Canon image Prograf iPF780 Series, Руководство по обслуживанию

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Chapter 2
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Multi sensor
A photo reflective type multi sensor consists of three red LEDs, one red/blue/green LED array, and three light receiving sensors and is used for media end, skew,
and width adjustment, registration adjustment, head height adjustment, and print position adjustment.
Media leading edge detection, head height (GAP) detection, and print density detection are performed by independent LED and sensor.
A clear film media detection (regular reflection) LED and a non-clear film media detection (diffused reflection) LED are used for end of media detection.
The head height is detected by receiving the reflection of red LED from the media with two sensors in a light receiving sensor and calculating the difference in
measurements.
The print density is detected by receiving the reflection of red/blue/green LED array from the media and determining the density of the printed surface.
F-2-44
Service mode: After SERVICE MODE > ADJUST > GAP CALIB. has been carried out, pass paper to make sure that it is detected properly.
Platen
Media
Red LED(Paper Edge:
Regular reflection)
Red LED(GAP)
Red LED(Paper edge:
Diffused reflection)
Light-sensitive sensor
(Density detection)
Light-sensitive sensor
(GAP detection)
Light-sensitive sensor
(Paper edge detection)
Red/Blue/Green LED Array(Density)