Staggered Liquid Ejection Head Chip Overlap for Thermal Warping

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Solution Overview

Problem

Existing liquid ejection heads with multiple head chips disposed in a staggered manner experience temperature differences due to heat generation, leading to warping and potential deterioration in print quality.

Innovation Solution

The liquid ejection head is designed with a staggered arrangement of head chips, featuring overlapping regions where the second overlapping region is larger than the first, strategically positioned to dissipate heat more effectively, reducing temperature differences and minimizing warping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If five or more head chips are disposed in a staggered manner in a predetermined direction, then the liquid ejection head becomes elongated in the predetermined direction, but temperature difference occurs in the liquid ejection head leading to warping

Engineering Contradiction:

Improveejection widthVSAvoidtemperature uniformity

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent applies local quality by creating non-uniform overlapping regions with different sizes. Specifically, the first overlapping region has a smaller overlap amount while the second overlapping region has a larger overlap amount. This local variation in overlapping configuration allows different regions to serve different thermal management functions, enabling heat dissipation in specific areas without compromising the overall ejection width.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs asymmetry by deliberately designing the overlapping regions to have different characteristics. The first and second overlapping regions are asymmetric in terms of overlap amount, with the second region having a larger overlap. This asymmetric arrangement creates intentional temperature differences in specific regions to counteract the natural heat accumulation at the center, thereby achieving more uniform temperature distribution across the entire liquid ejection head.

Inventive Principle:

Principle #4Asymmetry

2Area of stationary object

If head chips are disposed in a staggered manner with multiple overlapping regions, then nozzle coverage is improved, but heat generation increases causing warping of members

Engineering Contradiction:

Improvenozzle coverage areaVSAvoidheat generation

Core Design Contradiction:

Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful effect of heat generation into a beneficial thermal management strategy. By creating overlapping regions with different overlap amounts, the patent intentionally allows certain regions to generate more heat (second overlapping region with larger overlap) while other regions generate less heat (first overlapping region with smaller overlap). This controlled heat distribution helps balance the overall temperature field, transforming the problematic heat generation into a tool for achieving uniform temperature and preventing warping.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

Inventive Principle:

Principle #3Local quality

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 ensures uniform temperature distribution across the head chips, mitigating warping and maintaining print quality by effectively managing heat dissipation.

Implementation Method 1

head chips disposed on a center side with respect to the predetermined direction being adjacent to four head chips, temperature of the center side of the liquid ejection head is higher than a size of end sides due to heat generation of the five or more head chips

Methodology Applied

Scientific EffectHeat generation: Joule Heating

Implementation Method 2

the second overlapping region is larger than the first overlapping region with respect to the first direction... strategically positioned to dissipate heat more effectively

Methodology Applied

Scientific EffectHeat dissipation: Convection

Data Source

PatentUS20250108614A1Liquid ejection head and liquid ejection apparatus

Publication Date: 2025.04.03 SEIKO EPSON CORP

AI summary

A liquid ejection head includes: five or more head chips disposed along a first-direction in a staggered manner, and a support member supporting the head chips, the head chips are disposed to have overlapping regions where a part of a nozzle forming region of one head chip of adjacent head chips and a part of a nozzle forming region of other head chip overlap when viewed in a second-direction that is perpendicular to the first direction, the overlapping regions include a first-overlapping region, and a second-overlapping region that is farther away from a center position of a total nozzle forming region with respect to the first-direction than the first-overlapping region, the total nozzle forming region including all the nozzle forming regions of the head chips, and the second-overlapping region is larger than the first-overlapping region with respect to the first-direction.