| 摘要 |
PURPOSE:To lessen a dispersion of printing density during the acceleration and deceleration of speed by switching by using a system in which in the switching of the time-division drive and the single drive, the driving of a heating resistor immediately after switching is made during driving time immediately before switching. CONSTITUTION:When ratio of black dots is 25% or less, pulse of time limit t1 is concurrently applied to the terminals (a)-(d) of AND circuits 3, whereupon receording signal converted from serial to parallel in a shift register 4 is added to the base of a transistor 2 and a heating resistor 1 is heated by the recording signal. When the ratio of the black dots exceeds 25%, pulse t1 of single drive period is orderly applied to the terminals (a)-(d) of AND circuit 3, and the terminals are heated in the order of (a)-(d) in comply with the recording signals. From the second period of the time-division drive, pulse of longer time limit t3 than t1 is put in (a)-(d) in a time-division manner and the heating resistors 1 are energized in the order of (a)-(d) in comply with the recording signals (e). The dispersion of printing density during the switching period can thus be lessened. |
