Liquid Ejection Drive Signal Pulse Interval Control
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Solution Overview
Problem
Increasing micro-vibration of the meniscus in a liquid ejection nozzle leads to instability in ink droplet ejection, causing potential image quality issues.
Innovation Solution
A liquid ejection apparatus with a drive signal generation system that alternates between ejection and non-ejection pulses, with specific pulse and coupling intervals defined by expressions (1.7×Tc×n ≤ T1 ≤ 1.9×Tc×n and 1.2×Tc×n ≤ T2 ≤ 1.4×Tc×n) to stabilize ink ejection, where Tc is the natural vibration cycle of the ejection section and n is a natural number.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If micro-vibration of the meniscus is increased to stir the ink in the nozzle, then the thickening of the liquid in the nozzle is suppressed, but the ejection of the ink droplets becomes unstable
Solution Approach 1:
The patent applies periodic action by implementing a drive signal that alternates between non-ejection pulses (for stirring) and ejection pulses (for droplet ejection) in a cyclic manner. The non-ejection pulse causes micro-vibration of the meniscus to stir the ink, while the ejection pulse follows after a specific time interval to eject the droplet. This periodic alternation between stirring and ejection actions resolves the contradiction by ensuring that stirring occurs without compromising ejection stability.
Solution Approach 2:
The patent applies preliminary action by performing the non-ejection pulse (stirring action) before the ejection pulse. The drive signal is configured such that a non-ejection pulse is applied first to stir the ink and suppress thickening, and then after a predetermined time interval, an ejection pulse is applied to eject the ink droplet. This sequential arrangement ensures that the stirring action is completed before ejection begins, preventing instability.
2Stability of the object's composition
If micro-vibration is applied continuously to prevent ink thickening, then ink flow stability is maintained, but residual vibrations cause ejection instability
Solution Approach 1:
The patent implements periodic action by alternating between non-ejection pulses (that generate micro-vibration for stirring) and ejection pulses (that eject droplets). The drive signal includes multiple non-ejection pulses followed by an ejection pulse in a cyclic manner, allowing the meniscus to return to a stable state before each ejection, thus preventing residual vibrations from affecting ejection reliability.
Solution Approach 2:
The patent applies preliminary action by using non-ejection pulses to stir the ink and suppress thickening before the ejection pulse is applied. The time interval between the non-ejection pulse and the subsequent ejection pulse is carefully controlled to allow residual vibrations to dampen, ensuring that the ejection occurs when the meniscus is stable.
3Productivity
If the pulse interval is shortened to increase ejection frequency, then productivity is improved, but vibration resonance causes ejection instability
Solution Approach 1:
The patent applies periodic action by structuring the drive signal to include a specific number of non-ejection pulses followed by an ejection pulse in a repeating cycle. This periodic structure allows the system to operate at high frequencies while maintaining stability, as each cycle is designed to complete the stirring action before initiating ejection, preventing vibration resonance.
Solution Approach 2:
The patent applies parameter changes by optimizing the time interval between non-ejection pulses and ejection pulses, as well as the duration of each pulse. By carefully adjusting these temporal parameters, the system achieves high ejection frequency while avoiding resonance conditions that would cause instability. The drive signal parameters are tuned to match the natural vibration characteristics of the ejection section.
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
Stabilizes ink ejection by minimizing the influence of residual vibrations, thereby improving image quality by reducing variations in ink droplet velocity and preventing defects.
Implementation Method 1
a pressure generation unit that generates a pressure fluctuation in liquid in the pressure chamber
Implementation Method 2
when the non-ejection pulse is selected in a preceding cycle of two consecutive cycles among the repetitive cycles, and the ejection pulse is selected in a following cycle, a pulse interval T1 between the non-ejection pulse of the preceding cycle and the ejection pulse of the following cycle satisfies any one of following expressions (1) and (2):(1) 0.6×Tc×n ≤ T1 ≤ 0.8×Tc×n(2) 1.2×Tc×n ≤ T1 ≤ 1.4×Tc×nwhere Tc is a natural vibration cycle of the ejection section
Data Source
AI summary
A liquid ejection apparatus includes an ejection section that is configured to generate a pressure fluctuation in liquid in a pressure chamber that is communicating with a nozzle by driving a pressure generation unit in accordance with a pulse selected from the ejection pulse and the non-ejection pulse. When the non-ejection pulse is selected in a preceding cycle of two consecutive cycles among the repetitive cycles, and the ejection pulse is selected in a following cycle of the two consecutive cycles, a pulse interval T1 between the non-ejection pulse of the preceding cycle and the ejection pulse of the following cycle satisfies any one of following expressions (1) and (2):1.7×Tc×n≤T1≤1.9×Tc×n(1)1.2×Tc×n≤T1≤1.4×Tc×n.(2)