Service manual

TRAY 3 PAPER FEED UNIT
2-K-5
2 UNIT EXPLANATION
[5] Paper Size Detection Control
The paper size in tray 3 is detected using PS38 (paper
size 1-3), PS39 (paper size 2-3) and paper size detec-
tion VR3. Based on the detection signals, the PRCB
(printer control board) judges the paper size.
1. Operation
The length of paper is detected using PS38 and
PS39. A variable resistor (VR3) is installed at the
bottom of the tray to detect the width of paper.
The relationships between the switches and
paper sizes (lengths) are as follows:
2. Signals
a. Input signals
(1) PS38 (PS38 to PRCB)
Paper size detection switch ON/OFF signal.
(2) PS39 (PS39 to PRCB)
Paper size detection switch ON/OFF signal.
(3) VR3 (VR3 to PRCB)
Paper width detection signal.
[6] No Paper Detection Control
No paper in the tray is detected by PS28 (no paper 3)
which is controlled by the PRCB (printer control board).
1. Operation
When the tray becomes empty, PS28 is turned
ON, displaying a message on the LCD via the
OB1 (operation board 1).
2. Signal
a. Input signals
(1) PS28 (PS 28 to PRCB)
No paper detection signal.
[L]: Paper does not exist in tray
[H]:Paper exists in tray
Paper size
Switch
8.5 x 11
or less
A4R to
B5R
F4
8.5 x 14
or larger
PS38
OFF OFF ON ON
PS39
OFF ON ON OFF
5VDC
PS38
SGND
PS39
VR3
5VDC
SGND
PRCB DCPS1
PS38
PS39
VR3
5VDC
PS28
SGND
5VDC
SGND
PRCB DCPS1
PS28
Di850g.book5ページ2002年7月12日 金曜日 午前8時36分