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Constant Distance Print Gap in a Variable Forms Compensating Printing Mechanism

IP.com Disclosure Number: IPCOM000104272D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 1 page(s) / 55K

Publishing Venue

IBM

Related People

Dorsett, HL: AUTHOR [+2]

Abstract

Customer applications require that printers be designed to operate with a variety of papers and forms. These papers and forms come in different sizes and thickness. In order to accommodate the variation in thickness, some type of forms compensation mechanism is incorporated into the design of the printer. This compensation device must allow variable spacing between the printhead and the platen, the backup mechanism for the paper or form that is to be printed, to maintain a constant distance from the tip of the printhead to the surface of the form.

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Constant Distance Print Gap in a Variable Forms Compensating Printing Mechanism

      Customer applications require that printers be designed to
operate with a variety of papers and forms.  These papers and forms
come in different sizes and thickness.  In order to accommodate the
variation in thickness, some type of forms compensation mechanism is
incorporated into the design of the printer.  This compensation
device must allow variable spacing between the printhead and the
platen, the backup mechanism for the paper or form that is to be
printed, to maintain a constant distance from the tip of the
printhead to the surface of the form.

      Manual lever designs were one of the first methods used to
accomplish this.  They were reliable, but they required the operator
to adjust the lever to match the form or document that was to be
printed.  Later designs incorporated an automatic compensation by
spring loading the feed and pressure rolls used to drive the paper.

One of the rollers was attached to the printhead carrier through a
pivot plate.  The thickness of the form would separate the rollers
and cause the head to move proportional to the thickness of the form,
thus eliminating the need for operator intervention.

      As printer technology advanced and print speed increased, the
gap between the printhead and the document became more critical to
the quality of the print.  It also became more critical to the life
and reliability of the printhead.  The s...