Image recording apparatus

Abstract

Abstract PURPOSE:To record a stable gradation image excellent in image quality, by a method wherein an image signal is formed to a Modulo-N system and either one of (N-1) pieces of light sources corresponding to the level of the Modulo-N system is selected to be driven to perform image recording. CONSTITUTION:The digital image signal inputted to comparators 1, 2 is read, for example, by a CCD to be converted by an A/D converter. A dither matrix is considered as a kind of a mask and, when the image signal is larger than the corresponding threshold value level with respect to each of the pixels of the image signal, the comparator 1 judges the pixel as a black pixel to output '1' and, when said signal is lower than the threshold value level, the comparator 1 judges the pixel as a non-black pixel to output '0'. The same comparing operation is also performed with respect to the comparator 2. Therefore, either one of three states comes to be taken and the image signal is formed to a Modulo-3 system and laser diodes 9, 10 are driven in a time sharing manner only by a constant curreut and stable laser beam is obtained. (N-1) pieces of laser diodes may be constituted so as to be driven by the output of a Modulo- N system forming circuit (N is 3 or more). As N becomes large, image quality is also enhanced.

Inventors

• 👤 Masahiko Matsunawa
• 👤 松縄　正彦

Bibliographic Details