Image forming apparatus provided with an image carrying member that has a toner image formed on its surface

1. An image forming apparatus comprising:

an image carrying member on a surface of which a toner image is formed;

a driving device for driving the image carrying member to rotate;

a charging member for electrostatically charging the image carrying member;

a cleaning member arranged in contact with the surface of the image carrying member for cleaning the surface of the image carrying member;

a voltage applying device for applying a charging voltage to the charging member;

a braking distance detector for detecting a braking distance of the image carrying member;

a storage for storing a predetermined braking distance value Lc which relates to the braking distance of the image carrying member and which is a constant larger than one; and

a control portion for checking condition of the surface of the image carrying member based on the braking distance of the image carrying member detected by the braking distance detector,

wherein

the control portion obtains as Lon the braking distance detected by the braking distance detector when the charging voltage is applied and obtains as Loff the braking distance detected by the braking distance detector when no charging voltage is applied, and

let the braking distance observed when no charging voltage is applied at an early stage of use of the image carrying member be represented by Loff(0), then, when relations Loff<Loff(0) and Lc<Loff/Lon hold, the control portion determines that a degree of smoothness of the surface of the image carrying member is equal to or higher than a predetermined degree of smoothness.

2. The image forming apparatus of claim 1 , wherein

when the control portion determines that the degree of smoothness of the surface of the image carrying member is equal to or higher than the predetermined degree of smoothness, the control portion performs a friction resistance suppression process to reduce a friction resistance between the surface of the image carrying member and the cleaning member.

3. The image forming apparatus of claim 2 , further comprising:

a developing device which develops into a toner image an electrostatic latent image formed on the surface of the image carrying member by attaching thereto toner containing abrasive particles, wherein

the control portion performs the friction resistance suppression process by feeding toner from the developing device to the image carrying member when image formation is not performed.

4. The image forming apparatus of claim 3 , wherein

the control portion increases an amount of toner fed from the developing device to the image carrying member as the degree of smoothness of the surface of the image carrying member increases.

5. The image forming apparatus of claim 2 , wherein

the voltage applying device applies the charging voltage having an AC voltage and a DC voltage superimposed on each other to the charging member, and

the control portion performs the friction resistance suppression process by reducing the AC voltage applied from the voltage applying device to the charging member during image formation.

6. The image forming apparatus of claim 5 , wherein

the charging member is arranged in contact with or close to the surface of the image carrying member.

7. The image forming apparatus of claim 1 , wherein

the braking distance detector is an encoder that detects a rotation angle of the image carrying member.

8. The image forming apparatus of claim 1 , wherein

on the surface of the image carrying member, an amorphous silicon photosensitive layer is formed.