When the tray is pushed into the machine:
- The pickup solenoid [A] switches on and lowers the pickup arm and pickup roller [B]. With the pickup roller down on top of the paper stack, the machine raises the paper stack and roller.
- When the upper limit sensor [C] (an interrupt sensor) detects the actuator on the arm of the pickup roller, this switches the tray lift motor off with the top of the stack at the paper feed position.
- Next, in order to confirm that the top of the stack is at the optimum feed position, the lift motor reverses momentarily, the upper limit position sensor checks the position, and the lift motor reverses to correct raise the tray and correct the position.
- The tray lift sensor actuator [D] ascends gradually as sheets are fed for printing until it actuates the tray lift sensor and signals the machine to switch on the lift motor to raise the tray again to the correct paper feed position.