Electrode Pin Oxidation Aging for Liquid Level Detection

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Solution Overview

Problem

The existing pin remaining-amount-detection system for liquid ejection systems, which uses stainless steel electrode pins, suffers from oxidization and reduction reactions that increase electrical resistance and degrade detection precision, leading to incorrect liquid level readings and unnecessary liquid replacement or discard.

Innovation Solution

The system employs oxidization aging signals to intentionally promote oxide layer formation on the electrode pins, ensuring consistent electrical resistance and improved detection precision by setting the first electrode pin as the anode and the second as the cathode, and applying specific voltage pulses and durations to accelerate oxidization during initial use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If stainless steel electrode pins are used for liquid level detection, then detection precision is improved, but electrical resistance increases due to oxidization and reduction reactions

Engineering Contradiction:
Improveliquid level detection precisionVSAvoidelectrical resistance stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies oxidization aging signals to the electrode pins before actual liquid level detection to pre-form a stable oxide layer. This preliminary action prevents subsequent oxidization during detection, maintaining consistent electrical resistance and reliable detection precision throughout the device lifecycle.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the electrical parameters by applying specific oxidization aging signals (voltage pulses) to the electrode pins. This parameter change induces controlled oxidization that stabilizes the electrode surface, transforming the electrical resistance characteristics from unstable to stable, thereby resolving the contradiction between detection precision and reliability.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If oxidization aging signals are applied to electrode pins, then detection precision is stabilized, but additional processing steps are required

Engineering Contradiction:
Improvedetection precision consistencyVSAvoidinitialization process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements self-service by having the image recording apparatus automatically perform oxidization aging on its own electrode pins during initialization. The control unit generates and applies the oxidization aging signals without external intervention, and the system is automatically ready for accurate detection after this self-performed preprocessing step.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If electrode pins are used for liquid detection, then cost is reduced compared to other methods, but oxidization reactions occur during repeated use

Engineering Contradiction:
Improvedetection system costVSAvoidelectrode surface stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent applies oxidization aging signals to the electrode pins before actual liquid level detection to pre-form a stable oxide layer. This preliminary action prevents subsequent oxidization during detection, maintaining consistent electrical resistance and reliable detection precision throughout the device lifecycle.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the electrical parameters by applying specific oxidization aging signals (voltage pulses) to the electrode pins. This parameter change induces controlled oxidization that stabilizes the electrode surface, transforming the electrical resistance characteristics from unstable to stable, thereby resolving the contradiction between detection precision and reliability.

Inventive Principle:
Principle #35Parameter 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

This approach stabilizes the oxide layer on the electrode pins, maintaining consistent electric current flow and enhancing the accuracy of liquid level detection, preventing erroneous liquid depletion warnings and reducing waste.

Implementation Method 1

The majority of liquids such as ink, used in image recording as described above, are electroconductive. Accordingly, in a case in which there is liquid in the liquid accommodation chamber (in a state where the two electrode pins are in contact with liquid), and electric signals are applied to the electrode pins, electric current flows between the electrode pins via the liquid.

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the configuration in which electric signals are applied across electrode pins and electric response is obtained, thereby determining whether or not there is liquid, has been employed (Japanese Patent Application Publication No. 2015-223830). However, there is a possibility that the configuration described in Japanese Patent Application Publication No. 2015-223830 may have the following problem. Metal stainless steel material or the like is the primary material used for the electrode pins. When one of the two electrode pins is used as an anode side and the other as a cathode side, and operations of applying electric current in one direction in a state of liquid being interposed between the electrode pins is repeatedly performed, oxidizing and reducing reactions of metal may occur at the surfaces of the electrode pins.

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentEP3925781B1Image recording apparatus
Publication Date: 2024.02.28 CANON KK
  • EP3925781B1 patent drawingFigure 1A~1B
  • EP3925781B1 patent drawingFigure 2A~2B
  • EP3925781B1 patent drawingFigure 3

AI summary

An image recording apparatus includes a liquid chamber that stores liquid, a first electrode pin and a second electrode pin to be inserted into the liquid chamber, applying unit for applying voltage across the first electrode pin and the second electrode pin, with the first electrode pin as an anode side and the second electrode pin as a cathode side, and detecting unit for detecting electric current flowing, and detection operation of detecting amount of liquid in the liquid chamber by the detecting unit detecting the electric current when the applying unit applies voltage. Prior to the detection operation, an oxidization aging operation is performed, in which the applying unit applies voltage across the first electrode pin and the second electrode pin. An amount of an oxide layer formed on at least a portion of the first electrode pin exposed inside the liquid chamber is greater than the second.