Xerox 6250N - Phaser Color Laser Printer, Service Manual

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2-12 Phaser 6250 Color Laser Printer Service Manual
Toner Control
Toner Cartridge installation is detected by the Toner Present (CTG-In) Switch, and the
presence of toner is detected by the Toner Low Sensor. These switches and sensors are
provided for each toner color (CMYK), and detection is made for each individually.
Toner Low Sensor
The toner low sensor checks one color every 3.5 seconds, requiring 14 seconds to
detect all four colors.
The toner low sensor is attached to the Toner Cartridge Holder Assembly. It detects
toner dispensed by the toner motor from the toner cartridge into the auger tube.
The toner low sensor can make a false detection if toner has stuck to the surface of the
sensor. To prevent this, a film attached near the auger in the toner cartridge holder
assembly cleans the sensor surface whenever toner is dispensed. This film rotates with
the auger as toner is dispensed, scraping toner off the toner low sensor surface.
The toner low sensor may detect toner even if toner is not present or may not detect
the toner even if toner is present, depending on the film position when the toner motor
stops. This is avoided by the printer’s internal toner presence control.
Toner Presence Control
1. Checks for toner presence when the power is turned on, or after the front cover is
opened and closed. Checks every 14 seconds when printing.
2.
The "Toner Empty” warning is displayed when the counter on the Customer
Replaceable Unit Monitor (CRUM) indicates that the toner is empty.
3.
The "Toner Empty” error is displayed when the toner low sensor detects that
toner is empty.
4. When a new toner cartridge is installed (“Toner Empty error” not being
generated), toner is dispensed for 1.7 seconds. At the next toner control timing, if
the toner low sensor detects toner present, the “Toner Full”, "Toner Empty
Warning", and "Toner Empty Error" are reset. When toner is dispensed and the
toner low sensor detects toner present three or more times consecutively, the
controller regards this status as "Toner Present".
5.
If the toner low sensor does not detect toner present, toner will be dispensed for
1.7 seconds again 5 seconds later. If toner present is not detected after executing
toner dispense three times and if toner cartridge dispense time shows 0, “Remove
Ribbon From ‘x’ Cartridge” error is displayed.