Service manual
BY-PASS TRAY
2-L-4
2 UNIT EXPLANATION
[5] Paper Size Detection Control
The size of paper in the by-pass tray is detected by
PS55 (paper size 1 (by-pass tray)), PS56 (paper size
2 (by-pass tray)), and VR4 (paper size detection (by-
pass tray)). Based on the detection signals, the PRCB
(printer control board) judges the paper size.
1. Operation
The length of paper is detected using PS55 and
PS56. The by-pass tray is provided with a vari-
able resistor (VR4) interlocked with the guide
position to judge the width of paper according to
the change in the resistance value.
2. Signals
a. Input signals
(1) PS55 (PS55 to PRCB)
Paper size detection switch ON/OFF signal.
(2) PS56 (PS56 to PRCB)
Paper size detection switch ON/OFF signal.
(3) VR4 (VR4 to PRCB)
Paper width detection signal.
[6] No Paper Detection Control
No paper in the tray is detected by PS29 (no paper (by-
pass tray)) which is controlled by the PRCB (printer
control board).
1. Operation
When the tray becomes empty, PS29 is turned
ON, displaying a message on the LCD via the
OB1 (operation board 1).
2. Signals
a. Input signals
(1) PS29 (PS29 to PRCB)
No tray paper detection signal.
[L]: Paper does not exist in tray
[H]:Paper exists in tray
5VDC
PS55
SGND
PS56
VR4
5VDC
SGND
PRCB DCPS1
PS55
PS56
VR4
5VDC
PS29
SGND
5VDC
SGND
PRCB DCPS1
PS29
Di850g.book4ページ２００２年７月１２日 金曜日 午前８時３６分