Liquid Ejecting Head Nozzle Electrostatic Propensity Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid ejecting heads face issues with electrostatic charging during the ejection process, leading to mist attachment on the nozzle forming surface, especially when the ejection target is electrostatically charged, due to the negative charging of the liquid repellent film containing fluorine, which enhances wiping but induces electrostatic induction and repulsion.
Innovation Solution
A liquid ejecting head design with a reduced amount of fluorine per unit area in the nozzle section compared to the nozzle forming surface, along with a two-region configuration where the second region has a thinner liquid repellent film, reduces electrostatic charging by minimizing the contact-induced charge on the nozzle section, and a pressure cleaning process that uses a pressurizing unit to gently discharge liquid, reducing friction-related charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid repellent film containing fluorine is provided on the nozzle forming surface to enhance wiping and reduce ejection failure, then liquid repellent properties are improved, but electrostatic charging occurs causing mist attachment on the nozzle forming surface
Solution Approach 1:
The patent applies different fluorine contents to different regions: the nozzle forming surface has a first fluorine content to provide liquid repellency, while the nozzle section has a second fluorine content that is smaller than the first to reduce electrostatic charging. This spatial differentiation of material properties resolves the contradiction between needing liquid repellency and avoiding electrostatic problems.
Solution Approach 2:
The patent changes the fluorine content parameter between different regions. By controlling the fluorine content in the nozzle section to be lower than in the nozzle forming surface, the patent modifies the electrostatic properties while maintaining liquid repellent properties where needed, thus resolving the contradiction.
2Ease of operation
If the nozzle section has high fluorine content to maintain liquid repellent properties, then wiping performance is improved, but electrostatic charging of ejected liquid increases
Solution Approach 1:
The patent differentiates the fluorine content between the nozzle forming surface (first fluorine content) and the nozzle section (second fluorine content). The nozzle forming surface maintains high fluorine content for effective wiping, while the nozzle section has reduced fluorine content to minimize electrostatic charging of the ejected liquid.
Solution Approach 2:
The patent segments the nozzle structure into two distinct regions with different fluorine contents: the nozzle forming surface region and the nozzle section region. This segmentation allows each region to have optimized fluorine content for its specific function, resolving the contradiction between wiping performance and electrostatic charging.
3Reliability
If a liquid repellent film is applied uniformly across the entire nozzle structure, then liquid repellency is maximized, but electrostatic charging and mist attachment increase
Solution Approach 1:
Instead of uniform application, the patent applies liquid repellent properties selectively: the nozzle forming surface has high fluorine content for liquid repellency, while the nozzle section has low fluorine content to reduce electrostatic charging that would cause mist attachment. This localized differentiation resolves the contradiction.
Solution Approach 2:
The patent extracts the liquid repellent film from the nozzle section while maintaining it on the nozzle forming surface. By removing or reducing the fluorine-containing liquid repellent film in the nozzle section, the patent eliminates the source of electrostatic charging that causes mist attachment, while preserving liquid repellency where it is needed.
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 effectively reduces electrostatic charging of the liquid ejected from the nozzle section, minimizing attachment on the nozzle forming surface and ensuring accurate ejection while maintaining required liquid repellent properties for wiping.
Implementation Method 1
a portion of the liquid repellent film which is in contact with the liquid is negatively charged due to frictional electrostatic charge by the liquid
Implementation Method 2
the liquid is positively charged, which is opposite polarity from that (negative polarity) of the charged site, due to electrostatic induction of the charged site
Implementation Method 3
a pressure cleaning process that uses a pressurizing unit to gently discharge liquid, reducing friction-related charging
Data Source
AI summary
A liquid ejecting head has a nozzle forming surface to which a nozzle section through which liquid is ejected is open, wherein an electrostatic propensity of the nozzle section due to contact with the liquid is lower than an electrostatic propensity of the nozzle forming surface due to contact with the liquid. The amount of fluorine per unit area in the nozzle section is smaller than the amount of fluorine per unit area in the nozzle forming surface.