Liquid Discharge Head Micro-Vibration for Meniscus Stability

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Solution Overview

Problem

Circulation-type liquid discharge heads face challenges in preventing meniscus drying and ink thickening, particularly in low humidity or hot environments, leading to discharge defects and reduced printing quality.

Innovation Solution

A liquid discharge device with a waveform data memory that generates specific drive waveforms for both discharge and micro-vibration of the meniscus, using piezoelectric actuators to manage pressure and circulation of ink, ensuring efficient ink flow and preventing thickening by slight vibrations outside the printing area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If liquid is circulated through individual liquid chambers in a circulation-type head, then ink thickening is prevented, but meniscus drying occurs in low humidity or hot environments

Engineering Contradiction:

Improveink viscosityVSAvoidmeniscus drying

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent applies mechanical vibration to the meniscus surface through the piezoelectric actuator to prevent drying. The vibration creates surface movement that inhibits evaporation and maintains meniscus stability without disrupting the circulation flow that prevents ink thickening.

Inventive Principle:

Principle #18Mechanical vibration

Solution Approach 2:

The patent implements periodic vibration cycles at the meniscus region while maintaining continuous circulation. The periodic activation of vibration during non-printing periods creates rhythmic surface disturbance that prevents drying, while the circulation system operates continuously to maintain ink composition stability.

Inventive Principle:

Principle #19Periodic action

2Object-affected harmful factors

If meniscus vibration is applied to prevent drying, then meniscus stability is improved, but liquid discharge precision deteriorates

Engineering Contradiction:

Improvemeniscus dryingVSAvoiddischarge precision

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies vibration only to the meniscus region through selectively positioned piezoelectric actuators, leaving the liquid chambers and nozzle discharge regions unaffected. This localized approach protects the meniscus from drying while maintaining discharge precision by not vibrating the liquid ejection path.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent divides the liquid discharge head into distinct functional zones: a circulation zone where liquid flows through chambers, and a discharge zone where precision ejection occurs. Vibration is applied only to the meniscus at the boundary between these zones, allowing independent optimization of each function.

Inventive Principle:

Principle #1Segmentation

3Productivity

If discharge frequency is increased to improve printing speed, then productivity increases, but meniscus thickening occurs

Engineering Contradiction:

Improveprinting speedVSAvoidink viscosity

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent implements continuous circulation of liquid through the individual chambers during the entire printing process, ensuring constant refreshment of the liquid supply. This continuous flow prevents thickening even as discharge frequency increases, allowing sustained high-speed operation without viscosity degradation.

Inventive Principle:

Principle #20Continuity of useful action

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 solution effectively prevents meniscus drying and ink thickening, enhancing printing quality and speed by maintaining ink flow and viscosity, even in challenging environmental conditions.

Implementation Method 1

each of the plurality of liquid chambers is provided with a pressure generator configured to generate a pressure to discharge the liquid

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

micro-vibration drive waveform data for causing, in a non-print area, a micro vibration of a meniscus of the liquid discharge head

Methodology Applied

Scientific EffectPressure wave: Pressure Gradient

Data Source

PatentUS10994533B2Liquid discharge device and liquid discharge apparatus

Publication Date: 2021.05.04 RICOH CO LTD

AI summary

A liquid discharge device includes a liquid discharge head including a plurality of liquid chambers respectively communicating with a plurality of nozzles and circulating liquid therethrough. Each liquid chamber is provided with a pressure generator for discharging the liquid from a corresponding nozzle. The liquid discharge device further includes a waveform data memory to store drive waveform data including discharge drive waveform data for discharging the liquid according to image data and micro-vibration drive waveform data for causing a micro vibration of a meniscus of the liquid discharge head. The liquid discharge device further includes circuitry configured to generate a drive waveform based on the drive waveform data; apply, to the pressure generator, a discharge drive waveform based on the discharge drive waveform data, in a printing area; and apply, to the pressure generator, a micro-vibration drive waveform based on the micro-vibration drive waveform data, in a non-print area.