CASSETTE SIZE DETECTOR OF COPYING MACHINE

摘要

PURPOSE:To require no microswitch, simplify a circuit, and reduce the cost by providing a required resistor element to a cassette and connecting it in parallel with a condenser connected to a comparator circuit when the cassette is fitted to a copying machine so as to count and judge the cassette size. CONSTITUTION:In detecting the size of a cassette 6, a reference voltage is connected to one input terminal of a comparator circuit 9 and a condenser C is connected to the other input terminal, and a resistor element RA arranged on the cassette side is connected in parallel with the condenser C when the cassette is fitted to a copying machine 1. The discharge time of the condenser C is counted until the output signal of the comparator circuit is generated, and the cassette size is displayed on LEDs 11-1-11-N based on the counted data. Accordingly, by varying the resistance value of the resistor element RA on the cassette side in accordance with the size of the cassette 6, multiple types of cassette sizes can be detected with, e.g., even one comparator circuit.