METHOD OF FORMING PICTURE

PURPOSE: To improve the efficiency of image forming by throwing primary color light to read out picture data while moving liquid crystal cells in the direction opposite to that for write at the time of picture read. CONSTITUTION: At the time of picture write, beam light from a laser diode 2 is scanned in the Y-axis direction (main scanning direction), and three liquid crystal cells 111 to 113 arranged in the X-axis direction (subscanning direction) are moved in the subscanning direction, thus writing picture data in liquid crystal cells 111 to 113. A the time of picture read, primary color light is thrown to read out picture data while moving liquid crystal cells 111 to 113 in the direction opposite to that for write. That is, picture read is performed when liquid crystal cells 111 to 113 are moved in the direction opposite to that for write, and further, picture read is performed on the going way and the return way while moving liquid crystal cells back and forth. Thus, picture write and read operations are continuously performed, and the image forming speed is increased.