Electrophotographic Photosensitive Member and Image Forming Apparatus Using Same

Abstract

The present invention relates to an electrophotographic photosensitive member including a substantially cylindrical body and a photosensitive layer formed on the outer circumference of the body. The body has an outer diameter larger at a middle portion of a latent image forming area than at end portions of the latent image forming area in the axial direction. The electrophotographic photosensitive member may further include a heating member accommodated within the body and extending along the axial direction of the body, for heating the latent image forming area of the photosensitive layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating an example of an image forming apparatus according to the present invention.

FIG. 2 is a sectional view of the principal portions illustrating the relationship between an electrophotographic photosensitive member and an electrification mechanism of the image forming apparatus shown in FIG. 1.

FIG. 3 is a sectional view and an enlarged view of the principal portions illustrating an example of the electrophotographic photosensitive member according to the present invention.

FIGS. 4A and 4B are sectional views illustrating other examples of the electrophotographic photosensitive member according to the present invention.

FIG. 5 is an overall perspective view illustrating a heater provided at the electrophotographic photosensitive member shown in FIG. 3 or 4.

FIG. 6 is an exploded perspective view illustrating the heater shown in FIG. 5.

FIG. 7 is a sectional view illustrating a CVD apparatus for forming a photosensitive layer of the electrophotographic photosensitive member shown in FIG. 3 or 4.

FIG. 8 is a schematic view corresponding to FIG. 1, illustrating another example of the image forming apparatus according to the present invention.

FIG. 9 is a sectional view corresponding to FIG. 2, illustrating the principal portions of the image forming apparatus shown in FIG. 8.

Claims

1. An electrophotographic photosensitive member comprising: a substantially cylindrical body; anda photosensitive layer formed on outer circumference of the body and having a latent image forming area;wherein the body has an outer diameter larger at a middle portion of the latent image forming area than at end portions of the latent image forming area in the axial direction.

2. The electrophotographic photosensitive member according to claim 1, wherein the outer diameter of the body gradually becomes larger as proceeding from the end portions to the middle portion of the latent image forming area.

3. The electrophotographic photosensitive member according to claim 1, wherein the outer diameter of the body becomes larger stepwise as proceeding from the end portions to the middle portion of the latent image forming area.

4. The electrophotographic photosensitive member according to claim 1, wherein in the body, a difference between the outer diameter at the end portions of the latent image forming area and the outer diameter at the middle portion of the latent image forming area is set to not less than 5 μm and not more than 150 μm.

5. The electrophotographic photosensitive member according to claim 1, further comprising a heating member accommodated within the body and extending along axial direction of the body, for heating the latent image forming area.

6. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer comprises a photoconductive layer made of inorganic material and a surface layer made of inorganic material and laminated on the photoconductive layer.

7. An image forming apparatus comprising: an electrophotographic photosensitive member including a substantially cylindrical body having outer circumference on which a photosensitive layer having a latent image forming area is formed; anda non-contact electrification unit positioned substantially parallel to axial direction of the body;wherein a distance between a surface of the electrophotographic photosensitive member and the electrification unit is shorter at a middle portion of the latent image forming area than at end portions of the latent image forming area.

8. The image forming apparatus according to claim 7, wherein the distance gradually becomes shorter as proceeding from the end portions to the middle portion of the latent image forming area.

9. The image forming apparatus according to claim 7, wherein the distance becomes shorter stepwise as proceeding from the end portions to the middle portion of the latent image forming area.

10. The image forming apparatus according to claim 7, wherein a ratio of the distance at the end portions of the latent image forming area to the distance at the middle portion of the latent image forming area is not less than 1.1 and not more than 2.5 to 1.

11. The image forming apparatus according to claim 7, wherein the distance is not less than 7 μm and not more than 350 μm at the end portions, while being not less than 5 μm and not more than 300 μm at the middle portion.

12. The image forming apparatus according to claim 7, wherein the electrophotographic photosensitive member further comprises a heating member for heating the latent image forming area of the photosensitive layer.

13. The image forming apparatus according to claim 7, wherein during operation, temperature of the latent image forming area is higher at the middle portion than at the end portions of the latent image forming area.

14. The image forming apparatus according to claim 7, wherein the electrification unit comprises a conductive member which is a hollow or solid cylinder and a resistor layer covering a surface of the conductive member, the resistor layer having a volume resistivity value of not less than 104 Ω·cm and not more than 1012 Ω·cm.

15. The image forming apparatus according to claim 7, wherein the photosensitive layer comprises a photoconductive layer made of inorganic material and a surface layer made of inorganic material and laminated on the photoconductive layer.

16. An image forming apparatus comprising: an electrophotographic photosensitive member including a substantially cylindrical body having outer circumference on which a photosensitive layer having a latent image forming area is formed; anda non-contact electrification unit positioned substantially parallel to axial direction of the body;wherein a length of a perpendicular line extending from a reference point on the latent image forming area to the electrification unit is adjusted according to temperature at the reference point.

17. The image forming apparatus according to claim 16, wherein the electrophotographic photosensitive member further comprises a heating member for heating the latent image forming area of the photosensitive layer.

18. The image forming apparatus according to claim 16, wherein the electrification unit comprises a conductive member which is a hollow or solid cylinder and a resistor layer covering a surface of the conductive member, the resistor layer having a volume resistivity value of not less than 104 Ω·cm and not more than 1012 Ω·cm.

19. The image forming apparatus according to claim 16, wherein the photosensitive layer comprises a photoconductive layer made of inorganic material and a surface layer made of inorganic material and laminated on the photoconductive layer.

20. An image forming apparatus comprising: an electrophotographic photosensitive member including a substantially cylindrical body having outer circumference on which a photosensitive layer having a latent image forming area is formed; anda non-contact electrification unit positioned substantially parallel to axial direction of the body;the image forming apparatus satisfying the following Formula 1; 0.6 [μm/° C.]≦D [μm]/T[° C.]≦10.0 [μm/° C.]  Formula 1wherein in the Formula 1, T indicates a difference between temperature of the electrophotographic photosensitive member at a first reference point on the latent image forming area and temperature of the electrophotographic photosensitive member at a second reference point on the latent image forming area, while D indicates a difference between a length of a first perpendicular line extending from the first reference point to the electrification unit and a length of a second perpendicular line extending from the second reference point to the electrification unit.

21. The image forming apparatus according to claim 20, wherein the electrophotographic photosensitive member further comprises a heating member for heating the latent image forming area of the photosensitive layer.

22. The image forming apparatus according to claim 20, wherein the electrification unit comprises a conductive member which is a hollow or solid cylinder and a resistor layer covering a surface of the conductive member, the resistor layer having a volume resistivity value of not less than 104 Ω·cm and not more than 1012 Ω·cm.

23. The image forming apparatus according to claim 20, wherein the photosensitive layer comprises a photoconductive layer made of inorganic material and a surface layer made of inorganic material and laminated on the photoconductive layer.