Recording Element Substrate Dual-Layer Heater Sensor Design
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Solution Overview
Problem
Existing thermal inkjet recording systems face limitations in improving the sensitivity of temperature sensors for detecting ink temperature changes, as the temperature sensor is typically positioned directly below the heater, leading to reduced sensitivity due to thermal resistance and inter-layer insulating film thickness.
Innovation Solution
A recording element substrate is designed with a first layer containing a heater and a temperature sensor overlapping the liquid chamber, and a second layer with an auxiliary heater that overlaps the temperature sensor, allowing for improved heat transfer and sensitivity by heating the temperature sensors independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the temperature sensor is positioned directly below the heater, then the structure is simple, but the sensitivity of detecting ink temperature change is limited due to thermal resistance and inter-layer insulating film thickness
Solution Approach 1:
The patent introduces a second heater in a lower layer (first layer) that is spatially separated from the temperature sensor in the upper layer (second layer). This dimensional redistribution allows the temperature sensor to be positioned closer to the ink discharge orifice while the first heater provides baseline heating. The separation into different spatial dimensions enables independent optimization of heating function and temperature sensing function, resolving the contradiction between structural simplicity and detection sensitivity.
Solution Approach 2:
The heating function is segmented into two independent heaters: the first heater in the first layer for general heating, and the second heater in the second layer specifically for heating the temperature sensor. This segmentation allows the temperature sensor to be positioned optimally for detecting ink temperature changes without being constrained by a single heater structure, thereby improving sensitivity while maintaining manageable structural complexity through modular design.
2Measurement precision
If the temperature sensor is brought closer to the heater, then thermal resistance is reduced, but the temperature change detection through the inter-layer insulating film and heater remains limited
Solution Approach 1:
The first heater acts as an intermediary heating element that pre-heats the liquid chamber and creates a thermal baseline. The second heater then acts as a focused thermal stimulus that specifically heats the temperature sensor without requiring the sensor to be directly adjacent to it. This intermediary approach allows thermal energy to be distributed more effectively, reducing the impact of inter-layer insulating films while maintaining detection sensitivity.
3Device complexity
If the heater itself is used as a temperature sensor, then the structure is simplified, but temperature change can only be detected during periods when electricity is being applied to the heater
Solution Approach 1:
The patent segments the heating and temperature sensing functions into separate components: the first heater for general heating and the second heater specifically for heating the temperature sensor. This segmentation allows the temperature sensor to operate independently of the main heating cycle, enabling temperature detection at any time without requiring continuous electricity application to the heater, thus resolving the contradiction between structural simplicity and detection timing flexibility.
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 enhances the sensitivity of detecting temperature changes in the ink, allowing for more precise temperature monitoring and improved recording performance.
Implementation Method 1
a first heater configured to generate heat by application of a drive pulse, and to heat and discharge the liquid from the discharge orifice
Implementation Method 2
a temperature sensor that is disposed with at least a portion overlapping the liquid chamber in plan view
Implementation Method 3
a second heater that is disposed with at least a portion overlapping the temperature sensor in plan view
Data Source
AI summary
A recording element substrate is used in which a liquid chamber is formed between a substrate and a channel-formation member. A discharge orifice configured to discharge liquid in the liquid chamber is provided. The substrate includes at least a first layer, and a second layer that is farther away from the liquid chamber than the first layer. A first heater configured to heat and discharge the liquid by application of a drive pulse, and a temperature sensor that is disposed with at least a portion overlapping the liquid chamber in plan view, are provided in the first layer. A second heater that is disposed with at least a portion overlapping the temperature sensor in plan view is provided in the second layer.