Patent ID: 9740136
Date: 2017-08-22
CPC Classifications: G03G

Claim:
1. An image forming apparatus comprising: a photosensitive member; a charger that charges the photosensitive member; an optical scanning apparatus configured to scan the photosensitive member with a light beam output from a light source when a driving current modulated based on image information is supplied to the light source; a developer configured to develop an electrostatic latent image formed on the photosensitive member by scanning of the light beam by the optical scanning apparatus to form an image on the photosensitive member, and a control unit configured to control the optical scanning apparatus, wherein the optical scanning apparatus comprises: wherein the control unit is configured to control the charging unit so that the capacitor is charged by the charging unit and configured to control the value of the driving current, wherein the control unit is configured to control the charging unit so that the capacitor is charged by the charging unit in a state where the driving current is not supplied to the light source, to control the charging unit based on a detection result of the detection unit so that the voltage held in the capacitor is controlled from the voltage of the capacitor charged in the state where the driving current is not supplied to the light source, and to control the value of the driving current based on the voltage held in the capacitor controlled by the control unit, wherein the control unit is configured to control the value of the driving current such that the light power of the light beam is controlled to a target light power, by changing the voltage of the capacitor based on a comparison result of the comparison unit such that the voltage corresponding to the light power detected by the detection unit approaches the reference voltage, wherein the charging unit comprises a switch configured to selectively apply one of the reference voltage and the voltage corresponding to the detected light power to the capacitor, and a resistive element connected between the switch and the capacitor, wherein the charging unit is configured to apply, in a turn-off state of the light source before the light beam scans the photosensitive member, the reference voltage to the capacitor during a period after charging of the capacitor has started until the capacitor is charged to a voltage corresponding to a predetermined amount of charges, and wherein the period is determined depending on the reference voltage, a predetermined voltage to which the capacitor is charged by the charging unit, and a time constant determined by a capacitance of the capacitor and a resistance value of the resistive element.