Canon iPF8000 series Service Manual page 86

Chapter 2
c) Pump
The pump (suction pump) is a tube pump that pressurizes the ink tubes with rotating rollers to generate a negative pressure for sucking inks.
A single tube is sequentially pressurized by a pair of rotating rollers to control the level of ink suction by a wide margin.
The timing at which the rotating rollers rotate is detected by the pump cam sensor, with the distance of rotation being controlled by the driving of the purge motor.
Cap
Pump cam sensor
Suction pump
Cap
Rotating rollers
Ink tubes
Purge motor
Pump encoder
Suction pump
F-2-17
2-20