Patent ID: 7583908

Claim:
An image forming apparatus comprising: a photoconductor; an exposure unit configured to expose the photoconductor by outputting a light signal subjected to a pulse width modulation; developing unit configured to develop the photoconductor to form a developed image on the photoconductor; a transfer unit configured to transfer the developed image onto a transfer-receiving member to form a transfer image; an image patch creation unit configured to create an image patch including a minute point; a sensor unit configured to detect density information of a developed image of the image patch formed on the photoconductor or a transfer image of the image patch formed on the transfer-receiving member; a picture quality maintaining control unit configured to change, in a case where the density information detected by the sensor unit is outside a range of a specified reference density, an exposure parameter for forming an image of the minute point so that the density information falls within the range of the specified reference density; and a counter to count a usage time, wherein the picture quality maintaining control unit changes the exposure pattern according to an increase in a count value of the counter.