Multilayer Printhead Substrate Vertical Temperature Detection
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Solution Overview
Problem
Conventional inkjet printheads face challenges in detecting ink discharge failures quickly and accurately due to restricted space for temperature detection elements, limiting their sensitivity and ability to differentiate between normal and failed ink discharge temperatures.
Innovation Solution
A multilayer structured element substrate with series-connected wiring and conductive vias is used to enhance the sensitivity of temperature detection elements, allowing for precise detection of heater temperatures and rapid identification of nozzle failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the temperature detection element is made thin and long to increase resistance value, then the sensitivity is improved, but the area occupied increases which is restricted by the heater area
Solution Approach 1:
The temperature detection element is configured to extend in the vertical direction (thickness direction of the substrate) rather than only in the horizontal plane. By making the element protrude from the substrate surface, the patent utilizes the third dimension to increase the effective length and resistance value without consuming additional planar area, thereby resolving the contradiction between sensitivity improvement and area restriction.
2Measurement precision
If the resistance value of temperature detection element is increased to improve sensitivity, then temperature detection accuracy is improved, but the element requires more space which conflicts with restricted heater area
Solution Approach 1:
The patent extends the temperature detection element in the vertical dimension by making it protrude from the substrate. This dimensional transition allows the element to achieve higher resistance values (improved accuracy) through increased effective length without requiring additional horizontal space, thus resolving the contradiction between detection accuracy and space requirements.
Solution Approach 2:
The temperature detection element is positioned to be located below the heater, utilizing the vertical space underneath the heater structure. This nesting arrangement allows the detection element to extend vertically without interfering with the heater's horizontal footprint, enabling high resistance values while maintaining compact overall dimensions.
3Productivity
If conventional temperature detection elements are used with restricted area, then device compactness is maintained, but detection speed and accuracy for discharge failure are insufficient
Solution Approach 1:
By extending the temperature detection element vertically from the substrate surface, the patent increases the effective sensing length without increasing planar area. This dimensional approach enables faster thermal response and higher detection accuracy for discharge failures, resolving the contradiction between productivity (detection speed) and measurement precision.
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 solution enables high-speed and high-accuracy detection of heater temperatures, improving the sensitivity of temperature changes and facilitating quicker recovery from ink discharge failures in full-line printheads.
Implementation Method 1
a plurality of heaters which generate heat energy for discharging ink from orifices
Implementation Method 2
a temperature detection element of a thin film is formed via an interlayer insulation film immediately below each heater... detects temperature information from the respective temperature detection elements
Data Source
AI summary
According to embodiments of the present invention, an element substrate capable of detecting a temperature immediately below a heater with high sensitivity is provided. The element substrate has a multilayer structure, and includes a heater, a first wiring below a position where the heater is provided, and a second wiring below the first wiring. The element substrate further includes a temperature detection element formed by series-connecting a first conductive via for connecting the first wiring and the second wiring, a constant electric current source which supplies a constant electric current, and a voltage detection circuit which detects a voltage obtained by supplying the constant electric current to the temperature detection element.