Patent ID: 7639956

Claim:
An image forming apparatus operable in a first image formation mode for forming an image on an image bearing member by using developer under a first predetermined image forming condition and a second image formation mode for forming an image on an image bearing member by using developer under a second image forming condition which is different from the first predetermined image forming condition and is set so that an amount of consumption of developer with respect to an identical image in the second image formation mode is smaller than that in the first image formation mode, the apparatus comprising: a storing device configured to store threshold information on an amount of usage of the image bearing member; a controller configured to set said image forming apparatus in the first image formation mode or the second image formation mode; and an image processing controller configured to discriminate a size of a concentrated pixel area in image information when the second image formation mode is set, and to perform first and second image density lowering processes on image information representing pixel areas of different sizes, depending on the discriminated size of the pixel area, wherein in a state in which said controller is configured to set said image forming apparatus in the second image formation mode, an image density lowering process performed on the image information by said image processing controller is changed depending on the discrimination result of said image processing controller in such a manner that the first image density lowering process is performed so that image information representing pixels in pixel areas of a first size of the image to be formed is a first image density, and the second image density lowering process is performed so that image information representing pixels in pixel areas of a second size of the image to be formed is a second image density lower than the first image density; and wherein said controller sets the second image forming condition on the basis of the discrimination result of said image processing controller and the threshold information stored in said storing device when the amount of usage of the image bearing member reaches a predetermined threshold represented by the threshold information.