| 摘要 |
PURPOSE:To shorten time for key operation and at the same time, minimize wiring space from a control panel to MPU by allowing analog voltage to generate respectively in response to the operation of switches and then the voltage to be entered in a control device for imaging operation through a common signal line. CONSTITUTION:A key switch 13 for controlling an imaging operation indicated by a control panel 14 provided on the top of a main laser printer system 1 consists of a key switch 13-1. Each key switch has a connection with a divided voltage resistor 13-2. A voltage divided by a resistor when each key is switched ON is output to a single analog signal line 13-4 respectively through a diode 13-3, then is entered in an A/D converter 13-5. A digital signal voltage after A/D conversion is entered in MPU 13-6 on a printer control substrate to detect which of the key switches is pressed and allows and appropriate imaging operation to be indicated on an LED display part 11. At the same time, the activated condition is displayed in a segment 12. Thus it is possible to minimize the number of signal lines between the key switch and the control part for the miniaturization of the subject device and make a response rapidly. |
