Inkjet Nozzle Plate Meniscus Control via Two-Step Pull Pulse
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Solution Overview
Problem
Inkjet recording systems face challenges with ejection stability due to low static surface tension and large receding contact angles, leading to image quality issues and nozzle clogging, especially when the water-repellent film on the nozzle plate deteriorates.
Innovation Solution
An inkjet recording method that uses a two-step pull pulse to pull the ink into the nozzle, maintaining a meniscus at a predetermined position, and an ink with a static surface tension of 18.0 mN/m to 27.0 mN/m and a receding contact angle of 50° or more on the nozzle plate, ensuring stable ejection and image quality even with a deteriorated water-repellent film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a water-repellent film is applied to the nozzle plate to prevent ink adhesion, then ink-repellency is improved, but the film is gradually peeled off by wiping, leading to deterioration of ink-repellency over time
Solution Approach 1:
The invention changes the surface properties of the nozzle plate by forming a water-repellent film with specific surface energy characteristics. The film is designed to have low surface energy to repel ink while maintaining adhesion to the substrate, resolving the contradiction between ink-repellency and durability through careful selection of film composition and formation parameters
Solution Approach 2:
The water-repellent film is formed as a composite structure on the nozzle plate, combining the substrate material with a surface coating layer that provides both ink-repellency and mechanical durability. This composite approach allows the film to resist both ink adhesion and mechanical damage from wiping operations
2Reliability
If the static surface tension of ink is reduced to improve ejection stability, then ejection stability is improved, but ink adhesion to the nozzle plate increases, leading to clogging
Solution Approach 1:
The invention carefully controls the static surface tension parameter of the ink within a specific range (18.0-27.0 mN/m) to achieve optimal balance between ejection stability and adhesion prevention. This parameter optimization resolves the contradiction by finding the sweet spot where ink ejects stably without adhering excessively to the nozzle plate
Solution Approach 2:
The water-repellent film on the nozzle plate acts as an intermediary layer between the ink and the solid substrate. This film modifies the interaction between ink and nozzle plate, allowing low surface tension ink to maintain ejection stability while the film prevents direct adhesion to the nozzle plate surface
3Object-generated harmful factors
If a large receding contact angle is used to prevent ink adhesion, then ink adhesion is reduced, but ejection stability deteriorates
Solution Approach 1:
The invention optimizes the receding contact angle parameter within a specific range to balance ink adhesion prevention and ejection stability. By controlling this parameter, the system achieves sufficient ink-repellency while maintaining stable ejection performance
4Reliability
If the water-repellent film deteriorates, then ink-repellency is reduced, but the nozzle plate becomes more susceptible to ink clogging
Solution Approach 1:
The water-repellent film serves as a protective cushion layer that prevents ink from directly contacting and clogging the nozzle plate. Even when the film deteriorates, it provides a barrier that delays and mitigates the harmful effects of ink adhesion, protecting the nozzle plate from clogging
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 method achieves stable ink ejection and excellent image quality by effectively managing ink overflow and adhesion on the nozzle plate, preventing deflection and clogging, and maintaining ejection stability even when the water-repellent film is deteriorated.
Implementation Method 1
An inkjet recording method is performed by an inkjet recording device... the ink has a static surface tension of 18.0 mN/m to 27.0 mN/m at 25°C... maintaining a meniscus at a predetermined position
Implementation Method 2
the ink has a receding contact angle of 50° or more on the nozzle plate... effectively managing ink overflow and adhesion on the nozzle plate
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
AI summary
An inkjet recording method performed by inkjet recording device including nozzle plate with nozzle to eject droplets of ink; recording head including liquid chamber with which the nozzle is in communication, and pressure-generating unit configured to generate pressure in the liquid chamber; and signal-generating unit configured to generate signal applied to the pressure-generating unit, and allowing the droplets of ink to eject by pressure generated by the pressure-generating unit according to the signal, wherein the ink has static surface tension of 18.0mN/m to 27.0mN/m at 25°C, the ink has receding contact angle on the nozzle plate of 50° or more, the signal has two-step pull pulse for pulling the ink into the nozzle in two-step manner within one printing unit cycle, and the method includes pulling the ink located in proximity to nozzle outlet into the nozzle of the two-step pull pulse, to form meniscus at predetermined position.