Liquid Ejection Apparatus Ink Composition Control

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Solution Overview

Problem

Existing liquid ejection apparatuses face issues with degradation of ejection performance due to evaporation of volatile components, leading to increased viscosity and composition changes near the ejection port, which complicates and costs ink density measurement systems, making miniaturization difficult.

Innovation Solution

A liquid ejection apparatus that circulates ink between an ink tank and an ejection head, using an impedance detection unit to measure the percentage of volatile components and an adjusting unit to replenish the ink based on the measurement, maintaining ink composition and viscosity through a simple, inexpensive, and compact configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If ink is circulated between ink tank and ejection head to suppress composition change, then ejection performance is maintained, but volatile component percentage decreases over time causing ink thickening

Engineering Contradiction:

Improveink composition stabilityVSAvoidvolatile component percentage

Core Design Contradiction:

Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent implements a feedback control system where a sensor detects the volatile component percentage in the circulating ink and provides signals to a control unit. The control unit adjusts the replenishment rate of volatile components based on detected values, maintaining the volatile component percentage within a predetermined range and preventing ink thickening while preserving composition stability.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts the concentration of volatile components in the circulating ink by replenishing them based on detected percentages. This parameter change approach maintains the ink's physical properties within optimal ranges, preventing viscosity increase and composition degradation that would otherwise occur during continuous circulation.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If density measurement system is used to control ink density, then ink density can be controlled, but system becomes complicated and expensive

Engineering Contradiction:

Improveink density measurementVSAvoidmeasurement system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical density measurement systems with an electrical sensing approach. A sensor detects the volatile component percentage in the ink, and since ink density is directly related to volatile component concentration, this electrical detection method achieves density control functionality with significantly reduced complexity and cost.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs a relatively simple and inexpensive sensor to detect volatile component percentage, replacing expensive and complex density measurement instruments. This cost-effective sensing approach provides sufficient measurement precision for controlling ink properties without requiring sophisticated measurement equipment.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Manufacturing precision

If miniaturized ejection port is used for high printing resolution, then printing resolution increases, but viscosity increase causes non-ejection and displaced landing position

Engineering Contradiction:

Improveprinting resolutionVSAvoidejection performance

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent performs preliminary action by continuously replenishing volatile components in the ink before viscosity increase causes ejection problems. The control system detects when volatile component percentage approaches levels that would cause viscosity increase and proactively replenishes volatiles, preventing non-ejection and landing position displacement before they occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements continuous circulation and continuous monitoring of volatile component percentage in the ink supply system. This continuous action ensures that ink viscosity remains stable over time, maintaining reliable ejection performance from miniaturized ports throughout extended operation periods without interruption or performance degradation.

Inventive Principle:

Principle #20Continuity of useful 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 configuration effectively suppresses the degradation of ejection performance by maintaining ink composition and viscosity, ensuring stable and efficient ink circulation with reduced complexity and cost, while allowing for miniaturization of the apparatus.

Implementation Method 1

a detecting unit configured to detect a percentage of a volatile component of the liquid by measuring impedance of the circulating liquid

Methodology Applied

Scientific EffectImpedance measurement: Electrical Resistance

Data Source

PatentUS10618303B2Liquid ejection apparatus

Publication Date: 2020.04.14 CANON KK

AI summary

There is provided a liquid ejection apparatus configured to circulate ink between an ink tank and an ejection head, the liquid ejection apparatus being capable of suppressing degradation of an ejection performance with a simple, inexpensive, and compact configuration. For this purpose, the liquid ejection apparatus measures impedance of the ink, and supplies, based on this measurement result, an adjusting liquid to a circulating ink.