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Ribbon Control Method for Improved Print Quality

IP.com Disclosure Number: IPCOM000110513D
Original Publication Date: 1992-Dec-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 2 page(s) / 78K

Publishing Venue

IBM

Related People

Arai, A: AUTHOR [+3]

Abstract

Described is a ribbon control method to improve print density variations occurring in bidirectional printing. In conventional mechanism motions of Serial Impact Printers, the ribbon direction is always in one direction independent of the printing direction. In this conventional method, print density tends to vary for every other line. The new ribbon control method presented below is very effective in solving this problem.

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Ribbon Control Method for Improved Print Quality

       Described is a ribbon control method to improve print
density variations occurring in bidirectional printing.  In
conventional mechanism motions of Serial Impact Printers, the ribbon
direction is always in one direction independent of the printing
direction.  In this conventional method, print density tends to vary
for every other line.  The new ribbon control method presented below
is very effective in solving this problem.

      To improve print density variations, the ribbon direction must
move the same as the printing direction.  Fig. 1 shows a ribbon shift
mechanism with a layered ink ribbon cartridge that can reverse the
ribbon direction for each line.  The ribbon direction can be switched
during acceleration and deceleration of carriage motion by shifting
up or down of the ribbon cartridge.  When a carriage moves to the
right, the ribbon must be wound up in the same direction, and when
the carriage direction changes to the left, the ribbon cartridge is
shifted to another stair which winds up the ribbon to the left.  The
velocity of these ribbons in the layered cartridge must be the same
to get the same print density.

      There would be some way to implement this ribbon control
through mechanical design.  For example, it is easily realized by
using three stepping motors and two conventional ribbon cartridges
layered.  One motor drives the ribbon shift motion; the others wind
up the ribbo...