Trench Electrode Capacitor for Fluid Impedance Sensing

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Solution Overview

Problem

Fluid reservoirs, particularly in printing systems, face challenges in distinguishing between genuine and counterfeit or low-quality printing fluids, leading to reduced print quality and customer dissatisfaction.

Innovation Solution

A fluid property sensing device is introduced, featuring a substrate with a trench and plated electrodes forming a capacitor to measure complex impedance, which identifies fluid properties by comparing measured values to a database, ensuring the use of authentic and high-quality fluids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional fluid detection systems are used, then fluid level detection is achieved, but fluid property identification and authentication are not possible

Engineering Contradiction:
Improvefluid property identification accuracyVSAvoidsensing device structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensing device integrates multiple functions into a single unit: fluid level detection, fluid property measurement, and fluid authentication. The electrodes serve dual purposes as both level sensors and impedance measurement elements, eliminating the need for separate detection systems and reducing overall device complexity while enhancing measurement precision.

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

Solution Approach 2:

The system measures complex impedance parameters (real and imaginary components) of the fluid to identify fluid properties and authenticate genuine fluids. By analyzing changes in electrical impedance parameters across different frequencies, the device can distinguish between genuine and counterfeit fluids with high precision without requiring complex mechanical or chemical sensing mechanisms.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If genuine fluids are ensured through sensing, then print quality is maintained, but device complexity increases

Engineering Contradiction:
Improvefluid quality controlVSAvoidsensing system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or chemical fluid analysis systems with an electrical impedance-based sensing system. By measuring the electrical properties (complex impedance) of the fluid, the device can reliably identify genuine fluids and maintain print quality without requiring mechanical fluid sampling, chemical reagents, or complex analytical instrumentation.

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

3Measurement precision

If complex impedance measurement is used, then fluid authentication is achieved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvefluid authentication accuracyVSAvoidelectrode fabrication tolerance
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The system measures both the real and imaginary components of complex impedance, providing redundant information for fluid authentication. This partial measurement approach (measuring multiple parameters rather than a single value) enhances authentication accuracy while being tolerant of manufacturing variations in electrode dimensions and positioning, as the multi-parameter measurement compensates for individual parameter uncertainties.

Inventive Principle:
Principle #16Partial or excessive 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

The device provides enhanced control over fluid quality, prevents counterfeit usage, and ensures consistent print quality, leading to increased customer satisfaction through accurate fluid identification and authentication.

Implementation Method 1

The first electrode and second electrode form a capacitor to detect a complex impedance of a fluid

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

detect a complex impedance of a fluid that fills a space between the first electrode and the second electrode

Methodology Applied
Scientific EffectElectrical Impedance: Electrical Resistance

Data Source

PatentEP3446112B1Fluid property sensing with electrodes
Publication Date: 2021.06.02 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3446112B1 patent drawingFigure 1
  • EP3446112B1 patent drawingFigure 2A~2B
  • EP3446112B1 patent drawingFigure 3A~3B

AI summary

In one example in accordance with the present disclosure a fluid property sensing device is described. The fluid property sensing device includes a substrate having a trench formed therein. The trench includes a bottom surface and opposite side surfaces. A first electrode is disposed on a first side surface of the trench and a second electrode is disposed on a second side surface of the trench. The first electrode and second electrode form a capacitor to measure a complex impedance of a fluid that fills a space between the first electrode and the second electrode. This complex impedance indicates a property of the fluid. A fluid level sensing die, having a number of fluid level sensing components disposed thereon, may be attached to the substrate, preferably in such a way that the fluid level sensing die is surrounded by the trench. In this way the surface area of the electrodes provided in the trench can be increased. The number of level sensing components may be thermal sensing components.