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Proportional Spacing Raster Printer Character Generator

IP.com Disclosure Number: IPCOM000078422D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 101K

Publishing Venue

IBM

Related People

Dattilo, AJ: AUTHOR [+2]

Abstract

A raster printer generates a line of proportionally spaced characters, by generating successive horizontal scan lines equal to the width of the printed line. The characters are stored on a character font in a fashion such that the escapement value of each character is readily detected during each horizontal scan.

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Proportional Spacing Raster Printer Character Generator

A raster printer generates a line of proportionally spaced characters, by generating successive horizontal scan lines equal to the width of the printed line. The characters are stored on a character font in a fashion such that the escapement value of each character is readily detected during each horizontal scan.

The font memory is organized so that a 32 by 32 bit matrix box is allocated for each character. The width of the coded character within the box is determined by the escapement of the character. The character is coded left adjusted in the assigned memory space (see figure). The character is placed in the box so that it does not touch the right edge of the box and includes a blank column, thereby assuring a white vertical bar at least one column wide at the right edge of the character. The unused escapement units are all coded ones.

When a line is generated, the first scan of the first character is accessed. All 32 bits of the first scan line are read into the output logic. The highest number escapement unit with at least one white dot is considered the right edge of the character and only this number of escapement units are printed. The process is repeated for the first scan of the second character etc. During the second scan line, the escapement of the character is determined in the same manner. The escapement is marked by the first 1-0 (black, white) transition in the scan, when moving from the hig...