Liquid Ejection Head Common Channel Vector Alignment

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Solution Overview

Problem

The existing liquid ejection head experiences an under-refilling phenomenon due to ink flow from the supply flow path via the manifold to the air bubble return flow path hindering the ink flow from the manifold to the pressure chambers, resulting in insufficient ink supply.

Innovation Solution

A liquid ejection head design featuring a common channel with a supply portion, return portion, and connection portion, where the vectors of ink flow from the supply portion to the return portion and from the common channel to the pressure chambers have components in the same direction, preventing the ink flow from being hindered and ensuring adequate ink supply to the pressure chambers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the manifold connects the supply flow path and air bubble return flow path, then air bubbles can be returned, but ink flow from supply to return hinders ink supply to pressure chambers causing under-refilling

Engineering Contradiction:

Improveair bubble return functionVSAvoidink supply to pressure chambers

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The common channel is segmented into supply portion, return portion, and connection portion, with separate flow paths for ink supply and air bubble return. The communicating portion connects the common channel to pressure chambers independently, creating distinct flow routes that prevent mutual interference between supply and return flows.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a new spatial dimension by adding the communicating portion that extends from the common channel to the pressure chambers in a direction different from the supply-return flow. This dimensional separation allows ink to reach pressure chambers without being hindered by the supply-to-return flow in the manifold.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If the supply portion and return portion are arranged alongside each other, then compact structure is achieved, but flow direction conflict causes insufficient ink supply

Engineering Contradiction:

Improvehead structure compactnessVSAvoidink supply efficiency

Core Design Contradiction:

Volume of moving objectVSProductivity

Solution Approach 1:

The common channel is divided into functionally distinct segments (supply portion, return portion, connection portion) with dedicated flow paths. This segmentation allows compact arrangement while maintaining independent flow control to prevent supply flow from interfering with pressure chamber refilling.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The communicating portion acts as an intermediary channel that mediates between the common channel and pressure chambers. It provides a dedicated route for ink to reach pressure chambers, separating this function from the supply-return flow path and eliminating flow conflict while maintaining compact structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If vectors of supply flow and pressure chamber flow point in opposite directions, then manifold connection is simplified, but under-refilling phenomenon occurs

Engineering Contradiction:

Improvemanifold connection structureVSAvoidink refilling performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The flow path is segmented into supply portion, return portion, and connection portion within the common channel, with a separate communicating portion for pressure chamber supply. This segmentation allows simple manifold connection while ensuring reliable ink refilling through the dedicated communicating path that avoids vector conflict.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The communicating portion introduces a new directional dimension for ink flow to pressure chambers, separate from the supply-return flow direction. This dimensional separation resolves the vector conflict while maintaining simplified manifold connection structure.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 design effectively prevents the under-refilling phenomenon by aligning the ink flow components, ensuring efficient ink distribution and preventing the accumulation of settling ingredients and air bubbles, thereby maintaining smooth operation and consistent ejection performance.

Implementation Method 1

The component in the second direction of the first vector and the component in the second direction of the second vector point in the same direction

Methodology Applied

Scientific EffectFluid flow:

Data Source

PatentUS11141982B2Liquid ejection head

Publication Date: 2021.10.12 BROTHER KOGYO KK

AI summary

A liquid ejection head includes pressure chambers arranged in a first direction, a common channel, and a communicating portion communicating with the common channel and each of the pressure chambers. The common channel includes a supply portion, a return portion, and a connection portion connecting them in a second direction crossing the first direction. The liquid ejection head has a first vector directed from the supply portion via the connection portion toward the return portion and has a component in the second direction. The second vector is directed from the common channel via the communicating portion toward each of the pressure chambers and has a component in the second direction. The component in the second direction of the first vector and the component in the second direction of the second vector point in the same direction.