Liquid Jet Head Pulse Width Control for High-Viscosity Stability
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Solution Overview
Problem
Liquid jet heads face challenges in maintaining ejection stability when jetting high-viscosity liquids, as existing technologies struggle to ensure consistent performance regardless of the head's structure.
Innovation Solution
The liquid jet head incorporates a drive signal with specific pulse width ranges for expansion and contraction pulses, ensuring stable ejection by optimizing the volume changes in the pressure chamber, with pulse widths for expansion pulses set between 0.2 and 1.0 AP and contraction pulses between 1.0 and 1.8 AP, preventing excessive pressure amplification and bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-viscosity liquid is jetted using conventional drive signals, then the liquid can be ejected from the nozzle, but ejection stability deteriorates due to inconsistent pressure control
Solution Approach 1:
The drive signal employs periodic pulse waves with specific timing relationships between expansion pulses and contraction pulses. The contraction pulse is timed to occur during the expansion phase, creating a periodic action pattern that prevents pressure amplification and ensures stable ejection of high-viscosity liquid.
Solution Approach 2:
The invention changes the temporal parameters of the drive signal, specifically setting the pulse width of the expansion pulse within 0.2-1.0 AP and the contraction pulse within 1.0-1.8 AP, with the contraction pulse occurring during the expansion phase. This parameter optimization enables stable ejection without increasing drive voltage or circuit complexity.
2Productivity
If drive voltage is increased to improve ejection of high-viscosity liquid, then ejection capability improves, but risk of bubble formation and pressure amplification increases
Solution Approach 1:
The contraction pulse is applied preliminarily during the expansion phase to counteract potential pressure amplification before it occurs. This preliminary anti-action prevents bubble formation and maintains stable ejection without requiring higher drive voltages.
Solution Approach 2:
The invention converts the potential harmful effect of pressure buildup during expansion into a beneficial controlled pressure waveform by introducing the contraction pulse. The pressure waveform's downward slope during expansion creates optimal ejection conditions without causing harmful pressure amplification or bubble formation.
3Force
If pulse width in expansion phase is increased to improve liquid ejection, then ejection force increases, but pressure amplification occurs leading to unstable ejection
Solution Approach 1:
The drive signal uses periodic pulse waves where the contraction pulse occurs during the expansion phase. This periodic action pattern maintains sufficient ejection force while preventing pressure amplification, ensuring both force and pressure stability.
Solution Approach 2:
The expansion pulse width is limited to 0.2-1.0 AP, which is sufficient for ejection but controlled to prevent excessive pressure buildup. The contraction pulse further ensures that even if some pressure amplification occurs, it remains within stable limits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures ejection stability and prevents deterioration of inkjet performance, allowing for reliable operation with high-viscosity inks without the need for increased drive voltage or circuit changes, thereby improving printing quality and convenience.
Implementation Method 1
an actuator having a plurality of pressure chambers communicated individually with the nozzles, and each filled with the liquid, and a drive section configured to apply a drive signal having a plurality of pulses in one cycle to the actuator to thereby expand and contract a volume of the pressure chamber to jet the liquid filling the pressure chamber from the nozzle
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
There are provided a liquid jet head and so on capable of ensuring the ejection stability of the liquid even when jetting the liquid high in viscosity irrespective of the structure of the liquid jet head. The liquid jet head according to an embodiment of the present disclosure includes a plurality of nozzles configured to jet liquid, an actuator having a plurality of pressure chambers communicated individually with the nozzles, and each filled with the liquid, and a drive section configured to apply a drive signal having a plurality of pulses in one cycle to the actuator to thereby expand and contract a volume of the pressure chamber to jet the liquid filling the pressure chamber from the nozzle. The plurality of pulses in the drive signal include a plurality of first pulses configured to expand the volume of the pressure chamber, and a plurality of second pulses configured to contract the volume of the pressure chamber. Further, with reference to an on-peak pulse (AP) in the pulses, a pulse width in at least one of the first pulses other than a final first pulse as last one of the first pulses out of the plurality of first pulses in the one cycle is set within a range of 0.2 AP through 1.0 AP, as well as, a pulse width in at least one of the second pulses other than a final second pulse as last one of the second pulses out of the plurality of second pulses in the one cycle is set within a range of 1.0 AP through 1.8 AP.