| 摘要 |
PURPOSE:To prevent defects of printing arising from radical changes of density by providing a timer circuit which controls the time for printing of data for one line outputted from a memory, and also by providing a correction means which corrects the image data indicating density in accordance with the output from the timer circuit. CONSTITUTION:A correction means 8 having a pulse duration modulation circuit makes correction on image data read out of a memory 3 in accordance with output from a timer circuit 7 and a sensor 9, and changes the pulse duration in accordance with the density of the data, and sends out electrification control signals to a print head 10. Then a memory table for pulse durations in large memory capacity equivalent to image data and bit numbers of digital output values from the timer 7 and various sensors 9 is provided, and the timer circuit 7 that determines the length of electrification is controlled by a CPU 1 on the output from the above-mentioned memory table. Or a first table on a basic pulse duration for the image data, and a second and a third correction factor tables equivalent to temperature and printing rate are provided, and correction pulse duration is obtained by multiplying the basic pulse duration by the correction factors, and the result of the multiplication is converted into the length of electrification in the timer circuit 7. |
