Method of driving liquid-drop-ejecting recording head, and liquid-drop-ejecting recording device
A liquid-drop-ejecting recording head carries out image recording by applying a jetting pulse having a binary digital driving waveform to a piezoelectric element, providing a vibration wave to liquid accommodated in an accommodating chamber, and ejecting a liquid drop from a eject opening. The liquid-drop-ejecting recording head classifies each pixel in accordance with density data thereof. When recording a pixel belonging to a high density range, plural jetting pulses, whose pulse width is ½ times a natural vibration period of a liquid flow at a flow path of the liquid, are applied within a single printing cycle at an interval which is set in advance in accordance with density data of the pixel.
1. A method of driving a liquid-drop-ejecting recording head which, by applying a jetting pulse having a binary digital driving waveform to a piezoelectric element, provides a vibration wave to liquid accommodated in an accommodating chamber, and ejects a liquid drop from a eject opening, and carries out image recording, the method comprising:
classifying each pixel in accordance with density data of the pixel into a density range among density ranges expressing low density, medium density and high density; and
when recording a pixel belonging to the high density range, applying a plurality of jetting pulses, whose pulse width is ½ times a natural vibration period of a liquid flow at a flow path of the liquid, within a single printing cycle at an interval which is set in advance in accordance with density data of the pixel.
2. The method of driving a liquid-drop-ejecting recording head of claim 1 , wherein the interval is in a range of from ½ times to 3/2 times the natural vibration period.
3. The method of driving a liquid-drop-ejecting recording head of claim 1 , wherein the interval is in a range of from ½ times to 1 time the natural vibration period.
4. The method of driving a liquid-drop-ejecting recording head of claim 1 , wherein, when recording a pixel of the medium density range, only a single jetting pulse is applied.
5. The method of driving a liquid-drop-ejecting recording head of claim 1 , wherein, when recording a pixel of the low density range, the jetting pulse and a non-jetting pulse, whose pulse width is smaller than a pulse width of the jetting pulse, are applied successively in one printing cycle with an predetermined interval therebetween.
6. The method of driving a liquid-drop-ejecting recording head of claim 5 , wherein the predetermined interval is selected in accordance with the density data of the pixel to be recorded, from a plurality of intervals which are set in advance.
7. A liquid-drop-ejecting recording device comprising:
a liquid-drop-ejecting recording head carrying out recording of an image by varying a volume of an accommodating chamber in which a liquid is accommodated by using a piezoelectric element driven by application of a jetting pulse having a binary digital driving waveform, and ejecting a liquid drop from a eject opening; and
a recording head controller of the liquid-drop-ejecting recording head,
wherein the recording head controller has:
a classifying section to which pixel data to be recorded is inputted, and which classifies each pixel in accordance with density data of the pixel into a density range among density ranges expressing low density, medium density and high density, and
a driving section which, when recording a pixel of the high density range applies jetting pulses, whose pulse width is ½ times a natural vibration period of a liquid flow at a flow path of the liquid, to the recording head plural times within a single printing cycle at an interval which is set in advance in accordance with density data of the pixel.
8. The liquid-drop-ejecting recording device of claim 7 , wherein the interval is in a range of from ½ times to 3/2 times the natural vibration period.
9. The liquid-drop-ejecting recording device of claim 7 , wherein the interval is in a range of from ½ times to 1 time the natural vibration period.
10. The liquid-drop-ejecting recording device of claim 7 , wherein, when recording a pixel of the medium density range, only a single jetting pulse is applied.
11. The liquid-drop-ejecting recording device of claim 7 , wherein, when recording a pixel of the low density range, the jetting pulse and a non-jetting pulse, whose pulse width is smaller than a pulse width of the jetting pulse, are applied successively in one printing cycle with an predetermined interval therebetween.
12. The liquid-drop-ejecting recording device of claim 11 , wherein the predetermined interval is selected in accordance with the density data of the pixel to be recorded, from a plurality of intervals which are set in advance.