PURPOSE: To maintain a constant concentration of printing by varying the energization time with the control of clock counts based on the results of comparison of outputs of a temperature detection element as substrate of a recording head with outputs of a digital-analog converter.
CONSTITUTION: An output voltage b of a temperature detection element 2 is compared with outputs P of a digital-analog converter 19. When b is higher than the level of P, the output g goes to 'H'. Only at this moment, an AND gate 30 allows clocks 20 into a counter 21 to count. The output of the counter 21 is applied to a digital-analog converter 19 to raise the output P and when it P becomes higher than the output b of the temperature element 2, the counting is halted, where the value of the output P almost corresponds to the temperature of the substrate of the recording head 1. The output P is applied to a pulse generation circuit 17 to select a pulse width corresponding to the output P thereby allowing the energization time to correspond to the temperature of the substrate of the recording head 1.
YAMADA AKITSUGU
INOUE KUNIHIKO
MATSUSHITA GRAPHIC COMMUNIC
| JPS6128516A | 1986-02-08 |