Method of driving ink jet printing head

Claim 1

A method of driving an ink jet printing head for ink jet recording of image data, said method comprising the steps of: providing an ink jet printing head including a plurality of transversely spaced parallel liquid passages having a plurality of discharge ports for discharging ink therethrough, ink supplying means for supplying ink to each of said liquid passages, and piezoelectric means associated with each of said discharge ports for discharging ink when said associated piezoelectric means is driven, and a prescribed source voltage being constantly applied to said piezoelectric means to maintain a capacity of each of said liquid passages at a predetermined level; applying a voltage falling edge of a first pulse signal to cause said associated piezoelectric means vertically contract so that the capacity of a corresponding liquid passage is increased from said predetermined level so as to supply ink from said ink supplying means to said corresponding liquid passage; applying a voltage rising edge of the first pulse signal to cause said associated piezoelectric means to vertically expand so that the capacity of the corresponding liquid passage is decreased, for discharging an ink droplet through a corresponding discharge port, said first pulse signal having a first pulse width between said falling edge and said voltage rising edge and having a first peak voltage amplitude; and applying a voltage rising edge of a second pulse signal to said associated piezoelectric means after a predetermined delay time has elapsed since application of said voltage rising edge of said first pulse signal for discharging the ink droplet, a pulse width of said second pulse signal between a voltage falling edge thereof and said voltage rising edge being smaller than said first pulse width, and a peak voltage amplitude of said second pulse signal being equal to said first peak voltage amplitude, wherein said predetermined delay time is set to a value equal to a multiple of a half-period of a residual oscillation, the multiple being three, said residual oscillation occurring to said piezoelectric means due to application of the first pulse signal.

Claim 2

A method of driving an ink jet printing head for ink jet recording of image data, said method comprising the steps of: providing an ink jet printing head including a plurality of transversely spaced parallel liquid passages having a plurality of discharge ports for discharging ink therethrough, ink supplying means for supplying ink to each of said liquid passages, and piezoelectric means associated with each of said discharge ports for discharging ink when said associated piezoelectric means is driven, and a prescribed source voltage being constantly applied to said piezoelectric means to maintain a capacity of each of said liquid passages at a predetermined level; applying a voltage falling edge of a first pulse signal to cause said associated piezoelectric means vertically contract so that the capacity of a corresponding liquid passage is increased from said predetermined level so as to supply ink from said ink supplying means to said corresponding liquid passage; applying a voltage rising edge of the first pulse signal to cause said associated piezoelectric means to vertically expand so that the capacity of the corresponding liquid passage is decreased, for discharging an ink droplet through a corresponding discharge port, said first pulse signal having a first pulse width between said falling edge and said voltage rising edge and having a first peak voltage amplitude; and applying a voltage rising edge of a second pulse signal to said associated piezoelectric means after a predetermined delay time has elapsed since application of said voltage rising edge of said first pulse signal for discharging the ink droplet, a pulse width of said second pulse signal between a voltage falling edge thereof and said voltage rising edge being smaller than said first pulse width, and a peak voltage amplitude of said second pulse signal being equal to said first peak voltage amplitude, wherein said predetermined delay time is set to a value equal to a multiple of a half-period of a residual oscillation, the multiple being three, said residual oscillation occurring to said piezoelectric means due to application of the first pulse signal.

Claim 5

A method of driving an ink jet printing head for ink jet recording of image data, said method comprising the steps of: providing an ink jet printing head including a plurality of transversely spaced parallel liquid passages having a plurality of discharge ports for discharging ink therethrough, ink supplying means for supplying ink to each of and liquid passages, said piezoelectric means associated with each of said discharge ports for discharging ink when said associated piezoelectric means is driven, and a prescribed source voltage being constantly applied to said piezoelectric means to maintain a capacity of each of said liquid passages at a predetermined level; applying a voltage falling edge of a first pulse signal to cause said associated piezoelectric means to vertically contract so that the capacity of a corresponding liquid passage is increased from said predetermined level and ink is supplied to said corresponding liquid passage; applying a voltage rising edge of the first pulse signal to cause said associated piezoelectric means to vertically expand so that the capacity of the corresponding liquid passage is decreased, for discharging an ink droplet through a corresponding discharge port, the first impulse signal having a first pulse width between said voltage falling edge and said voltage rising edge and having a first peak voltage amplitude; and applying a voltage rising edge of a second pulse signal to said associated piezoelectric means after a predetermine delay time has elapsed since application of said voltage rising edge of said first pulse signal for discharging the ink droplet, said second pulse signal having a pulse width equal to said first pulse width and having a peak voltage amplitude smaller than said first peak voltage amplitude, wherein said predetermined delay time is set to a value equal to a multiple of a half-period of a residual oscillation, the multiple being three, said residual oscillation occurring to said piezoelectric means due to application of the first pulse signal.

Claim 6

A method of driving an ink jet printing head for ink jet recording of image data, said method comprising the steps of: providing an ink jet printing head including a plurality of transversely spaced parallel liquid passages having a plurality of discharge ports for discharging ink therethrough, ink supplying means for supplying ink to each of and liquid passages, said piezoelectric means associated with each of said discharge ports for discharging ink when said associated piezoelectric means is driven, and a prescribed source voltage being constantly applied to said piezoelectric means to maintain a capacity of each of said liquid passages at a predetermined level; applying a voltage falling edge of a first pulse signal to cause said associated piezoelectric means to vertically contract so that the capacity of a corresponding liquid passage is increased from said predetermined level and ink is supplied to said corresponding liquid passage; applying a voltage rising edge of the first pulse signal to cause said associated piezoelectric means to vertically expand so that the capacity of the corresponding liquid passage is decreased, for discharging an ink droplet through a corresponding discharge port, the first impulse signal having a first pulse width between said voltage falling edge and said voltage rising edge and having a first peak voltage amplitude; and applying a voltage rising edge of a second pulse signal to said associated piezoelectric means after a predetermine delay time has elapsed since application of said voltage rising edge of said first pulse signal for discharging the ink droplet, said second pulse signal having a pulse width equal to said first pulse width and having a peak voltage amplitude smaller than said first peak voltage amplitude, wherein said predetermined delay time is set to a value equal to a multiple of a half-period of a residual oscillation, the multiple being three, said residual oscillation occurring to said piezoelectric means due to application of the first pulse signal.