2-12 Phaser 6250 Color Laser Printer Service ManualToner ControlToner Cartridge installation is detected by the Toner Present (CTG-In) Switch, andthe presence of toner is detected by the Toner Low Sensor. These switches andsensors are provided for each toner color (CMYK), and detection is made for eachindividually.Toner Low SensorThe toner low sensor checks one color every 3.5 seconds, requiring 14 seconds todetect all four colors.The toner low sensor is attached to the Toner Cartridge Holder Assembly. It detectstoner 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 thesensor. To prevent this, a film attached near the auger in the toner cartridge holderassembly cleans the sensor surface whenever toner is dispensed. This film rotateswith 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 detectthe toner even if toner is present, depending on the film position when the toner motorstops. This is avoided by the printer’s internal toner presence control.Toner Presence Control1. Checks for toner presence when the power is turned on, or after the front cover isopened and closed. Checks every 14 seconds when printing.2. The "Toner Empty” warning is displayed when the counter on the CustomerReplaceable Unit Monitor (CRUM) indicates that the toner is empty.3. The "Toner Empty” error is displayed when the toner low sensor detects thattoner is empty.4. When a new toner cartridge is installed (“Toner Empty error” not beinggenerated), toner is dispensed for 1.7 seconds. At the next toner control timing, ifthe toner low sensor detects toner present, the “Toner Full”, "Toner EmptyWarning", and "Toner Empty Error" are reset. When toner is dispensed and thetoner low sensor detects toner present three or more times consecutively, thecontroller regards this status as "Toner Present".5. If the toner low sensor does not detect toner present, toner will be dispensed for1.7 seconds again 5 seconds later. If toner present is not detected after executingtoner dispense three times and if toner cartridge dispense time shows 0, “RemoveRibbon From ‘x’ Cartridge” error is displayed.
