Liquid Ejection Apparatus Flow Path Design for Ink Drying Prevention

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Solution Overview

Problem

Inkjet image forming apparatuses face nozzle clogging due to ink viscosity increases and foreign matter, leading to inefficiencies in purge processing, particularly in the liquid flow paths where ink remains after pumping stops, causing drying and solidification, which can jam the flow paths.

Innovation Solution

The liquid ejection apparatus incorporates a guide flow path with obliquely extending partial flow paths that allow ink to flow and accumulate in a U-shaped portion, minimizing air contact and thus reducing drying, along with a pump stop mechanism before purge processing ends to manage ink flow effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pump continues to operate throughout the entire purge processing, then the liquid can be continuously circulated, but the liquid in the flow path may dry out when the pump stops, causing clogging

Engineering Contradiction:

Improvenozzle clogging preventionVSAvoidliquid drying in flow path

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The pump is stopped before the purge processing ends, performing the action of stopping the pump in advance. This preliminary action allows liquid to accumulate in the liquid reception portion before the pump actually stops, ensuring the flow path remains filled with liquid and preventing drying and clogging when the pump stops.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The liquid flow path is designed as an intermediary structure that guides liquid from the liquid reception portion to the pump. By controlling the pump stop timing, the system uses the liquid in the flow path as a mediator to maintain continuous liquid presence, preventing air entry and drying that would cause clogging.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the pump stops immediately when purge processing ends, then the processing time is reduced, but liquid remains in the flow path causing drying and solidification

Engineering Contradiction:

Improvepurge processing efficiencyVSAvoidflow path jamming

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The pump is stopped before the purge processing officially ends, performing a preliminary stop action. This timing control allows liquid to accumulate in the liquid reception portion while the pump is still running, ensuring the flow path remains filled when the pump stops, thus preventing drying and solidification that would jam the flow path.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If the liquid flow path is designed straight and simple, then the device complexity is reduced, but liquid accumulates in dead zones causing drying and clogging

Engineering Contradiction:

Improveflow path structureVSAvoidliquid accumulation and drying

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The liquid flow path is designed with curved sections instead of straight lines. The flow path includes a first section extending obliquely downward, a second section extending downward while bent, and a third section extending upward while bent. These curved sections eliminate dead zones where liquid could accumulate and dry out, while maintaining relatively simple device structure.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 suppresses ink drying in the flow paths, preventing jamming and ensuring smooth operation by aggregating ink in a smaller contact area with air, thereby maintaining flow path integrity during purge processing.

Implementation Method 1

a pump which is arranged apart from the liquid reception portion in a direction intersecting with a vertical direction and sucks in the liquid discharged to the liquid reception portion

Methodology Applied

Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

The first partial flow path extends obliquely downwardly from the liquid reception portion toward a side of the pump. The second partial flow path extends downwardly from an extension end portion of the first partial flow path while being bent.

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentUS20240391244A1Liquid ejection apparatus capable of suppressing drying of liquid and liquid ejection method

Publication Date: 2024.11.28 KYOCERA DOCUMENT SOLUTIONS INC

AI summary

A liquid ejection apparatus includes: a liquid reception portion, a pump, and a liquid flow path. The liquid reception portion receives liquid ejected from an ejection portion on a lower side of the ejection portion. The pump is arranged apart from the liquid reception portion in a direction intersecting with a vertical direction and sucks in the liquid discharged to the liquid reception portion. The liquid flow path guides the liquid from the liquid reception portion to the pump. The liquid flow path includes first, second, and third partial flow paths. The first partial flow path extends obliquely downwardly from the liquid reception portion toward the pump side. The second partial flow path extends downwardly from an extension end portion of the first partial flow path while being bent. The third partial flow path extends upwardly from an extension end portion of the second partial flow path while being bent.