Sharp DM-1505 - B/W Laser Printer Service Manual page 34

DM-1505
(1) Cassette paper feed operation
1) The figure below shows the positions of the pick-up roller, the paper
feed clutch sleeve, and the paper feed latch in the initial state
without pressing the COPY button after lighting the ready lamp.
The paper feed latch is in contact with the projection of the clutch
sleeve.
2) When the COPY button is pressed, the main drive motor starts
rotating to drive each drive gear.
The pick-up drive gear also is driven at that time. Since, however,
the paper feed latch is in contact with the projection of the clutch
sleeve, rotation of the drive gear is not transmitted to the pick-up
roller, which does not rotate therefore.
PFS
OFF
3) After about 0.1 sec from when the main motor start rotating, the
tray paper feed solenoid (PFS) turns on at a moment.
This disengages the paper feed latch from the projection of the
clutch sleeve, transmitting rotation of the pick-up drive gear to the
paper feed roller shaft, rotating the pick-up roller to feed the paper.
PFS
OFF
4) After more than half rotation of the pick-up roller, the paper feed
latch is brought in contact with the projection of the clutch sleeve,
stopping rotation of the pick-up roller.
5) At this time, the paper is fed passed the paper entry detection
switch (PPD1), and detected by it. After about 0.15 sec from detec-
tion of paper by PPD1, the tray paper feed solenoid (PFS) turns on
so that the clutch sleeve projection comes into contact with the
paper feed latch to stop the pick-up roller. Then the pick-up roller
rotates for about 0.15 sec so that the lead edge of the paper is
evenly pressed on the resist roller, preventing against skew feed-
ing.
RRS
OFF
6) To release the resist roller, the tray paper feed solenoid and the
resist solenoid are turned on by the paper start signal to disengage
the resist start latch from the clutch sleeve projection, transmitting
rotation of the resist drive gear to the resist roller shaft. Thus the
paper is transported by the resist roller.
7) After the resist roller starts rotating, the paper is passed through the
pre-transfer guide to the transfer section. Images are transferred on
the paper, which is separated from the OPC drum by the drum
curve and the separation section.
RRS
OFF
8) The paper separated from the drum is passed through the fusing
paper guide, the heat roller (fusing section), POD (paper out detec-
tor) to the copy tray.
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PFS
RRS
ON
OFF
PFS
RRS
OFF
ON