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Browse Prior Art Database

Printer Control Unit Architecture

IP.com Disclosure Number: IPCOM000099485D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 3 page(s) / 124K

Publishing Venue

IBM

Related People

Bell, BC: AUTHOR [+2]

Abstract

Disclosed is a printer control unit architecture for a medium-speed line printer using print band technology. With heavy emphasis on distributed processing using microprocessors, this architecture supports a wide variety of host system attachments, satisfies a broad spectrum of throughput requirements, and facilitates functional changes throughout the product life.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Printer Control Unit Architecture

       Disclosed is a printer control unit architecture for a
medium-speed line printer using print band technology.  With heavy
emphasis on distributed processing using microprocessors, this
architecture supports a wide variety of host system attachments,
satisfies a broad spectrum of throughput requirements, and
facilitates functional changes throughout the product life.

      Fig. 1 illustrates the main components of the printer control
unit.  The Task Interface separates the System Adapter 10 from the
mechanism control function.  Different system adapters are
implemented depending on the host system attachment 12.  Typical host
attachments for this architecture are Twinax, New Display System and
System/370 Channel.  The System Adapter 10, contains the analog
circuits that interface directly with the system link, the digital
hardware required to satisfy the link protocol, and an Intel
microprocessor with the microcode required to convert the information
on the link to a Task Control Block.  This control block is placed in
the Shared Store 9 for interpretation by the printer mechanism
control function.

      The mechanism control function is implemented with a
microcomputer (MP) 2 coordinating the actions of several mechanism
sub-adapter (Disk Controller 4, Hammer Fire Controller 6, Op Panel
Controls 8, Carriage Controller 14, Print Time and Ribbon Controller
17) manages the unique, real-time control of its mechanical function.
 The bus 11 is used for communication between the MP 2 and the
sub-adapters when time is not critical.  When immediate control must
be exercised, the sub-adapters assert a high priority interrupt to MP
2.

      The MP 2 interprets the Task Control Block in the Shared Store
9, and sends the appropriate commands to the individual mechanism
sub- adapters.  Each sub-adapter then interprets its command, and
executes it when the print band 18 is at the right position, as
determined by the Print Time Controller 17.  When an exception
condition is detected, the sub-adapter shuts down its mechanism, and
reports status to the MP 2.  The MP 2 then coordinates the shut-down
of the other mechanisms, if necessary, and creates an entry in the
error log.  The error log is periodically written to the floppy disk
3 for future reference.

      The synchronization between the Printer Control Unit and the
print mechanism is accomplished with the Print Time Controller 17.
It detects the positions of each character on the print band and
electronically divides the space between them into 128 even
increments.  Each of the 49,152 spaces (128 spaces/character x 384
characters) on the continuous print band is indicated to the rest of
the Printer Control Unit with a pulse or "tick" generated by the...