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:
Dec. 09, 2003
Filed:
Oct. 23, 2000
Hiroshi Shirotori, Nagano, JP;
Hisashi Watamura, Nagano, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
For a print head in an impact dot printer, a drive transistor is connected in series to a head coil that drives a print wire, and a pulse is used to turn the drive transistor on and off. Thus, the drive current i is supplied to the head coil to drive the print wire. The input end of a DC/DC converter is connected to the juncture of the head coil and the drive transistor , and the output end of the DC/DC converter is connected to the juncture of a power source and the head coil . The DC/DC converter clamps, at a constant level, e.g., 90V, the inductive electromotive force of a high voltage that is generated by the head coil when the drive transistor is rendered off. Then, the DC/DC converter transforms the clamped voltage to a voltage equivalent to the voltage level of the power source , e.g., 35V. As a result, instead of energy being wasted by the transistor , the energy accumulated by the head coil is returned to the power source and can again be employed, while the input voltage of the DC/DC converter is maintained at a constant level by an initial charger