SPREAD DIVISION PWM GRADATION PROCESSING UNIT

摘要

PROBLEM TO BE SOLVED: To realize stable high density gradation processing having a high highlight gradation density with a memory and a circuit of a small scale in an image processor for a laser printer. SOLUTION: Gradation control by laser pulse width modulation(PWM) and spread dot gradation processing where gradation is spread among 4 dots are used in common and a problem can be solved by a PWM pulse pattern at a highlight is switched into a discontinuous pattern depending on a high-order bit of a threshold.