Drum Cartridge Toner Full Detection - Lexmark Optra SC 1275 Service Manual

Drum Cartridge Toner Full Detection

The drum cartridge toner full board (PWB-D1), on top of the image
transfer belt assembly, determines when the PC drum waste toner
box is full.
Waste toner full is detected by an LED (LED1) and a photo-sensor
(PT1) on the PWB-D1. Light from the LED (LED1) passes through
the LED passing window, is reflected by a mirror in the drum car-
tridge, and then received by the photo sensor (PT1). The amount of
this light determines whether the drum cartridge is nearly full or full.
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