Browse Prior Art Database

Printer Data Stream Method to Allow Dynamic Stream Switching

IP.com Disclosure Number: IPCOM000100987D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 5 page(s) / 179K

Publishing Venue

IBM

Related People

Bushaw, KA: AUTHOR [+3]

Abstract

Many printers can accept several printer data streams. For example, the IBM 4216-020 Personal Pageprinter can accept PostScript*, PCL and the Proprinter XL data stream. Such "multi-stream" printers allow customers a wider range of supported applications than printers that accept only one data stream. However, many multi-stream printers require an operator to flip switches or press buttons on the operating panel in order to change the active data stream. Setting the switches incorrectly results in print errors, a nuisance to a single user who must then try the job again with a different switch setting. Worse, there is no operator present to flip switches on a printer that is shared over a Local Area Network. The manual switches essentially limit the printer to a single data stream when shared over a network.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 38% of the total text.

Printer Data Stream Method to Allow Dynamic Stream Switching

       Many printers can accept several printer data streams.
For example, the IBM 4216-020 Personal Pageprinter can accept
PostScript*, PCL and the Proprinter XL data stream.  Such
"multi-stream" printers allow customers a wider range of supported
applications than printers that accept only one data stream.
However, many multi-stream printers require an operator to flip
switches or press buttons on the operating panel in order to change
the active data stream.  Setting the switches incorrectly results in
print errors, a nuisance to a single user who must then try the job
again with a different switch setting.  Worse, there is no operator
present to flip switches on a printer that is shared over a Local
Area Network.  The manual switches essentially limit the printer to a
single data stream when shared over a network.

      The solution to this problem adds controls to the printer data
stream that instruct the printer to change its active data stream.  A
host computer can then precede its print job with the appropriate
"switch active data stream" control.  Such a method will work even
when the print job is sent to a remote print server on a Local Area
Network. There are three forms of this approach, each applicable to
its own environment.  The description of each method uses a
hypothetical multi-stream printer that accepts Data Stream "A", Data
Stream "B" and Data Stream "C."

      The simplest implementation of controls extends each data
stream to include controls to switch to the others.  To switch
between data streams, the host simply includes the appropriate
"Switch from XXX to YYY" control between the two data streams.  In
Fig. 1:
      Data Stream "A" includes controls to switch to Data
      Stream "B" and Data Stream "C";
      Data Stream "B" includes controls to switch to Data
      Stream "A" and Data Stream "C"; and
      Data Stream "C" includes controls to switch to Data
      Stream "A":  and Data Stream "B."
      This approach has some disadvantages:
      A printer with N data streams requires addition of (N -
      1) controls in each of the N data streams for a total
      of N * (N - 1) new controls.
      Typically, the multi-stream printer does not have
      complete freedom to choose the control in each data
      stream; often some, or all, of the data streams are
      already implemented in single-stream printers.  To add
      new controls in such an environment, the multi- stream
      printer must find an unused control, and every addition
      makes compatibility with single-stream printers more
      difficult.
      In addition, if a later release of the printer includes
      a new data stream, each of the earlier data streams
      must change to add the new stream-switch control.

      Most multi-stream printer...