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Browse Prior Art Database

Low Paper Sensing in a Point-of-Sale Printer

IP.com Disclosure Number: IPCOM000106384D
Original Publication Date: 1993-Nov-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Beaton, LG: AUTHOR [+2]

Abstract

Current methods for sensing low paper in a journal station of a POS (Point-of-Sale) printer include either an optical sensor that looks at the edge of the paper spool, or a mechanical switch that rides on the spool, and when the paper is out, these devices will switch. However, due to movement of the spool and varying sizes of the core that the paper is rolled on, these methods, at best, will leave as much as four to 14 feet of paper on the core when a low paper detect signal occurs.

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This is the abbreviated version, containing approximately 100% of the total text.

Low Paper Sensing in a Point-of-Sale Printer

      Current methods for sensing low paper in a journal station of a
POS (Point-of-Sale) printer include either an optical sensor that
looks at the edge of the paper spool, or a mechanical switch that
rides on the spool, and when the paper is out, these devices will
switch.  However, due to movement of the spool and varying sizes of
the core that the paper is rolled on, these methods, at best, will
leave as much as four to 14 feet of paper on the core when a low
paper detect signal occurs.

      Using an out-of-paper sensor (optical or mechanical) and a
software algorithm shown in the Figure, an accurate lower paper
sensing scheme can be achieved.  The sensor detects the presence of
paper.  When journal out-of-paper signal occurs, the printer
microprocessor sends this status to the system printer driver.  At
this point, all future journal print messages are sent to a system
buffer until the transaction is completed.  No further printer
operations are allowed until a new roll of paper is loaded into the
printer.  The buffered messages are then printed out on the new
journal roll and store operation is back to normal.  The number of
journal lines that can be buffered is a function of system memory.
The end results of this process is an uninterrupted print transaction
for a given store customer.