Liquid Discharge Apparatus Thermal Coupling for Cooling Efficiency

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Solution Overview

Problem

Conventional liquid discharge apparatuses face inefficiencies in cooling, leading to fluctuations in liquid discharge properties due to heat generated by components like piezoelectric elements, which affect the temperature of the liquid and require precise temperature control for efficient operation.

Innovation Solution

A liquid discharge apparatus with a circulation passage for temperature-controlled liquid, a radiator with a fan for cooling, a head drive board with a power amplification unit, and a controller that adjusts the fan rotation and heating waveform based on detected temperatures to maintain a target temperature, ensuring efficient cooling and stable discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional cooling structure with a container and radiator is used, then the liquid temperature can be controlled, but the cooling efficiency is insufficient due to heat generation from the head drive board

Engineering Contradiction:
Improvecooling efficiencyVSAvoidliquid temperature stability
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The head drive board is integrated into the cooling circulation system by thermally coupling it with the collection manifold. The board's heat-generating components directly transfer heat to the cooling liquid flowing through the manifold, converting waste heat into useful cooling effect and significantly improving overall cooling efficiency.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat generated by the head drive board, which was previously a harmful factor causing temperature instability, is now utilized as a beneficial cooling source. The thermal energy from the power amplification unit and processor is transferred to the cooling liquid, enhancing the cooling capacity of the system without requiring additional external cooling power.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Ease of manufacture

If the head drive board is disposed away from the head, then manufacturing is easier, but heat generation causes liquid discharge property fluctuations

Engineering Contradiction:
Improvehead drive board installationVSAvoidliquid discharge stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The collection manifold serves as a thermal intermediary between the head drive board and the cooling liquid circulation system. It provides a dedicated thermal coupling interface that efficiently transfers heat from the drive board to the cooling liquid, isolating the head from direct heat exposure while maintaining stable liquid discharge properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If temperature control is implemented, then liquid discharge properties are stabilized, but the system complexity increases

Engineering Contradiction:
Improveliquid discharge stabilityVSAvoidtemperature control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The head drive board itself serves as a heat source for the cooling system through thermal coupling with the collection manifold. This self-service approach allows the system to utilize its own waste heat for cooling purposes, reducing the need for additional external cooling components and simplifying the overall temperature control system.

Inventive Principle:
Principle #25Self-service

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 enables effective temperature control, reducing fluctuations in liquid discharge properties and enhancing the efficiency of the cooling process, thereby improving the overall performance of the liquid discharge apparatus.

Implementation Method 1

a pressure generator, such as a piezoelectric element, to generate pressure to discharge the liquid

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a radiator including a fan configured to cool the temperature-controlled liquid

Methodology Applied
Scientific EffectForced convection: Forced Convection

Implementation Method 3

The circulation passage and the head drive board are thermally coupled with each other

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3771568B1Liquid discharge apparatus
Publication Date: 2023.04.05 RICOH CO LTD
  • EP3771568B1 patent drawingFigure 1
  • EP3771568B1 patent drawingFigure 2~3
  • EP3771568B1 patent drawingFigure 4~5

AI summary

A liquid discharge apparatus (1) includes a head (100) to discharge a liquid; a circulation passage (500) coupled to the head (100), through which a temperature-controlled liquid circulates; a radiator (511) including a fan (511a), to cool the temperature-controlled liquid; a head drive board (160) mounted with a power amplification unit (161) to amplify a drive waveform applied to the head (100); an ambient temperature sensor (811) to detect an ambient temperature of the radiator (511); a liquid temperature sensor (812) to detect a temperature of the temperature-controlled liquid at an inlet of the radiator (511); and a controller (801). The controller (801) controls at least one of a rotation of the fan (511a) and a heating waveform applied to the head drive board (160), based on a target temperature of the temperature-controlled liquid, the ambient temperature of the radiator (511), and the temperature of the temperature-controlled liquid at the inlet of the radiator (511).