Inkjet Printhead Vibration Pulse Control for Ink Homogeneity
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Solution Overview
Problem
Ink printing apparatuses face issues with viscosity changes in the ink within printing elements during downtimes, leading to nozzle clogging and reduced printing efficiency due to evaporation, which can be exacerbated by unwanted pressure wave interference and crosstalk between adjacent elements.
Innovation Solution
Applying control voltages to the printing elements that include a vibration voltage pulse before a print dot voltage pulse, with the amplitude of the vibration pulse adjusted based on the size of the ink droplet to be emitted, ensuring thorough ink mixing without ejecting droplets during the vibration phase, thereby minimizing viscosity changes and reducing pressure wave interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If vibration voltage pulses are applied to mixing the ink in printing elements, then ink homogeneity is improved and nozzle clogging is prevented, but ink droplet ejection may occur unintentionally and power consumption increases
Solution Approach 1:
The patent applies parameter changes by adjusting the amplitude of vibration voltage pulses based on ink droplet size. Smaller amplitudes are used for smaller droplets, optimizing the balance between ink mixing effectiveness and power consumption. This prevents excessive vibration that would cause unwanted droplet ejection while still maintaining ink homogeneity.
Solution Approach 2:
The patent implements dynamics by making the vibration pulse amplitude adaptive rather than fixed. The amplitude dynamically adjusts according to the required ink droplet size, allowing the system to optimize mixing effectiveness while minimizing energy consumption and preventing unwanted ejection for each specific printing scenario.
2Reliability
If vibration voltage pulses are applied to prevent ink drying, then ink flow is maintained, but adjacent printing elements may experience crosstalk and pressure wave interference
Solution Approach 1:
The patent applies local quality by spatially selective activation of printing elements. Only the printing element requiring ink ejection is activated with vibration pulses, while adjacent elements remain inactive. This localized approach maintains ink flow in the active element without generating pressure waves that would cause crosstalk in neighboring elements.
Solution Approach 2:
The patent implements preliminary action by applying vibration pulses chronologically before the print dot voltage pulse. This timing ensures ink mixing and homogeneity are established before ejection, maintaining reliable ink flow while the sequential timing prevents pressure wave interference with other elements.
3Stability of the object's composition
If higher amplitude vibration pulses are used to ensure thorough ink mixing, then ink homogeneity is improved, but the number of pulses required increases and power consumption rises
Solution Approach 1:
The patent optimizes the balance between amplitude and number of pulses by making amplitude adaptive to ink droplet size. For smaller droplets, lower amplitudes with fewer pulses are used, while larger droplets receive higher amplitudes. This parameter adaptation achieves thorough ink mixing with minimal pulse numbers, reducing both time loss and power consumption.
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 prevents nozzle clogging, reduces power consumption, minimizes acoustic crosstalk, and optimizes prefire intensity by reducing the number of vibration pulses required, ensuring continuous and efficient printing operations.
Implementation Method 1
the piezoelectric activators of the printing elements are respectively set into vibration oscillations (also called prefire or meniscus oscillations) before or after a printing process
Implementation Method 2
A piezoelectric printing element thereby comprises a piezoactivator that is arranged at an ink channel that is connected with a nozzle
Implementation Method 3
Due to the effect of the evaporation from the nozzle opening, the danger exists that the viscosity of the ink then changes
Data Source
AI summary
In a method to control printing elements of an ink print head for ejection of a respective ink droplet, respective control voltages are applied to activators of the printing elements. The control voltages comprise at least one vibration voltage pulse that induces at least one vibration oscillation in the associated printing element, and an associated print dot voltage pulse that induces an ejection of the respective ink droplet by the associated printing element. The at least one vibration voltage pulse is chronologically arranged before the associated print dot voltage pulse, and an amplitude of the at least one vibration voltage pulse is respectively chosen depending on a size of the respective ink droplet to be subsequently emitted by the respective printing element.