Print Head Interconnection Structure With Adhesive-Anchored Contact Pads

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Solution Overview

Problem

Inkjet printers face issues with electrical connection reliability due to moisture sensitivity and mechanical stress, leading to nozzle failures and poor bonding at the interconnection structure, which affects the print head's reliability and performance.

Innovation Solution

A print head design featuring recessed contact pad structures with adhesive anchoring, where the adhesive flows into recesses to form a protrusion, securing the contact pads against mechanical forces, ensuring stable electrical connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a flexible electrical connection element is used to connect the droplet jetting device to the controller, then the electrical connections can be made flexible and adaptable, but the electrical connections become sensitive to damage from displacement and pulling forces during production and operation

Engineering Contradiction:
Improveflexibility of electrical connectionVSAvoidelectrical connection reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The contact pad structure is segmented into distinct functional zones: a bonding area for adhesive attachment, a wider portion for mechanical reinforcement, and a connection area for electrical contact. This segmentation allows each zone to optimize its specific function while working together to resolve the contradiction between flexibility and reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The wider portion of the contact pad structure acts as a pre-designed reinforcement zone that cushions and distributes pulling forces before they can damage the adhesive bonding area. This beforehand cushioning prevents force concentration at critical bonding points, maintaining connection reliability despite flexible sheet displacement.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Object-affected harmful factors

If the electrical connections are made sensitive to moisture and ink protection measures are implemented, then the electrical connections are protected against ingress, but the bonding structure becomes more complex and requires additional protective measures

Engineering Contradiction:
Improveprotection against moisture and inkVSAvoidbonding structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The bonding structure merges mechanical reinforcement and environmental protection functions into a single integrated design. The wider portion serves dual purposes: reinforcing the bonding mechanically while also acting as a barrier against moisture and ink ingress, thereby reducing overall structure complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The adhesive bonding structure is designed to perform multiple functions simultaneously: providing mechanical adhesion, distributing mechanical stresses, and protecting against environmental contaminants. This multi-functionality reduces the need for separate protective structures, simplifying the overall design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If stud bumps are applied as connecting means for the interconnection structure, then electrical connections can be established, but the bonding reliability is insufficient and connections may disconnect under pulling forces

Engineering Contradiction:
Improveease of applying connecting meansVSAvoidbonding reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The contact pad structure extends in the vertical dimension with a wider portion that protrudes beyond the bonding area. This dimensional extension creates a mechanical leverage advantage, distributing pulling forces over a larger area and preventing disconnection, thereby improving reliability while maintaining ease of manufacture.

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

Enhances manufacturing yield and operational reliability of inkjet printers by providing secure electrical connections resistant to mechanical stress and moisture, improving the print head's performance and longevity.

Implementation Method 1

an adhesive covering the first and second contact pad structures and securing them together

Methodology Applied
Scientific EffectAdhesive: Adhesive

Data Source

PatentEP4032708B1Interconnection structure for a print head
Publication Date: 2026.01.07 CANON KK
  • EP4032708B1 patent drawingFigure 1~2
  • EP4032708B1 patent drawingFigure 3~4
  • EP4032708B1 patent drawingFigure 5~6(d)

AI summary

The actuator of droplet jetting device is electrically connected to its controller via pressure contact between a first contact pad structure on the droplet jetting device and second contact pad structure on a flexible connection element extending towards the controller. Adhesive is applied to hold the contact pad structures together. The securing together of the contact pad structures is improved by the first contact pad structure comprising a recessed portion as compared to a wider portion, which wider portion is positioned between the recessed portion and the second contact pad structure. A portion of the adhesive is 'trapped' underneath the wider portion and acts as an anchor preventing the contact pad structures from being separated when pulling forces are present in the flexible connection element.