Controlling The Scanning Lamp (La2); Outline; Turning On/Off The Lamp - Canon Image Reader-A1 iR5000i Service Manual

3. Controlling the Scanning Lamp (LA2)

3.1 Outline

The system used to control the scanning lamp is constructed as follows and the items of
control include the following:
[1] Turning on and off the scanning lamp.
[2] Monitoring the scanning lamp for errors.
Xenon lamp
LA2
3.2 Scanning Lamp
The machine's scanning lamp is a xenon lamp of a non-electrode discharge type, in which
xenon gas is sealed in a tube.
On the outside of the glass tube, two electrodes are arranged parallel to the tube axis, and
the inner side of the glass tube is coated with fluorescent material.
The internal gas discharges and, as a result, the fluorescent material glows when a high-
frequency voltage is applied across the electrodes.

3.3 Turning On/Off the Lamp

The scanning lamp is turned on/off in response to the drive signal (LAMP_ON) from the
CPU on the reader controller PCB. When the signal is generated, the inverter generates a
high-frequency, and high-voltage using the drive voltage (+24 V) supplied by the reader
controller PCB to turn on the xenon tube.
COPYRIGHT © 2001 CANON INC.
CHAPTER 2 ORIGINAL EXPOSURE SYSTEM
Inverter PCB
Activation
control
circuit
F02-301-01
Electrode
Electrode
F02-302-01
2000 2000 2000 2000 CANON iR5000i/iR6000i REV.0 JUNE 2001
Reader controller
J5101 J5007
+24V
1 5
LAMP_ON
3
3
INV_ERR
4
2
2 4
Electrode
Fluorescent
Opening
material
Glass tube
Electrode
PCB
CPU
2-9 R