DEVELOPING APPARATUS

Abstract

A developing apparatus includes: a developing sleeve that carries a mono-component developer; and a developing blade that abuts on the sleeve to regulate a layer thickness of the developer on the sleeve, wherein surface roughness parameters of the sleeve satisfy: 3.0≦Rpk≦9.0; and 2≦Pc2≦10. At an abutment portion between the sleeve and the blade, surface roughness parameters of the blade satisfy: 0.030≦Sm≦0.170; and 0.10≦Rvk×(100−Mr2)/100≦1.30, where Sm is a mean spacing of profile irregularities [mm]; Rpk is an initial wear height [μm]; Rvk is an oil retaining depth [μm]; Mr2 is a profile bearing length ratio 2 [%]; and Pc2 denotes the number of profile peaks having a height larger than a count level from a center line per the evaluation length of 1 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic configuration cross-sectional view of an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a schematic configuration cross-sectional view of an embodiment of a developing apparatus according to the present invention.

FIG. 2A is an enlarged view of the encircled portion IIA in FIG. 2.

FIG. 3 is a diagrammatic sketch representing exaggeratedly a surface shape of an abutment portion (blade nip portion) between a developer layer thickness regulating member and a developer carrying member.

FIG. 4 is a diagrammatic sketch of a surface in one example of a development blade used in the present embodiment.

FIG. 5A and FIG. 5B are roughness curves for illustrating a surface roughness parameter Ry.

FIG. 6A is a bearing curve for illustrating surface roughness parameters Rvk and Mr2. FIG. 6B is a bearing curve for illustrating a surface roughness parameter Rpk.

FIG. 7 is a roughness curve for illustrating a surface roughness parameter Pc2.

FIG. 8 is a graph representing a surface shape of the developing blade with surface roughness parameters A2 and Sm.

FIG. 9 is a graph representing a surface shape of the developing blade with surface roughness parameters Rz and A2.

FIG. 10 is a graph representing a surface shape of the developing blade with surface roughness parameters Rz and Ry.

FIG. 11 is a graph representing a surface shape of a developing sleeve with surface roughness parameters Rpk and Ra.

FIG. 12 is a diagrammatic sketch of a developing sleeve surface equivalent to Example 1-1-1.

FIG. 13 is a diagrammatic sketch of a developing sleeve surface equivalent to Comparative Example 1-1-1.

Claims

1. A developing apparatus comprising: a developer carrying member that carries a mono-component developer; anda developer regulating member that abuts on the developer carrying member to regulate a thickness of a layer of the developer carried by the developer carrying member,wherein, surface roughness parameters of a surface of the developer carrying member satisfy the following equations (1) and (2), 3.0≦Rpk≦9.0   (1)2≦Pc2≦10 (where, count level=average particle diameter of developer (μm)/2, evaluation length=1 mm)   (2),and at least at an abutment portion between the developer carrying member and the developer regulating member, surface roughness parameters of a surface of the developer regulating member satisfy the following equations (3) and (4), 0.030≦Sm≦0.170   (3)0.10≦Rvk×(100−Mr2)/100≦1.30   (4),

2. A developing apparatus according to claim 1, wherein the surface of the developer regulating member is made of an elastic member at the abutment portion.

3. A developing apparatus according to claim 1, wherein an abutment width of the developer regulating member to the developer carrying member is 0.40 mm or more.

4. A developing apparatus according to claim 1, wherein a surface roughness parameter of the surface of the developer carrying member satisfies the following equation: 0.5≦Ra≦2.0

5. A developing apparatus according to claim 1, wherein the mono-component developer has an average degree of circularity of 0.940 or more.

6. A developing apparatus according to claim 1, wherein the mono-component developer is a magnetic developer, and the developing apparatus further comprises a magnetic field generating member within the developer carrying member.

7. A developing apparatus according to claim 1, wherein the developing apparatus is provided in a cartridge that is detachably mountable to a main body of an image forming apparatus.

8. A developing apparatus according to claim 1, wherein the developing apparatus is provided in a cartridge that is detachably mountable to a main body of an image forming apparatus together with an image bearing member that bears an electrostatic image thereon.