Liquid Discharge Head Temperature Detection with Insulating Layer

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Solution Overview

Problem

Existing liquid discharge devices face a challenge in accurately detecting the temperature of ink within the pressure chamber due to the placement of temperature detection sections outside the liquid discharge head, which can lead to decreased accuracy.

Innovation Solution

A liquid discharge head is designed with a detection resistor made of the same material as the individual and common electrodes, and drive wiring, integrated within the head to detect the temperature of the ink in the pressure chambers. Additionally, a low thermal conductive layer is provided on the surface opposite to the pressure chamber substrate to reduce heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the temperature detection section is disposed outside the liquid discharge head, then the device structure is simpler, but the temperature detection accuracy of the ink in the pressure chamber decreases

Engineering Contradiction:

Improvedevice structureVSAvoidtemperature detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The detection resistor is integrated into the liquid discharge head structure, merging the temperature detection function with the discharge head. The detection resistor is formed in the same insulating layer as the electrode, eliminating the need for separate temperature detection sections and improving temperature detection accuracy while maintaining structural simplicity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

A low thermal conductive layer is introduced as an intermediary between the detection resistor and the external environment. This layer reduces heat conduction from the detection resistor, minimizing heat interference and improving temperature detection accuracy without requiring complex cooling systems

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If the detection resistor is formed of the same material as the electrode, then the manufacturing process is simplified, but the detection resistor may be affected by heat from the piezoelectric body

Engineering Contradiction:

Improvemanufacturing processVSAvoidheat interference

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

A low thermal conductive layer is positioned between the piezoelectric body and the detection resistor to act as a thermal barrier. This intermediary layer reduces heat conduction from the piezoelectric body to the detection resistor, protecting the detection resistor from heat interference while maintaining the manufacturing simplicity of using the same material for both electrode and detection resistor

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulating layer is designed with different thermal conductivity characteristics in different regions. The portion forming the detection resistor has low thermal conductivity to reduce heat reception from the piezoelectric body, while other portions maintain normal electrical insulation properties

Inventive Principle:

Principle #3Local quality

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 improves the temperature detection accuracy of the ink within the pressure chambers by directly integrating the detection resistor within the liquid discharge head and utilizing a low thermal conductive layer to minimize heat dissipation.

Implementation Method 1

a detection resistor that is formed of the same material as any of the individual electrode, the common electrode, and the drive wiring for detecting temperature of the liquid in the pressure chambers

Methodology Applied

Scientific EffectTemperature-dependent resistance: Electrical Resistance

Implementation Method 2

a first layer that is provided on a surface opposite to a surface facing the pressure chamber substrate in of the detection resistor, and has a lower thermal conductivity than the detection resistor

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

a piezoelectric body that is provided between the individual electrode and the common electrode for applying pressure to liquid in the pressure chambers

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS12296589B2Liquid discharge head and liquid discharge device

Publication Date: 2025.05.13 SEIKO EPSON CORP

AI summary

A liquid discharge head includes an individual electrode that is individually provided for the plurality of pressure chambers, a common electrode that is commonly provided for the plurality of pressure chambers, a piezoelectric body that is provided between the individual electrode and the common electrode for applying pressure to liquid in the pressure chambers, a drive wiring that is electrically coupled to the individual electrode and the common electrode, and applies a voltage for driving the piezoelectric body, a detection resistor that is formed of the same material as any of the individual electrode, the common electrode, and the drive wiring for detecting temperature of the liquid in the pressure chambers, and a first layer that is provided on a surface opposite to a surface facing the pressure chamber substrate in the detection resistor, and has a lower thermal conductivity than the detection resistor.