Lexmark T652 Service Manual - Page 285

4062-XXX Heat roll The heat roll is a hollow metal tube with a coated surface. This tube is heated by the inner heater lamp. The heat is applied to the media passing between the heat roll and pressure roll, fusing the toner on the media. Pressure roll The pressure roll is used to apply pressure to the media surface for fusing. Pressure is applied to the media between the pressure roll and heat roll, pressing the melted toner against the media. Heater lamp The heater lamp is a quartz glass tube containing a heater coil. A terminal is mounted to the end of the heater rod via a harness. Thermal cutoff If the heat roll temperature exceeds the preset temperature, the thermal cutoff cuts off the circuits of the main heater lamp and sub heater lamp. Thermistor The thermistor monitors the surface temperature of the media-feed portion of the heat roll to control on/off of the main heater lamp and sub heater lamp. Sensor (fuser output) The sensor (fuser output) detects the arrival of media at the detection point in the exit area of the fuser, and also detects the ejection of media from this point. Sensor (narrow media) The sensor (narrow media) detects the arrival of narrow media at the detection point in the exit area of the fuser, and also detects the ejection of media from this point. It is used to make adjustments to ensure that narrow media is properly fused. Fuser unit assembly (type 1 and type 2) Type 1 fuser unit assembly In the type 1 fuser unit assembly, the detacs, which are used to prevent the media from sticking to the hot roll, do not make contact with the hot roller. The type 1 fuser unit assembly has a life of 300K. Hot roll Fuser lamp Non contact detac Pressure roll Hot roll Pressure roll Non contact detac Diagnostic aids 3-73