Liquid Ejection Head Substrate Electrode Segmentation for Kogation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing liquid ejection heads face instability in liquid ejection due to uneven heat transfer caused by kogation on the protective film, which is exacerbated by variations in the elution speed of the protective film components during electrochemical cleaning, leading to inconsistent bubble formation and potential size increases in the ejection head.
Innovation Solution
A liquid ejection head substrate design with a heating resistor array, a protective film, and an electrode configuration where the electrode is positioned between supply openings to maintain a consistent distance from the protective film, reducing the variation in elution speed and ensuring stable liquid ejection while minimizing the size of the ejection head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode is disposed close to the protective film to enable electrochemical cleaning, then the cleaning effectiveness is improved, but the variation in elution speed across the protective film increases leading to unstable heat transfer
Solution Approach 1:
The electrode is divided into multiple segments arranged in an array, with each electrode segment positioned to clean a specific region of the protective film. This segmentation allows for more uniform distribution of cleaning action across the entire protective film surface, reducing the variation in elution speed that occurs with a single distant electrode.
Solution Approach 2:
Different regions of the protective film receive tailored cleaning treatment from corresponding electrode segments. The local arrangement of electrodes ensures that each portion of the protective film is cleaned by the nearest electrode segment, creating localized cleaning zones that maintain uniform thickness across the entire film while enabling effective electrochemical cleaning.
2Stability of the object's composition
If the electrode is disposed at a sufficient distance from the protective film to reduce elution speed variation, then the heat transfer stability is improved, but the size of the liquid ejection head increases
Solution Approach 1:
The electrode array is arranged in a planar configuration parallel to the protective film, utilizing the two-dimensional space available on the substrate. This dimensional arrangement allows multiple electrodes to be positioned close to different regions of the protective film without requiring increased distance in the vertical direction, thereby maintaining compact head size while achieving uniform cleaning.
Solution Approach 2:
Multiple electrode segments are combined in an array configuration to collectively perform the cleaning function across the entire protective film. This merging of multiple cleaning zones into a single integrated electrode array enables uniform cleaning of the entire film surface without requiring each individual electrode to be positioned far from the film, thus avoiding size increase.
3Reliability
If electrochemical cleaning is applied to eliminate kogation, then the liquid ejection stability is improved, but the variation in elution speed causes uneven protective film thickness
Solution Approach 1:
The protective film cleaning process is segmented into multiple localized zones, each served by a corresponding electrode segment. This segmentation ensures that elution occurs uniformly across all regions of the protective film simultaneously, preventing the development of thickness variations that would compromise manufacturing precision while maintaining liquid ejection stability.
Solution Approach 2:
The electrochemical cleaning parameters are optimized by adjusting the voltage applied to each electrode segment and the composition of the cleaning liquid. These parameter changes enable controlled elution rates that are uniform across the entire protective film surface, eliminating thickness variations while effectively removing kogation to ensure stable liquid ejection.
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 achieves stable and consistent liquid ejection by reducing the variation in elution speed across the protective film, maintaining even heat transfer, and preventing size increases in the ejection head, thus ensuring reliable operation.
Implementation Method 1
The liquid ejection head substrate includes a heating resistor configured to generate thermal energy for forming a bubble in the liquid
Implementation Method 2
an electrode is disposed and a voltage is applied such that the protective film becomes a positive side and the electrode becomes a negative side. This causes an electrical chemical reaction between the liquid and a component of the protective film, causing the surface of the protective film to be eluted in the liquid
Data Source
AI summary
A liquid ejection head substrate includes a heating resistor array including a plurality of heating resistors and a protective film covering at least one of the heating resistors. The liquid ejection head substrate further includes a supply opening array and an electrode. The supply opening array is disposed on a side of a surface of the liquid ejection head substrate on which the protective film is provided. The supply opening array includes a plurality of supply openings through which a liquid is supplied arranged in a direction along the heating resistor array. The electrode is disposed on the side of the surface in a space between the supply openings adjacent to each other in a direction along the supply opening array. The electrode is configured such that a voltage is applied between the electrode and the protective film.