Canon SmartBase PC1200s Service Manual page 186

CHAPTER 4 OPERATION
The CPU on the DC controller PCB executes the following 4 types of fixing temperature
control:
• Start-Up Temperature Control
In response to a print command from the image processor PCB, the temperature of the
fixing heater is started up to a level 15°C/59°F lower than paper passage control temperature
target.
• Paper Passage Temperature Control
While printing is taking place, the fixing heater temperature is controlled so that it is iden-
tical with the paper passage control temperature target.
• Sheet-to-Sheet Temperature Control
To prevent overheating of areas not covered by paper (between sheets), the fixing heater
temperature is controlled to a level relatively lower than the paper passage control tempera-
ture target.
• Rest Heating Temperature Control
While the machine is at rest, the fixing pressure roller is heated so that the toner collecting
on it is melted and moved to the fixing film, thereby ridding the roller of toner.
The rest heating control mechanism is used to control the temperature of the fixing heater
to a level lower than the paper passage target level when LTR or larger paper is used for
printing.
The control temperature targets are switched in reference to the following 4 conditions:
• paper type (as indicated by a command during printing)
• type of control (cover paper or between sheets)
• change in fixing temperature control (OFF → start-up → paper passage, etc.)
• count of prints in continuous mode
4-28
COPYRIGHT © 2001 CANON INC. 2000 2000 2000 2000 CANON SmartBase PC1200s/iR1200s REV. 0 DEC. 2001