Canon imagePROGRAF iPF8400, Service Manual

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Chapter 2
2-25
2.3.3.2 Paper Path
2.3.3.2.1 Structure of Feed Roller Unit
0024-9813
a) Paper feed assembly
The paper feed assembly consists of paper feeding mechanisms, such as a feed roller that is driven by the feed motor and a pinch roller unit that follows up the
motion of the feed roller.
Paper feeds horizontally under the printheads on the carriage as it is kept level on the platen to prevent cockle.
b) Sensors
The paper feed assembly includes sensors for detecting the status of paper feeding and that of the mechanical components that make up the paper passage.
For more details, see TECHNICAL REFERENCE > Detection Functions with Sensors.
c) Roll media pick-up drive unit
When the roll media feeds, the roll media pick-up pressure clutch 1 turns on to actuate the torque limiter in the pick-up drive unit. Thus the back tension works to
prevent the roll media from sags or skew.
At this time, if the paper tube of roll media is inside diameter of 3 inches, the pick-up pressure solenoid and roll media pick-up pressure clutch 2 turn on to increase
the back tension (about 2.6 times higher than before).
F-2-21
Feed motor
Roll media pick-up
pressure clutch 1
Roll media pick-up
pressure clutch 2
Pick-up pressure solenoid
Feed roller
HP sensor
Feed roller
encoder sensor
Roll media
Release lever
Roll holder
Media sensor
Pinch roller
Feed roller
Printhead