Abstract: An image forming apparatus is provided with a modulator producing a modulated signal of a pulse width decided on given image data and a driver driving an optical generator such as laser to generate a light beam. The image forming apparatus is further provided with a scanner periodically scanning the light beam generated by the optical generator and a power detector detecting information indicative of a power of the light beam scanned by the scanner. A pulse width adjustor uses the information detected by the power detector, in order to adjust the pulse width of the light beam.

Abstract: An image data processing section subjects input image data to image processing, and outputs first to fourth image data. First to fourth pulse width modulation circuits are PWM circuits in each of which a plurality of reference positions are set in one pixel, and output pulses corresponding to the first to fourth image data. A synthesis circuit synthesizes the pulses output from the first to fourth pulse width modulation circuits, and a laser emits a light beam in accordance with the synthesized pulse.

Abstract: According to an aspect of the present invention, a light beam scanning apparatus comprises light emitting unit for emitting a light beam, scanning control unit for controlling scanning of the light beam, light quantity detecting unit for detecting the quantity of light in the light beam, light quantity control signal output unit for outputting a light quantity control signal that performs control such that the quantity of light in the light beam is kept fixed on the basis of a result of detection of the quantity of light in the light beam, and light emission control unit for controlling a light emission timing for the light beam on the basis of image data and controlling the quantity of light in the light beam on the basis of the light quantity control signal while the light emission timing is being controlled.

Abstract: A beam detection sensor detects power of a laser beam from one of a plurality of light sources for each scanning of a scanning section to provide a light power signal. A laser control circuit compares a value of the light power signal with a predetermined value, adjusts a terminal voltage of a capacitor based on a result of the comparison, controls emission power of one of the light sources in accordance with the terminal voltage of the capacitor, and executes the control once for each light source during a plurality of scanning operations. An APC correction circuit corrects a reduction in the power of a laser beam in accordance with a reduction in electric charges applied to the capacitor caused by a leakage current during the plurality of scanning operations.

Abstract: According to an aspect of the present invention, a light beam scanning apparatus comprises light emitting unit for emitting a light beam, scanning control unit for controlling scanning of the light beam, light quantity detecting unit for detecting the quantity of light in the light beam, light quantity control signal output unit for outputting a light quantity control signal that performs control such that the quantity of light in the light beam is kept fixed on the basis of a result of detection of the quantity of light in the light beam, and light emission control unit for controlling a light emission timing for the light beam on the basis of image data and controlling the quantity of light in the light beam on the basis of the light quantity control signal while the light emission timing is being controlled.

Abstract: A light beam scanning apparatus according to an embodiment of this invention includes a reflection unit for reflecting a light beam, a rotation unit for rotating the reflection unit, a rotation control unit for controlling rotation of the rotation unit, a rotational speed detection unit for detecting a rotational speed of the rotation unit, a light amount control unit for, before the rotational speed detection unit detects that the rotational speed has reached a predetermined rotational speed, controlling light emission of the light beam and controlling the light amount of the light beam to a predetermined value, and a light emission control unit for, after the rotational speed detection unit detects that the rotational speed has reached the predetermined rotational speed, controlling a light emission timing of the light beam.

Abstract: An image forming apparatus according to an embodiment of this invention includes a light emission unit for emitting a light beam, a scanning control unit for controlling scanning of the light beam, a first light emission control unit for controlling the light emission timing of the light emission unit on the basis of a reference clock, a second light emission control unit for controlling the light emission timing of the light emission unit in correspondence with image data of one line in the main scanning direction on the basis of the generation timing of a horizontal sync signal, and an image forming unit for forming an image on the basis of the light beam.

Abstract: A beam light scanning device includes an image data processing unit operable to output image-processed data of neighboring pixels in such a way that the data is divided for distribution into first pixel data and second pixel data. The scanner also includes a synchronizer circuit that receives the first and second pixel data as output from the image data processor and outputs these pixel data while letting them be synchronized with clocks as synchronized based on a horizontal synchronous signal. The scanner further includes a couple of pulse width modulators or “PWMs”, a synthetic circuit, and a laser diode module. The PWMs are for adjustment of the pulse widths of the first and second pixel data as output from the synchronizer circuit respectively. The synthetic circuit combines together the pulse width-adjusted first and second pixel data. The LD emits a light beam indicative of the resultant combined pixel data.