Liquid Ejecting Apparatus Ink Stability Waveform Control
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Solution Overview
Problem
Inkjet printers face instability and variability in ejecting ink with low surface tension, leading to inconsistent droplet size and frequency, particularly when ejecting at higher frequencies, due to increased residual vibration and altered ink flow characteristics.
Innovation Solution
A liquid ejecting apparatus with a liquid ejecting head that maintains constant ejecting intervals for ink with surface tension between 22 mN/m and 30 mN/m, utilizing a specific waveform configuration to minimize residual vibration and stabilize ejection, including the use of silicon-based or fluorine-based surfactants and a penetrating agent with a high HLB value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the voltage of the driving waveform is increased to increase the flying speed of the ink, then the flying speed is improved, but the amount of ink which is ejected also increases
Solution Approach 1:
The patent applies dynamics by making the driving waveform adjustable and adaptable. The waveform parameters (voltage, gradient, duration) are dynamically adjusted based on the specific liquid characteristics (surface tension 22-30 mN/m) and ejection requirements, allowing optimization of both flying speed and amount ejected without fixed constraints
Solution Approach 2:
The patent changes physical parameters of the driving waveform to resolve the contradiction. By adjusting voltage levels, waveform gradients, and temporal characteristics within specific ranges, the system achieves optimal flying speed while controlling the amount of ink ejected, preventing both too much ink and insufficient speed
2Speed
If the gradient of the driving waveform is set to be steep to increase the flying speed, then the flying speed is improved, but the residual vibration increases and ejection stability is deteriorated
Solution Approach 1:
The patent uses dynamics by making the waveform gradient adjustable rather than fixed. The gradient is dynamically optimized based on the liquid's surface tension properties, allowing steep gradients for speed when needed while maintaining stability through adaptive control that compensates for residual vibration effects
Solution Approach 2:
The patent implements feedback mechanisms where the system monitors ejection characteristics and adjusts waveform parameters accordingly. When residual vibration is detected or anticipated, the system modifies subsequent waveform gradients to compensate, maintaining stable ejection despite high initial gradients that provide necessary flying speed
3Productivity
If ink with low surface tension is ejected continuously at higher frequency, then productivity is improved, but the amount and flying speed of ink ejected vary greatly depending on the phase of residual vibration
Solution Approach 1:
The patent applies periodic action by using repeatedly adjusted waveforms that account for residual vibration cycles. The driving waveform is periodically optimized based on the rhythmic nature of residual vibration, synchronizing ejection cycles to maintain consistent ink amount and speed even at high frequencies
Solution Approach 2:
The patent uses dynamics by making the waveform parameters adaptively adjustable for each ejection cycle. The system dynamically modifies voltage, gradient, and duration based on real-time conditions and residual vibration state, allowing continuous high-frequency ejection while maintaining precision through adaptive control rather than fixed parameters
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 ensures stable ejection of ink droplets with consistent size and frequency, regardless of ejection frequency, by averaging residual vibration and optimizing the waveform to maintain target ink amount and flying speed, enhancing the effectiveness in textile printing applications.
Implementation Method 1
a pressure generating means such as a piezoelectric element by selectively applying a driving waveform (driving pulses) to the pressure generating means, and controlling the pressure variations
Implementation Method 2
a surfactant is also added in order to increase the permeation with respect to the transfer object by lowering the surface tension
Data Source
AI summary
To provide a liquid ejecting apparatus which is able to eject a liquid where the surface tension is comparatively low in a stable manner. In relation to a driving signal for ejecting ink for textile printing where the surface tension is 22 [mN] or more and 30 [mN] or less from a nozzle, the interval between the first ejection driving pulse DP1 and the second ejection driving pulse DP2 and the interval between the second ejection driving pulse DP2 of a cycle T(n) and the first ejection driving pulse DP1 of a cycle T(n+1) are set to be Δt1. Due to this, in a case where medium dots are continuously formed over a plurality of continuous cycles, the ejecting intervals of the ink are set to be constant.