Image forming system using digital ASIC and analog ASIC for processing image data and controlling semiconductor laser, and half-tone pixel representing method

Abstract

A digital ASIC inputs pixel data thereto and an analog ASIC inputs the output signal of the digital ASIC thereto. A combination of the digital ASIC and the analog ASIC controls a semiconductor laser so as to pulse-width-modulate and amplitude-modulate the light emitted by the semiconductor laser that may be pulse-width-modulated and amplitude-modulated. The digital ASIC comprises a reference pulse generator having delay time control unit and a pulse width generator for generating a plurality of different pulse widths using pulses having a plurality of phases generated by the reference pulse generator. The analog ASIC comprises control/modulation unit for controlling the semiconductor laser so as to pulse-width-modulate and amplitude-modulate the light emitted by the semiconductor laser using the plurality of different pulse widths generated by the pulse width generator. The reference pulse generator comprises an oscillator comprising combined multiple delay-time control unit, and control unit for controlling the oscillator so as to make the frequency supplied by the oscillator identical to the clock of the pixel data.

Dependencies are inferred from the claim text.