Liquid Discharge Head Waveform Control for High-Frequency Stability
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Solution Overview
Problem
Existing liquid discharge apparatuses experience deflection and mist generation when operating at high frequencies due to residual vibrations in liquid chambers and pressure fluctuations.
Innovation Solution
A liquid discharge apparatus with a drive waveform that includes multiple pulses to control droplet size and reduce pressure fluctuations, utilizing a piezoelectric member to manage liquid chamber volumes and minimize mist formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid discharge head is driven at high frequency to discharge liquid droplets, then productivity is improved, but discharged liquid droplets deflect and mist is generated
Solution Approach 1:
The patent applies periodic action by using multiple drive waveforms with different periods to control the liquid discharge head. The control unit selects and applies different drive waveforms (first, second, third waveforms) with varying pulse patterns and periods to manage the discharge frequency and prevent residual vibrations, thereby maintaining droplet discharge stability at high frequencies.
Solution Approach 2:
The patent implements parameter changes by varying the drive waveform parameters (pulse width, pulse interval, amplitude) based on the desired discharge frequency and droplet size. The control unit adjusts these parameters dynamically to optimize discharge performance and minimize mist generation while maintaining high-frequency operation.
2Productivity
If liquid discharge head is driven at high frequency, then productivity is improved, but mist generation increases
Solution Approach 1:
The patent uses periodic drive waveforms with carefully designed pulse intervals to allow liquid chambers to stabilize between discharges. The multiple waveforms provide different periodic patterns that prevent continuous vibration buildup, thereby reducing mist generation while maintaining high discharge frequencies.
Solution Approach 2:
The patent converts the potential harmful effect of residual vibrations into a beneficial control mechanism by using specific waveform patterns that exploit the natural vibration characteristics of the liquid chambers. The drive waveforms are designed to dampen unwanted vibrations while enhancing desired discharge effects, turning vibration problems into solution opportunities.
3Productivity
If liquid discharge head is driven at high frequency, then productivity is improved, but droplet deflection occurs
Solution Approach 1:
The patent employs periodic drive waveforms with optimized pulse timing to synchronize with the natural response of the liquid chambers. By selecting appropriate periods and intervals, the system maintains precise droplet discharge even at high frequencies, preventing deflection caused by residual vibrations.
Solution Approach 2:
The patent achieves precise droplet discharge at high frequencies by dynamically adjusting drive waveform parameters such as pulse width, pulse amplitude, and pulse interval. The control unit selects from multiple waveform configurations to optimize discharge precision for different operating conditions and droplet sizes.
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
Enables high-frequency operation with reduced droplet deflection and mist generation, enhancing discharge efficiency and stability.
Implementation Method 1
a piezoelectric member that changes a volume of the liquid chamber when a voltage is applied thereto
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A liquid discharge apparatus (1) includes a liquid discharge head (34a, 34b) including a plurality of nozzles (104) to discharge liquid droplets, a plurality of individual liquid chambers (106) communicating with the plurality of nozzles (104), and a plurality of pressure generators (112) to generate a pressure that pressurizes liquid in the plurality of individual liquid chambers, and a head drive controller (509) to output, to the plurality of pressure generators (112), a drive waveform including one pulse or two or more pulses selected according to a droplet size. In a case that the drive waveform includes the two or more pulses, the drive waveform includes a final pulse at an end of the two or more pulses. The final pulse includes a first expansion waveform element, a first contraction waveform element, a second expansion waveform element, a second contraction waveform element, and a third expansion waveform element for expanding the plurality of individual liquid chambers, the third expansion waveform element being subsequent to the second contraction waveform element. A time period from a start of the first contraction waveform element to a start of the second expansion waveform element is less than 0.5 Tc. A time period from the start of the first contraction waveform element to a start of the second contraction waveform element is within a range from 0.5 Tc to 0.6 Tc.