Patent ID: 6987576

Claim:
An image forming apparatus comprising: luminance-density conversion means for converting an original luminance signal into an original density signal; output density conversion means for converting the original density signal into an output density signal; gamma conversion means for converting the output density signal into an output signal; charging means for providing an electrophotographic photosensitive member with a uniform charge; digital exposure means for exposing the electrophotographic photosensitive member, after charging, to the output signal after said gamma conversion, thereby forming a latent image; development means for developing said latent image with toner into a visible image, wherein the image is rendered visible by forming a latent image potential which is the surface potential of the electrophotographic photosensitive member formed by said charging means and said exposure means and a development potential applied to said development means; and environment detection means for detecting at least one of the temperature and the humidity of the location where the image forming apparatus is installed, wherein the content of conversion of said gamma conversion means is modulated according to a development contrast which is the difference between the latent image potential causing adhesion of the toner flying from said development means to the electrophotographic photosensitive member and the development potential, with a change in said gamma conversion means corresponding to the change in the development contrast resulting from the result of detection of said environment detection means and a weight in said gamma conversion means corresponding to other changes in the development contrast.