Browse Prior Art Database

Re-Rastering a Horizontal Line Printed by a Serial Printer to Prevent Background Stripes

IP.com Disclosure Number: IPCOM000061279D
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Czyszczewski, JS: AUTHOR [+5]

Abstract

Serial printers print a horizontal swath of data, then index and print the next horizontal swath of data. How well the two swaths of data line up is dependent on the index accuracy. If the index does not go far enough, there is a slight overlap between the two swaths of print. If the index goes too far, then there is a space between the lines. If the two lines were supposed to come together, as in text, image, or graphics, extra space will look like a stripe of the paper color showing through. If a slight overlap occurs, then diagonal lines will have a jagged appearance. A method to prevent the stripe of paper showing through and to reduce the effect that the angle of a diagonal line has on appearance of overlapping swaths of data is described.

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Re-Rastering a Horizontal Line Printed by a Serial Printer to Prevent Background Stripes

Serial printers print a horizontal swath of data, then index and print the next horizontal swath of data. How well the two swaths of data line up is dependent on the index accuracy. If the index does not go far enough, there is a slight overlap between the two swaths of print. If the index goes too far, then there is a space between the lines. If the two lines were supposed to come together, as in text, image, or graphics, extra space will look like a stripe of the paper color showing through. If a slight overlap occurs, then diagonal lines will have a jagged appearance. A method to prevent the stripe of paper showing through and to reduce the effect that the angle of a diagonal line has on appearance of overlapping swaths of data is described. This method prevents both incorrect color and ragged diagonal lines while preventing stripes of paper showing through for index overshoot. The method puts the data on the paper in the following manner: 1. The top swath of printing is put on the paper. 2. The paper is indexed one dot height less than the full height of the swath of printing so that the two swaths will overlap by one pel. 3. The data for the bottom row of dots of the top swath of print is now used as the top row of data on the bottom swath of print. 4. The new data is used for the rest of the bottom row. The procedure, described above, is an improvement over the prior art because it re- rasterizes the same row twice between adjoining swaths instead of using hardware to merely duplicate the bottom row of data one pel below the end of the swath (Fig. 1)....