Liquid Discharge Head Meniscus Tuning Against Chamber Resonance

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Solution Overview

Problem

Existing liquid discharge heads face issues with restricted drive frequencies due to resonance frequencies in the common supply passage, leading to variations in discharge speed and deteriorated image quality.

Innovation Solution

The liquid discharge head design includes nozzles, individual chambers, fluid restrictors, and actuators, where the meniscus natural vibration period is distinct from the common chamber's resonant and half/quarter resonant periods, preventing resonance-induced pressure variations and maintaining consistent discharge rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the drive frequency is set to avoid resonance frequency of the common supply passage, then discharge speed variation is reduced, but drive frequency is restricted

Engineering Contradiction:
Improvedischarge speed uniformityVSAvoiddrive frequency range
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent utilizes the natural vibration period of the meniscus as a key parameter. By designing the meniscus natural vibration period to differ from the common chamber resonant period and its multiples, the system exploits vibrational characteristics to achieve stable discharge across a wide frequency range without resonance-induced variations.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The patent changes the critical parameter from drive frequency constraints to meniscus natural vibration period design. By controlling the meniscus formation and its natural vibration characteristics through nozzle and chamber design, the system achieves uniform discharge speed without restricting drive frequency choices.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the common supply passage is designed with standard dimensions, then manufacturing is simplified, but resonance causes discharge rate variations

Engineering Contradiction:
Improvecommon chamber design simplicityVSAvoiddischarge rate consistency
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent addresses resonance issues by matching vibrational periods rather than avoiding them through complex design. By ensuring the meniscus natural vibration period differs from the common chamber resonant period, standard-dimensional chambers can be used without suffering from resonance-induced discharge variations.

Inventive Principle:
Principle #18Mechanical vibration

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 allows for driving actuators without frequency restrictions, reducing discharge speed variations and ensuring high-quality image formation by stabilizing droplet landing positions and areas.

Implementation Method 1

a meniscus formed at each of the multiple nozzles has a natural period of vibration different from each of: a resonant period of the common chamber; half of the resonant period of the common chamber; and a quarter of the resonant period of the common chamber

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4360890B1Liquid discharge head, liquid discharge unit, and liquid discharge apparatus
Publication Date: 2026.02.18 RICOH CO LTD
  • EP4360890B1 patent drawingFigure 1
  • EP4360890B1 patent drawingFigure 2
  • EP4360890B1 patent drawingFigure 3

AI summary

1. A liquid discharge head (100) includes: multiple nozzles (4); multiple individual chambers (6) respectively communicating with the multiple nozzles (4); a common chamber (10) communicating with each of the multiple individual chambers (6); multiple fluid restrictors (7) between each of the multiple individual chambers (6) and the common chamber (10); and multiple actuators (11) driven to cause a liquid in the multiple individual chambers (6) to be discharged from the multiple nozzles (4), a meniscus formed at each of the multiple nozzles (4) has a natural period of vibration different from each of: a resonant period of the common chamber (10); half of the resonant period of the common chamber (10); and a quarter of the resonant period of the common chamber (10).