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Printing Mechanism using Thermally Expanded Ink

IP.com Disclosure Number: IPCOM000103701D
Original Publication Date: 1993-Jan-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 4 page(s) / 124K

Publishing Venue

IBM

Related People

McLean, JG: AUTHOR

Abstract

Described is the use of thermally expanded ink in several printing mechanism implementations. The use of thermally expanded ink in printing mechanisms is an improvement over methods which required the use of embossed paper, such as in the printing of braille characters.

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Printing Mechanism using Thermally Expanded Ink

       Described is the use of thermally expanded ink in several
printing mechanism implementations.  The use of thermally expanded
ink in printing mechanisms is an improvement over methods which
required the use of embossed paper, such as in the printing of
braille characters.

      Typically, braille code is based on a cell of six or eight dots
which are raised in various combinations to form characters which are
then sensed by touching.  In prior art, braille printers formed
raised dots by embossing, or forming indentations onto special paper
which required specialized hardware.  In addition, the embossing onto
the paper tended to wear down with usage, making the text less
readable.  Thermoform braille printers, which use a heat/vacuum
process to permanently emboss plastic sheets to reduce the wear
problem, have been used but were complex and expensive.

      The concept described herein improves on the aforementioned
prior-art methods by using thermally expanded ink which puffs up or
expands to several times the applied thickness when exposed to heat
or air.  The result is the formation of the required raised
characters.  Several methods of transferring the thermally expanded
ink formula to ordinary paper are described as follows:

      A direct printing method is the use of hollow pressure-fed
pens, as shown in Fig. 1a.  Ink in tube 10 is pressure-fed into pen
array unit 11 which contains the required number of pens 12 for the
application.  Fig. 1b shows an enlarged view of one of the pens.  Pen
12 contains a hollow shaft 13 and a spring-loaded stopper 14.  When
pen 12 is pressed against the paper, stopper 14 moves back allowing a
consistent dot of ink to be applied to the paper (not shown).
Solenoid 15 provides individual control to each pen enabling each pen
to be extended or retracted depending on whether it is used in the
particular character formation.  Solenoid 15 is driven by printer
logic (not shown).  Many pen array u...