Browse Prior Art Database

Printer Cover Open Algorithm

IP.com Disclosure Number: IPCOM000110657D
Original Publication Date: 1992-Dec-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Barker, RB: AUTHOR [+2]

Abstract

Various types of printers often have sensors that are used to verify proper print element movement during a print operation. However, there may not be a sensor in every rest position of the print element, so some provision must be made for cases where the print element comes to rest away from a sensor position. If an error is found when arriving at a sensor position, all lines that have been printed since arrival at the last correct sensor position must be reprinted to ensure that each line has appeared on the paper.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 56% of the total text.

Printer Cover Open Algorithm

       Various types of printers often have sensors that are
used to verify proper print element movement during a print
operation.  However, there may not be a sensor in every rest position
of the print element, so some provision must be made for cases where
the print element comes to rest away from a sensor position.  If an
error is found when arriving at a sensor position, all lines that
have been printed since arrival at the last correct sensor position
must be reprinted to ensure that each line has appeared on the paper.

      When the printer cover is opened, an assumption is made that
the operator may move the print head away from its rest position.
Because of this assumption, it is necessary to handle error recovery
immediately after the cover is opened rather than after the cover is
closed.  In some cases, an operator could move the print element a
small amount so that it might still register in the correct sensor,
even though the print alignment would be affected.  To handle this
situation, a relocation of the print element to the center of a
sensor position is required after the cover is closed.

      A sufficient Cover Open algorithm is defined as follows:
1.  Detect Cover Open condition.
2.  Complete the current print operation.
3.  Attempt to move the print element to a sensor position and check
for arrival errors.  (If there were errors, then the print lines must
be reprinted after the cover is closed.)
4. ...