Liquid Ejection Head Element Substrate with Embedded Connecting Members

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Solution Overview

Problem

The increasing number of ejection orifices and higher ejection speeds in liquid ejection heads lead to increased power consumption, which is exacerbated by the difficulty in achieving high thermal conductivity while maintaining the dimensional accuracy of heating resistance elements.

Innovation Solution

The implementation of a connecting structure that includes connecting members embedded in the insulating film, which connect the electrical wirings and heating resistance elements, allowing for a thinner protective film and improved thermal conductivity, while maintaining the dimensional accuracy of the heating resistance elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the thickness of the protective film is reduced to improve thermal conductivity, then power consumption is reduced, but the protective performance for electrical wirings and heating resistance element deteriorates

Engineering Contradiction:
Improvepower consumptionVSAvoidprotective performance
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies different thicknesses of the protective film at different locations: a first thickness in a first region and a second thickness (greater than the first) in a second region. This local variation allows the film to be thin where thermal conductivity is critical while maintaining sufficient thickness for protection where needed, thus resolving the contradiction between power consumption and protective performance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The protective film is segmented into different thickness regions rather than being uniformly thick. This segmentation enables optimized thermal performance in specific areas while maintaining structural integrity and protection in other areas, balancing energy efficiency with reliability.

Inventive Principle:
Principle #1Segmentation

2Loss of energy

If the taper angle of electrical wirings is reduced to achieve thinner protective film, then thermal conductivity improves, but the dimensional accuracy of heating resistance element deteriorates

Engineering Contradiction:
Improvethermal conductivityVSAvoiddimensional accuracy
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent implements a non-uniform protective film thickness with different regions having different thicknesses, allowing the film to be thin near the heating resistance element for thermal efficiency while maintaining greater thickness in other areas for manufacturing accuracy and protection.

Inventive Principle:
Principle #3Local quality

3Productivity

If the number of ejection orifices and ejection speed are increased to improve productivity, then recording quality improves, but power consumption increases

Engineering Contradiction:
Improveejection speedVSAvoidpower consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent changes the physical parameters of the protective film (thickness distribution) to optimize thermal conductivity. By reducing film thickness in critical regions, heat transfers more efficiently from the heating resistance element to the liquid, enabling effective ejection at lower power consumption levels and supporting higher productivity without proportionally increasing energy use.

Inventive Principle:
Principle #35Parameter changes

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 reduces power consumption, enhances image quality through stable foaming, and improves manufacturing efficiency by allowing for more precise control over the heating resistance elements and reduced voltage loss.

Implementation Method 1

a heating resistance element 101 that generates heat energy for ejecting liquid

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

at least one connecting member extending into the insulating film to connect the first electrical wiring layer and the heating resistance element

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

a protective film for covering the heating resistance element

Methodology Applied
Scientific EffectPhysical barrier protection: Physical Containment

Data Source

PatentEP3970977B1Element substrate and liquid ejection head
Publication Date: 2025.04.23 CANON KK
  • EP3970977B1 patent drawingFigure 1A
  • EP3970977B1 patent drawingFigure 1B
  • EP3970977B1 patent drawingFigure 2~3

AI summary

An element substrate of a liquid ejection head, comprising a base material; an insulating film; a heating resistance element; a protective film; first and second electrical wiring layers; a plurality of first connecting members to connect the first electrical wiring layer and a heating resistance element back surface; and a plurality of second connecting members to connect the first electrical wiring layer the heating resistance element back surface, the heating resistance element comprising a first connecting region to which the plurality of first connecting member are connected on one end in the first direction, a second connecting region to which the plurality of second connecting members are connected on another end, and a center region positioned between the first and second connecting regions, the first and second connecting regions extending in a second direction intersecting the first direction, and the element substrate comprising a further wiring in the insulating film arranged between the center region and the base material, and away from the center region.