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:
Jun. 07, 1977
Filed:
Oct. 21, 1975
Richard S Quaif, Dryden, NY (US);
NCR Corporation, Dayton, OH (US);
Abstract
A matrix printer impact energy control is disclosed wherein the impact energy supplied to the drive solenoids of matrix print heads is maintained substantially constant notwithstanding variations in the printer power supply output. The hammer power supply voltage is monitored and coupled, together with a derived reference voltage to a summing amplifier which is then pulse width modulated to produce a pulsed hammer drive output having constant print energy. The print energy may be increased to provide multiple copy printing capability. A single impact energy control circuit controls all of the print hammer of each print head. Synchronization of the pulse width modulator is provided by a variable frequency clock from which the pulse width modulator trigger frequency is derived.