2-40 Phaser 4500/4510 Service ManualTheory of OperationFunctional ComponentsThe paper tray used in the optional feeder is identical to the 550-Sheet papertray used by the base engine, so the description of the paper tray is omittedhere.Option paper size switch assembly A bank of switches for setting the size ofpaper supplied from each paper tray is mounted in the left tray guide. A signalindicating the paper size is transmitted as a voltage to the HVPS/engine logicboard.No paper actuator This actuator is kept in a raised position by the paper in thetray. If the paper tray runs out of paper, the no paper actuator drops and theflag of the no paper actuator moves from between the sensor arms, allowingthe sensor to turn on.No paper sensor This is a photo sensor that remains in the OFF state whenpaper is present in the tray. The sensor turns on when there is no paper in thetray and the flag on the no paper actuator moves out of the sensor.Low paper actuator When paper is low in the paper tray, the arm of the lowpaper actuator is pushed up by the bottom plate assembly, moving theactuator flag out of the sensor.Low paper sensor This photo sensor remains in an OFF state until the paperlevel in the tray drops sufficiently to move the low paper actuator flag out ofthe sensor.Optional 550-sheet feeder This is a mechanism for supplying paper from thepaper tray into the printer. The driving force from the feeder motor istransmitted via the feed clutch assembly to the feed roller and nudger roller,transporting paper from the tray into the printer.As the nudger roller picks up paper and the paper level lowers, the position ofthe nudger roller drops accordingly. The lowered nudger roller pushes downthe lock lever of the bottom plate assembly, releasing it. The spring below thebottom plate assembly pushes it up and lifts the paper, which lifts the nudgersupport assembly off of the lock lever of the bottom plate assembly stoppingits upward motion.Turn roller This roller, working with the turn pinch roller, advances the paperpicked by the nudger and feed rollers into the printer. The feeder motor drivesthe turn roller through the turn roller clutch.550-sheet feeder PWBA A CPU installed in the 550-sheet feeder PWBAreceives instructions from the HVPS/engine logic board and from sensors andswitches; the CPU controls feeding operation in the 550-sheet feeder.
