Patent ID: 7787002

Claim:
A digital writing apparatus comprising: a plurality of array units each including a light-emitting device array in which a plurality of light-emitting devices are arrayed in one direction, the light-emitting devices configured to emit light based on binary image data; and an image forming unit configured to form an image with light emitted from the light-emitting device array on a photosensitive member; and an image transfer unit configured to divide image data equivalent to one line for each of the array units, to transfer to respective array unit, and to drive each of the light-emitting devices to perform main scanning, wherein the array units are arranged such that each of the array units is shifted by a predetermined amount from each other in a sub-scanning direction and overlapped with each other by a predetermined amount in a main scanning direction, the main scanning direction being an axial direction of the photosensitive member, the image transfer unit is configured to transfer divided data for a plurality of times and to variably control, using a control signal having a varying period, a lighting time of a plurality of light-emitting devices at a same time using the control signal having the varying period while subjecting the image data to data processing in a period of scanning one line in the main scanning direction, and depending on whether or not the data processing related to the image data is performed, a ratio of a duty width of the control signal is varied to control a lighting time for a one-dot isolated point.