Asymmetric Inkjet Head Flow Paths for Standing Wave Suppression
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Solution Overview
Problem
Inkjet heads with common ejection flow paths experience pressure waves due to standing waves, leading to fluctuations in ink discharge and deterioration of image quality, particularly in configurations with two common ejection flow paths where superposed pressure waves significantly degrade image quality.
Innovation Solution
The inkjet head design features first and second common ejection flow paths with distinct shapes and volumes, where the first section's shape differs from the second section's, effectively absorbing pressure changes and misaligning standing wave phases to minimize crosstalk and improve image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common ejection flow path is used to eject air bubbles and foreign substances, then air bubbles and foreign substances can be effectively ejected, but pressure waves with standing wave characteristics are generated causing ink discharge fluctuations and image quality deterioration
Solution Approach 1:
The patent applies asymmetry by configuring the first and second common ejection flow paths with different cross-sectional areas. Specifically, the first common ejection flow path has a larger cross-sectional area than the second common ejection flow path. This asymmetric design causes the standing waves generated in each flow path to have different characteristics (different wavelengths and amplitudes), preventing them from superimposing constructively and reducing the overall pressure wave impact on ink discharge stability.
2Reliability
If two common ejection flow paths are used to improve air bubble ejection, then air bubble removal is enhanced, but pressure waves from both paths superpose and significantly deteriorate image quality
Solution Approach 1:
The patent resolves the superposition problem by making the two common ejection flow paths asymmetric in cross-sectional area. The first common ejection flow path has a larger cross-sectional area while the second has a smaller cross-sectional area. This asymmetry ensures that standing waves generated in each path have different characteristics, preventing coherent superposition and significantly reducing the harmful pressure wave effects on ink discharge.
3Ease of manufacture
If common ejection flow paths are made larger to reduce resistance, then ink flow resistance decreases, but standing wave characteristics become more pronounced causing greater pressure fluctuations
Solution Approach 1:
The patent avoids making both common ejection flow paths large by implementing asymmetric sizing. The first common ejection flow path has a larger cross-sectional area with lower resistance, while the second has a smaller cross-sectional area. This asymmetric configuration allows one path to handle higher flow with lower resistance while the other path generates standing waves with different characteristics, preventing constructive superposition and reducing overall pressure fluctuations.
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 configuration significantly suppresses the deterioration of image quality by canceling or reducing the influence of standing waves, ensuring stable ink discharge and effective ejection of air bubbles and foreign substances.
Implementation Method 1
a pressure wave with characteristics corresponding to the shape of the common ejection flow path is generated as a standing wave in the common ejection flow path
Implementation Method 2
A pressure wave generated in the ink storage by the standing wave further causes pressure in ink in the ink storage to deviate from the desirable pressure
Data Source
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AI summary
Provided are an inkjet head and an inkjet recording apparatus capable of effectively suppressing a reduction in image quality. The inkjet head is provided with: a plurality of ink ejection units each of which includes an ink storage unit, a nozzle which ejects ink according to fluctuations in pressure of the ink inside the ink storage unit, and a first individual discharge flow path (122a) and a second individual discharge flow path (122b) which are in communication with the one ink storage unit and through each of which the ink that is discharged without being supplied from the ink storage unit to the nozzle passes; a first common discharge flow path (142a) which is in communication with the plurality of first individual discharge flow paths of the plurality of ink ejection units; and a second common discharge flow path (142b) which is in communication with the plurality of second individual discharge flow paths of the plurality of ink ejection units. The shape of a first section (SI) of the first common discharge flow path into which the ink flows from the plurality of first individual discharge flow paths is different from the shape of a second section (S2) of the second common discharge flow path into which the ink flows from the plurality of second individual discharge flow paths.