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Measuring Method for Print Hammer Flight Times

IP.com Disclosure Number: IPCOM000081342D
Original Publication Date: 1974-May-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Hartwich, R: AUTHOR [+2]

Abstract

This method permits measuring hammer flight times from the leading edge of the firing pulse to the time the hammer touches a contact bar. The chain carrier with chain (train cartridge) is replaced by a contact bar on which, facing the hammer unit, a plastic contact strip is arranged carrying two land patterns that are isolated against each other. A hammer is fired against these land patterns, galvanically connecting the latter.

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Measuring Method for Print Hammer Flight Times

This method permits measuring hammer flight times from the leading edge of the firing pulse to the time the hammer touches a contact bar. The chain carrier with chain (train cartridge) is replaced by a contact bar on which, facing the hammer unit, a plastic contact strip is arranged carrying two land patterns that are isolated against each other. A hammer is fired against these land patterns, galvanically connecting the latter.

One land pattern is linked with a voltage and the other land pattern with the resetting line of a Hammer Flight Flip Latch (HFL). This HFL is set by the signal triggering the firing pulse and is reset by the hammer touching a contact bar. Thus, the HFL ON state constitutes the hammer flight time.

After a print operation has been initiated, the program, as illustrated, tests the condition of the HFL. If the HFL is found to be ON, the program branches to a delay loop of 1200 mu sec. This delay time is a function of the printer used. The actual measuring process begins after the delay time has elapsed. The ON state of the HFL is tested, and the register content N, which was previously set to 0, is incremented by 1 for each test.

After the HFL has been reset by the hammer touching the contact bar, the result is evaluated. The register content (N) corresponds to the number of tests,
i.e., the measuring loop passes. A measuring loop pass, in its turn, corresponds to a time of 1.8 mu sec, since measu...