Liquid Discharging Head Guard Pad Electrostatic Protection

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Solution Overview

Problem

Existing liquid discharging heads are prone to electrostatic breakdown, especially when static electricity is created at contact pads with low electrostatic capacity, particularly on the outer circumferential portion of the contact area, which can lead to electrical failure and restrict the arrangement of contact pads.

Innovation Solution

Incorporating a guard pad with high electrostatic capacity connected to the ground, extending linearly outside the contact pads with low electrostatic capacity to divert static electricity and prevent breakdown, while maintaining the flexibility in arranging contact pads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If contact pads with low electrostatic capacity are arranged on the outer circumferential portion of the contact area, then the degree of freedom of contact pad arrangement is improved, but electrostatic breakdown is more likely to occur

Engineering Contradiction:

Improvedegree of freedom of contact pad arrangementVSAvoidelectrostatic breakdown resistance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

A guard pad is introduced as an intermediary element between the low electrostatic capacity contact pad and the external environment. The guard pad extends linearly outside the low electrostatic capacity contact pad and is connected to ground, serving as a mediator that intercepts static electricity before it can reach the vulnerable contact pad, thus protecting it without constraining the overall layout

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The guard pad is selectively positioned only where needed - extending linearly outside the low electrostatic capacity contact pad on the outer circumferential side. This localized protection approach provides electrostatic shielding precisely where the vulnerability exists without requiring changes to the entire contact pad arrangement, maintaining design flexibility while improving reliability

Inventive Principle:

Principle #3Local quality

2Reliability

If contact pads are surrounded from four directions by contact pads with large electrostatic capacity, then electrostatic breakdown is inhibited, but the degree of freedom of arrangement decreases

Engineering Contradiction:

Improveelectrostatic breakdown resistanceVSAvoiddegree of freedom of arrangement

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The guard pad serves as an intermediary protective element that provides the necessary electrostatic shielding without requiring surrounding contact pads with large electrostatic capacity. By placing the guard pad outside the low electrostatic capacity contact pad and connecting it to ground, the invention achieves protection while maintaining arrangement flexibility

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of surrounding the low electrostatic capacity contact pad with large electrostatic capacity contact pads (traditional approach), the invention inverts the approach by placing a ground-connected guard pad outside the low electrostatic capacity contact pad. This reversal of the protective structure maintains functionality while improving design freedom

Inventive Principle:

Principle #13The other way round (Inversion)

3Area of stationary object

If inspection contact pad is disposed on the outer circumferential side, then the area of contact pins on the main body is decreased, but electrostatic breakdown risk increases

Engineering Contradiction:

Improvearea of contact pins on main bodyVSAvoidelectrostatic breakdown resistance

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The guard pad acts as a protective intermediary that enables the inspection contact pad to be positioned on the outer circumferential side without compromising reliability. The guard pad intercepts static electricity before it can reach the inspection contact pad, allowing space optimization on the main body while maintaining protection

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

Effectively inhibits electrostatic breakdown at the outer circumferential portion of the contact area, allowing for greater freedom in contact pad arrangement without increasing the size of the liquid discharge apparatus.

Implementation Method 1

a guard pad extending linearly outside the second contact pad... connected to a ground of the print element substrate... divert static electricity and prevent breakdown

Methodology Applied

Scientific EffectElectrostatic induction: Electrostatic Induction

Data Source

PatentUS10093098B2Liquid discharging head

Publication Date: 2018.10.09 CANON KK

AI summary

A liquid discharging head includes a print element substrate including an energy-generating element that generates energy used to discharge a liquid from a discharge port, and an electric wiring member including a plurality of contact pads arranged thereon. The plurality of contact pads are disposed in a contact area and include a first contact pad to which power for driving the energy-generating element is supplied and a second contact pad that has an electrostatic capacity lower than an electrostatic capacity of the first contact pad and that is disposed on an outer circumferential side of the contact area. The electric wiring member is connected to a ground of the print element substrate and includes a guard pad extending linearly outside the second contact pad.