Lamp Lighting Circuit - Canon CanoScan 9900F Service Manual

B. Lamp Lighting Circuit
1. Scanning Lamp Lighting Circuit
When the scanner is turned on, or the host computer sends a scan command, ASIC turns
on the scanning lamp lighting signal (LAMP) to light the scanning lamp.
The reflected light of the original is focused on CCD (charge-coupled device) via the five
mirrors, lens and FARE unit.
The scanner is equipped with a lamp OFF function for energy saving. A built-in timer
automatically turns off the lamp if no scanning command is sent from the host computer for
a certain period of time. Setting up of the timer is conducted by the device driver.
Host
Computer
COPYRIGHT 2003 CANON INC. CANOSCAN 9900F REV.0 FEB. 2003 PRINTED IN JAPAN (IMPRIME AU JAPON)
Lens
Main PCB
LAMP
GND
ASIC
Figure 2-6
Document Glass
Scanning Lamp
CCD
FARE Unit
Scanning Unit
CCD
Inverter
PCB
PCB
GND
CHAPTER 2
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