Annular body for suppressing electrical discharge, annular body stretching device and image forming apparatus

1. An annular body consisting of a single layer, the single layer comprising a resin and a conductive agent, and the single layer having a carbonized region on its inner surface, wherein

the carbonized region comprises a carbonized portion which resides from the inner surface in the thickness direction of the single layer,

the thickness of the carbonized region is up to about 10 μm, and

the carbonized region is dispersed on the inner surface of the single layer.

2. The annular body of claim 1 , wherein the carbonized region is formed by a process to give conductivity to the inner surface of the single layer.

3. The annular body of claim 1 , wherein the surface resistivity of the inner surface of the single layer is in a range of about 1×10 11 Ω/□ to about 1×10 13 Ω/□, and the surface resistivity of the inner surface of the single layer is lower than that of an outer surface of the single layer by about 0.5 log Ω/□ to about 2.0 log Ω/□.

4. The annular body of claim 1 , wherein the thickness of the carbonized region is from about 0.1 μm to about 7.0 μm.

5. An annular body stretching device comprising:

the annular body of claim 1 ; and

a stretching unit pushing outward the annular body with tension from an inner circumferential side of the annular body.

6. The annular body stretching device of claim 5 , wherein the carbonized region is formed by a process to give conductivity to the inner surface of the single layer.

7. The annular body stretching device of claim 5 , wherein the surface resistivity of the inner surface of the single layer is in a range of about 1×10 11 Ω/□ to about 1×10 13 Ω/□, and the surface resistivity of the inner surface of the single layer is lower than that of an outer surface of the single layer by about 0.5 log Ω/□ to about 2.0 log Ω/□.

8. The annular body stretching device of claim 5 , wherein the thickness of the carbonized region is from about 0.1 μm to about 7.0 μm.

9. An image forming apparatus comprising:

an image holding unit;

a charging unit that charges a surface of the image holding unit;

a latent image forming unit that forms a latent image on a surface of the image holding unit;

a developing unit that develops the latent image into a toner image;

a primary transfer unit that transfers the toner image to an intermediate transfer body;

a secondary transfer unit that transfers the toner image from the intermediate transfer body to a recording medium; and

a fixing unit that fixes the toner image onto the recording medium,

the intermediate transfer body being the annular body of claim 1 .

10. The image forming apparatus of claim 9 , wherein the carbonized region is formed by a process to give conductivity to the inner surface of the single layer.

11. The image forming apparatus of claim 9 , wherein the surface resistivity of the inner surface of the single layer is in a range of about 1×10 11 Ω/□ to about 1×10 13 Ω/□, and the surface resistivity of the inner surface of the single layer is lower than that of an outer surface of the single layer by about 0.5 log Ω/□ to about 2.0 log Ω/□.

12. The image forming apparatus of claim 9 , wherein the thickness of the carbonized region is from about 0.1 μm to about 7.0 μm.

13. A method for forming the annular body of claim 1 , comprising forming the carbonized region by a process to give conductivity to the inner surface of the single layer.

14. The method of claim 13 , wherein the process to give conductivity to the inner surface of the single layer comprises bringing paper into contact with the inner surface of the single layer to provide an electric field to the single layer.