Image forming apparatus

An image forming apparatus comprising:

• a photosensitive member;
• an exposure portion, which includes a plurality of surface emitting elements, and is configured to expose the photosensitive member by the plurality of surface emitting elements, the exposure portion including:
• a plurality of surface emitting element array chips each including the plurality of surface emitting elements configured to expose the photosensitive member;
• a drive unit configured to turn ON each of the plurality of surface emitting elements based on image information;
• and
• a light amount control unit configured to adjust a drive current value of a drive current to be supplied to the drive unit for each of the plurality of surface emitting element array chips to control an amount of light to be emitted from each of the plurality of surface emitting elements of the plurality of surface emitting element array chips;
• and
• a controller configured to output the image information to the exposure portion to control image formation, the controller including:
• a light amount adjustment unit configured to correct the image information for causing each of the plurality of light emitting elements to emit light based on an adjustment value provided for each of the plurality of surface emitting elements, to thereby adjust the amount of light to be emitted from each of the plurality of surface emitting elements;
• and
• a medium tone processing unit configured to quantize the image information corrected by the light amount adjustment unit by error diffusion to reduce a number of tones in the image information.