| Revision A |
Rush current preventing circuit for heater lamp
To prevent rush current when an AC voltage is applied to the heater lamp, the CPU turns off the Remote 1 signal and turns on the Remote 2 signal in the form of pulse. By outputting Remote 2, the additional resistor is connected in series to the heater lamp to
suppress the rush current flowing into the heater lamp.
Thermostat (TS1) and heater lamp fuse (TF1)
If an abnormal current flows into the heater lamp because of thermistor trouble, etc. and the upper fusing roller temperature reaches about 220°C, the contact of the thermostat automatically opens to shut off an AC voltage. (As the temperature decreases, the contact of the thermostat closes again. However, once the thermostat has been activated, it must be replaced with new one.) When a large abnormal current suddenly flows into the heater lamp, since the thermostat cannot respond quickly, the heater lamp fuse is
blown to protect the heater lamp. Fusing temperature control
1.When the main switch is turned ON, the fuser starts
2.To maintain the upper fusing roller temperature above 190°C, the control circuit raises the temperature and keeps at approximately. 210°C for approximately. five minutes. (Mode 1)
3.The control circuit gradually decreases the temperature by 190°C in five minutes. (Mode 2)
4.Preparing for printing, the control circuit keeps the upper fusing roller temperature at approximately. 190°C. (Mode 3)
5.While the printer is in the idle status, the control circuits maintain the temperature at 180 °C.
6.In energy saving mode, the control circuit turns OFF the heater lamp.
NOTE:190°C
Figure |
Fuser temperature control depending on the paper type
Normal paper:190°C
Special paper (thick paper):200°C
OHP:180°C
PPM (Print Per Minute) control
When the printer prints on more than specified number of paper whose width is 250 mm or less, the temperature of the fuser rises by its edge areas. To avoid abnormal rise of the temperature, the printer prints with larger intervals than normal. (Print speed reduces.) When the interval is more than 2 minutes, the printer release the PPM control.
In Mode 3:After 1000 sheets, PPM control is activated. In Mode 1 or 2:After 30 sheets, PPM control is activated.
Operating Principles | Printer Mechanism Operating Principles | 73 |
