Browse Prior Art Database

Implementation of Intellegent Printer Data Stream Overlays on HPCL/PPDA ASCII Printers

IP.com Disclosure Number: IPCOM000104661D
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 91K

Publishing Venue

IBM

Related People

Black, B: AUTHOR [+2]

Abstract

No native command support is available for the processing and printing of IPDS* overlays on Hewlett-Packard Printer Command Language (HP PCL)** and Personal Printer Data Stream (PPDS)*** printers. To provide this support, special processing algorithms and techniques were developed that made use of existing PCL and PPDS commands. A high-level overview of these algorithms and techniques is disclosed here.

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

Implementation of Intellegent Printer Data Stream Overlays on HPCL/PPDA ASCII Printers

      No native command support is available for the processing and
printing of IPDS* overlays on Hewlett-Packard Printer Command
Language (HP PCL)** and Personal Printer Data Stream (PPDS)***
printers.  To provide this support, special processing algorithms and
techniques were developed that made use of existing PCL and PPDS
commands.  A high-level overview of these algorithms and techniques
is disclosed here.

      Print Services Facility/2 (PSF/2) provides support of IPDS
overlays on PCL and PPDS printers using specialized processing
techniques in a device driver hereafter referred to as the PCL/PPDS
device driver.  The PCL/PPDS device driver provides support of IPDS
overlays using the macro function provided in PCL and PPDS.  Using
macros increases overall performance by reducing the amount of data
transmitted between the PCL/PPDS device driver and the printer.

      The main problems addressed in this implementation are:

      -Characters referenced by the IPDS overlay cannot by downloaded
as normal by the PCL/PPDS device driver.

      This is because the driver uses font sieving (e.g., only
characters that will be used are downloaded).  As fonts cannot be
downloaded while the PCL or PPDS printer is in macro state, the
download of characters has to be postponed until after the entire
IPDS overlay has been downloaded to the printer.

      -PCL and PPDS printers do not support text suppression.

      At the time information is loaded from the PCL/PPDS device
driver to the printer to generate a page or overlay, it is not
possible to determine if some of the data has been processed within
suppression fields, and if it should be suppressed or not.

      -PCL and PPDS macros cannot contain vector graphics.

      If an overlay contains vector graphics commands, it must be
stored separately and sent to the printer each time the overlay is
includ ed for printing.

      When the IPDS begin overlay command is received, all page and
font environment information is recorded.  The overlay is stored in
the sequence it is received in IPDS format.  The overlay is assigned
an internal identifier which is later used by other components of the
PCL/PPDS device driver.

      Actual interpretation of the overlay occurs only when the IPDS
Include Overlay or Load Copy Control commands are processed.  The
overlay is transformed from IPDS into an internal format within the
PCL/PPDS device driver.  This process re...