[0018] Also, in the axial direction, the dimension of the second surface may be less than half the dimension of the developer roller and more than one-quarter the dimension of the developer roller.

[0019] In the axial direction, the dimension of the second surface is smaller than half the dimension of the developing roller and larger than 1 / 4 the dimension of the developing roller, so that when the developing roller bends, the circumferential surface of the developing roller and the second surface can come into contact over a relatively wide area, thereby preventing large pressure from being applied to the developing roller.

[0020] The second surface may also have a flat surface.

[0021] Since the second surface has a flat surface, when the developing roller is bent, the circumferential surface of the developing roller and the second surface can come into surface-to-surface contact with each other.

[0022] Additionally, the axial end of the second surface may be rounded.

[0023] By rounding the axial end of the second surface, it is possible to prevent the developing roller from being damaged when the end of the second surface comes into contact with the developing roller.

[0024] Furthermore, when a protective cover is attached to the developing cartridge, the distance from the circumferential surface of the developing roller to the first surface may be 5 mm or more and 10 mm or less.

[0025] The protective cover may also have a third surface located opposite the second surface and facing away from the developing roller, and a rib protruding from the third surface and extending in a direction perpendicular to the axial direction.

[0026] By providing the protective cover with a rib disposed on the opposite side to the second surface, the second surface is less likely to bend due to the rib, and therefore the developing roller is less likely to bend when the developing cartridge is dropped.

[0027] The developing cartridge may also be held in a packaging material made of pulp mold and housed in a box. Effect of the Invention

[0028] According to the present disclosure, it is possible to prevent the developing roller from bending when the developing cartridge is dropped. [Brief description of the drawings]

[0029] [Figure 1] FIG. 2 is a cross-sectional view showing the developing cartridge. [Diagram 2] FIG. 2 is a perspective view of the developing cartridge with a protective cover attached. [Diagram 3] 2 is a perspective view of the developing cartridge and the protective cover with the protective cover removed. FIG. [Figure 4] 4 is a perspective view of the developing cartridge and the protective cover as viewed from a different direction than that in FIG. 3. [Diagram 5] FIG. 1A is a diagram showing the protective cover and the developing roller side by side as viewed from the developing roller side, and FIG. 1B is a diagram showing the protective cover as viewed from the opposite side to the developing roller. [Figure 6] 4 is an enlarged cross-sectional view of the developing cartridge with a protective cover attached; FIG. [Figure 7] 1 is a perspective view showing a developing cartridge held in a packing material made of pulp mold and housed in a box. FIG. [Figure 8] 1A is a diagram illustrating the positional relationship between the developing roller and the protective cover in a normal state, and FIG. 1B is a diagram illustrating the positional relationship between the developing roller and the protective cover in a state in which the developing roller is bent due to the development cartridge being dropped. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Next, an embodiment of the present disclosure will be described in detail with reference to the drawings as appropriate. In the following description, the direction along the first axis X1, which is the rotation axis of the developing roller 12 shown in FIG. 1, is referred to as the "axial direction." Also, the direction from the third axis X3, which is the rotation axis of the agitator 15, toward the first axis X1 of the developing roller 12 is referred to as the "first direction." The "axial direction" and the "first direction" are perpendicular to each other. Also, the direction perpendicular to the "axial direction" and the "first direction" is referred to as the "second direction." Also, the arrows indicating each direction in the drawings refer to "one side" in each direction.

[0031] 1, the developer cartridge 10 is mounted in an image forming device such as a laser printer and used. The developer cartridge 10 includes a housing 11, a developer roller 12, a supply roller 13, a layer thickness regulating blade 14, an agitator 15, a handle 16, and a film 17.

[0032] The housing 11 has a toner storage section 11A. The toner storage section 11A stores toner therein.

[0033] The developing roller 12 is located at one end of the housing 11 in the first direction. The developing roller 12 is arranged so as to cover an opening 11B located at one end of the housing 11 in the first direction. When the developing roller 12 is mounted on an image forming device or the like, it supplies toner to a photosensitive drum of the image forming device. The developing roller 12 is supported by the housing 11 so as to be rotatable around a first axis X1 extending in the axial direction.

[0034] The supply roller 13 is located between the development roller 12 and the toner storage section 11A. The supply roller 13 supplies toner in the housing 11 to the development roller 12. The supply roller 13 is supported by the housing 11 so as to be rotatable about a second axis X2 extending in the axial direction.

[0035] The layer thickness regulating blade 14 regulates the thickness of the toner layer on the developing roller 12. The layer thickness regulating blade 14 comes into contact with the developing roller 12. More specifically, the layer thickness regulating blade 14 is fixed to the housing 11 via a blade holder PL. The base end of the layer thickness regulating blade 14 is fixed to the blade holder PL, and the tip end comes into contact with the developing roller 12. In this way, the layer thickness regulating blade 14 prevents toner from leaking from between the developing roller 12 and the housing 11.

[0036] The agitator 15 is located inside the housing 11. The agitator 15 is rotatable about a third axis X3 extending in the axial direction. The agitator 15 agitates the toner. The agitator 15 also supplies the toner in the housing 11 to the supply roller 13.

[0037] The handle 16 is located at the other end of the housing 11 in the first direction. The handle 16 is located on the opposite side of the toner containing section 11A from the developing roller 12. The handle 16 is a grip that the user holds when installing or removing the developing cartridge 10.

[0038] The film 17 is disposed between the housing 11 and the circumferential surface of the developing roller 12. More specifically, the film 17 is attached to an attachment portion 11C of the housing 11. The attachment portion 11C is located on the opposite side of the developing roller 12 from the layer thickness regulating blade 14. The film 17 contacts the housing 11 and the circumferential surface of the developing roller 12 from one end to the other end in the axial direction of the developing roller 12. This prevents the toner from leaking from between the developing roller 12 and the housing 11. The film 17 is made of a resin such as PET (polyethylene terephthalate). The affixing portion 11C protrudes from the toner containing portion 11A to one side in the first direction.

[0039] 2, the developing cartridge 10 further includes a coupling 18 and a protective cover 20. The protective cover 20 is removed when the developing cartridge 10 is to be mounted in an image forming apparatus.

[0040] The coupling 18 is located on the other axial side of the housing 11. The coupling 18 is rotatable by receiving a driving force from the image forming apparatus. The coupling 18 meshes with a driving member (not shown) of the image forming apparatus or the like. The driving force received from the driving member is transmitted to the developing roller 12, the supply roller 13, and the agitator 15 via the coupling 18 and a gear train (not shown).

[0041] 2 and 3, the protective cover 20 is detachable from the housing 11 of the developing cartridge 10. When the protective cover 20 is attached to the developing cartridge 10, the protective cover 20 extends in the axial direction and covers the developing roller 12. The protective cover 20 is made of a resin such as polypropylene.

[0042] As shown in FIG. 3, the protective cover 20 has a first wall W1, a second wall W2, a third wall W3, a fourth wall W4, and a fifth wall W5.

[0043] The first wall W1 faces the circumferential surface of the developing roller 12 when the protective cover 20 is attached to the developing cartridge 10 (see FIG. 6). As shown in FIGS. 3 and 4, the first wall W1 has a first surface 21, a second surface 22, a third surface 23, and a rib 24.

[0044] 6, the first surface 21 faces the circumferential surface of the developing roller 12 when the protective cover 20 is attached to the housing 11. The first surface 21 has an arcuate surface 21A and a flat surface 21B. The arcuate surface 21A extends along the circumferential surface of the developing roller 12. The flat surface 21B extends from one end of the arcuate surface 21A in the second direction to the third wall W3.

[0045] In this embodiment, when the protective cover 20 is attached to the developing cartridge 10, the distance D1 from the circumferential surface of the developing roller 12 to the first surface 21 is 5 mm or more and 10 mm or less (5 mm≦D1≦10 mm). Note that, in this embodiment, the distance from the circumferential surface of the developing roller 12 to the arcuate surface 21A is the shortest distance from the circumferential surface of the developing roller 12 to the first surface 21.

[0046] The second surface 22 protrudes from the first surface 21. More specifically, the second surface 22 protrudes from the arcuate surface 21A of the first surface 21 toward the developing roller 12. The second surface 22 also protrudes from the flat surface 21B of the first surface 21 toward the developing roller 12. The second surface 22 has a flat surface facing the developing roller 12. An end 22T in the axial direction of the second surface 22 is rounded (see also FIG. 8(a)).

[0047] As shown in FIG. 5(a), the second surface 22 is located at the center of the first wall W1 of the protective cover 20 in the axial direction. In the axial direction, the dimension L1 of the second surface 22 is smaller than half of the dimension L2 of the developing roller 12 and larger than one-fourth of the dimension L2 of the developing roller 12 (L2 / 4 < L1 < L2 / 2).

[0048] As shown in FIG. 6, the second surface 22 is spaced apart from the circumferential surface of the developing roller 12 in a state where the protective cover 20 is attached to the housing 11. Specifically, in a state where the protective cover 20 is attached to the housing 11, the distance D2 from the circumferential surface of the developing roller 12 to the second surface 22 is 0.3 mm or more (D2 ≧ 0.3 mm). Also, the second surface 22 is located at the central portion of the first wall W1 of the protective cover 20 in the second direction. The second surface 22 extends from a part of the arc surface 21A of the first surface 21 to a part of the flat surface 21B of the first surface 21 in the second direction.

[0049] Also, in a state where the protective cover 20 is attached to the housing 11, the distance D2 from the circumferential surface of the developing roller 12 to the second surface 22 is smaller than the distance D3 from the circumferential surface of the developing roller 12 to the tip PP of the attachment portion 11C (D2 < D3). In the first direction, the second surface 22 is located between the circumferential surface of the developing roller 12 and the tip PP of the attachment portion 11C. Note that the tip PP of the attachment portion 11C is the farthest from the handle 16 in the housing 11 (see FIG. 4). Also, in the second direction, the tip PP of the attachment portion 11C is located between the second surface 22 and the third wall W3.

[0050] Also, in a state where the protective cover 20 is attached to the housing 11, the distance D2 from the circumferential surface of the developing roller 12 to the second surface 22 is preferably less than 2 mm (D2 < 2 mm), and more preferably less than 1 mm (D2 < 1 mm).

[0051] As shown in FIGS. 4 and 5(b), the third surface 23 is the surface on the opposite side of the second surface 22. The third surface 23 faces away from the developing roller 12.

[0052] The rib 24 protrudes from the third surface 23 in a direction away from the developing roller 12. The rib 24 has a first rib 24A and a second rib 24B.

[0053] The first rib 24A extends from the second wall W2 along the first wall W1 and further extends to the third wall W3. The first rib 24A is an example of a rib extending in a second direction perpendicular to the axial direction. In the second wall W2 and the third wall W3, the first rib 24A extends in the first direction. In this embodiment, a plurality of the first ribs 24A are arranged side by side in the axial direction. The second rib 24B extends in the axial direction and connects the plurality of first ribs 24A.

[0054] The second wall W2 is a wall extending from the other end of the first wall W1 in the second direction toward the other side in the first direction. The second wall W2 has a grip portion W21 and a contact portion W22.

[0055] The grip portion W21 is located at the center of the second wall W2 in the axial direction. The grip portion W21 protrudes from the second wall W2 to the other side in the second direction. The grip portion W21 is a portion that a user grasps when removing the protective cover 20 from the developer cartridge 10.

[0056] The contact portions W22 are disposed on both sides of the grip portion W21 in the axial direction. The contact portions W22 protrude to one side of the second wall W2 in the second direction. The contact portions W22 are portions that come into contact with the housing 11 when the protective cover 20 is attached to the developing cartridge 10. In more detail, as shown in FIG. 6, the contact portions W22 come into contact with the blade holder PL when the protective cover 20 is attached to the developing cartridge 10.

[0057] As shown in FIG. 3, the third wall W3 is a wall extending from one end of the first wall W1 in the second direction toward the other end in the first direction. As shown in FIG. 6, the third wall W3 extends toward one side in the second direction as it moves toward the other side in the first direction. The third wall W3 comes into contact with the housing 11 when the protective cover 20 is attached to the developing cartridge 10. In detail, the third wall W3 comes into contact with the outer surface of the attachment portion 11C of the housing 11 when the protective cover 20 is attached to the developing cartridge 10. When the protective cover 20 is attached to the developing cartridge 10, the contact portion W22 of the second wall W2 and the third wall W3 come into contact with the housing 11 of the developing cartridge 10, and the second wall W2 and the third wall W3 sandwich the housing 11, so that the protective cover 20 is fixed to the developing cartridge 10.

[0058] As shown in Fig. 3, the fourth wall W4 is a wall that connects one axial end of the first wall W1, one axial end of the second wall W2, and one axial end of the third wall W3. The fourth wall W4 has a first notch W41. As shown in Fig. 2, the first notch W41 exposes a part of the developer cartridge 10 to the outside of the protective cover 20 when the protective cover 20 is attached to the developer cartridge 10.

[0059] The fifth wall W5 is a wall that connects the other axial end of the first wall W1, the other axial end of the second wall W2, and the other axial end of the third wall W3. The fifth wall W5 has a second notch W51. When the protective cover 20 is attached to the developer cartridge 10, the second notch W51 exposes a part of the developer cartridge 10 to the outside of the protective cover 20 (not shown).

[0060] Next, packaging for transporting the developing cartridge 10 will be described. 7, the developing cartridge 10 is shipped and transported from a factory, a store, etc. in a state where the protective cover 20 is attached and then housed in a package PA (hereinafter referred to as a "packaged state") In this embodiment, the developing cartridge 10 is held by a first pad 30 and a second pad 40, which are packaging materials made of pulp mold, and housed in a box 50.

[0061] The box 50 is made of, for example, cardboard. The box 50 accommodates the developer cartridge 10 therein with the first pad 30 and the second pad 40 attached to the developer cartridge 10. The box 50 is a hollow rectangular parallelepiped.

[0062] The first pad 30 covers one end of the developer cartridge 10 in the axial direction. That is, the first pad 30 is disposed between the developer cartridge 10 and the box 50. The first pad 30 is a cushioning material made of pulp mold. Pulp mold refers to a molded product made from pulp, which is the raw material for paper, recycled paper, or the like. Pulp mold is easy to reuse, and therefore has superior environmental performance compared to polystyrene foam, etc. As a result, the first pad 30 suppresses the transmission of an external impact applied to the package PA to the developer cartridge 10 during transportation, etc.

[0063] The second pad 40 covers the other end of the developer cartridge 10 in the axial direction. That is, the second pad 40 is disposed between the developer cartridge 10 and the box 50. The second pad 40 is a cushioning material made of pulp mold. As a result, the second pad 40 prevents an external impact applied to the packaging body PA from being transmitted to the developer cartridge 10 during transportation, etc.

[0064] Next, the action when the packaged developer cartridge 10 is dropped will be described.

[0065] 8A, in a normal state, the developing roller 12 of the packaged developing cartridge 10 is not bent. Therefore, the second surface 22 of the protective cover 20 is spaced apart from the circumferential surface of the developing roller 12.

[0066] As shown in FIG. 8(b), when the packaged developer cartridge 10 is dropped with the developer roller 12 facing downward, the first pad 30 and the second pad 40 receive an impact from below through the box 50. When the first pad 30 and the second pad 40 receive an impact from below, the developer roller 12 may bend due to the impact at the time of the drop. When the developer roller 12 bends, the circumferential surface of the developer roller 12 comes into contact with the second surface 22 of the protective cover 20. When the circumferential surface of the developer roller 12 comes into contact with the second surface 22, the developer roller 12 does not bend any further.

[0067] As described above, the following effects can be obtained in this embodiment. In the developing cartridge 10 of this embodiment, when the protective cover is attached to the housing 11, the second surface 22 is separated from the peripheral surface of the developing roller 12, so that the protective cover 20 does not come into contact with the developing roller 12 unless it is subjected to an impact such as being dropped, thereby preventing damage to the developing roller 12. In addition, since the second surface 22 of the protective cover 20 protrudes from the arc surface 21A toward the developing roller 12 when the developing cartridge 10 is dropped in a state where the protective cover 20 is attached to the housing 11, the developing cartridge 10 can come into contact with the developing roller 12 when the developing cartridge 10 is dropped. The contact of the second surface 22 with the developing roller 12 can prevent the developing roller 12 from being bent when the developing cartridge 10 is dropped.

[0068] In addition, since the distance D2 from the circumferential surface of the developing roller 12 to the second surface 22 is smaller than the distance D3 from the circumferential surface of the developing roller 12 to the tip PP of the attachment portion 11C, when the developing cartridge 10 is dropped, the second surface 22 is likely to come into contact with the developing roller 12. By the second surface 22 coming into contact with the developing roller 12, it is possible to prevent the developing roller 12 from being bent due to the dropping of the developing cartridge 10.

[0069] Furthermore, since the distance D2 from the peripheral surface of the developing roller 12 to the second surface 22 is less than 2 mm, when the developing cartridge 10 is dropped, the second surface 22 is likely to come into contact with the developing roller 12. Since the second surface 22 comes into contact with the developing roller 12, it is possible to prevent the developing roller 12 from being bent due to the developing cartridge 10 being dropped.

[0070] Furthermore, since the distance D2 from the peripheral surface of the developing roller 12 to the second surface 22 is less than 1 mm, when the developing cartridge 10 is dropped, the second surface 22 is likely to come into contact with the developing roller 12. Since the second surface 22 comes into contact with the developing roller 12, it is possible to prevent the developing roller 12 from being bent due to the developing cartridge 10 being dropped.

[0071] In addition, since the distance D2 from the peripheral surface of the developing roller 12 to the second surface 22 is 0.3 mm or more, the second surface 22 does not come into contact with the developing roller 12 unless the developing cartridge 10 is dropped, so that damage to the developing roller 12 can be prevented.

[0072] In addition, since the second surface 22 is located at the center of the protective cover 20 in the axial direction, the developing roller 12 is likely to come into contact with the second surface 22 when it is bent.

[0073] In addition, in the axial direction, the dimension L1 of the second surface 22 is smaller than half the dimension L2 of the developing roller 12 and is larger than 1 / 4 of the dimension L2 of the developing roller 12. Therefore, when the developing roller 12 bends, the circumferential surface of the developing roller 12 and the second surface 22 can come into contact over a relatively wide area, thereby preventing large pressure from being applied to the developing roller 12.

[0074] Furthermore, since the second surface 22 has a flat surface, when the developing roller 12 is bent, the circumferential surface of the developing roller 12 and the second surface 22 can come into surface-to-surface contact with each other.

[0075] Furthermore, by having the axial end 22T of the second surface 22 be rounded, when the end 22T of the second surface 22 comes into contact with the developing roller 12, damage to the developing roller 12 can be suppressed.

[0076] Furthermore, as shown in FIG. 8(b), the protective cover 20 has the rib 24 disposed on the side opposite the second surface 22, so that the second surface 22 is less likely to bend.

[0077] Although the embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment. The specific configuration can be appropriately changed without departing from the spirit of the present disclosure.

[0078] In the above-described embodiment, the box 50 is made of cardboard, but it may be made of other materials such as resin or metal.

[0079] In the above-described embodiment, a cushioning material made of molded pulp is used for the package PA, but the cushioning material may be made of other materials such as polystyrene foam or air packing.

[0080] In the above-described embodiment, the protective cover 20 is made of polypropylene resin, but is not limited thereto. For example, the protective cover 20 may be made of other resins than polypropylene resin, such as polyethylene or ABS, or may be made of materials other than resin, such as metal or paper.

[0081] The elements described in the above-mentioned embodiment and modified examples may be implemented in any combination. [Explanation of symbols]

[0082] 10 Developer cartridge 11. Cabinet 11A Toner storage section 11B opening 11C Attachment part 12 Developing roller 17 Film 20 Protective cover 21 Page 1 21A Circular surface 22 Side 2 23 Page 3 24 Ribs 30 1st Pad 40 2nd Pad 50 boxes

Claims

1. A housing that contains toner therein; a developing roller supported by the housing so as to be rotatable about a rotation axis extending in an axial direction; A developing cartridge comprising: a protective cover that is detachable from the housing and covers the developing roller, the protective cover having a first surface that faces the circumferential surface of the developing roller when the protective cover is attached to the housing, the first surface having an arcuate surface that follows the circumferential surface of the developing roller, and a second surface that protrudes from the arcuate surface toward the developing roller, the second surface being spaced apart from the circumferential surface of the developing roller when the protective cover is attached to the housing.

2. a film disposed between the housing and a peripheral surface of the developing roller and in contact with the developing roller from one end to the other end in the axial direction; the housing has an attachment portion to which the film is attached, the attachment portion protruding in a direction away from the developing roller, The developing cartridge according to claim 1 , wherein, when the protective cover is attached to the housing, the distance from the peripheral surface of the developing roller to the second surface is smaller than the distance from the peripheral surface of the developing roller to the tip of the attachment portion.

3. 2. The developing cartridge according to claim 1, wherein a distance from a peripheral surface of the developing roller to the second surface is less than 2 mm when the protective cover is attached to the housing.

4. 4. The developing cartridge according to claim 3, wherein a distance from the circumferential surface of the developing roller to the second surface is less than 1 mm when the protective cover is attached to the housing.

5. 4. The developing cartridge according to claim 3, wherein a distance from the circumferential surface of the developing roller to the second surface is 0.3 mm or more in a state where the protective cover is attached to the developing cartridge.

6. The protective cover extends in the axial direction, 2. The developing cartridge according to claim 1, wherein the second surface is located at a center of the protective cover in the axial direction.

7. 2. The developing cartridge according to claim 1, wherein the dimension of said second surface in said axial direction is smaller than half the dimension of said developing roller and larger than 1 / 4 the dimension of said developing roller.

8. 2. The developing cartridge according to claim 1, wherein the second surface has a flat surface.

9. 2. The developing cartridge according to claim 1, wherein an end portion of the second surface in the axial direction is rounded.

10. 2. The developing cartridge according to claim 1, wherein when the protective cover is attached to the developing cartridge, a distance from the circumferential surface of the developing roller to the first surface is 5 mm or more and 10 mm or less.

11. The protective cover is a third surface located opposite the second surface and facing away from the developing roller; 2. The developing cartridge according to claim 1, further comprising a rib protruding from the third surface and extending in a direction perpendicular to the axial direction.

12. 2. The developing cartridge according to claim 1, wherein the developing cartridge is held in a packaging material made of pulp mold and housed in a box.

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