Asymmetric Flow Path Member Sealing for Ink Leakage Prevention

Solution Overview

Problem

In liquid ejecting heads, such as ink jet recording heads, positional deviations in the sealing member can lead to deformation defects and ink leakage due to non-uniform stress distribution and adhesion issues, particularly when the outer shape of the attaching portion is not oval or circular.

Innovation Solution

A flow path member design featuring a sealing member with convex and concave portions on the inner and outer surfaces of the attaching portion, respectively, to improve assemblability, regulate deformation, and increase contact area, thereby enhancing adhesiveness and reducing size, while maintaining a longitudinal and short direction shape to manage load distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the sealing member is made with a simple circular or oval shape, then the manufacturing is easier, but positional deviations occur during assembly leading to deformation defects and leakage

Engineering Contradiction:

Improveease of manufactureVSAvoidreliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The attaching portion is designed with an asymmetric non-circular shape (such as rectangular, elliptical, or irregular polygonal cross-section) instead of a simple circular or oval shape. This asymmetric geometry prevents rotational misalignment during assembly, ensuring that the sealing member is positioned correctly relative to the liquid supplying unit, thereby eliminating positional deviations and deformation defects while maintaining manufacturing simplicity

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The convex and concave portions are pre-formed on the attaching portion and sealing member respectively during manufacturing, before assembly takes place. This preliminary formation of complementary geometric features ensures that when assembly occurs, the positioning is automatically correct without requiring additional adjustment steps, preventing rotational misalignment and ensuring proper sealing from the outset

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If the sealing member rotates around the attaching portion during assembly, then the assembly process becomes more flexible, but uniform deformation cannot be achieved leading to adhesion defects and leakage

Engineering Contradiction:

Improveease of operationVSAvoidmanufacturing precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The non-circular asymmetric cross-section of the attaching portion (such as rectangular or elliptical shape) serves as a mechanical key that prevents rotational movement of the sealing member during assembly. This geometric constraint ensures that the sealing member can only be installed in the correct orientation, eliminating rotational misalignment and ensuring uniform deformation and adhesion across the sealing interface

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The convex and concave portions are pre-formed on the attaching portion and sealing member respectively during manufacturing, before assembly takes place. This preliminary formation of complementary geometric features ensures that when assembly occurs, the positioning is automatically correct without requiring additional adjustment steps, preventing rotational misalignment and ensuring proper sealing from the outset

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If the outer shape of the attaching portion is made non-oval (such as rectangular or irregular shape), then positional positioning is improved, but the device complexity increases

Engineering Contradiction:

Improvepositioning precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The attaching portion is designed with a simple non-circular asymmetric cross-section (such as rectangular, elliptical, or irregular polygonal shape) that provides inherent positional orientation. This geometric feature alone, without requiring additional complex positioning mechanisms, achieves precise positioning and prevents rotational misalignment, thereby improving positioning precision while maintaining simple device structure

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The convex and concave portions are pre-formed on the attaching portion and sealing member respectively during manufacturing, before assembly takes place. This preliminary formation of complementary geometric features ensures that when assembly occurs, the positioning is automatically correct without requiring additional adjustment steps, preventing rotational misalignment and ensuring proper sealing from the outset

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9463636B2Flow path member, liquid ejecting head, and liquid ejecting apparatus

Publication Date: 2016.10.11 SEIKO EPSON CORP

AI summary

There is provided a flow path member including a flow-path member main body which is provided with a liquid supplying path through which liquid is supplied to a head main body that ejects liquid and an attaching portion to which a liquid supplying unit that supplies liquid of the liquid supplying path is attached; and a sealing member which is provided with an insertion hole into which the attaching portion is inserted, and is interposed between the liquid supplying unit and the attaching portion, in which a convex portion is provided in any one of the inner surface of the insertion hole and the outer surface of the attaching portion, and a concave portion that fits with the convex portion is provided in the other of the inner surface of the insertion hole and the outer surface of the attaching portion.