Canon LBP5000 Series, Service Manual

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Chapter 2
2-25
F-2-28
2.5.2.5 Transport Speed Control
0010-9411
LBP5000 / LBP5100
The machine is designed to switch the speed at which paper is moved according to type so as to prevent fixing faults.
Specifically, the DC controller switches the speed over 2 settings in response to the media selection command coming from the video control. The particulars of
speed control are as follows:
T-2-4
2.5.2.6 Paper loop control
0010-6137
LBP5000 / LBP5100
The machine has a mechanism to keep the arching of paper between the fixing pressure roller and the ETB to a specific degree to prevent image faults and feeding
faults.
The arching is controlled to a specific degree by varying the speed of the fixing/delivery motor with reference to the output of the pre-fixing paper sensor (SR5) by
the DC controller.
Normally, when print paper is moved to the fixing assembly, it is made to arch by the work of the fixing inlet guide as long as the speed of the fixing pressure roller
and that of the ETB are identical.
If the speed of rotation of the fixing pressure roller is lower than that of the ETB, however, the arching will increase, resulting in a disruption in the image or wrin-
kling of the paper. The presence of a discrepancy in speed will cause the pre-fixing paper detection signal (LOOPSNS) to go Low; and, in response, the DC con-
troller PCB increases the rotation speed of the fixing/delivery motor to decrease the arching of the print paper.
If the rotation speed of the fixing pressure roller is higher than that of the ETB, on the other hand, the print paper will not arch, and color displacement will be likely
in sub scanning direction as the paper is pulled by the fixing pressure roller. At this time, the LOOPSNS signal will go High, and the DC controller will decrease
the rotation speed of the fixing/delivery motor to cause the paper to arch.
Paper type Weight Paper type Speed
Thin paper 60-74g/m2 Plain paper L 1/1
Plain paper 74-90g/m2 Plain paper 1/1
Heavy paper 91-120g/m2 Heavy paper 1 1/2
Heavy paper 121-163g/m2 Heavy paper 2 1/2
Label sheet Label sheet 1/2
Envelope Envelope 1/2
Transparency Transparency sheet 1/2
Registration Shutter
warp
Print Paper
warp
Skew Correction