Browse Prior Art Database

End-of-Life Detector for Inked Printer Ribbons

IP.com Disclosure Number: IPCOM000105557D
Original Publication Date: 1993-Aug-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Winarski, DJ: AUTHOR

Abstract

Currently, printer ribbons or printer output must be manually checked to see if the ribbon is transferring enough ink to the paper. An automated means of making this check is desirable for PC users who are visually impaired.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 58% of the total text.

End-of-Life Detector for Inked Printer Ribbons

      Currently, printer ribbons or printer output must be manually
checked to see if the ribbon is transferring enough ink to the paper.
An automated means of making this check is desirable for PC users who
are visually impaired.

      A simple circuit can discriminate between a new printer ribbon
and one at its end of life (Figure).  The goal is to check the
condition of the inked printer ribbon 10.  This ribbon is the nylon
webbed ribbon common to PCs.

      Near the print head, ribbon 10 is screened on both sides by
masks 21 so that the illumination of the Light Emitting Diode (LED)
22 only falls upon the "working zone" of the printer ribbon.  This
working zone is the region traversed by the printer head.  A DC
voltage to LED 22 is provided by source 23.

      A Cadmium diSulfide (CdS) photocell 30 receives illumination
from LED 22 depending on the condition of ribbon 10.  Interestingly
enough, the CdS photocell 30 receives more illumination from a new
ribbon than a worn one.  The webbing in the new ribbon forms a porous
woven matrix, one which easily lets light from LED 22 pass.  However,
when ribbon 10 is at its end of life, the webbing in its working zone
has been hammered by the impact print head into a dense mat, one
which light has difficulty passing through.  This may be observed by
holding a new and an old webbed ribbon over a source of illumination.
The new ribbon easily passes light and...