Image forming unit and image forming apparatus

1. An image forming unit, comprising:

an image supporting member including a photosensitive layer, the photosensitive layer being configured to support a latent image;

a developer supporting member configured to support a developer, and perform a development process on the latent image with use of the developer; and

a developer feeding member including a surface that comes into contact with the developer supporting member, and configured to feed the developer to the developer supporting member, the developer feeding member including an elastic layer, the elastic layer having a plurality of cells each including an opening that is exposed on the surface, and an area occupancy rate of the openings in area of the surface being in a range from 40% to 85%.

2. The image forming unit according to claim 1 , wherein the developer feeding member further includes a coating layer, the coating layer covering the elastic layer and filling a part of the cells.

3. The image forming unit according to claim 1 , wherein the elastic layer has an Asker F hardness in a range from 48 degrees to 63 degrees.

4. An image forming unit comprising:

an image supporting member including a photosensitive layer, the photosensitive layer being configured to support a latent image;

a developer supporting member configured to support a developer, and perform a development process on the latent image with use of the developer; and

a developer feeding member including a surface that comes into contact with the developer supporting member, and configured to feed the developer to the developer supporting member, the developer feeding member including an elastic layer, the elastic layer having a plurality of cells each including an opening that is exposed on the surface, an area occupancy rate of the openings in area of the surface being in a range from 40% to 85%, and the elastic layer having an expansion rate in a range from 300% to 450%.

5. An image forming unit comprising:

an image supporting member including a photosensitive layer, the photosensitive layer being configured to support a latent image;

a developer supporting member configured to support a developer, and perform a development process on the latent image with use of the developer; and

a developer feeding member including a surface that comes into contact with the developer supporting member, and configured to feed the developer to the developer supporting member, the developer feeding member including an elastic layer, the elastic layer having a plurality of cells each including an opening that is exposed on the surface, and an area occupancy rate of the openings in area of the surface being in a range from 40% to 85%,

wherein the following expression is satisfied:

0.6 mm≦( A−B )≦1.3 mm

where A is sum in mm of a radius of the developer supporting member and a radius of the developer feeding member, and B is a distance in mm from center of rotation of the developer supporting member to center of rotation of the developer feeding member.

6. The image forming unit according to claim 1 , wherein

the elastic layer is made of a material including one of a silicone rubber and a silicone modified rubber, and

the coating layer is made of a material including a silicone resin and carbon black.

7. An image forming apparatus comprising:

a printing medium feeding section configured to feed a printing medium; and

the image forming unit according to claim 1 , and configured to form an image on the printing medium fed from the printing medium feeding section.

8. The image forming unit according to claim 5 , wherein the developer feeding member further includes a coating layer, the coating layer covering the elastic layer and filling a part of the cells.

9. The image forming unit according to claim 5 , wherein the elastic layer has an Asker F hardness in a range from 48 degrees to 63 degrees.

10. The image forming unit according to claim 5 , wherein

the elastic layer is made of a material including one of a silicone rubber and a silicone modified rubber, and

the coating layer is made of a material including a silicone resin and carbon black.

11. An image forming apparatus, comprising:

a printing medium feeding section configured to feed a printing medium; and

the image forming unit according to claim 4 , and configured to form an image on the printing medium fed from the printing medium feeding section.

12. An image forming apparatus, comprising:

a printing medium feeding section configured to feed a printing medium; and

the image forming unit according to claim 5 , and configured to form an image on the printing medium fed from the printing medium feeding section.

13. The image forming unit according to claim 1 , wherein the cells are independent from each other.

14. The image forming unit according to claim 5 , wherein the cells are independent from each other.

15. The image forming unit according to claim 1 , wherein a mean diameter of the cells is in a range from 150 μm to 400 μm.

16. the image forming unit according to claim 5 , wherein a mean diameter of the cells is in a range from 150 μm to 400 μm.

17. The image forming unit according to claim 1 , wherein the elastic layer has an electrical resistance in a range from 1×10 4 Ω to 1×10 7 Ω upon application of minus 100 V.

18. The image forming unit according to claim 5 , wherein the elastic layer has an electrical resistance in a range from 1×10 4 Ω to 1×10 7 Ω upon application of minus 100 V.

19. the image forming unit according to claim 2 , wherein

the surface has a first region coated with the coating layer and a second region exposed without being coated with the coating layer, and

the area occupancy rate of the openings in the area of the surface is equivalent to an area occupancy rate of the second region in the area of the surface.