Color image forming apparatus which reduces toner consumption during image formation

摘要

A full-color printer which reduces toner consumption by lowering the overall image density without changing the overall image tonality. An invalid data masking unit 31 masks non-printing area of a image signal 39 outputted from a FIFO buffer 30, and outputs the masked image data into a toner-saving image converter 32. The toner-saving image converter 32 zigzag masks the image signal every other pixel in main-scanning and subscanning directions based on a toner-saving mode designation signal A from a CPU 38. The masked image signal density is "00[H]". Thereafter, a gamma corrector 35 gamma corrects the masked image signal, and a PWM 36 performs pulse-width modulation on the gamma -corrected image signal. Image output is made by driving a semiconductor laser 120 with the pulse-width modulated signal.