Patent ID: 8836742

Claim:
An image forming apparatus comprising: a photosensitive body; an exposing section which includes a light source that emits a light beam and which scans, in a main scanning direction, the light beam emitted by the light source to render a main scanning line on the photosensitive body; a pulse generating section which generates a periodic pulse signal; a smoothing section which smoothes the pulse signal generated by the pulse generating section and generate an analog signal; a driving-current generating section which generates a driving current for the light source on the basis of the analog signal generated by the smoothing section; a light-amount storing section which stores, in the main scanning line divided into a plurality of blocks, in advance light amounts of the light beam irradiated on the blocks; a change-data storing section which stores in advance a plurality of change data items set in a vicinity of each of block boundaries of the plurality of blocks, the plurality of change data items being used to cope with each of a plurality of events that are likely to affect image quality of the vicinity of the block boundary and the plurality of change data items respectively representing changes in a value of the analog signal at time when the blocks on which the light beam is irradiated are switched in the vicinity of the block boundary; and an irradiation control section which selects, out of the plurality of change data items stored in the change-data storing section, change data for coping with an event selected out of the plurality of events and instruct the pulse generating section to generate, (a) in the vicinity of the block boundary, the pulse signal from which the analog signal indicating a change in a value represented by the selected change data is obtained and (b) in the blocks, the pulse signal indicating the light amounts of the light beam irradiated on the blocks stored in the light-amount storing section, wherein, when the event selected out of the plurality of events is a ripple that occurs in the analog signal, in each rendering of the main scanning line, the irradiation control section selects, at random, any one of the plurality of change data items stored in the change-data storing section and instructs the pulse generating section to generate the pulse signal in (a).