Canon BJC-8500 Service Manual

Also see for BJC-8500: User manual

Contents

3.5.2 Sheet feeder unit structureThe printing paper is stacked on the sheet feeder hooked by the claws at the left andright corners of the sheet feeder. The loading claw is provided for improving the paperloading performance. The left and loading claw follows sliding movement of the sideguide.When purge motor drive is transferred to the sheet feeder gear via the sheet feederdrive gear, the pick-up roller rotates, and the printer starts printing operations.Printing paper such as plain paper is held by the claws on both sides, picked up onesheet at a time, and pushed into the paper feed section. When thicker printing papersuch as envelopes are picked up, raise the left and right guides so that the printingpaper is picked up without being hooked by the left and right claws. When photoglossy papers GP-301 are picked up, raise the left guide only.The initial position of the pick-up roller is detected by the photo-interrupter pick-uproller sensor on the carriage board, and is determined by the number of pulses outputfrom the paper feed motor.When the paper end sensor detects the printing paper, the number of paper feedmotor (stepping feed) pulses is managed to prevent skew feed, and the printing paperis automatically fed to the printing start position. If the printing paper is not detectedby the paper end sensor, a paper pick-up error is generated.During manual feed, the user must insert the printing paper into the manual feed slotuntil the paper end sensor detects the printing paper. Also, the printing paper passesalong a pick-up path different to that during automatic pick-up by the sheet feeder.So, printing paper can be fed manually even if printing paper is stacked in the sheetfeeder.When the printing paper pushed into the paper feed section is detected by the paperend sensor within the preset time, paper is picked up from the printing start position.Part 4: Technical Reference BJC-85004-32Left GuidePick-up RollerDuring Sheet Feeder DriveSheet Feeder GearPurge MotorLoading Claw Right ClawRight GuideSide GuideLeft ClawFigure 4-30 Structure of Sheet Feeder Unit