Automatic Hammer Flight Time Compensation in Impact Printers With a Print Hammer Bank and a Revolving Type Carrier
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-05
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.