No Paper Detection Control; Control Of Paper Level Detection - Konica Minolta 7020 Service Manual

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PAPER FEED UNIT
[6]

No Paper Detection Control

SGND
DCPS
No paper detection is carried out by PS8 (no paper detect
PS (upper)), PS11 (no paper detect PS (lower)), and PS13
(by-pass no paper detect). Detection is controlled by the
PRDB (printer drive board).
1. Operation
a. No paper detection control
When the upper, lower, or bypass tray runs out of
paper, the corresponding PS comes ON (PS8, PS11,
or PS13), causing the LCD (display board) to display
a paper out message.
2. Signals
a. Input signals
2
(1) PS8 SIG (PS8 −> PRDB)
No paper detection signal for upper tray.
[H]: Paper does not exist
[L]: Paper exist
(2) PS11 SIG (PS11 −> PRDB)
No paper detection signal for lower tray.
[H]: Paper does not exist
[L]: Paper exist
(3) PS13 SIG (PS13 −> PRDB)
No paper detection signal for bypass tray.
[H]: Paper exist
[L]: Paper does not exist
SGND
PS13 SIG
5VDC
SGND
5VDC PS8 SIG
5VDC
SGND
PS11 SIG
5VDC
PRDB
[7]

Control of Paper Level Detection

2
PS13
PS8
PS11
After the trays have been set in the machine, paper level is
detected by PS9 (tray detect sensor (upper)) and PS12
(tray detect sensor (lower)).
As the paper level in tray runs low, the actuator at the rear
part of the tray gradually rotates as illustrated below. The
level is detected by the number of times the sensor goes
ON/OFF (the number of slits detected).
View looking from rear
Operation
a. Detection of paper level in tray
The following shows the relation between the paper
level and the number of slit detections by the sensor
(PS9 or PS12).
0 slits : Full
1 slit :
2 slits : Low
2-J-6
SGND SGND
5VDC PS9 SIG
5VDC
SGND
PS12 SIG
5VDC
DCPS PRDB
Direction of rotation
when the paper lifting
plate rises.
Slit 1
Slit 2
Actuator
Medium
PS9
PS12
Tray detect
sensor