Patent ID: 7616908

Claim:
An image forming apparatus comprising: a photoconductive unit; an exposure unit configured to output a pulse-width-modulated light signal and expose the photoconductive unit; a developing unit configured to develop the photoconductive unit and form a developed image on the photoconductive unit; a transfer unit configured to transfer the developed image to a transfer target unit and form a transferred image; an image patch generating unit configured to generate an image patch formed by a predetermined pattern; a sensor unit configured to detect density information of a developed image of the image patch formed on the photoconductive unit or a transferred image of the image patch formed on the transfer target unit; and an image quality maintenance control unit configured to decide a proper quantity of exposure and a proper pulse width on the basis of the density information detected by the sensor unit and set the decided proper quantity of exposure and the proper pulse width in the exposure unit, wherein the image patch generating unit generates a first image patch having a micro-point or thin line as a first pattern and a second image patch having a high-density pattern as a second pattern, and wherein the image quality maintenance control unit decides the proper quantity of exposure based on the density information of the first image patch detected by the sensor unit when a maximum pulse width is set in the exposure unit, and decides the proper pulse width based on the density information of the second image patch detected by the sensor unit when the decided proper quantity of exposure is set in the exposure unit.