Paper Up Drive Control - Minolta Di850 Service Manual

[4] Paper Up Drive Control

Papers stacked in the tray are pushed up by transmit-
ting the drive force of M19 (up drive 1) or M20 (up drive
2) to the paper up/down plate in the tray via up/down
wires. M19 and M20 are controlled directly by PRCB
(printer control board). Related signals are PS20
(upper limit detection 1), PS21 (upper limit detection
2), PS34 (remaining paper detection 1) and PS37
(remaining paper detection 2). To prevent pull-out of
tray during copying operation that cause paper jam-
ming, a tray lock mechanism is implemented by PS14
(handle release 1), PS15 (handle release 2), SD5 (lock
SD1), and SD6 (lock SD2).
1. Operation
a. Paper up drive control
When tray 1 or 2 is loaded, M19 or M20 goes ON
for a fixed time, raising the paper up/down plate
in the tray. When PS20 or PS21 detects the
upper limit of paper as the paper up/down plate
in the tray goes up, it goes ON and consequently
M19 or M20 goes OFF, stopping raising the
paper up/down plate. When PS20 or PS21 goes
OFF after a paper is fed, M19 or M20 goes ON
5VDC
PS14
PS14
SGND
PS20
PS20
PS34
PS34
5VDC
PS15
PS15
SGND
PS21
PS21
PS37
PS37
5VDC
SGND
24VDC
PGND
24VDC
M19
M19 CONT
24VDC
SD5
SD5 CONT
24VDC
M20
M20 CONT
24VDC
SD6
SD6 CONT
PRCB
again, moving the paper up/down plate upward.
The up/down plate in the tray is lowered mechan-
ically by its own weight.
b. Paper up drive timing
(1) ON timing
M19 or M20 is turned ON when loading of a tray
is detected (by shorting wires at both ends of the
drawer connector) or when PS26 or PS27 is
turned ON.
(2) OFF timing
M19 or M20 is turned OFF when PS20 or PS21
is turned ON.
2-J-5
TRAY 1/2 PAPER FEED UNIT
DCPS1
DCPS2