Basic Sequence; Wait; Standby; Last Rotation - Canon LBP-CX Series Service Manual

C. Basic Sequence
Power ON
y
WAIT
About
120 sec.
STBY
Drum rotations
Print command
PRNT
1
INTR
About
5.0 sec.
1.2
PRINT
~STR STBY
About
About
10 sec.
5.7 sec.
2.2
1.4
Note: The sequence is based on the example of printing one sheet of A4 paper.
Figure 2-3
The microcomputer in the DC controller func-
tions as a sequence controller, counting the signals
generated by the main motor drive circuit (T ACHO-
GENERATOR signal (TG)), proportional to main
motor rotations. The microcomputer directs printer
sequencing and switches electrical components ON
and OFF based on the TG signals counted.
1. WAIT (WAIT)
The time required for the fixing roller and laser
chip to reach operating temperature is called the
WAIT period. The WAIT time is normally about 120
seconds from a cold start (20°C).
When the power is switched ON, the fixing roller
heater (upper roller) and the laser chip heater (which
controls the laser chip temperature) operates, and the
R.EADY /WAIT indicator flashes.
2. STANDBY (STBV)
When the WAIT period is completed, the
READY/WAIT indicator changes from flashing to a
steady glow. This phase is called STANDBY. The
printer is ready to print.
3. INITIAL ROTATION (INTR)
This sequence ensures good drum photosensitivity
by putting a uniform layer of charges on the drum, in
the preconditioning exposure and primary corona
steps.
When the DC controller receives a TRUE PRINT
command (PRNT) from the external device, the DC
controller actuates the main and scanner motors, and
lights the preconditioning exposure lamps. Along
with the main motor, the drum begins rotating. The
corona assemblies also begin functioning in sync with
drum rotation.
4. PRINT (PRINT)
In this sequence the laser beam is modulated by
video signals transmitted from the external device
to the DC controller. The modulated laser beam scans
the photosensitive drum. The electrostatic latent
image produced on the drum by laser beam scanning
is changed to a visible image electrophotographically
and printed onto paper. While the previous image is
being printed, the DC controller requests the external
device to transmit a TRUE PRNT command (for the
next page). If a TRUE PRNT command
is
not receiv-
ed within a specified time, the printer goes on to the
LAST ROTATION (LSTR) period.
5. LAST ROTATION (LSTR)
During this period the drum rotates once after
printing, preparing the drum for the next printing.
If
a TRUE PRNT command is not received during
LSTR, the drum continues rotating, delivers the
paper, are remove and any residual charges on the
drum. After LSTR, the drum stops rotating and the
printer is in STBY.
If
the printer receivers a TRUE
PRNT command, the sequence starts again from
INTR.
Note:
INTR and PRINT timing are different for different
paper sizes and paper feed method (cassette or
manual feed).
~
INTR
PRINT
(sec.) (sec.) r
e
Cassette feed
5.0
LEGAL
9.9
LETTER 8.6
BS 8.6
A4 8.6
Manual feed
9.0
9.9
(all paper sizes)
Table 2-1 Time periods
COPYRIGHT
©
BY CANON lllC. CAllDN LBP-CX SERIES REY.2 JULY 1985 PRINTED IN JAPAll (IMPR!ME AU JAPON)
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