Canon LBP6670dn Series Service Manual

22 2-92-9Technology > Fixing System > Fixing control circuit > Small Size Paper Printing Speed Control (Throughput Reduction Control)Technology > Fixing System > Fixing control circuit > Small Size Paper Printing Speed Control (Throughput Reduction Control)Fixing control circuitThe fixing control circuit controls the temperature in the fixing unit. The printer uses an on-demand fixing method.The Figure below shows the configuration of the fixing control circuit.FIXING TEMPERA TURE signalPressure rollerFIXNG HEATER CONTROL signalFixing filmFixing heatercontrol circuitFixing heatersafety circuitDC controllerLow-voltage power supply unitEngine controllerFixing control circuitH1TP1TH1• Fixing heater (H1): Heats the fixing film• Thermistor (TH1): Detects fixing temperature (Contact type)• Thermoswitch (TP1):Prevents an abnormal temperature rise of the fixing heater(Contact type)These temperature controls in the fixing unit are performed by the fixing heater control circuitand the fixing heater safety circuit according to the commands from the DC controller.F-2-14■ Small Size Paper Printing Speed Control (ThroughputReduction Control)During continuous printing, the throughput is changed to reduce heat buildup on parts not incontact with paper, to improve fixing characteristics and reduce curling.The throughput reduction is implemented according to the following conditions.Fixing Mode ThroughputEnvelope 1 – 23 imprints 23 – 39 imprints 40 – 47 imprints 48 imprints or more17 ppm 12 ppm 8 ppm 6 ppmEnvelope 2 1 – 27 imprints 28 – 62 imprints 63 – 174 imprints 175 imprints or more17 ppm 12 ppm 8 ppm 6 ppmEnvelope 3 1 – 31 imprints 32 – 47 imprints 48 – 79 imprints 80 imprints or more12 ppm 8 ppm 6 ppm 4 ppmPostcard 1 – 31 imprints 32 – 47 imprints 48 imprints or more12 ppm 8 ppm 6 ppm16K 1 – 89 imprints 90 imprints or more16 ppm 14 ppm16K Rough 1 – 34 imprints 35 imprints or more16 ppm 8 ppmLong Narrow 1 imprint or more3 ppmT-2-2