- HP Printer User Manual

ENWW Tray 1 (bypass tray) 91
MFP unit explanation
1 Operation
a Paper up/down control
M20 (up/down motor/BP) is turned on to
push up paper. When PS34 (tray upper
limit/BP) detects the paper upper limit
and turns on, M20 turns off to stop
pushing up paper. When paper is fed
and consequently PS34 turns off, M20
turns on again, maintaining the upper
limit position of paper.
b Paper up timing
1 ON timing
At start of copying
2 OFF timing
M20 (up/down motor/BP) is turned off
when PS34 (tray upper limit /BP) is
turned on.
c Paper down timing
1 ON timing
When there is no paper or a paper
jam occurs.
2 OFF timing
M20 (up/down motor/BP) is turned off
when PS35 (tray lower limit/BP) is
turned on.
2 Signals
a PRCB input signals
1 BPUP_PS (PS34 to PRCB)
Paper upper limit position detection
signal (Tray 1)
[L]: Not detected
[H]: Detected
2 BPDN_PS (PS35 to PRCB)
Paper lower limit position detection
signal (Tray 1)
[L]: Not detected
[H]: Detected
b PRCB output signal
1 BPUDM_A, B (PRCB to M20)
M20 drive control signal
Paper size detection control
The size of paper in the Tray 1 is detected
by PS31 (paper size/1-BP), PS32 (paper
size/2-BP), and VR5 (paper size/BP). Based
on the detection signals, PRCB (printer
control board) judges the paper size.
1 Operation
The length of paper is detected by PS31
(paper size/1-BP) and PS32 (paper
size/2-BP). Tray 1 is provided with a
variable resistor (VR5) interlocked with the
guide position to judge the paper width
according to the change in the resistance
value.
The relationships between the sensors
and paper sizes (lengths) are as follows:
2 Signals
a PRCB input signals
1 BPSIZE_S_PS (PS31 to PRCB)
Paper size detection signal
[L]: Paper does not exist.
[H]: Paper exists.
Paper size
Sensor
8.5 by 11
or less
A4R to
B5R
F4 or
larger
PS31 OFF ON ON
PS32 OFF OFF ON
VR5
PRCB
DCPS
5V2
S.GND
5VA
BPSIZE_VR
PS32
5V3
BPSIZE_L_PS
SGND
PS31
5V3
BPSIZE_S_PS
SGND