Cartridge and image forming apparatus
An image forming apparatus includes: an image bearing member; a charging member for electrically charging the image bearing member in contact with the image bearing member; and a developing member for supplying developer in contact with the image bearing member. The developer remaining on the image bearing member after transfer is collected by the developing member. A Martens hardness HMR of a surface of the charging member and a Martens hardness HMD of a surface of the developer satisfy the following relationship: HMD>HMR.
1. An image forming apparatus comprising:
an image bearing member;
a charging member for electrically charging the image bearing member, the charging member being in contact with the image bearing member; and
a developing member for supplying developer, the developing member being in contact with the image bearing member,
wherein the developer remaining on the image bearing member after transfer is collected by the developing member, and
wherein a Martens hardness HMR of a surface of the charging member and a Martens hardness HMD of a surface of the developer satisfy the following relationship:
HMD>HMR.
2. An image forming apparatus according to claim 1 , wherein the Martens hardness of the surface of the charging member is 0.5 or more and 19 or less.
3. An image forming apparatus according to claim 1 , wherein the Martens hardness of the surface of the charging member is 1 or more and 10 or less.
4. An image forming apparatus according to claim 1 , wherein the Martens hardness of the surface of the developer is 2 or more and 50 or less.
5. An image forming apparatus according to claim 1 , wherein the Martens hardness of the surface of the developer is 2.5 or more and 20 or less.
6. An image forming apparatus according to claim 1 , wherein an arithmetic average roughness Ra of the surface of said charging member is 0.1 μm or more and 10 μm or less.
7. An image forming apparatus according to claim 1 , wherein when a dispersion showing a range of a variation in Martens hardness of the surface of the charging member is σ, the following relationship is satisfied:
HMD>HMR+ 3σ.
8. An image forming apparatus according to claim 1 , wherein the surface of the charging member is deformed so that the developer remaining on said image bearing member bites into the surface of the charging member at a contact position with the image bearing member.
9. An image forming apparatus according to claim 1 , further comprising a developing blade for uniformly thinning a layer of the developer in contact with the developing member,
wherein a contact position relationship is an order of a contact position between the image bearing member and the charging member, a contact position between the image bearing member and the developing member, and a contact position between the developing member and the developing blade from above with respect to a direction of gravity.
10. An image forming apparatus according to claim 1 , wherein the charging member is a charging roller.
11. An image forming apparatus according to claim 1 , wherein the developer is one component developer.
12. An image forming apparatus according to claim 11 , wherein the developer is magnetic developer.
13. An image forming apparatus according to claim 1 , wherein a rotational direction of the charging member is set as the same direction as a rotational direction of the image bearing member at a contact point between the image bearing member and the charging member.
14. An process cartridge detachably mountable to an image forming apparatus, the process cartridge comprising:
an image bearing member;
a charging member for electrically charging the image bearing member, the charging member being in contact with the image bearing member; and
a developing member for supplying developer, the developing member being in contact with the image bearing member,
wherein the developer remaining on the image bearing member after transfer is collected by the developing member, and
wherein a Martens hardness HMR of a surface of the charging member and a Martens hardness HMD of a surface of the developer satisfy the following relationship:
HMD>HMR.
15. A process cartridge according to claim 14 , wherein the Martens hardness of the surface of the charging member is 0.5 or more and 19 or less.
16. A process cartridge according to claim 14 , wherein the Martens hardness of the surface of the charging member is 1 or more and 10 or less.
17. A process cartridge according to claim 14 , wherein the Martens hardness of the surface of the developer is 2 or more and 50 or less.
18. A process cartridge according to claim 14 , wherein the Martens hardness of the surface of the developer is 2.5 or more and 20 or less.
19. A process cartridge according to claim 14 , wherein an arithmetic average roughness Ra of the surface of said charging member is 0.1 μm or more and 10 μm or less.
20. A process cartridge according to claim 14 , wherein when a dispersion showing a range of a variation in Martens hardness of the surface of the charging member is σ, the following relationship is satisfied:
HMD>HMR+ 3σ.
21. A process cartridge according to claim 14 , wherein the surface of the charging member is deformed so that the developer remaining on said image bearing member bites into the surface of the charging member at a contact position with the image bearing member.
22. A process cartridge according to claim 14 , further comprising a developing blade for uniformly thinning a layer of the developer in contact with said developing member,
wherein a contact position relationship is an order of a contact position between the image bearing member and the charging member, a contact position between the image bearing member and the developing member, and a contact position between the developing member and the developing blade from above with respect to a direction of gravity.
23. A process cartridge according to claim 14 , wherein the charging member is a charging roller.
24. A process cartridge according to claim 14 , wherein the developer is one component developer.
25. A process cartridge according to 24 , wherein the developer is magnetic developer.
26. A process cartridge according to claim 14 , wherein a toner cartridge is detachably mountable to the process cartridge.
27. A process cartridge according to claim 14 , wherein a rotational direction of the charging member is set as the same direction as a rotational direction of the image bearing member at a contact point between the image bearing member and the charging member.
28. A cartridge comprising:
an image bearing member on which developer is supplied to form a developer image; and
a charging member for electrically charging the image bearing member, the charging member being in contact with the image bearing member,
wherein a Martens hardness HMR of a surface of the charging member and a Martens hardness HMD of a surface of the developer satisfy the following relationship:
HMD>HMR.
29. A cartridge according to claim 28 , wherein the Martens hardness of the surface of the charging member is 0.5 or more and 19 or less.
30. A cartridge according to claim 28 , wherein the Martens hardness of the surface of the charging member is 1 or more and 10 or less.
31. A cartridge according to claim 28 , wherein the Martens hardness of the surface of the developer is 2 or more and 50 or less.
32. A cartridge according to claim 28 , wherein the Martens hardness of the surface of the developer is 2.5 or more and 20 or less.
33. A cartridge according to claim 28 , wherein an arithmetic average roughness Ra of the surface of the charging member is 0.1 μm or more and 10 μm or less.
34. A cartridge according to claim 28 , wherein, when a dispersion showing a range of a variation in Martens hardness of the surface of the charging member is σ, the following relationship is satisfied:
HMD>HMR+ 3σ.
35. A cartridge according to claim 28 , wherein the surface of the charging member is deformed so that the developer remaining on the image bearing member bites into the surface of the charging member at a contact position with the image bearing member.
36. A cartridge according to claim 28 , wherein the charging member is a charging roller.
37. A cartridge according to claim 28 , wherein a toner cartridge accommodating the developer is detachably mountable to the cartridge.
38. A cartridge according to claim 28 , wherein a developing device including developer carrying member for carrying the developer is detachably mountable to the cartridge.
39. A cartridge according to claim 28 , wherein the developer is one component developer.
40. A cartridge according to claim 39 , wherein the developer is magnetic developer.
41. A cartridge according to claim 28 , further comprising an image bearing member for bearing an image.
42. A cartridge according to claim 41 , wherein a rotational direction of the charging member is set as the same direction as a rotational direction of the image bearing member at a contact point between the image bearing member and the charging member.
43. A cartridge according to claim 28 , wherein the cartridge is detachably mountable to an image forming apparatus and a developing cartridge is detachably mountable to the image forming apparatus.