System for driving ink drop generator of ink-jet printer

A system for driving an ink drop generator, comprising:

• (A) a plurality of first ink drop issuing chambers each communicating with an ink drop issuing nozzle,
• (B) a plurality of second pressure biasing chambers each of which communicates with a common ink source and with each of said plurality of first ink chambers,
• (C) pairs of said first and second chambers being alternately formed in both the side surfaces of a base of a multiple nozzle ink drop generator unit;
• (D) first transducer means for applying alternating pressure to ink in said first chambers;
• (E) second transducer means for applying alternating pressure to ink in said second chambers;
• and
• (F) means for driving said first transducer means at a frequency twice as high as the frequency of said second transducer means in synchronism with the driving of said transducer means during the positive going half cycle of the driving voltage applied to said second transducer means to thereby issue ink drops through said nozzles.

An ink drop generator with an array of nozzle matrix comprising:

• a plurality of multiple nozzle ink drop generator units assembled in side-by-side relationship and communicated with a common ink source,
• each ink drop generator unit comprising
• (A) a base whose both side surfaces are alternately formed with a plurality of ink drop generating cells each consisting of a first ink drop issuing chamber and a second pressure biasing chamber communicating with said common ink source and said first ink chamber,
• (B) two first diaphragms ink-tightly bonded to said base to define four side walls of said ink drop generator unit,
• (C) a plurality of first piezoelectric elements mounted on said first diaphragms in opposed relationship with respective first ink chambers in said base,
• (D) a second diaphragm ink-tightly bonded to said base to define the top wall of said ink drop generator unit,
• (E) a common second piezoelectric element mounted on said second diaphragm,
• (F) a nozzle plate ink-tightly bonded to said base to define the bottom of said ink drop issuing nozzles which are lined up and communicate with respective first ink chambers,
• (G) printed circuit boards attached to said first diaphragms to establish the electrical connection between the first piezoelectric elements and a first piezoelectric element driving circuit,
• (H) connection means for establishing the electrical connection between said second piezoelectric element and a second piezoelectric element driving circuit,
• (I) said second piezoelectric element being driven by a second driving voltage from said second piezoelectric element driving circuit in such a way that the pressure imparted to the ink in said ink drop generating cell by said second piezoelectric element will not cause the ink to issue through said nozzle,
• (J) said first piezoelectric element being driven by a first driving voltage or an ink drop placement signal voltage from said first piezoelectric element driving circuit, the frequency of said first driving voltage being twice as high as that of said second driving voltage, said first driving voltage being applied in synchronism with said second driving voltage to one or more selected first piezoelectric elements during the positive going half cycle of said second driving voltage in such a way that one or more ink drops may be issued through one or more nozzles during the positive going half cycle of said first driving voltage.