| 摘要 |
PURPOSE:To reproduce a picture element comprising low and high density sections under a good condition by correcting the condition of a bit information group for determining the strength of beam based on a bit information group for determining the irradiating time of beam. CONSTITUTION:Multi-level digital image information 1 is fed from a host through a page memory 3 to a line buffer 5 and subjected to D-D conversion through a look-up table, i.e. a RAM 6, then upper 4 bits of corrected 8 bit data are fed to a D/A converter 7 for PWM conversion and the lower 4 bits are fed to a laser beam amount modulating section 11. A laser driver 12 turns a laser diode 13 ON/OFF based on the pulse width information of higher 4 bits while the amount of light is controlled based on the density information of lower 4 bits when the laser diode 13 is turned ON. By such arrangement, a good multi-tone image is obtained and an image comprising low and high density sections can be reproduced under good condition. |
