Browse Prior Art Database

Image Processing

IP.com Disclosure Number: IPCOM000100088D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 4 page(s) / 150K

Publishing Venue

IBM

Related People

Cole, CP: AUTHOR [+4]

Abstract

The IBM LaserPrinter is targeted at a wide range of applications, including those that currently run on the IBM Proprinter and IBM Quietwriter series of serial printers, as well as competitive page printers such as the Hewlett Packard LaserJet Series II. Each of these printers provides unique image formats and resolutions.

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This is the abbreviated version, containing approximately 39% of the total text.

Image Processing

       The IBM LaserPrinter is targeted at a wide range of
applications, including those that currently run on the IBM
Proprinter and IBM Quietwriter series of serial printers, as well as
competitive page printers such as the Hewlett Packard LaserJet Series
II.  Each of these printers provides unique image formats and
resolutions.

      Image Image is a means of specifying graphic content using
picture element (pel) information rather than vector or fill
descriptions.  Image is sometimes referred to as
all-points-addressable (APA), although that is actually a description
of a printer capable of printing image data rather than the data
itself.

      Resolution Resolution, in this context, refers to the source or
native resolution, in dots per inch (dpi) for which the image format
was intended.  The IBM LaserPrinter has a fixed 300 dpi resolution
and must convert other resolutions so that a satisfactory result is
obtained at 300 dpi.

      Raster Line A raster line is one row of pels in the direction
perpendicular to the process direction of the printer.  The bit map,
into which data to be printed is placed, is organized in raster
lines.  In portrait orientation, image data in raster line format can
be placed without rotation into the bit map.

      Printhead Stripe A printhead stripe is one column of pels, a
printhead or less in height, in the direction perpendicular to the
movement of the printhead in a serial printer.  In portrait
orientation, image data in printhead stripe format must be rotated
before it can be placed into the bit map.

      Supported Formats
Resolution    Format                   Conversion
300 by 300    Raster Line              1:1 by 1:1
150 by 150    Raster Line              1:2 by 1:2
100 by 100    Raster Line              1:3 by 1:3
75 by  75     Raster Line              1:4 by 1:4
240 by  72    Printhead Stripe         Rotate, 4:5 by 6:25
120 by  72    Printhead Stripe         Rotate, 2:5 by 6:25
60 by  72     Printhead Stripe         Rotate, 1:5 by 6:25
40 by 240     Printhead Stripe         Rotate, 4:5 by 4:5
120 by 120    Printhead Stripe         Rotate, 2:5 by 2:5
60 by  60     Printhead Stripe         Rotate, 1:5 by 1:5

      Hardware Support

      Field Insert The bit field insert function allows the software
to specify a bit address without having to handle word- or
byte-alignment problems.  A word (16 bits) or byte (8 bits) can be
placed into the bit map on any bit boundary.

      Rotation The hardware provides a 16-bit by 64-row orthogonally
addressable memory cache that can be rotated by 90o in either
direction.

      Horizontal Resolution Conversion For data that is not being
rotated, the hardware provides for a bit-wise resolution conversion,
including automatic dithering.

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