Head Module Thermal Expansion Matching for Nozzle Stability

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Solution Overview

Problem

Existing liquid discharge head modules experience significant displacement of nozzle positions due to temperature changes, leading to reduced precision and increased vulnerability to load and vibration stress, as the coefficients of linear expansion between different components are not adequately matched.

Innovation Solution

A head module design where the nozzle plate, individual channel member, and base have substantially identical coefficients of linear expansion, typically within 25% of each other, ensuring minimal thermal expansion and improved bonding between these components to maintain nozzle position stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If different materials with different coefficients of linear expansion are used for the base, nozzle plate, and individual channel member, then ease of manufacture is improved, but nozzle position stability deteriorates due to thermal expansion differences

Engineering Contradiction:

Improveease of manufactureVSAvoidnozzle position stability

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies homogeneity by selecting materials for the base, nozzle plate, and individual channel member that have substantially identical coefficients of linear expansion. This ensures uniform thermal expansion behavior across all components, preventing relative displacement and maintaining nozzle position stability during temperature changes.

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The patent changes the material selection parameter by specifically choosing materials with matched thermal expansion coefficients. This parameter matching resolves the contradiction by ensuring that all components expand and contract uniformly with temperature changes, eliminating the precision problems that would arise from using easily manufactured but thermally incompatible materials.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If materials with different coefficients of linear expansion are used for bonding components, then adaptability in material selection is improved, but reliability deteriorates due to increased vulnerability to load and vibration stress

Engineering Contradiction:

Improveadaptability in material selectionVSAvoidresistance to load and vibration stress

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies homogeneity by selecting materials with matched thermal expansion properties for the base, nozzle plate, and individual channel member. This uniformity in thermal behavior reduces internal stresses during bonding and operation, thereby improving the reliability and resistance to load and vibration stress.

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

This principle is not directly applicable here. The patent focuses on material compatibility rather than replacing components.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Adaptability or versatility

If materials with mismatched coefficients of linear expansion are used, then design flexibility is improved, but nozzle position precision deteriorates under temperature changes

Engineering Contradiction:

Improvedesign flexibilityVSAvoidnozzle position precision

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies homogeneity by selecting materials with substantially identical coefficients of linear expansion for all key components. This ensures that thermal expansion occurs uniformly across the entire assembly, preventing relative displacement between the base, nozzle plate, and individual channel member, thereby maintaining nozzle position precision under temperature changes.

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

Inventive Principle:

Principle #35Parameter changes

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 significantly reduces nozzle position displacement due to temperature changes and enhances the head module's resistance to load and vibration stress, maintaining precision and performance across varying conditions.

Implementation Method 1

Coefficients of linear expansion of the nozzle plate and the individual channel member are substantially identical to a coefficient of linear expansion of the base

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10717281B2Head module and liquid discharge apparatus

Publication Date: 2020.07.21 RICOH CO LTD

AI summary

A head module includes a base including a plurality of openings, and a plurality of heads inserted into the plurality of openings, respectively, to be mounted on the base. The plurality of heads includes a nozzle plate including a nozzle, an individual channel member disposed on the nozzle plate and including an individual chamber communicating with the nozzle, and a frame fixed to the individual channel member. Coefficients of linear expansion of the nozzle plate and the individual channel member are substantially identical to a coefficient of linear expansion of the base, and one of the nozzle plate and the individual channel member is bonded to the base.