| 摘要 |
PURPOSE:To obtain a timer suitable to control over the AC voltage application time during picture exposure in a synchronous electrostatic latent-image transferring method, by obtaining an AC voltage in an invariably constant phase without adjusting application timing by controlling the phase of the AC voltage. CONSTITUTION:A commercial power source waveform from AC voltage source 43 is inputted to level converting circuit L to output a (c) part signal, which is inverted by inverter INV1 into a (p) part signal; it is inputted to NAND gate NG2 and also inputted to NG1 after differentiation d1. This output is inputted as a signal to terminal S of FF-P, which is set. As FF-P is set, its output is led to a timer as an input signal and at its rise, the timer is set to obtain a timer output in the period of time constant Tw determined by CT and VR. The other output signal of FF-P, on the other hand, is inputted to the gate trigger circuit of thyristor SCR as an A part signal via inverter INV3. Consequently, thyristor SCR turns on to obtain a high-voltage output from a high-voltage unit. |
