Liquid Ejection Head Wiring Board Depression Fixing

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Solution Overview

Problem

The existing liquid ejection heads experience lifting issues with their electrical wiring boards during production and usage, leading to increased dimensions in the traveling direction, which causes interference with sheet pressing rollers and results in printing failures and paper jams due to the increased interval between rollers.

Innovation Solution

The liquid ejection head design includes a depressed portion on the housing surface for additional fixing points of the electrical wiring board, allowing it to be securely attached both around the signal input portion and within a depressed area closer to the bent portion, reducing warping and wrinkling and thus suppressing protrusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the electrical wiring board is bent along the housing surfaces to reduce size, then the electrical signal input portion size is reduced, but lifting occurs near the bent portion causing increased Y direction dimension

Engineering Contradiction:

Improveelectrical signal input portion sizeVSAvoidwiring board position stability

Core Design Contradiction:

Area of stationary objectVSStability of the object's composition

Solution Approach 1:

The housing is designed with a depressed portion in advance, closer to the bent portion of the wiring board, to prevent lifting before it occurs. This preliminary structural preparation ensures that when the wiring board is installed, it is immediately constrained against lifting, maintaining position stability while preserving the compact design.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The depressed portion acts as an intermediary structure between the wiring board and the housing surface. It provides an intermediate fixing location that mediates the conflict between the wiring board's flexible nature and the housing's rigid structure, preventing lifting without requiring additional complex fixation mechanisms.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the electrical wiring board is made flexible to enable bending, then it can be routed along housing surfaces, but it cannot be completely bent along the housing shape causing protrusion

Engineering Contradiction:

Improvewiring board flexibilityVSAvoidwiring board conformity to housing

Core Design Contradiction:

Adaptability or versatilityVSShape

Solution Approach 1:

The housing surface is modified locally by creating a depressed portion specifically at the location where the wiring board needs to be fixed closest to the bent portion. This local structural change provides the necessary constraint to achieve complete conformity without requiring the entire housing or wiring board to be redesigned.

Inventive Principle:

Principle #3Local quality

3Stability of the object's composition

If the Y direction dimension is increased to accommodate wiring board lifting, then the wiring board can be properly fixed, but sheet pressing rollers interfere causing printing failures

Engineering Contradiction:

Improvewiring board fixation stabilityVSAvoidsheet pressing function

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The depressed portion is designed in advance to prevent wiring board lifting before it can cause interference with sheet pressing rollers. By proactively constraining the wiring board in its correct position, the system avoids the need to increase the Y direction dimension, thereby maintaining proper sheet pressing function.

Inventive Principle:

Principle #10Preliminary action

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 design effectively reduces the Y-direction dimension of the liquid ejection head, minimizing interference with sheet pressing rollers and preventing printing failures and paper jams by maintaining a consistent and stable electrical wiring board position.

Implementation Method 1

The liquid droplets are ejected by heating the liquid by an energy-generating element including a heat generating resistor, thereby causing film boiling in the liquid

Methodology Applied

Scientific EffectFilm boiling: Phase Change

Implementation Method 2

a piezoelectric element may be used sometimes to eject the liquid droplets

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 3

a method involving irradiating the liquid with an electromagnetic wave generated by a laser or the like is also sometimes employed

Methodology Applied

Scientific EffectLaser: Laser

Data Source

PatentUS9156263B2Liquid ejection head and method of producing the same

Publication Date: 2015.10.13 CANON KK

AI summary

A liquid ejection head includes a recording element substrate for ejecting liquid in response to an externally supplied electrical signal; an electrical wiring board having a first and second part mutually joined via a bent portion, the first part having an electrical joint portion for supplying the signal to the substrate, the second part having an electrical signal input portion into which the signal is input and to which the joint portion is connected; and a housing having first and second surfaces mutually adjoining, the first and second surfaces respectively supporting the first and second parts. The second part is fixed to the second surface at plural first fixing positions around the input portion. The second surface has a depressed portion formed closer to the bent portion than the first fixing positions. The second part is fixed to the housing at a second fixing position inside the depressed portion.