Liquid Ejection Head Electrode Placement for Kogation Control
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Solution Overview
Problem
In liquid ejection heads, the adhesion of 'koge' (hardly-soluble substances) to the heater surface causes non-uniform heat conduction and unstable foaming, and existing solutions like forming an electric field between electrodes can lead to bubble stagnation, reducing the effectiveness of kogation suppression.
Innovation Solution
A liquid ejection head configuration with a wall member partitioning two liquid chambers, a first energy generation element, a second energy generation element, a first electrode near the first energy generation element, and a second electrode forming an electric field, along with a detection unit and generation unit to manage bubble flow, reduces bubble stagnation near the paired electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an electric field is formed between a heater upper electrode and a paired electrode to suppress kogation, then the adhesion of koge to the heater surface is reduced, but bubbles may stagnate in the vicinity of the paired electrode, increasing resistance and reducing the effectiveness of kogation suppression
Solution Approach 1:
The liquid chamber is divided into multiple regions by positioning the paired electrode at a specific location, creating distinct zones for electric field application and bubble removal. The paired electrode is arranged in the liquid supply channel rather than directly in the liquid chamber, segmenting the functional areas to prevent bubble stagnation while maintaining electric field effectiveness for kogation suppression.
Solution Approach 2:
The liquid supply channel acts as an intermediary region where the paired electrode is positioned. This intermediary location allows the electrode to influence the liquid flow and remove bubbles without directly interfering with the electric field formation between the heater upper electrode and the liquid, thereby preventing bubble stagnation while maintaining kogation suppression effectiveness.
2Object-affected harmful factors
If the paired electrode is positioned to form an electric field for kogation suppression, then charged colloidal particles are kept away from the heater, but this arrangement may cause stagnation in the flow of ink, allowing bubbles to gather and stay
Solution Approach 1:
The paired electrode is repositioned from a location within the liquid chamber to the liquid supply channel, changing the spatial dimension of its operation. This dimensional shift allows the electrode to affect liquid flow in the supply channel without creating stagnation zones in the main liquid chamber, thereby maintaining ink flow speed while still achieving kogation suppression through electric field formation.
3Object-affected harmful factors
If a paired electrode is arranged in the liquid chamber to form an electric field, then kogation is suppressed, but the resistance between electrodes increases due to bubble accumulation, reducing the amount of charged particles that can be moved
Solution Approach 1:
The paired electrode is positioned in the liquid supply channel to perform preliminary action on the liquid before it reaches the heater region. This preliminary positioning allows the electrode to influence liquid flow and prevent bubble accumulation in advance, maintaining low resistance and ensuring sufficient charged particle movement for effective kogation suppression without requiring direct electrode placement in the liquid chamber.
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 suppresses koge adhesion to the heater surface by minimizing bubble stagnation, ensuring uniform heat conduction and stable foaming.
Implementation Method 1
a liquid ejection head which ejects liquid by foaming the liquid with heat generated by a heater
Implementation Method 2
a heater upper electrode arranged in a vicinity of a heater as a heating element and an electrode paired with this heater upper electrode form an electric field in ink between these electrodes
Implementation Method 3
this formed electric field keeps a charged colloidal particle in the ink away from the heater upper electrode
Implementation Method 4
the wall member having formed therein a void for communicating between the first liquid chamber and the second liquid chamber
Data Source
AI summary
The liquid ejection head includes a wall member having formed therein a void for communicating between a first liquid chamber and a second liquid chamber; a first energy generation element to eject the liquid in the first liquid chamber; a second energy generation element to eject the liquid in the second liquid chamber; a first electrode arranged in a vicinity of the first energy generation element in the first liquid chamber; a second electrode for forming, between the first electrode and the second electrode, an electric field in liquid inside the first liquid chamber; and a supply port which supplies liquid to the first energy generation element. The wall member includes a channel wall defining a channel through which the second liquid chamber, the void, and the supply port communicate, and the second electrode is arranged between the second liquid chamber and the supply port in the channel.