Liquid Ejection Head Orifice Water-Repellent Coating
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Solution Overview
Problem
Inkjet print heads face issues with ink thickening in ejection orifices due to volatile component evaporation, leading to increased viscosity and ejection failures, especially when no ejection operation is performed for a prolonged period, causing solid components to be fixedly attached and increasing flow resistance.
Innovation Solution
A liquid ejection head design featuring pressure chambers, channels for ink circulation, and ejection orifices with a mortar-shaped inner surface treated for water repellency, where a meniscus is formed at the bottom of the orifice, facilitating ink circulation and suppressing thickening by ensuring the meniscus enters the orifice, thereby maintaining ink ejection performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ink is circulated through the pressure chamber to suppress thickening, then ink ejection reliability is improved, but circulation speed must be maintained high which increases energy consumption
Solution Approach 1:
The invention changes the physical-chemical parameters of the ejection orifice by applying a water-repellent coating to its inner surface. This modification alters the interaction between ink and the orifice surface, enabling effective thickening suppression at lower circulation speeds. The coating changes surface energy characteristics, preventing ink adhesion and facilitating easier ink flow through the orifice even when circulation is reduced.
Solution Approach 2:
The water-repellent treatment is applied specifically to the inner surface of the ejection orifice where ink thickening occurs, rather than treating the entire circulation system. This localized treatment targets the critical area where ink-volatile component evaporation causes thickening, allowing selective modification of surface properties at the orifice while leaving the rest of the circulation system unchanged.
2Loss of energy
If circulation speed is reduced to save energy, then energy consumption is decreased, but ink thickening suppression becomes insufficient leading to ejection failures
Solution Approach 1:
By modifying the surface parameters of the ejection orifice through water-repellent coating, the system achieves effective ink thickening suppression at lower circulation speeds. The coating changes the surface energy and wettability characteristics, creating a non-stick surface that prevents ink adhesion and facilitates flow even when circulation is reduced for energy savings.
Solution Approach 2:
The invention converts the harmful effect of reduced circulation (which would normally cause ink thickening) into a beneficial situation. The water-repellent coating creates conditions where ink does not adhere to the orifice surface, effectively turning the low-circulation state into one that still prevents thickening through the non-stick surface property rather than relying on high flow velocity.
3Loss of time
If no ejection operation is performed for a prolonged period, then device idle time increases, but ink solid components become fixedly attached to ejection orifices increasing flow resistance
Solution Approach 1:
The water-repellent coating on the ejection orifice inner surface prevents ink solid components from adhering during idle periods. By creating a non-stick surface, the coating converts the idle time period (which would normally allow solid component deposition and clogging) into a safe state where ink remains non-adhesive, preventing flow resistance increase even when the device is not in use.
Solution Approach 2:
The water-repellent coating provides preliminary protection against ink solid component attachment before any ejection operation occurs. This pre-applied protective layer actively prevents the harmful adhesion process during idle periods, so when the device is next used, the orifices are already protected against clogging and require minimal or no maintenance.
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 design effectively suppresses ink thickening even at low circulation speeds, ensuring reliable ink ejection and high-quality printing without color misregistration, and is applicable to various liquid ejection applications.
Implementation Method 1
a meniscus of the liquid is formed at an end portion of the ejection orifice communicating with the pressure chamber
Implementation Method 2
the inner surface of the ejection orifice is treated with a water-repellent treatment
Data Source
AI summary
A liquid ejection head, a liquid ejection apparatus, and a liquid ejection method are capable of sufficiently suppressing the thickening of a liquid in an ejection orifice. The liquid ejection head includes a pressure chamber, a channel in which a liquid is caused to flow through the pressure chamber, an ejection orifice communicating with the pressure chamber, and an ejection energy generation element configured to eject the liquid in the pressure chamber from the ejection orifice. A meniscus of the liquid is formed at an end portion of the ejection orifice communicating with the pressure chamber.