Inkjet Head Channel Geometry and Circulation for Droplet Stability
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Solution Overview
Problem
Inkjet printing apparatuses face instability in ink ejection due to the production of satellite droplets, leading to decreased image quality and malfunction, particularly at high driving frequencies, and reduced productivity at lower frequencies.
Innovation Solution
A liquid ejection method and apparatus that utilizes a circulation path with differential pressure control and optimized channel configurations to maintain stable ink flow, preventing satellite droplet formation and ensuring consistent ink ejection speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the height of the ink channel and the depth of the ejection opening are reduced to prevent satellite droplets, then satellite droplet formation is suppressed, but ink ejection stability deteriorates at high driving frequencies
Solution Approach 1:
The patent changes the physical parameters of the ink channel (height, width, length) and ejection opening (depth, diameter) to optimize the balance between preventing satellite droplets and maintaining ejection stability. Specifically, the ink channel height is set to 5μm or less, width to 10μm or less, and length to 100μm or less, while the ejection opening depth is set to 15μm or less, creating conditions that prevent satellite droplet formation while maintaining stable ink ejection at high driving frequencies
Solution Approach 2:
The patent introduces a circulation path that enables dynamic ink flow through the ejection opening even when not ejecting, preventing ink stagnation and maintaining consistent ink properties during repeated ejection operations. This dynamic circulation system ensures that ink continuously moves through the channel, preventing the instability that occurs with static ink columns
2Productivity
If the driving frequency of the printing head is increased to improve productivity, then productivity increases, but ink ejection stability deteriorates due to satellite droplet formation
Solution Approach 1:
The patent optimizes the ink channel dimensions (height ≤5μm, width ≤10μm, length ≤100μm) and ejection opening depth (≤15μm) to enable stable ink ejection at high driving frequencies. These parameter changes allow the system to operate at high productivity levels without the satellite droplet formation that typically occurs at high frequencies
Solution Approach 2:
The circulation path ensures continuous ink flow through the ejection opening during both ejection and non-ejection periods, maintaining consistent ink properties and preventing stagnation. This continuous action enables stable operation at high driving frequencies by ensuring fresh ink is always available at the ejection opening
3Object-generated harmful factors
If the ink channel height and ejection opening depth are reduced, then satellite droplets are prevented, but ink ejection speed variation increases during repeated ejections
Solution Approach 1:
The patent sets the ink channel height to 5μm or less, width to 10μm or less, and length to 100μm or less, while the ejection opening depth is set to 15μm or less. These specific parameter changes create optimal flow conditions that prevent satellite droplets while maintaining consistent ink ejection speed during repeated ejections
Solution Approach 2:
The circulation path maintains continuous ink movement through the channel, preventing ink stagnation and ensuring consistent ink properties during repeated ejection operations. This continuous circulation prevents the speed variation that occurs when ink sits stationary in the channel
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 achieves stable ink ejection and high-quality image printing across varying driving frequencies, reducing the occurrence of satellite droplets and maintaining productivity while ensuring image quality.
Implementation Method 1
a heating surface that heats the liquid
Implementation Method 2
the liquid is bubbled and the liquid is ejected
Implementation Method 3
a circulation path with differential pressure control
Data Source
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AI summary
A liquid ejection method includes ejecting liquid from an ejection opening, using a liquid ejection head including a heating surface configured to heat the liquid and the ejection opening corresponding to the heating surface, by heating the liquid with the heating surface to produce a bubble communicating with air through the ejection opening such that at least a part of the heating surface is exposed to the air through the ejection opening, wherein the liquid is heated with the heating surface for 0.5 microseconds or shorter to produce a bubble communicating with the air through the ejection opening such that at least a part of the heating surface is exposed to the air through the ejection opening, in order to eject the liquid from the ejection opening.