Element Substrate Potential Control for Heat Transfer and Insulation

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Solution Overview

Problem

In liquid discharge recording apparatuses, densely disposed heat-generating resistor elements lead to substrate temperature rise, affecting liquid discharge stability due to inefficient heat transfer, and thinner insulating layers compromise insulation properties.

Innovation Solution

An element substrate with a heat-generating resistor element, an electrically conductive protective layer, and an insulating layer, where the potential of the protective layer is set between the potentials of the heat-generating resistor element's ends to reduce the voltage applied to the insulating layer, allowing for a thinner insulating layer while maintaining insulation properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the insulating layer is made thinner to improve heat transfer efficiency, then heat transfer to the liquid is improved, but insulation properties deteriorate

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidinsulation properties

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent applies parameter changes by controlling the thickness of the insulating layer within a specific range (50-200 nm) to optimize both heat transfer efficiency and insulation properties. By precisely adjusting this parameter, the invention achieves adequate heat transfer to the liquid while maintaining sufficient insulation to prevent anodic oxidation of the protective layer.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining the insulating layer with the electrically conductive protective layer and heat-generating resistor element in a multi-layer structure. This composite structure allows the insulating layer to perform dual functions: transferring heat efficiently to the liquid while providing electrical insulation to protect the protective layer from oxidation.

Inventive Principle:

Principle #40Composite materials

2Productivity

If heat-generating resistor elements are densely disposed to increase discharge ports, then productivity is improved, but substrate temperature rises

Engineering Contradiction:

Improvenumber of discharge portsVSAvoidsubstrate temperature

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent applies local quality by directing heat preferentially toward the liquid rather than the substrate. The insulating layer is positioned to facilitate localized heat transfer to the liquid at each discharge port, ensuring efficient heat utilization without causing overall substrate temperature rise, thus enabling dense disposal of heat-generating resistor elements.

Inventive Principle:

Principle #3Local quality

3Reliability

If a potential difference exceeds a certain level between the protective layer and liquid, then insulation is improved, but anodic oxidation or dissolution of the metal occurs

Engineering Contradiction:

Improveinsulation propertiesVSAvoidanodic oxidation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses the insulating layer as an intermediary between the heat-generating resistor element and the electrically conductive protective layer. This intermediary structure allows the system to maintain adequate electrical insulation to prevent anodic oxidation of the protective layer while still permitting efficient heat transfer to the liquid, thus mediating between electrical and thermal requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 efficient heat transfer to the liquid, reducing substrate temperature and maintaining adequate insulation, thus stabilizing liquid discharge and preventing anodic oxidation of the protective layer.

Implementation Method 1

a heat-generating resistor element which generates thermal energy used for discharging a liquid

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

an insulating layer provided between the heat-generating resistor element and the protective layer

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 3

a potential applying unit for applying a potential to the protective layer such that a potential of the protective layer is lower than a potential at one end of the heat-generating resistor element and higher than a potential at the other end

Methodology Applied

Scientific EffectElectrochemical protection: Anodising

Data Source

PatentUS9561651B2Element substrate and method for discharging liquid

Publication Date: 2017.02.07 CANON KK

AI summary

An element substrate including a base having a heat-generating resistor element which generates thermal energy used for discharging a liquid; an electrically conductive protective layer covering the heat-generating resistor element; an insulating layer provided between the heat-generating resistor element and the protective layer; and a potential applying unit for applying a potential to the protective layer such that a potential of the protective layer is lower than a potential at one end of the heat-generating resistor element and higher than a potential at the other end of the heat-generating resistor element with a voltage being applied between the one end and the other end of the heat-generating resistor element.