Inkjet Head Cap Electrode for Uniform Kogation Removal
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Solution Overview
Problem
The uneven thermal conduction caused by kogation on the heat-acting unit of inkjet heads leads to unstable ink foaming and discharge characteristics, due to the uneven dissolution of the upper protection layer during electrochemical reactions.
Innovation Solution
A liquid discharge device with a cap containing an electrode that applies voltage between the protection film and the upper protection layer, ensuring a uniform electric field for even dissolution and preventing film thickness variations, thereby maintaining consistent thermal conduction and ink discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If voltage is applied to generate electrochemical reaction between the upper protection layer and ink to remove kogation, then kogation is removed, but the upper protection layer dissolves unevenly causing film thickness variation
Solution Approach 1:
A resin layer is introduced as an intermediary between the upper protection layer and the ink. This resin layer acts as a buffer that controls the electrochemical reaction, preventing direct contact between the ink and the protection layer while still allowing ion transport. This mediator enables kogation removal through controlled electrochemical reactions while preventing uneven dissolution of the protection layer.
Solution Approach 2:
The system uses the ink itself as the electrolyte solution for the electrochemical reaction, eliminating the need for separate cleaning solutions. The ink's natural composition provides the necessary ions for the electrochemical process that removes kogation, while the resin layer ensures this self-service process does not damage the protection layer's uniformity.
2Strength
If the upper protection layer is made of metallic materials to resist cavitation and chemical action, then protection against physical and chemical damage is improved, but kogation adheres to the heat-acting unit causing uneven thermal conduction
Solution Approach 1:
The resin layer serves as an intermediary that prevents kogation from adhering to the metallic upper protection layer's heat-acting unit. By placing this resin barrier between the ink and the metal surface, the system maintains the metal's protective properties while preventing kogation formation that would disrupt thermal conduction.
Solution Approach 2:
The system combines metallic materials for the upper protection layer (to provide cavitation and chemical resistance) with a resin material (to prevent kogation adhesion). This composite structure integrates the advantages of both materials: the metal provides durability while the resin ensures uniform thermal conduction by preventing kogation formation.
3Object-affected harmful factors
If the cap is positioned to cover the discharge port surface, then protection of the discharge ports is achieved, but access for electrochemical reaction is limited
Solution Approach 1:
The resin layer is pre-applied to the discharge port surface before the cap is attached. This preliminary action ensures that when the cap is in place, the electrochemical reaction can still occur effectively through the resin layer without requiring the cap to be removed or repositioned. The resin layer maintains accessibility for ion transport while the cap provides physical protection.
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 removes kogation by ensuring uniform electrochemical reactions, stabilizing ink foaming and discharge characteristics, and preventing film thickness unevenness.
Implementation Method 1
an electrothermal conversion element that generates thermal energy used for discharging ink. The electrothermal conversion element generates thermal energy by being driven. The generated thermal energy quickly heats a contact portion (heat-acting unit) with the ink above the electrothermal conversion element to generate foams
Implementation Method 2
an upper protection layer is provided that acts as an electrode for generating an electrochemical reaction with the ink and, by an electrochemical reaction, the surface of the upper protection layer is eluted into ink to remove kogation on the heat-acting unit
Data Source
AI summary
A liquid discharge device includes a liquid discharge head including a discharge port surface on which discharge ports for discharging liquid are formed, an electrothermal conversion element configured to generate energy for discharging liquid from the discharge ports, and a protection film configured to cover at least the electrothermal conversion element, and a cap configured to cover the discharge port surface, wherein the cap is arranged along the discharge port surface at a position opposite to the protection film via the discharge ports in a state where the cap covers the discharge port surface, and wherein the cap includes an electrode configured to be used to apply voltage between the protection film and the electrode.