Patent ID: 7499660

Claim:
An image forming apparatus, which visualizes an image, according to a latent image potential, on an image bearing body, which includes a charging unit and an exposing unit, in which a development potential is applied to a developing unit, and a development contrast is a difference between the latent image potential and the development potential, wherein a designated development contrast is defined as a sum of a basic development contrast Vcont, and a development correction amount ΔVcont 1 , for correcting the basic development contrast Vcont, said image forming apparatus comprising: (a) a γ conversion unit having a γ conversion table γα i of a first value Vcontα of the designated development contrast in a case that the development contrast correction amount ΔVcont 1 is a first value, and a γ conversion table γβ i , different from the γ conversion table γα i , of a second value Vcontβ, different from the first value Vcontα, of the designated development contrast in a case that the development contrast correction amount ΔVcont 1 is a second value different from the first value of ΔVcont 1 ; and (b) an arithmetic operation unit for calculating a γ conversion table γNow i of a third value VcontNow of the designated development contrast in a case that the development contrast correction amount ΔVcont 1 is a third value, based on a formula: γNow i =γα i +(γβ i −γα i )×( V contα− V contNow)/( V contα− V contβ), wherein the subscript i is a value of an output density signal in the γ conversion table, and wherein the γ conversion unit conducts γ conversion of the third value VcontNow of the designated development contrast, based on the γ conversion table γNow i calculated by the arithmetic operation unit.