Liquid Ejection Head Alternating Port Arrangement for Temperature Uniformity

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Solution Overview

Problem

Liquid ejection heads, such as inkjet print heads, experience temperature distribution gaps between adjacent recording element substrates, leading to unevenness in image density due to variations in flow rate and pressure, which affects the quality of the recorded image.

Innovation Solution

The liquid ejection head is designed with a configuration where the supply-side and collection-side liquid communication ports are alternately arranged along the direction of the ejection modules, ensuring that the closest pair of ports in adjacent modules are either both supply-side or collection-side, minimizing temperature differences between adjacent recording element substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple recording element substrates are arranged adjacent to each other to increase ejection capacity, then productivity is improved, but temperature distribution uniformity deteriorates causing gaps between adjacent substrates

Engineering Contradiction:

Improveejection capacityVSAvoidtemperature distribution uniformity

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent applies asymmetry by alternating the arrangement pattern of communication ports between adjacent recording element substrates. Specifically, substrates are arranged such that supply-side communication ports on one substrate align with collection-side communication ports on adjacent substrates, creating an asymmetric but balanced configuration that prevents temperature gaps while maintaining high ejection capacity

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent achieves equipotentiality in temperature distribution by ensuring that adjacent recording element substrates have corresponding communication ports at the same liquid temperature potential. Through the alternating arrangement, supply-side ports connect to supply channels and collection-side ports connect to collection channels in a manner that equalizes temperature conditions across all adjacent substrates, eliminating temperature differences that would cause density unevenness

Inventive Principle:

Principle #12Equipotentiality

2Manufacturing precision

If recording element substrates are densely arranged to reduce image unevenness, then image quality is improved, but temperature control difficulty increases causing gaps in temperature distribution

Engineering Contradiction:

Improveimage qualityVSAvoidtemperature control difficulty

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the liquid circulation system into separate supply channels and collection channels that are independently managed. Each recording element substrate has its own supply-side and collection-side communication ports connected to respective channels, allowing independent temperature control and flow management for each segment while maintaining dense arrangement for image quality

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent ensures that all recording element substrates in the densely arranged configuration maintain equal temperature potential through the alternating port arrangement. This creates a balanced temperature field across the entire array, preventing gaps in temperature distribution even when substrates are densely packed, thereby maintaining image quality without excessive temperature control difficulty

Inventive Principle:

Principle #12Equipotentiality

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 prevents temperature gaps between adjacent recording element substrates, reducing density unevenness in the recorded image and ensuring high-quality image formation.

Implementation Method 1

prevent a rise in the viscosity of the liquids due to evaporation from the ejection ports

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

a difference appears in temperature distribution between the adjacent recording element substrates

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11597203B2Liquid ejection head including a plurality of recording element substrates formed adjacent to each other to form an array such that a gap in temperature distribution is prevented

Publication Date: 2023.03.07 CANON KK

AI summary

In a liquid ejection head in which ejection modules are arrayed on a flow path forming member, each ejection module includes a recording element substrate provided on a support member. The recording element substrate includes a liquid supply channel, a liquid collection channel, and ejection ports. The support member includes supply-side liquid communication ports communicating with the liquid supply channel and collection-side liquid communication ports communicating with the liquid collection channel. The supply-side liquid communication ports and the collection-side liquid communication ports are alternately provided along the direction in which the ejection modules are arrayed. The closest pair of liquid communication ports in the adjacent ends of two adjacent ejection modules are both supply-side or collection-side liquid communication ports.