Liquid Discharge Head With Dual-Modulus Elastic Valve Seal

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Solution Overview

Problem

Existing liquid discharge apparatuses with elastic members at the tip portion of on-off valves suffer from plastic deformation leading to sealing function deterioration and liquid leakage failures due to repeated operation.

Innovation Solution

A liquid discharge head design featuring a two-layer elastic member structure with different elastic moduli for the discharge-side and core-side portions, combined with a holder and piezoelectric element, to prevent retraction of the end face and reduce liquid leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an elastic member such as resin is used at the tip portion of the on-off valve, then the sealing function is improved, but the elastic member undergoes plastic deformation due to repeated operation, causing sealing function deterioration and liquid leakage

Engineering Contradiction:

Improvesealing functionVSAvoidservice life of elastic member

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The elastic member is divided into two distinct segments: a first elastic portion (discharge-side) and a second elastic portion (core-side), each with different elastic moduli. This segmentation allows each portion to perform its specific function optimally while reducing overall plastic deformation. The first elastic portion with higher elastic modulus resists plastic deformation better, while the second elastic portion with lower elastic modulus maintains good sealing contact.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the elastic member are given different local properties through varying elastic moduli. The discharge-side portion has higher elastic modulus for deformation resistance, while the core-side portion has lower elastic modulus for sealing compliance. This local quality differentiation resolves the contradiction by optimizing each region for its specific functional requirement.

Inventive Principle:

Principle #3Local quality

2Device complexity

If the elastic member is made with uniform elastic modulus, then the structure is simple, but the end face retracts due to plastic deformation, causing sealing failure

Engineering Contradiction:

Improvestructure of elastic memberVSAvoidsealing function

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The elastic member is constructed as a composite structure with two elastic portions having different elastic moduli. This composite approach combines materials or structures with different mechanical properties to achieve both deformation resistance and sealing effectiveness, preventing end face retraction while maintaining functional performance.

Inventive Principle:

Principle #40Composite materials

3Productivity

If the elastic member undergoes repeated compression, then the valve can be operated multiple times, but the elastic member plastically deforms and the sealing function deteriorates

Engineering Contradiction:

Improvenumber of operationsVSAvoidsealing function

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

By segmenting the elastic member into two portions with different elastic moduli, the structure can withstand repeated compression cycles better. The first elastic portion with higher modulus resists cumulative plastic deformation, enabling more operations while maintaining sealing integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The elastic moduli of different portions are specifically designed with different values to optimize performance under repeated operation. This parameter differentiation allows the elastic member to endure more compression cycles before plastic deformation causes sealing failure, thereby increasing productivity while maintaining reliability.

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

The design extends the maintenance cycle of the liquid discharge head to about twice that of conventional designs by preventing excessive plastic deformation and maintaining effective sealing, reducing liquid leakage and extending the operational life.

Implementation Method 1

a driver to move the valve body in the discharge direction

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The tip portion of the valve body is formed with an elastic resin

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 3

the elastic member at the tip portion is plastically deformed, and therefore, the sealing function deteriorates

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP4393713B1Liquid discharge head and liquid discharge apparatus

Publication Date: 2025.09.10 RICOH CO LTD

Figure 1A~2
Figure 3~4B
Figure 5~6

AI summary

A liquid discharge head includes: a discharge port (14) through which a liquid is discharged in a discharge direction; a valve body (31) to openably close the discharge port (14); and a driver (32) coupled to the valve body to move the valve body (31) in the discharge direction, wherein the valve body (31) includes: an elastic member (40) including: a first elastic portion (401, 401d, 401f, 411, 411s) having a first elastic modulus; and a second elastic portion (402, 412, 402a, 402b) having a second elastic modulus different from the first elastic modulus, the elastic member (40) to contact the discharge port (14) to close the discharge port (14); and a core (310) attached to the elastic member (40) to support the elastic member (40).