Xerox 721P85530 - Manual (Page 28)

OVERVIEW
1-2 XEROX DOCUPRINT 180 LPS PDL REFERENCE
LPS component types
LPS components consist of hardware and software.
Hardware
Hardware refers to all the physical components of the LPS.
Examples are the tape drives, the PC UI, the high-capacity feeder-
stacker, and the physical subsystems of the system controller and
the printer. Refer to your
Xerox DocuPrint 180 LPS Operator Guide
for detailed descriptions of the hardware components of your LPS.
Software
Software refers to all coded instructions (programs) which are
executed by the LPS. Some programs interface with LPS hardware,
some with LPS firmware, and some with other software. Examples
are the LPS operating system, the PDL compiler, and the output task.
LPS hardware components
The hardware components consist of the Advanced Image
Subsystem (AIS).
Advanced Image Subsystem (AIS)
The Advanced Image Subsystem (AIS) consists of three printed wire
boards which contain character dispatcher, font and graphic
memory. The three boards read the character and image data and
convert it into video format for printing. With AIS, imaging a page is a
two-stage process performed by the hardware/firmware
combination:
Step 1. In the first step, referred to as “fill”, the video format is stored into a
64-megabit memory called a ”page buffer.” The entire page is
processed and stored into this memory resulting in a bitmapped
image.
Step 2. In the second step, referred to as “dump”, the page buffer contents
are sent, one scan line at a time, to the laser.
Two page buffers enable one page’s video to be ”filled“ into one
buffer at the same time that the previous page’s video is being
”dumped” from the other page buffer.