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Browse Prior Art Database

Single Element Thermal Printer Head

IP.com Disclosure Number: IPCOM000122471D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 3 page(s) / 91K

Publishing Venue

IBM

Related People

Davis, MI: AUTHOR [+2]

Abstract

Disclosed is a robust print head which improves the speed of multi- element continuous tone thermal printers. A low-cost heat source via a strip lens applies energy in parallel across a line of LCD pixel- wide shutters, eliminating the complexity of controlled moving parts required by laser heads.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Single Element Thermal Printer Head

      Disclosed is a robust print head which improves the speed
of multi- element continuous tone thermal printers.  A low-cost heat
source via a strip lens applies energy in parallel across a line of
LCD pixel- wide shutters, eliminating the complexity of controlled
moving parts required by laser heads.

      The design can operate faster than laser methods but without
attendant safety problems and high unit control costs.  Rollers form
the paper path below the print position into a convex shape,
facilitating better control and thermal contact while removing
slackness in the paper/dye sheet sandwich.  Multicolour printing
requires three passes with appropriate coloured dye sheets.

      Continuous tone thermal printers are able to produce almost
photographic quality results due to their ability to transfer
graduated amounts of dye from a dye-sheet to a receiver sheet (the
paper) in a controlled way.  Although mainly employed by colour
printers because of cost, there is no reason why a true grey-scale
monochrome printer could not use this technique.  Conventional
continuous-tone thermal colour printers have individual resistive
pixel elements fed with a precise amount of electrical energy in
accordance with the amount of dye to be transferred.  Separate dye
sheets of the subtractive primary colours (yellow, cyan, magenta) are
passed, in turn, under the printhead.

      Although the print elements are small, they have a finite
thermal capacity so that the thermal history of each element must be
considered and the print speed kept low to avoid over-coloration.
Rapid heating and cooling of such elements, with a cycle time of just
a few milliseconds, can lead to print-head failure.

      Disclosed to overcome the foregoing disadvantages is a
print-head design s...