Buffer Tank Pressure Stabilization in Fluid Circulation

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Solution Overview

Problem

Existing fluid circulation and ejection systems face challenges in stabilizing fluid pressure and reducing fluctuations, which affect the performance of fluid ejection heads, particularly in inkjet recording apparatuses, due to pressure variations and air bubble issues.

Innovation Solution

A fluid circulation apparatus with a buffer tank having a larger cross-sectional area than the bypass flow path, equipped with pumps and pressure sensors, adjusts fluid output rates based on detected pressures to stabilize fluid pressure and alleviate fluctuations, using a deformable wall and air chamber to absorb pressure changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a buffer tank is added to the circulation path to stabilize fluid pressure, then pressure fluctuations are reduced, but device complexity increases

Engineering Contradiction:
Improvefluid pressure stabilityVSAvoidcirculation path structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The buffer tank is integrated into the circulation path by connecting its inlet to the outlet of the fluid ejection head and its outlet to the inlet of the fluid ejection head, nesting the pressure stabilization function within the existing circulation loop without requiring completely separate systems

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The buffer tank acts as an intermediary component between the fluid ejection head and the circulation pumps, absorbing pressure fluctuations and providing stable pressure to the ejection head while allowing the pumps to operate with variable pressure conditions

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the buffer tank cross-sectional area is increased to improve pressure stabilization, then pressure fluctuation absorption is enhanced, but device size increases

Engineering Contradiction:
Improvepressure fluctuation absorptionVSAvoidbuffer tank cross-sectional area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent specifies that the buffer tank cross-sectional area should be 1.05 to 5 times that of the bypass flow path, providing an optimized parameter range that balances pressure stabilization effectiveness with compact size, avoiding excessive tank dimensions while achieving sufficient fluctuation absorption

Inventive Principle:
Principle #35Parameter changes

3Reliability

If pumps are added to the circulation path to control fluid flow and pressure, then pressure control capability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvepressure control capabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control unit receives pressure information from the buffer tank and adjusts the operation of circulation pumps based on this feedback, enabling dynamic pressure control where the system automatically responds to pressure conditions without requiring complex mechanical pressure regulation mechanisms

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical pressure control mechanisms with an electronic control system that uses sensors and control units to regulate pump operation, substituting mechanical complexity with electronic control that achieves the same pressure management function

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution effectively stabilizes fluid ejection performance by absorbing pressure fluctuations and maintaining consistent fluid pressure, reducing pulsations and air bubble interference, thereby enhancing the reliability and efficiency of fluid ejection in inkjet recording and other applications.

Implementation Method 1

a buffer tank in the bypass flow path... the buffer tank has a flow path cross-sectional area that is larger than a flow path cross-sectional area of the bypass flow path... an accommodating chamber in the buffer tank having a deformable wall

Methodology Applied
Scientific EffectPressure fluctuation absorption: Damping

Implementation Method 2

an accommodating chamber in the buffer tank having a deformable wall... to absorb pressure changes

Methodology Applied
Scientific EffectCompressibility of gas: Compression

Data Source

PatentEP3459745B1Fluid circulation apparatus and fluid ejection apparatus
Publication Date: 2025.03.26 RISO TECH CORP
  • EP3459745B1 patent drawingFigure 1
  • EP3459745B1 patent drawingFigure 2
  • EP3459745B1 patent drawingFigure 3

AI summary

According to one embodiment, a fluid circulation apparatus includes a first tank to store fluid to be supplied to a fluid ejection head, a circulation path including a first flow path portion to provide fluid from the first tank to a supply port of the fluid ejection head, and a second flow path portion to return fluid from a collection port of the fluid ejection head to the first tank, a bypass flow path that connects the supply port to the collection port outside of the fluid ejection head, and a buffer tank in the bypass flow path.