Welded Sealed Interconnects for Accurate Print Liquid Level Sensing

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Solution Overview

Problem

Accurately sensing the remaining amount of print liquid in a reservoir is challenging due to issues like liquid bridging and environmental conditions, leading to frequent replacements and increased printing costs.

Innovation Solution

A print liquid supply unit with a sensor housed in a thermoplastic container, where an electrical interconnect is sealed through a welded joint using laser welding, allowing for precise liquid level sensing without additional materials, ensuring compatibility and robustness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional sealing materials are used to seal the electrical interconnect through the welded joint, then the sealing reliability is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvesealing reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The thermoplastic material itself performs the sealing function through its own deformation during welding. The material is heated above its glass transition temperature, becomes pliable, and conforms to seal around the electrical interconnect without requiring separate sealing components or additional materials.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent utilizes changes in the physical parameters of the thermoplastic material, specifically its glass transition temperature, to enable sealing. By heating the material above its glass transition temperature, it transitions from a rigid state to a pliable state that can deform and seal around the electrical interconnect, then solidifies upon cooling to maintain the seal.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If laser welding is used to seal the electrical interconnect, then the manufacturing efficiency is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidmanufacturing precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent utilizes changes in the physical parameters of the thermoplastic material, specifically its glass transition temperature, to enable sealing. By heating the material above its glass transition temperature, it transitions from a rigid state to a pliable state that can deform and seal around the electrical interconnect, then solidifies upon cooling to maintain the seal.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional mechanical sealing methods with laser-induced thermal welding. Instead of using mechanical pressure or assembly techniques to seal the electrical interconnect, the process uses localized laser heating to melt and fuse the thermoplastic material around the interconnect, creating a sealed joint.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If the sensor is accurately positioned to sense liquid level, then the measurement precision is improved, but the device complexity increases

Engineering Contradiction:
Improveliquid level sensing accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor utilizes the natural optical properties of the print liquid and air to determine liquid level. By measuring light transmission or reflection through the transparent sidewall, the sensor self-determines the liquid level without requiring additional mechanical positioning mechanisms or complex calibration systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent utilizes optical property changes at the liquid-air interface to detect liquid level. The sensor detects changes in light transmission or reflection that occur when the liquid level changes, allowing accurate liquid level sensing through optical property variations rather than mechanical position changes.

Inventive Principle:
Principle #32Color 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

Enhances the accuracy of print liquid level sensing, reduces waste, and minimizes the frequency of ink supply changes, maintaining print quality and reducing costs.

Implementation Method 1

the laser weldment seals the electrical interconnect through the welded joint

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Implementation Method 2

heating the thermoplastic material above a glass transition temperature of the thermoplastic material

Methodology Applied
Scientific EffectGlass transition:

Data Source

PatentEP3687799B1Sealed interconnects
Publication Date: 2022.08.31 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3687799B1 patent drawingFigure 1
  • EP3687799B1 patent drawingFigure 2A~2D
  • EP3687799B1 patent drawingFigure 3A~3C

AI summary

Examples of a print liquid supply unit are described herein. In some examples, the print liquid supply unit includes an electrical interconnect. In some examples, the electrical interconnect is sealed in a supply joint from an outside of the supply unit to an inside of the supply unit. In some examples, the supply joint is welded to join housing components of the supply unit.