Liquid Ejection Head Wiring Board Segmentation

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Solution Overview

Problem

Existing liquid ejection heads face challenges in managing heat generated by integrated circuit elements, which affects ejection performance due to increased viscosity and requires additional components like heat insulating members and radiation units, complicating the design and increasing costs.

Innovation Solution

A liquid ejection head configuration with a first electric wiring board close to the energy-generating element and a second electric wiring board further away, where the integrated circuit element is mounted, allowing for efficient signal processing and energy application while minimizing heat transfer through a structured heat conduction path and using a pressure chamber for ink circulation to manage heat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a driver IC is mounted on the electric wiring board to process driving signals at high speed, then the processing speed of electric signals is improved, but heat is generated which affects the viscosity of the liquid and deteriorates ejection performance

Engineering Contradiction:
Improveprocessing speed of electric signalsVSAvoidheat affecting ejection performance
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The electric wiring board is divided into two separate boards: a first electric wiring board for signal input and a second electric wiring board for mounting the driver IC. This segmentation separates the heat-generating component from the liquid ejection elements, allowing high-speed signal processing while preventing heat from affecting the liquid viscosity and ejection performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first electric wiring board acts as an intermediary between the control unit and the second electric wiring board. It transmits electric signals from the control unit to the driver IC on the second board, enabling signal processing while maintaining physical separation between the heat source and the liquid ejection elements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If heat insulating members and heat radiation units are added to suppress heat from the driver IC, then the ejection performance is protected from heat effects, but the device complexity and cost increase

Engineering Contradiction:
Improveheat affecting ejection performanceVSAvoidnumber of additional components
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The driver IC is extracted from the first electric wiring board and mounted on a separate second electric wiring board. This extraction removes the heat source from proximity to the liquid ejection elements, eliminating the need for additional heat insulating members and radiation units, thereby reducing device complexity while still protecting ejection performance from heat effects.

Inventive Principle:
Principle #2Taking out (Extraction)

3Volume of moving object

If the driver IC is mounted close to the energy-generating element for compact design, then the device size is reduced, but heat transfer to the liquid increases and affects ejection performance

Engineering Contradiction:
Improvesize of liquid ejection headVSAvoidheat transfer to liquid
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

Instead of arranging components along a single dimension where compactness would place the driver IC near the energy-generating element, the solution uses a two-dimensional arrangement with separate electric wiring boards positioned at different locations. This dimensional change allows compact overall design while maintaining sufficient distance between the heat-generating driver IC and the energy-generating element to prevent heat transfer from affecting liquid viscosity and ejection performance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 the impact of heat on ejection performance, maintains compactness, and eliminates the need for additional heat management components, resulting in improved printing quality and reduced costs.

Implementation Method 1

liquid in the pressure chamber is circulated between the pressure chamber and an outside of the pressure chamber

Methodology Applied
Scientific EffectCirculation: Convection

Implementation Method 2

the driver IC generates heat when processing the driving signal

Methodology Applied
Scientific EffectHeat generation: Joule Heating

Data Source

PatentEP3421246B1Liquid ejection head
Publication Date: 2020.10.28 CANON KK
  • EP3421246B1 patent drawingFigure 1
  • EP3421246B1 patent drawingFigure 2A~2B
  • EP3421246B1 patent drawingFigure 3

AI summary

The liquid ejection head 1 includes an element substrate 4 including an energy-generating element that applies ejection energy to liquid, a first electric wiring board 7 electrically connected to the element substrate 4, and a second electric wiring board 9 on which an integrated circuit element 10 is mounted and which is electrically connected to the first electric wiring board 7. An electric signal is supplied to the integrated circuit element 10 mounted on the second electric wiring board 9 through the first electric wiring board 7, processed by the integrated circuit element 10, and supplied to the energy-generating element through the second electric wiring board 9 and the first electric wiring board 7.