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Timing
The microprocessor on the engine control unit (ECU) controls the device operation sequences. Table
4-1 Operation sequences on page 58 describes engine operations for each period of a print
operation.
Table 4-2 Power-on sequence on page 58 describes each step of the power-on sequence.
Table 4-1 Operation sequences
Name Timing Purpose
WAIT From power-on until the end of the main motor initial
drive
Detects presence of a print cartridge. Clears potential
from the drum surface and cleans the transfer roller.
See
Table 4-2 Power-on sequence on page 58 for
a complete description of the WAIT (power-on)
period. Also see Figure 4-17 Timing diagram
on page 60 for detailed information about device
timing.
STBY (standby) From the end of the WAIT or LSTR period until either
a print command is sent from the formatter or the
power is turned off.
Prepares the device to receive print commands
INTR (initial
rotation)
From the time of the print command until the pickup
solenoid is turned on.
Prepares the photosensitive drum for printing.
PRINT From the end of the INTR period until the top-of-page
sensor detects the trailing edge of the media.
Forms the image on the photosensitive drum and
transfers the toner image to the media.
LSTR (last
rotation)
From the end of the PRINT period until the main
motor stops rotating.
Delivers the last page of a print job.
After LSTR, the device either returns to STBY or, if
another print command was sent from the formatter,
enters INTR.
Table 4-2 Power-on sequence
Step Action
1 Power-on
2 CPU initialization
3 Video-interface communication start
4 Sensors check for residual media
5 Main motor initial drive
6 Fuser heater initial drive. The fuser heater reaches a surface temperature of 120°C.
7 Fuser-motor initial drive
8 Laser/scanner-motor initial drive
9 High-voltage control
Detection of the presence of a print cartridge
Cleaning of the transfer roller after the primary charging AC bias is turned on
10 Failure/abnormality check: detection of laser/scanner failure, fuser failure, and open covers
11 Communication with the memory tag
58 Chapter 4 Theory of operation ENWW