Xerox 4400DT - Phaser B/W Laser Printer, Руководство по обслуживанию, Страница: 435 / 503

8-22 Phaser 4400 Laser Printer Service Manual
Engine Logic Board and Front Panel
Functions
The Engine Logic Board performs eight main functions:
■
Communicates with the Image Processor.
■
Controls the print sequence.
■
Controls the Fuser Assembly, Laser Assembly, and Drive components.
■
Distributes low DC voltages to various printer components.
■
Monitors printer status.
■
Maintains a running print count.
■
Writes the NVRAM settings.
■
Controls printer options.
The Engine Logic Board uses a 32 bit microcomputer and Application Specific
Integrated Circuits (ASICs). The 32 bit microcomputer includes: ROM, RAM, a
16 bit integrated timer, a programmable timing pattern controller, a watch dog timer,
serial communication interfaces, an A/D converter, a D/A converter, I/O ports, a
DMA controller, and a refresh controller.
Image Processor Board
The Image Processor (IP) is one of the major elements that make up the Phaser 4400
printer. The primary function of the Image Process is to receive Host data through one
of the following available ports (Parallel, USB, or Ethernet). The received host data is
buffered and stored and sent to the print engine in a rasterized format.
The secondary function of the Image Processor is to provide print control, front panel
control, configuration setup, error reporting and job recovery.
Before the IP can receive and process data it must first pass the Power On Self Test
(POST). This test process verifies proper operation of the Image Processor and
prepares it for processing the host data by putting the Image Processor in a known
state.
The Image Processor connects to the Engine Logic Board directly. The Front Panel is
connected to the Image Processor and signals pass through the Engine Logic Board
via the Image Processor.
5 VDC PWB
This board converts 24 VDC from the LVPS to 5 VDC, which it supplies to the Image
Processor board.