| 摘要 |
PURPOSE:To enhance image quality by increasing the expression number of gradations, by driving a blade on the basis of the time width dividing ratio of a fundamental time and scraping off the ink supplied and adhered to a head roller to apply change to an ink adhesion area at every pixel. CONSTITUTION:The pulse width T of the fundamental pulse P1 formed in a pulse generator 13 is determined on the basis of the voltage signal for controlling the fundamental pulse inputted through an F/V converter 12 so as to correspond to the width of the pixel formed to the outer peripheral surface 1a of a transfer roller 1. The ON/OFf ratio in the pulse width of the fundamental pulse P1 is determined on the basis of the ON/OFF ratio control voltage inputted through a D/A converter 16 and, on the basis of the fundamental pulse P2 determined in this ON/OFF ratio, a blade 5 is driven through a voice coil 18 and the ink adhered to the outer peripheral surface 1a is scraped off in accordance with the ON-width T1 of the fundamental pulse P2. An ink adhered part and an ink scraped-off part are generated in the pixel formed to the outer peripheral surface 1a of the transfer roller 1 and the expression of a gradation at every pixel printed on the surface of paper 7 can be attained on the basis of the area ratio of both parts. |
