Image forming apparatus

摘要

An image forming apparatus causes a BD sensor to generate two BD signals based on laser beams emitted from first and second light-emitting portions and measures the generation timing difference therebetween. When measurement is to be executed, the image forming apparatus executes APC as light power control on the first light-emitting portion that emits a laser beam for causing the BD sensor 210 to generate the first BD signal. On the other hand, the image forming apparatus executes ACC, rather than APC, as light power control on the second light-emitting portion that emits a laser beam for causing the BD sensor to generate the second BD signal that follows the first BD signal.

主权项

1. An image forming apparatus comprising:
a light source including a plurality of light-emitting portions that are each configured to emit a light beam for exposing a photosensitive member; a first light receiving unit configured to receive a plurality of light beams emitted from the plurality of light-emitting portions; a deflection unit configured to deflect a plurality of light beams emitted from the plurality of light-emitting portions, such that the plurality of light beams scan the photosensitive member; a second light receiving unit configured to, in response to receiving a light beam deflected by the deflection unit, generate a detection signal indicating that the light beam has been received; a current control unit configured to execute light power control of causing the plurality of light-emitting elements to emit light individually and controlling a driving current which is supplied to each of the plurality of light-emitting portions based on a light reception result of the first light receiving unit receiving a light beam emitted from each of the plurality of the light-emitting portions, and supply a driving current with a pre-determined value to at least a second light-emitting portion among the plurality of light-emitting portions, the current control unit being configured to supply driving currents to a first light-emitting portion and the second light-emitting portion among the plurality of light-emitting portions such that light beams emitted from the first light-emitting portion and the second light-emitting portion are incident on the second light receiving unit in sequence; and a timing control unit configured to measure a time interval between a first detection signal generated due to the second light receiving unit receiving a light beam from the first light-emitting portion and a second detection signal generated due to the second light receiving unit receiving a light beam from the second light-emitting portion, and based on the time interval, control relative emission timings according to which the plurality of light-emitting portions emit the plurality of light beams, wherein the current control unit is configured to:
cause the second light receiving unit to generate the first detection signal by supplying, to the first light-emitting portion, a driving current with a value based on a light reception result of the first light receiving unit receiving the light beam emitted from the first light-emitting portion; andcause the second light receiving unit to generate the second detection signal by supplying a driving current with a pre-determined value to the second light-emitting portion.