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# Wire Flight Time Adjustment Process

IP.com Disclosure Number: IPCOM000108643D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 3 page(s) / 99K

IBM

## Related People

Demick, TJ: AUTHOR [+2]

## Abstract

The process outlined here monitors print wire flight time and uses time as an indicator of wire flight distance (head to platen clearance). Experimental data has shown that for a single wire within a print head, that the time/distance relationship describing wire flight is a constant and therefore may be used to describe the distance "d" as shown in the figure.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

The process outlined here monitors print wire flight time
and uses time as an indicator of wire flight distance (head to platen
clearance).  Experimental data has shown that for a single wire
within a print head, that the time/distance relationship describing
wire flight is a constant and therefore may be used to describe the
distance "d" as shown in the figure.

Providing that drive current to the print head is maintained
throughout the wire flight, the distance from the head to the platen
is defined by the equation as:
2d = at2
where:       d = d on diagram
a = acceleration of the wire
t = wire flight time

Referring to the figure, the timer 11 measures the time from
the start of the wire fire signal to the output from the
accelerometer.  It also provides the signal to the driver circuit to
fire the print wire.

The driver circuit 13 provides the electrical energy to fire
the print wire in print head 19.

The platen 15 is part of the device under test.  It is the
surface that the printed medium is aligned against when printing.

The accelerometer 17 senses the existence of impact to the
platen by the print wire.

Distance "d" is the distance from the plane described by the
print wires when they are in the rest position to the platen surface.
This is the critical dimension.

Distance "b" is the distance from the print wire impact point
on the platen to the accelerometer.

Normal operation is as follows: The timer initiates the wire
fire sequence at t0.  The wire is put in motion by the driver
circuit.  The wire impacts the platen causing vibration in the
platen.  The induced vibration traverses distance "b" and is detected
by the accelerometer.  An electric signal is induced in the
piezo-electric crystal within the accelerometer and the signal is
detected by the timer which measures time tt.  The distance is
determined by utilizing that time to calculate distance "d".

The timer measures the time fr...