| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an interface circuit for a printer that can prevent transmission of an erroneous control signal at application of power to the printer so as to enhance the stability of the printer in the initial state of power supply voltage rising and prevent malfunction of the printer. SOLUTION: After application of power, a flip-flop X23 is reset in a changeover control section 110, a NAND gate X21 detects a level change in output signals s1-s5 of an input section 100 to raise an output signal s9 of the flip-flop X23 and a changeover section 120 holds output signals s10-s14 to a high level when the signal s9 is at a low level and outputs the output signals s1-s5 of the input section 100 when the signal s9 is at a high level. Thus, the output signals after application of power are latched, the signal transfer function is started after an input signal rises, the output of the erroneous control signal is prevented and the malfunction of the printer can be prevented.</p> |
