US 5,648,801 AGranted

Grayscale printing system

AssigneeInternational Business Machines Corporation

InventorsGary Scott Beardsley, Gary Scott Keller, Francis Chee-Shuen Lee

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Abstract

A system is provided for obtaining enhanced quality grayscale printing using standard printer architecture. An image to be printed is scanned to produce several bit maps for image pixels having different optical intensities. The different bit maps are handled by a standard print engine separately, in the same manner as multicolor bit maps would be handled. The image is then printed using a print head assembly having separate print heads for grayscale printing using different optical intensities. Thus, a printed image having enhanced resolution and quality, because of the optical intensity discrimination, is produced using a printer architecture which is the same as a standard multicolor printer architecture except for the front end, which scans for optical intensity, and the print head assembly, which has different print heads designed to produce different optical intensities. The print heads use either different ink dot sizes, inks having different pigment concentrations, or other suitable techniques for varying the optical intensity.

Claims7

Dependent claims

A printing system for printing color and greyscale images based, respectively, on color and grey tone image information, the system comprising:

an image processing and printing system having respective primary color information inputs, and a printer driver including respective multiple channels, for a set of respective primary colors;
a front-end color interpreter having:
(i) means for converting color image information into respective bodies of image information for respective primary colors, and
(ii) means for coupling color image information to respective ones of the primary color information inputs of the image processing and printing system:
a front-end grey tone interpreter having:
(i) means for converting grey tone image information into respective bodies of image information for respective grey tone levels, and
(ii) means for coupling the respective bodies of image information to respective ones of the primary color information inputs of the image processing and printing system;
the front-end color interpreter and the front-end grey tone interpreter being interchangeably couplable to the image processing and printing system:
a color print head having:
(i) a plurality of inputs for coupling to the image processing and printing system and for receiving respective bodies of image information for respective primary colors therefrom, and
(ii) means for printing respective primary colors based on the received respective bodies of image information for respective primary colors;
and
a greyscale print head having:
(i) a plurality of inputs for coupling to the image processing and printing system and for receiving respective bodies of image information for respective grey tone levels therefrom, and
(ii) means for printing respective grey tone levels based on the received respective bodies of image information for respective grey tone levels;
the color print head and the greyscale print head being interchangeably couplable to the image processing and printing system.

13 more elements

A method for operating a printing system for printing color images and high-resolution greyscale images made up, respectively, of color image information and greyscale image information, the system including an image processing and printing apparatus having a plurality of channels, a front-end color interpreter, a front-end greyscale interpreter, a color print head for printing a plurality of primary colors, and a greyscale print head for printing a plurality of greyscale intensities, the method comprising the steps of:

(A) printing a color image by performing the steps of:
coupling the front-end color interpreter and the color print head to the image processing and printing apparatus;
converting the color image information into respective bodies of image elements, each input image element having one of a predetermined set of primary colors,
dividing the image elements into respective bodies of color image elements based on the respective primary colors of the image elements;
coupling the respective bodies of image information to respective ones of the channels of the image processing and printing apparatus, and
providing the respective bodies of image information to the color print head to be printed according to respective ones of the primary colors of the color print head;
and
(B) printing a greyscale image by performing the steps of:
coupling the front-end greyscale interpreter and the greyscale print head to the image processing and printing apparatus,
converting the grey tone image information into respective bodies of image elements, each input image element having one of a predetermined set of greyscale optical intensity levels,
dividing the image elements into respective bodies of GRAYSCALE image elements based on the respective optical intensity levels of the image elements;
coupling the respective bodies of image information to respective ones of the channels of the image processing and printing apparatus, and
providing the respective bodies of image information to the greyscale print head to be printed according to respective ones of the greyscale intensities of the greyscale print head.

10 more elements

Dependencies are inferred from the claim text.