Canon iR C6800 Series Service Manual page 677

9.3.2.2 At Power On
The fixing roller is heated by the fixing main heater (H1) and the fixing sub heater (H2), while the pressure roller is
heated by the pressure heater (H3). The outside heating roller, on the other hand, is heated by the outside heating
roller heater (H4).
During the warm up period (other than start up sequence), as many as 3 heaters may simultaneously be turned on.
To start up each of the rollers in the shortest time possible, the fixing sub heater and the outside heating roller heater
are turned on for full activation, while alternately turning on the fixing main heater and the pressure heater.
When the outside heating roller reaches 190 deg C, the outside pressure roller shift motor (M22) goes on to move the
outside heating roller into contact with the fixing roller, thereby starting fixing idle rotation. The outside heating
roller remaining in contact with the fixing roller helps increase the temperature of the fixing roller.
When the fixing roller reaches 200 deg C, the outside heating roller shift motor (M22) goes on so that the outside
heating roller moves away from the fixing roller.
When the fixing roller reaches 200 deg C, the pressure roller reaches 140 deg C, and the outside heating roller reaches
225 deg C, the machine starts start up sequence, causing the fixing main heater to go off. The outside heating roller
heater is put under temperature control when the outside heating roller reaches 225 deg C; on the other hand, the
fixing sub heater is put under temperature control when the fixing roller reaches 200 deg C.
As no more than 2 heaters may be turned on simultaneously while start up sequence is under way, the pressure heater
may be turned on only while either the outside heating roller heater or the fixing sub heater remains off. When the
temperature of the pressure roller reaches 170 deg C, the pressure heater is put under temperature control.
The warm up period ends when the start up sequence ends, causing the machine to enter the standby state.
Fixing main
heater (H1)
Fixing sub
heater (H2)
Pressure
heater (H3)
Outside heating
roller heater (H4)
Fixing motor
(M4)
Outside heating
roller shaft motor (M22)
Number of heaters
permitted for
simultaneous activation
- when outside heating roller is 190 deg C,
starts initial multiple rotation
WMUP WMUPR1 (fixing idle rotation)
Alternate activation *1
Heater full activation
Alternate activation *1
Heater full activation Controlled to 225 deg C
*3
(in contact)
3 3
- fixing roller: 200 deg C
- pressure roller: 140 deg C or higher
- outside roller: 225 deg C
if above is true,
starts start-up sequence
*6
WMUP2 (start-up sequence)
Controlled to 200 deg C
Limit on pressure
heater activation *2
(off contact)
*5
2
F-9-10
at end of start-up sequence,
enters standby
STBY
Controlled to 170 deg C
*4
3
: heater full activation.
: heater temperature control.
: heater alternate activation control.
: activation limit control
: motor turned on.
Chapter 9
0003-2894
9-13