Paper Up Drive Control - Minolta Di551 Service Manual

[4] Paper Up Drive Control

Paper stacked in the tray is pushed up by trans-
mitting the drive force of M16/17 (tray up drive/
1/2) to the up/down plate in the tray via drive
wires. M16/17 are controlled by the PRCB
(printer control board). Related signals are PS2/
8 (tray upper limit/1/2) and PS4/10 (remaining
paper/1/2).
1. Operation
a. Paper up drive control
When tray 1/2 is loaded, M16/17 (tray up drive/1/
2) turns ON to lift the up/down plate in the tray.
When PS2/8 (tray upper limit/1/2) detects the
upper limit of paper as the paper up/down plate
in the tray goes up, it turns ON and consequently
M16/17 goes OFF, causing the tray to stop going
up. When PS2/8 turns OFF after paper is fed,
M16/17 goes ON again to move the paper up/
down plate upward. The up/down plate in the tray
is lowered mechanically by its own weight.
24V1
P.GND
5V2
S.GND
DCPS
T1RISEM_24V
M16
T1RISEM_D
T2RISEM_24
M17
T2RISEM_D
PRCB
2-J-5
TRAY 1/2 PAPER FEED UNIT
5V3
PS2
TIUP_PS
SGND
Tray 1
5V3
PS4
TIRM_PS
SGND
5V3
PS8
TIUP_PS
SGND
Tray 2
5V3
PS10
TIRM_PS
SGND
b. Paper up drive timing
(1) ON timing
M16/17 (tray up drive/1/2) is turned ON when
loading of a tray is detected. (by shorting wires at
both ends of the drawer connector)
(2) OFF timing
One of M16/17 (tray up drive/1/2) is turned OFF
when PS2/8 (tray upper limit/1/2) is turned ON.
c. Remaining Paper Detection Control
The level of paper remaining in each tray is
detected according to the time that M16/17 (tray
up drive/1/2) requires to lift up the up/down plate
when the tray is set. This lift-up time (operation
time of M16/17) is saved in the PRCB (printer
control board) . After this, the remaining paper
is detected using the paper feed counter. The
detected remaining paper level is displayed on
the operation panel in five steps.
(remaining paper/1/2) are used to detect the
remaining paper level when it lowers below about
10 %.
PS4/10