The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 28, 1981
Filed:
Oct. 03, 1979
Gordon B Barrus, El Segundo, CA (US);
Jerry Matula, Westminster, CA (US);
Printronix, Inc., Irvine, CA (US);
Abstract
In a dot matrix line printer in which selected ones of a plurality of hammers mounted on a reciprocating hammer bank are released in response to successive sets of serial data to print dots on a paper, the changing hammer release characteristics which are caused by different numbers of hammers being released with each new set of serial data are compensated for by an arrangement providing a varying hammer release signal in accordance with the number of hammers being released. The variable release signal is provided in the form of a variation in the time interval during which the drive amplifiers associated with hammer release coils are turned on, thereby effectively varying the length of a current pulse provided to each coil in direct proportion to the number of hammers to be released. A counter is preset, then counted down from the preset value in accordance with the number of hammers to be released as represented by a set of serial data being provided to a shift register. When the shift register is loaded, latches associated with the various stages of the shift register containing hammer release signals are set so as to turn on associated ones of the drive amplifiers. The counter counts up in response to clock pulses until it overflows and clears the latches so as to turn off the drive amplifiers.