Liquid Ejection Head Heater Placement for Thermal Conductivity
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Solution Overview
Problem
The existing liquid ejection heads face difficulties in effectively heating ink due to the low thermal conductivity of the supply channel structure, which hinders efficient ink ejection, especially for high viscosity inks.
Innovation Solution
A liquid ejection head configuration where the flow channel structure, made of inorganic material with higher thermal conductivity, has a heater disposed at its end portion protruding outward relative to the supply channel structure, allowing for effective heat transfer to the supply channel and ink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heater is disposed at the supply channel structure, then the structure can be heated, but the heating efficiency is low due to low thermal conductivity of the supply channel structure
Solution Approach 1:
The flow channel structure acts as an intermediary with high thermal conductivity to transfer heat from the heater to the ink more efficiently. By positioning the heater at the flow channel structure (which has higher thermal conductivity than the supply channel structure), heat is generated closer to the ink flow path and transferred more effectively through the intermediate medium.
Solution Approach 2:
The invention changes the material parameter of the flow channel structure to have higher thermal conductivity compared to the supply channel structure. This parameter change enables more efficient heat transfer from the heater to the ink, resolving the heating efficiency problem.
2Reliability
If the supply channel structure is made of synthetic resin, then it provides good sealing and flexibility, but the thermal conductivity is low making heat transfer difficult
Solution Approach 1:
The invention applies local quality by using different materials for different parts of the channel structure. The supply channel structure uses synthetic resin for sealing and flexibility, while the flow channel structure uses material with higher thermal conductivity for heat transfer. This localized material differentiation resolves both requirements.
Solution Approach 2:
The system effectively uses composite material properties by combining synthetic resin (for sealing) with high thermal conductivity material (for heat transfer) in different structural components. The flow channel structure's high thermal conductivity material compensates for the supply channel structure's low thermal conductivity.
3Strength
If the flow channel structure and supply channel structure are joined using thermosetting adhesive, then strong bonding is achieved, but thermal stress arises due to difference in thermal contraction
Solution Approach 1:
The invention changes the thermal parameter of the flow channel structure by using material with higher thermal conductivity and potentially different thermal expansion characteristics. This parameter change reduces the thermal contraction difference between the flow channel structure and supply channel structure, thereby reducing residual thermal stress in the joint.
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 enables appropriate heating of ink, improving the ejection efficiency and reducing thermal stress between the flow and supply channel structures.
Implementation Method 1
The flow channel structure may be made of inorganic material having a higher thermal conductivity than material used for the supply channel structure
Data Source
AI summary
A liquid ejection head includes a flow channel structure, a supply channel structure, and a particular heater. The flow channel structure defines an ejection channel that leads liquid toward a plurality of nozzles arranged in a nozzle row along a first direction. The supply channel structure defines a supply channel configured to allow liquid to flow therefrom to the ejection channel. The particular heater is configured to heat liquid. The flow channel structure is made of inorganic material having a higher thermal conductivity than material used for the supply channel structure. The flow channel structure includes an end portion protruding outward relative to a side surface of the supply channel structure. The particular heater is disposed at the end portion of the flow channel structure.