Patent ID: 9575432
Date: 2017-02-21
CPC Classifications: B41J,G03G

Claim:
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, wherein the plurality of light-emitting portions include a first light-emitting portion configured to emit a first light beam and a second light-emitting portion configured to emit a second light beam; 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, wherein the first light beam deflected by the deflection unit exposes a different position from the second light beam deflected by the deflection unit in a scanning direction of the plurality of light beams; a beam detection unit provided at a position on which a light beam deflected by the deflection unit is incident, the beam detection unit including a receiving surface configured to receive the first and second light beams deflected by the deflection unit, and being configured to generate a detection signal indicating that the light beam has been detected according to incidence on the receiving surface of the first and second light beams deflected by the deflection unit; a first driver IC configured to drive light-emitting portions included in the plurality of light-emitting portions, wherein the light-emitting portions driven by the first driver IC include the first light-emitting portion; a second driver IC configured to drive light-emitting portions that are included in the plurality of light-emitting portions and that are different from light-emitting portions driven by the first driver IC, wherein the light-emitting portions driven by the second driver IC include the second light-emitting portion; and a control unit, wherein the beam detection unit is configured to generate a first signal according to detection of a light beam emitted from a light-emitting portion driven by the first driver IC and to generate a second signal according to detection of a light beam emitted from a light-emitting portion driven by the second driver IC, and the first signal and the second signal are generated by the beam detection unit separately, and wherein the control unit is configured to measure a time interval between the first signal and the second signal, and is configured to control the first driver IC and the second driver IC so that with respect to relative emission timings at which the plurality of light-emitting portions emit light beams based on image data, the relative emission timings are controlled based on the measured time interval and by using as a reference a detection signal generated by the beam detection unit that has detected the first light beam.