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Print Quality Improvement Using Wide Wheel Base Platen

IP.com Disclosure Number: IPCOM000081449D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Dessel, JL: AUTHOR [+2]

Abstract

Because the print band is etched in the flat state and the ends are then welded together to form an endless band, it assumes the geometry shown in Fig. 1 when the band 10 is stretched around pulleys 12 and 14 and across a platen 15.

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Print Quality Improvement Using Wide Wheel Base Platen

Because the print band is etched in the flat state and the ends are then welded together to form an endless band, it assumes the geometry shown in Fig. 1 when the band 10 is stretched around pulleys 12 and 14 and across a platen
15.

Since the band 10 bulges in the center, it tends to push the ribbon 16 into the paper 18 causing smudging. Top to bottom print density variation also occurs, as well as shadow printing.

Because belt 10 rides over the platen 15 which interferes slightly with the tangent line between the pulleys 12, 14, it tips outward at the top as well as riding outward at the center, as shown in Fig. 2. Hammer action causes the belt to oscillate in a torsional manner, as shown in Fig. 3.

Backing the entire belt 10 in the plane of the platen 15 as shown in Fig. 4 does not correct the problem. However, the addition of a rail 2O at the base of the platen 15 which protrudes slightly beyond the platen, as shown in Fig. 5, solves the problem. The protruding rail 20 exerts a torque on the belt 10 to force the upper type carrying portion against the platen 15. There is no tendency to translate the entire belt toward the print line. The torsional stability is improved; and smudge, shadows, and density variations are noticeably improved.

The rail 20 appears to alleviate buckling of the belt 10 in the center under dynamic print loads as well, which improves the straightness of the print line. It also appear...