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:
May. 28, 1996
Filed:
Nov. 04, 1993
Seiko Epson Corporation, Tokyo, JP;
Abstract
The apparatus includes a circuit 49 for generating a first voltage waveform for expanding piezoelectric vibrators at a rate suitable to form ink drops, a second voltage for holding an expansion or contraction state, and a third voltage waveform for contracting the piezoelectric vibrators at a rate suitable to suck ink into pressure generating chambers; a circuit 52 for detecting the time when the process of forming ink drops by the first voltage waveform is ended; a delay circuit 53 for delaying a signal from the circuit 52 by a time .DELTA.T until vibration of menisci caused by the ink drop formation process, switches to motion toward nozzle openings; a charge signal generating circuit 48 for generating the third voltage waveform on the basis of a signal from the delay circuit 53; and a discharge signal generating circuit 51 for generating the first voltage waveform on the basis of a print timing signal. The third voltage waveform is generated when the menisci produced after forming ink drops have started moving toward the nozzle openings, so that ink required for the next formation of ink drops is sucked into the pressure generating chambers. Therefore, the force to retreat the menisci due to the expansion of the pressure generating chambers is canceled by motion of the menisci per se, and the retreat of the menisci caused by the suction of ink can be minimized. It is therefore possible to stabilize the menisci independently of the frequency.