Image forming apparatus for and method of compensating for variation in thickness of photosensitive body and development mass per area

A method of compensating for development mass per area caused by a thickness of a photosensitive body in an image forming apparatus, the method comprising:

• measuring charge current flowing from a charger to the photosensitive body;
• comparing the measured charge current 1, with a first reference current;
• comparing the measured charge current 1, with a second reference current when the measured charge current is larger than the first reference current;
• and
• generating a message to replace the photosensitive body when the measured charge current is larger than the second reference current, and performing an operation of controlling a developing unit control variable and a developing unit when the measured charge current is smaller than the second reference current.

An image forming apparatus comprising:

• a photosensitive body;
• a charger charging the photosensitive body;
• an exposure unit forming an electrostatic latent image on the charged photosensitive body;
• a developing unit developing the electrostatic latent image of the photosensitive body with a developer;
• and
• a regulator measuring a thickness variation of the photosensitive body and controlling a developing potential of the developing unit in response to the thickness variation of the photosensitive body.