| 摘要 |
PURPOSE:To inhibit a rush current at the start of printing and to print a sharp image, by a method wherein the drive of a resistance element is made to complete at a fixed point in a printing cycle when dots from the first step of gradation to a predetermined step of gradation are obtained, and it is started from the front end of the printing cycle when dots from the predetermined step of gradation to the n-th step of gradation are obtained. CONSTITUTION:Data SD for one line are supplied to an input terminal 11 and further supplied to a line memory 12 having a capacity for one line, thereafter being transferred to a line memory 13 at a predetermined timing. The inputted data for 512 dots are successively read dot by dot by a 512-notation address counter 14 and added to a comparison circuit 15. In the comparison circuit 15, the data for one line including 512 dots are compared with reference gradation data correspondingly one by one. PWM data each having a different pulse width are serially outputted from the comparison circuit 15 according to each gradation for 512 dots and supplied to a shift register 19. Head elements 41-4512 are made conductive only for a time of period according to the pulse widths of the respective PWM data. |
