Browse Prior Art Database

Raster Port High Speed Image Interface

IP.com Disclosure Number: IPCOM000121375D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 4 page(s) / 112K

Publishing Venue

IBM

Related People

Dodson, GR: AUTHOR [+6]

Abstract

A direct video interface is defined which allows the printer to print images at rated speed and synchronize image pages with text pages. For example, the user can print text pages and intersperse these with image pages and maintain throughput regardless of information exchange interface or the datastream protocol. This solution is called Raster Port. Currently, this synchronization is planned to work with all data stream protocols except PostScript*. Future implementations may include PostScript. This synchronization is provided for both the serial and parallel interface. Data Stream Initiated

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Raster Port High Speed Image Interface

      A direct video interface is defined which allows the
printer to print images at rated speed and synchronize image pages
with text pages.  For example, the user can print text pages and
intersperse these with image pages and maintain throughput regardless
of information exchange interface or the datastream protocol.  This
solution is called Raster Port.  Currently, this synchronization is
planned to work with all data stream protocols except PostScript*.
Future implementations may include PostScript.  This synchronization
is provided for both the serial and parallel interface.
Data Stream Initiated

      The essential hardware portion of this interface is 3
electrical signals:
RP_Video*:  This is an input to the printer and logically ANDed with
the printer's video line.
 WCLK*:    This is an output to the host computer which
           allows the host to know where the left edge
           of the printable page area is.
GHSYNC:    This is an output line from the printer which
           marks beginning of Raster Port image pages.
           Control of this signal provides information
           so the host computer can detect if a page should
           be printed via the Raster Port.

      To allow Raster Port printing to be initiated via the
datastream, an extension of the Set Initial Conditions (SIC)
datastream command will be used.  This command will be recognized
whenever the normal SIC command is recognized. This implies that it
will work when the printer is in PPDS, Printer Command Language, or
Graphic Language datastream modes BUT it will NOT be valid in
PostScript.

      When the printer receives the extended SIC Datastream command
it will:
1.   Print all data preceding the SIC command in its input
     buffers.
2.   Retain ALL permanent AND temporary resources in use by
     the current datastream.
3.   Enable the Raster Port interface by enabling GHSYNCs.
4.   Force a page to be printed from the current input tray
     at the current page size with all scan lines active for
     the page.
5.   Restore the previous datastream with ALL its resources.
6.   Datastream processing will resume following the SIC
     command.
     Hardware Initiated

      A hardware interface is defined which allows the user to print
images at rated printer speed.  This interface does not require
attachment to the printer via the existing serial/parallel interface
nor does it prohibit using the existing serial/parallel interface
either.  No commands are required to be sent via the serial/parallel
interface to initiate printing of image pages via the video hardware
interface.

      The essential hardware portion of this interface are 5
electrical sig...