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Automatic Hammer Flight Time Compensation in Impact Printers With a Print Hammer Bank and a Revolving Type Carrier

IP.com Disclosure Number: IPCOM000043602D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Bublitz, HR: AUTHOR

Abstract

Flight time variations, measured by known methods, are used to advance or delay the hammer firing time and to effect automatic flight time compensation during normal print operations. A previously proposed method measures the flight time of each hammer, contained in a bank, by means of a single photoelectric device. Flight time variations occur as a result of print hammer tolerances or when the thickness of the record carrier (paper) changes. In printers with precalculated hammer firing times for a line to be printed, the hammer that will be the last to be fired is determined. Unless other hammers will be actuated at the same time, its flight time can be readily measured in a known manner, preferably using the variation of its flight time from an average value, applicable to all hammers in the bank, as a reference value.

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Automatic Hammer Flight Time Compensation in Impact Printers With a Print Hammer Bank and a Revolving Type Carrier

Flight time variations, measured by known methods, are used to advance or delay the hammer firing time and to effect automatic flight time compensation during normal print operations. A previously proposed method measures the flight time of each hammer, contained in a bank, by means of a single photoelectric device. Flight time variations occur as a result of print hammer tolerances or when the thickness of the record carrier (paper) changes. In printers with precalculated hammer firing times for a line to be printed, the hammer that will be the last to be fired is determined. Unless other hammers will be actuated at the same time, its flight time can be readily measured in a known manner, preferably using the variation of its flight time from an average value, applicable to all hammers in the bank, as a reference value. Thus, any hammer which may probably be the last to be fired in a particular line is measured with regard to its flight time, and flight time variations, if any, are suitably compensated for. When the thickness of the record carrier changes, the flight time is initially measured only for one hammer (say, the first hammer in a print line). This yields a difference value from the average flight time prior to the paper change. As a result of this unique difference value, indicating a change in paper thickness, printing is shifted to the...