First Paper Feed Control - Konica Minolta 7155 Service Manual

BYPASS TRAY
*2 Paper size detection
The paper size is automatically detected by the
following three sensors:
• Lateral: Paper size detection VR/BP (VR5)
• Longitudinal: Paper size PS/1, 2-BP (PS31/
32)
Paper size PS/1-BP (PS31)
By-pass tray
Paper size VR/BP (VR5)
Paper size PS/2-BP (PS32)

[3] First Paper Feed Control

24V2
P.GND
5V2
S.GND
The first paper feed from the bypass tray takes
place as the result of the transmission of the drive
force from M6 (loop roller) to the paper feed
roller. M6 is controlled by PRCB (printer control
board). The related signal is PS36 (loop).
1. Operation
(1) When printing of the first copy starts
M6 (loop) is turned ON at the timing that is deter-
mined by the P counter (that starts when printing
starts), thus starting feed of paper.
M6 is stopped temporarily after lapse of a spec-
ified time from turning ON of PS44 (registration)
by the leading edge of paper, a loop is formed by
registration rollers, and the paper is fed to the
transfer unit.
(2) When printing of the second or subsequent copy
After lapse of the specified time from turning OFF
of PS44 (registration) by the trailing edge of the
preceding paper.
2. Signals
a. PRCB input signals
(1) LOOP_PS (PS36 to PRCB)
Paper passage detection signal
[L]: Paper does not exist.
[H]: Paper exist.
(2) 2ND_PS (PS44 to PRCB)
Second paper feed reference timing detection
signal
[L]: Paper exists.
[H]: Paper does not exist.
2-L-2
24V
24V
A
M6
/A
B
/B
5V3
PS36
LOOP_PS
S.GND
5V2
2ND_PS
PS44
S.GND
PRCB
Second paper
feed unit