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Browse Prior Art Database

Reversed Helix Matrix Printer

IP.com Disclosure Number: IPCOM000043112D
Original Publication Date: 1984-Jul-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Lane, R: AUTHOR [+3]

Abstract

Both the bar helix and the dot drum helix printers suffer from ghost printing due to the hammer blade pushing the ribbon and the paper into contact with an adjacent helix. This article describes a solution to this problem. The bar helix and the dot drum helix are back printers. The element which forms the dot is behind the paper, and the hammer blade drives both the paper and ribbon onto the print element which is mounted on a rotating drum, as shown relative to a dot drum helix printer in Fig. 1. Both the bar helix and the dot drum helix suffer from ghost printing, i.e., light print dots appear where not wanted. A major cause of the ghost printing is due to the twisting of the hammer blade. When the hammer blade strikes the dots or the bar at one end of the blade, the other end of the blade is twisted towards the paper.

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Reversed Helix Matrix Printer

Both the bar helix and the dot drum helix printers suffer from ghost printing due to the hammer blade pushing the ribbon and the paper into contact with an adjacent helix. This article describes a solution to this problem. The bar helix and the dot drum helix are back printers. The element which forms the dot is behind the paper, and the hammer blade drives both the paper and ribbon onto the print element which is mounted on a rotating drum, as shown relative to a dot drum helix printer in Fig. 1. Both the bar helix and the dot drum helix suffer from ghost printing, i.e., light print dots appear where not wanted. A major cause of the ghost printing is due to the twisting of the hammer blade. When the hammer blade strikes the dots or the bar at one end of the blade, the other end of the blade is twisted towards the paper. This twisting motion will cause both paper and ribbon to contact an adjacent element in the next helix, printing an unwanted dot or bar as shown in Figs. 2 and 5. The amount of twisting of the hammer blade has been measured on an optical shadow graph. When striking a dot at one end of the blade, the other end was observed to move 0.008 inch beyond the surface plane of the dots, as shown in Fig. 3. Both the bar helix and the dot helix are formed in the pattern of a continuous helix around the surface of the drum. This places the dot or the bar in the least desirable position relative to the twisting motion of the blade in Fig. 3. As can be seen, when th...