Liquid Ejection Head Circulation Detection by Ejection Speed Comparison

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Solution Overview

Problem

Existing liquid ejection apparatuses struggle to accurately detect abnormal circulation states, leading to ink adherence and clogging, which affects ejection quality and requires frequent head replacements.

Innovation Solution

A liquid ejection apparatus and method that measures ejection speed differences before and after a predetermined period to detect degradation in circulation capability, using ejection speed measurement units and temperature sensors to determine circulation state accurately.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If circulation mechanism operates continuously, then liquid circulation is maintained, but detection of abnormal circulation state is delayed

Engineering Contradiction:
Improvecirculation state detection accuracyVSAvoiddetection timing
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary ejection operations before normal ejection to refresh liquid in pressure chambers. By measuring ejection speeds during these preliminary operations and comparing them to reference values, the system detects circulation abnormalities before they affect normal printing, enabling early intervention while the circulation mechanism is still operating.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors ejection speeds during preliminary operations and compares them against reference ejection speeds. This feedback mechanism allows real-time detection of circulation degradation, triggering alerts or corrective actions before the abnormal state progresses to complete failure.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If ejection speed measurement is performed continuously, then circulation state is detected accurately, but measurement complexity increases

Engineering Contradiction:
Improveejection state measurement accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of continuous monitoring, the system performs ejection speed measurements periodically during preliminary ejection operations. This periodic measurement approach maintains detection accuracy while significantly reducing system complexity and computational burden compared to continuous monitoring.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses preliminary ejection operations as a preparation step before normal printing. During these preliminary operations, ejection speeds are measured to assess circulation state. This approach obtains necessary measurement data without requiring separate dedicated measurement operations, simplifying the overall system.

Inventive Principle:
Principle #10Preliminary 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

Prevents issues caused by faulty circulation by timely detection, maintaining ejection quality and extending the life of the ejection head.

Implementation Method 1

a circulation pump 500 that circulates the liquid

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 2

a light emission element 202 that emits light

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Implementation Method 3

a light reception unit 203 that receives the light

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP4610052A1Liquid ejection apparatus and circulation state determination method
Publication Date: 2025.09.03 CANON KK
  • EP4610052A1 patent drawingFigure 1
  • EP4610052A1 patent drawingFigure 2
  • EP4610052A1 patent drawingFigure 3

AI summary

A liquid ejection apparatus (50) and a circulation state determination method capable of helping prevent problems caused by a malfunction. An ejection state detected after a lapse of a first period of time and an ejection state detected after a lapse of a second period of time longer than the first period of time are compared with each other to detect whether an ink circulation operation is performed faultily.