Browse Prior Art Database

Automatic Compensation of Digital Fonts in Laser-Driven Printers

IP.com Disclosure Number: IPCOM000042063D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Wade, BW: AUTHOR

Abstract

This invention relates to a method for minimizing the bleed-through of black characters being swept out by the white beam of a laser-driven printer. The method steps include (1) thickening the black character by offset super-imposition of the character bit array upon itself by a predetermined amount; and (2) substituting subarrays having additional stroke thickness for selectively thin subarrays. Suppose it is desired to translate high resolution fonts to low resolution fonts, say, from 800 dots per inch to 240 dots per inch. When the converted fonts are printed, the stroke widths, as printed, are thinner than they should be. Indeed, very thin lines such as those one pel (picture element) in width completely disappear.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 55% of the total text.

Page 1 of 2

Automatic Compensation of Digital Fonts in Laser-Driven Printers

This invention relates to a method for minimizing the bleed-through of black characters being swept out by the white beam of a laser-driven printer. The method steps include (1) thickening the black character by offset super- imposition of the character bit array upon itself by a predetermined amount; and
(2) substituting subarrays having additional stroke thickness for selectively thin subarrays. Suppose it is desired to translate high resolution fonts to low resolution fonts, say, from 800 dots per inch to 240 dots per inch. When the converted fonts are printed, the stroke widths, as printed, are thinner than they should be. Indeed, very thin lines such as those one pel (picture element) in width completely disappear. This occurs on those printers using a relatively wide laser beam to write the white portions of a page, and, as such, characters appear only in those places where the laser did not shine. Typically, a laser beam may be two pels wide. The left half and then the right half of a single pel line are effectively erased leaving no line at all. Similarly, where lines are two pels wide they print out as though they were only one pel wide. In the method of this invention the overall thickening of converted characters is achieved in part by preprocessing the input character. Each black pel of an input character is copied to the pel position below it, to the pel position to its right, and to th...