Browse Prior Art Database

Home and End of Print Line Detection with a Single Sensor

IP.com Disclosure Number: IPCOM000122040D
Original Publication Date: 1991-Oct-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Harris, RH: AUTHOR

Abstract

Disclosed is a device which detects the position of a print head in a point of sale printer. Point of sale printers normally require a sensor at the center home position and a sensor at the end of the receipt line (on the right of home) and a sensor at the end of journal line (to the left of home). The disclosed device detects all three positions with a single sensor.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 63% of the total text.

Home and End of Print Line Detection with a Single Sensor

      Disclosed is a device which detects the position of a
print head in a point of sale printer.  Point of sale printers
normally require a sensor at the center home position and a sensor at
the end of the receipt line (on the right of home) and a sensor at
the end of journal line (to the left of home).  The disclosed device
detects all three positions with a single sensor.

      The figure shows the elements of transport of a point of sale
printer with the disclosed home and end of line sensor.  The essence
of the disclosure is that the timing belt which drives the print head
carrier contains the flags.  There are three flags which are
vulcanized to the timing belt.  The center flag senses the home
position when it is in the optical sensor.  The other two flags sense
the end of the receipt line and the journal line.  An adjustment
aligns the timing belt to the print head carrier.

      Since there is only one sensor and three flags, the system must
know which flag is at the sensor.  The following sequence will
determine which flag is at the sensor.
     1. The print head carrier is always initially driven to the
right.
     2. If a flag is in the sensor, the print head carrier is driven
to the right until the flag leaves the sensor. Continuing to the
right, the stepper motor pulses are counted until the next flag is
encountered.  If there were 196 steps counted between flags, the
pri...