| 摘要 |
<p>PURPOSE:To integrate a light emitting device and a reader by making an analog switch into a current switch at the time of an optical printing operation by means of a control signal, and making it into a photoelectric current input switch at the time of a reading operation. CONSTITUTION:An LED common terminal is grounded so that a voltage in a forward direction is applied to an LED array 7 at the time of the printing operation. Data in synchronization with a clock signal are inputted, when they are shifted by the number of the stages of the shift register, and the printing data are converted into parallel data, the LED emits light, and exposes a photosensitive drum. At the time of the light receiving operation, reverse bias is applied to the LED array 7, and a current/voltage converting circuit and an amplifying circuit are connected to a switch common terminal. When a high level latch signal is inputted to a latch circuit 2, MOS type transistor switches 50-1 to 50-n are successively opened, and the photoelectric currents of LEDs 70-1 to 70-n are outputted to the switch common terminal.</p> |
