RESIDUAL QUANTITY OF PAPER DETECTOR FOR LIFT TYPE PAPER FEED CASSETTE

摘要

PURPOSE:To detect residual quantity of paper without requiring a rotary encoder or a counter by providing an operating means for calculating the residual quantity of paper mounted on a lift board based on the magnitude of load current. CONSTITUTION:A lift board 23 to be guided freely and liftably/lowerably through a guide member 22 is provided to a lift type paper feed cassette. Papers 25 to be fed to a copy machine 24 provided with a call-in roller 24a and a feed roller 24b are mounted on the lift board 23. A drive motor 26 controlled through a controller 41 to lift or lower the lift board 23 is arranged at the lower section of the lift type paper feed cassette 21. A transistor 42 is grounded through a load current detecting resistor 45 and connected through an amplifier 46 to the A/D converting section 44a of CPU 44. CPU 44 controls the operation of the drive motor 26 and also serves as a means for detecting the amount of load current flowing through the drive motor 26 and an operating means for calculating the residual quantity of paper 25 mounted on the lift board 23.