Electrode Pin Oxidation Control in Ink Level Detection

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Solution Overview

Problem

The existing pin remaining amount detection method in image recording apparatuses, which uses metal electrode pins, suffers from reduced detection accuracy due to oxidation-reduction reactions, leading to incorrect liquid level detection and potential nozzle damage.

Innovation Solution

The method involves using a voltage signal with alternating polarity to reduce oxidation on the electrode pins during liquid remaining amount detection, maintaining a constant current flow and improving detection accuracy by applying a reduction pulse to counteract oxidation effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a metal electrode pin is used for liquid remaining amount detection, then detection accuracy is improved, but oxidation-reduction reactions occur on the electrode pin surface leading to reduced detection accuracy over time

Engineering Contradiction:
Improveliquid remaining amount detection accuracyVSAvoiddetection reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the electrical parameter by applying alternating polarity voltages to the electrode pins. Instead of using a constant voltage polarity, the system switches between positive and negative polarity, which prevents continuous oxidation on the electrode surface and maintains stable electrical characteristics for accurate detection throughout the ink tank's usage life.

Inventive Principle:
Principle #35Parameter changes

2Speed

If continuous current flow is maintained during detection, then detection speed is improved, but oxidation of the electrode pin accelerates reducing current flow stability

Engineering Contradiction:
Improvedetection speedVSAvoidcurrent flow stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent implements periodic action by alternating the voltage polarity at regular intervals during the detection process. This periodic reversal of current direction prevents cumulative oxidation effects while maintaining continuous detection capability, thus preserving both detection speed and current flow stability throughout the operation.

Inventive Principle:
Principle #19Periodic 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

This approach stabilizes the current flow and enhances the accuracy of liquid remaining amount detection, preventing unnecessary ink tank replacements and idle ejection printing, thus ensuring reliable operation and extending the life of the nozzle member.

Implementation Method 1

Most of liquid such as ink, which is used in the image recording described above, conducts electricity. Accordingly, in the case where liquid is present in the liquid accommodation chamber (a state in which two electrode pins are in contact with the liquid), when the electric signals are applied to the electrode pins, a current flows between the electrode pins via the liquid.

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

there are cases where an oxidation-reduction reaction of metal occurs on the electrode pin surface. That is, oxidation progresses on the surface of the anode-side electrode pin, and reduction progresses on the surface of the cathode-side electrode pin. When the above reaction progresses, electrical resistance is increased due to an influence of the oxidation of the anode-side electrode pin, and hence a current value of a current flowing between the electrode pins is decreased

Methodology Applied
Scientific EffectOxidation-reduction reaction: Redox Reactions

Data Source

PatentEP3925780B1Image recording apparatus
Publication Date: 2024.03.13 CANON KK
  • EP3925780B1 patent drawingFigure 1A~1B
  • EP3925780B1 patent drawingFigure 2A~2B
  • EP3925780B1 patent drawingFigure 3

AI summary

An image recording apparatus includes a liquid chamber, a first electrode pin and a second electrode pin which are inserted into the liquid chamber, application unit for applying a voltage between the first electrode pin and the second electrode pin, and detection unit for detecting a current which flows between the first electrode pin and the second electrode pin, the image recording apparatus has: a first period in which the application unit applies the voltage between 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 the detection unit detects the current; and a second period in which the application unit applies the voltage between the first electrode pin and the second electrode pin, with the first electrode pin as the cathode side and the second electrode pin as the anode side.