Canon iR C6800 Series, Service Manual

Page: 673 / 1404

Chapter 9
9-9
9.3 Various Control Mechanisms
9.3.1
Controlling the Speed of the Fixing Roller
9.3.1.1 Controlling the Speed According to Paper Type
0003-2889
The machine controls the fixing roller to any of 3 speeds according to paper yep.
T-9-4
9.3.1.2 Controlling the Speed for Large Volume Printing (downsequence)
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If the main thermistor (THM1) of the machine's fixing roller identifies the surface temperature of the fixing roller as
being any of the following, the machine starts downsequence, in which distance between sheets is increased to
decrease the speed of printing, thereby preventing poor fixing otherwise caused by drops in the roller temperature
when continuous printing is under way.
The speed of printing is relatively low in color mode and, therefore, the temperature of the fixing roller rarely drops,
thus not calling for downsequence.
The following is a table of control mechanisms used for downsequence prepared according to site environments and
paper types; the notations within the table indicate the following:
LV: downsequence level
deg C: temperature of the fixing roller triggering downsequence
PPM: printing speed
Toner fixing starts to fail when the temperature of the fixing roller drops to level 4 or below. The machine, therefore,
stops (suspends) printing when it detects a level 4 condition; it then starts (resumes) printing using the speed it used
at the start when the temperature of the fixing roller returns to the recovery level.
If the room temperature is less than 20 deg C and heavy paper or a transparency is used, the machine reduces its print
speed (except when heavy paper 1 is used for the 120V or 230V model).
Paper type Fixing speed
Mono color print plain paper normal speed (276 mm/sec)
heavy paper, transparency, postcard normal speed (276 mm/sec)
Color print plain paper (64 to 105 g/m2) normal speed (276 mm/sec)
heavy paper (106 to 163 g/m2), postcard 2/3 speed (184 mm/sec)
heavy paper 2 (164 to 209 g/m2), heavy paper 3
(210 to 250 g/m2), transparency
1/3 speed (92 mm/sec)