HP color laserjet 1600 series Service Manual

The operational sequence of the printer is controlled by the microcomputer on the DC controller
printed circuit board (PCB). The purposes of each period, from power-on until the main motor stops
after the completion of printing, are listed below. See 

 for a detailed

timing chart.

  Basic operational sequence

WAIT (wait period)

From power-on until the end
of the main motor initial drive.

To clear the drum surface
potential and to clean the
ETB.

Detects whether or not the
print cartridge is installed.

STBY (standby period)

From the end of WAIT or
LSTR until the input of print
command from the
formatter. Or, from the end
of LSTR until power-off.

To keep the printer ready to
print.

INTR (initial rotation period)

From the input of print
command from the formatter
until the pick-up solenoid is
turned on.

To stablize the
photosensitive drum
sensitivity for print
preparation.

PRINT (print period)

From the end of INTR until
the developing high-voltage
is off.

To form the image on the
photosensitive drum based
on the VIDEO signals input
from the formatter, and to
transfer the toner image
onto paper.

LSTR (last rotation period

From the developing high-
voltage off until the main
motor stops rotating.

To deliver the last page
completely. Also used to
clean the ETB.

The printer enters INTR after
the end of LSTR, when the
print command is input from
the formatter.

The engine control system coordinates all printer functions. It drives the laser/scanner system, the
image formation system, and the pickup and feed system. The engine control system contains the
following components:

●

DC controller PCB

●

Low-voltage power supply unit

●

High-voltage power supply PCB

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Chapter 4   Operational theory

ENWW