Triangular Delay Waveforms in Liquid Ejection Heads for Uniform Density
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Solution Overview
Problem
Existing piezoelectric inkjet heads with one-dimensional nozzle arrangements experience density unevenness due to discontinuous sub delay times in sawtooth wave shapes, leading to structural and fluid interference.
Innovation Solution
A liquid ejection head with a drive circuit that generates drive waveforms with a combination of triangular and periodic wave-shaped delay times, ensuring an optimal time difference between adjacent nozzles to minimize ejection speed variations and prevent density unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a sawtooth wave-shaped sub delay time is used to reduce current concentration and crosstalk, then structural and fluid interference between nozzles is reduced, but density unevenness occurs at discontinuous portions in one-dimensional nozzle arrangements
Solution Approach 1:
The patent changes the waveform parameter of the sub delay time from sawtooth wave to triangular wave, making it continuous with respect to the nozzle arrangement direction. This parameter change eliminates density unevenness while maintaining the crosstalk reduction effect through grouped nozzle driving with different delay times.
Solution Approach 2:
The patent introduces a dynamic delay time adjustment mechanism where the sub delay time varies continuously across nozzles in a triangular wave pattern rather than discontinuously in a sawtooth pattern. This dynamic adjustment prevents density unevenness while maintaining crosstalk reduction.
2Productivity
If nozzles are driven simultaneously to improve productivity, then output increases, but current concentration and structural or fluid mutual interference occur
Solution Approach 1:
The patent segments nozzles into multiple groups and applies different delay times to each group in a triangular wave pattern. This segmentation distributes current consumption over time while maintaining high overall ejection speed, preventing current concentration while preserving productivity.
3Productivity
If nozzles are driven simultaneously to improve productivity, then output increases, but structural or fluid mutual interference occurs
Solution Approach 1:
The patent segments nozzles into multiple groups with different delay times arranged in a continuous triangular wave pattern. This segmentation reduces structural and fluid mutual interference (crosstalk) between nozzles while maintaining high productivity through coordinated group driving.
Solution Approach 2:
The patent implements dynamic delay time adjustment across nozzle groups using a triangular wave pattern, creating continuous temporal separation that reduces crosstalk while preserving overall ejection speed and productivity.
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
The solution effectively reduces crosstalk and ensures consistent ink ejection, preventing density unevenness by distributing delay times in a triangular wave shape, thereby maintaining print quality.
Implementation Method 1
a plurality of pressure chambers that respectively communicate with the nozzles, a volume of each of the pressure chambers being varied to eject liquid through the corresponding nozzle; an actuator configured to vary the volumes of the pressure chambers independently according to drive waveforms respectively applied to the pressure chambers
Data Source
AI summary
A liquid ejection head includes nozzles arranged in a first direction, pressure chambers respectively communicating with the nozzles, a volume of each chamber being varied to eject liquid through the nozzle, an actuator varying the volumes according to drive waveforms applied to the chambers, and a drive circuit generating a drive waveform for each chamber with a delay time to cause the liquid to be ejected with the delay time. The drive circuit determines the delay time to be a sum of: a first delay time for the particular chamber, the first delay time for all the chambers varying so as to have a triangular wave shape with respect to positions of the chambers, and a second delay time for the particular chamber, the second delay time for all the chambers varying so as to have a periodic wave shape with respect to the positions of the chambers.