Damper Plate Compression Stress for Ink Flow Stability

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Solution Overview

Problem

Existing liquid discharging heads face a challenge in enhancing the damper effect for common liquid flow paths while maintaining the thickness of the damper plate, as reducing the thickness of the damper portions compromises their durability.

Innovation Solution

A liquid discharging head design where a damper plate with a smaller coefficient of linear expansion than adjacent plates is used, and compression stress is applied to the damper plate by cooling the plates after joining, reducing the natural frequency and enhancing the damper effect without reducing the thickness of the damper plate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thickness of the damper portions is decreased to enhance the damper effect, then the natural frequency of the damper portions is reduced and the damper effect is improved, but the durability of the damper portions is decreased remarkably

Engineering Contradiction:
Improvedamper effectVSAvoiddurability of damper portions
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies compression stress to the damper plate to change its physical state, reducing its natural frequency without changing its thickness. This parameter change in stress state allows the damper plate to provide enhanced damping effect while maintaining sufficient thickness for durability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The damper plate is pre-stressed with compression stress during the manufacturing process (by cooling after joining plates with different thermal expansion coefficients). This preliminary application of compression stress ensures the damper plate has optimized damping characteristics before actual use, preventing the need to reduce thickness.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If compression stress is applied to the damper plate by cooling after joining plates, then the natural frequency is reduced and damper effect is enhanced, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvedamper effectVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent utilizes the thermal expansion difference between the damper plate and adjacent plates to generate compression stress. By heating the assembled plates and then cooling them, the damper plate (with smaller expansion coefficient) contracts less than the adjacent plates, creating compressive stress in the damper plate automatically during the cooling phase of manufacturing.

Inventive Principle:
Principle #37Thermal expansion

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 approach increases the damper effect for common liquid flow paths while ensuring the durability and thickness of the damper plate, stabilizing ink discharging properties and maintaining the structural integrity of the head.

Implementation Method 1

the natural frequency of the portion is decreased due to stress softening

Methodology Applied
Scientific EffectStress softening:

Implementation Method 2

the damper plate is formed of a metallic material having a coefficient of linear expansion along the wall surface which is smaller than that of the plate which is adjacent to the damper plate

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2106911B1Liquid discharging head and method for manufacturing the same
Publication Date: 2012.05.16 BROTHER KOGYO KK
  • EP2106911B1 patent drawingFigure 1
  • EP2106911B1 patent drawingFigure 2
  • EP2106911B1 patent drawingFigure 3

AI summary

A liquid discharging head is provided. The liquid discharging head has a flow path unit in which a common liquid flow path for supplying liquid to a nozzle which discharges liquid is formed by a plurality of plates being stacked together, the plurality of plates including a damper plate of which one surface defines at least a part of a wall surface of the common liquid flow path and an area on an other surface which is opposed to the common liquid flow path across the damper plate is not in contact with the plurality of plates other than the damper plate, wherein compression stress along the wall surface is applied to a portion of the damper plate which configure a wall of the common liquid flow path.