Canon iPF8000 - imagePROGRAF Color Inkjet Printer, Service Manual

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Chapter 2
2-24
Multi sensor
The photoreflector-based multi sensor consists of four LEDs (red, blue, green, infrared) and two light-receiving sensors to detect the leading edges and width of
paper and skews in it, and to adjust its registration, head height and calibration.
At head height adjustment, the two light-receiving sensors detect infrared light reflected upon the paper to work out the head height from differences in its meas-
urement.
F-2-31
2.5.4 Paper path system
0014-8916
F-2-32
Media sensor
The photoreflector-based media sensor detects the presence or absence of paper on the platen.
The sensor detects the presence of paper when it receives sensor light reflected upon the paper.
Feed roller HP sensor
The feed roller HP sensor detects transitions from white (transmitted), or a reference, to black (shielded) when the printer is switched on, thereby setting the home
position of feed roller eccentricity correction.
Feed roller encoder
The feed roller encoder is driven to detect the length of paper feeding for each rotation of the feed roller from encoder slits.
2.5.5 Humidity sensor
0013-8116
F-2-33
Platen
Media
Infrared LED
LED(blue) LED(green) LED(red)
Infrared sensor
Media sensor
Feed roller HP sensor
Feed roller
encoder
Humidity sensor