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Program for Control of Hammer Flight Time

IP.com Disclosure Number: IPCOM000043323D
Original Publication Date: 1984-Aug-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Graham, PA: AUTHOR [+3]

Abstract

A print hammer is moved into engagement with a platen by applying a current for a selected period of time to a coil surrounding the hammer. The impression with which the hammer impacts the platen may be controlled by maintaining the hammer flight time substantially constant. The hammer flight time is the time from when current is first applied to the hammer coil to when the hammer impacts the platen. The hammer flight time also may be defined as the time from when the current to the hammer coil is turned off until the hammer impacts the platen. The hammer flight time is periodically measured, and the duration of the current to the hammer coil is adjusted to maintain the flight time within a specified tolerance range of a desired flight time.

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Program for Control of Hammer Flight Time

A print hammer is moved into engagement with a platen by applying a current for a selected period of time to a coil surrounding the hammer. The impression with which the hammer impacts the platen may be controlled by maintaining the hammer flight time substantially constant. The hammer flight time is the time from when current is first applied to the hammer coil to when the hammer impacts the platen. The hammer flight time also may be defined as the time from when the current to the hammer coil is turned off until the hammer impacts the platen. The hammer flight time is periodically measured, and the duration of the current to the hammer coil is adjusted to maintain the flight time within a specified tolerance range of a desired flight time. This is accomplished by measuring the hammer flight time every N times that the hammer fires (i.e., when current is initially supplied to the hammer coil) and comparing with the desired flight time. If the difference between the measured and desired times is greater than a specified maximum allowable error, the time period that current is supplied to the hammer coil is adjusted by an amount directly proportional to the difference between the measured and desired flight times. This measure/adjust sequence is repeated for successive firings of the hammer until the error difference is reduced below the specified maximum allowable error. The next measurement of hammer flight time will occ...