Liquid Discharge Apparatus Sub Tank Inclination Control

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Solution Overview

Problem

In liquid discharge apparatuses, variations in the inclination of sub tanks relative to the heads lead to differences in water head and negative pressure, causing inconsistent performance among the heads.

Innovation Solution

The apparatus adjusts the inclination of sub tanks and uses a displacement member with sensors to maintain a consistent negative pressure across all heads by controlling the liquid supply, ensuring uniform liquid levels and minimizing variations in water head differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If sub tanks are arranged to be inclined as the heads, then the structure adapts to the head inclination, but the water head difference between heads and sub tanks varies causing negative pressure variation

Engineering Contradiction:
Improvestructural adaptation to head inclinationVSAvoidnegative pressure consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by making each sub tank have a different inclination angle matched to its corresponding head's inclination angle. This allows each sub tank-head pair to have optimal structural adaptation while the system as a whole maintains consistent negative pressure through individualized configuration rather than uniform arrangement.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent achieves equipotentiality by adjusting the inclination angles of sub tanks so that the water head difference between each sub tank and its corresponding head remains equal despite different inclination angles. This creates equivalent hydraulic potential conditions across all head-sub tank pairs, ensuring consistent negative pressure application.

Inventive Principle:
Principle #12Equipotentiality

2Reliability

If sub tanks are made with different heights to equalize water head differences, then negative pressure variation is reduced, but the device complexity increases

Engineering Contradiction:
Improvenegative pressure consistencyVSAvoidsub tank configuration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by configuring each sub tank with a specific inclination angle that differs from other sub tanks, matching the asymmetry of head inclinations. This asymmetric arrangement naturally equalizes water head differences without requiring additional height adjustments or complex mechanical structures, simplifying the overall device design while maintaining reliability.

Inventive Principle:
Principle #4Asymmetry

3Adaptability or versatility

If the liquid level in sub tanks varies according to inclination degree, then the sub tank structure adapts to different angles, but the water head difference varies causing performance inconsistency

Engineering Contradiction:
Improveinclination angle adaptationVSAvoidliquid discharge consistency
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by systematically varying the inclination angle parameter of each sub tank to match its corresponding head's inclination angle. This parameter adjustment equalizes the water head difference across all sub tank-head pairs, ensuring consistent negative pressure and liquid discharge performance while maintaining adaptation to different inclination angles.

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

This solution reduces variations in negative pressure between heads, enhancing the stability and consistency of the liquid discharge process, thereby improving print quality and reducing downtime due to efficient liquid supply management.

Implementation Method 1

a negative pressure generating unit that generates negative pressure in order to supply the liquid from the sub tank to the head

Methodology Applied
Scientific EffectNegative pressure: Pressure Gradient

Implementation Method 2

an elastic member that presses the flexible film

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 3

a flexible film that is pressed by the elastic member; a displacement member that is displaced according to a remaining amount of the liquid in the liquid container

Methodology Applied
Scientific EffectPressure transmission: Pascal's Law

Data Source

PatentEP3792064B1Liquid discharge apparatus
Publication Date: 2023.07.26 RICOH CO LTD
  • EP3792064B1 patent drawingFigure 1
  • EP3792064B1 patent drawingFigure 2~3
  • EP3792064B1 patent drawingFigure 4~5

AI summary

A liquid discharge apparatus includes a plurality of head units (200) configured to discharge liquids, a plurality of sub tanks (300) configured to respectively store the liquids to be supplied to the plurality of head units (200), and a plurality of upper limit detectors (331) configured to respectively detect upper limits of remaining amounts of liquid in the plurality of sub tanks (300). At least two of the plurality of upper limit detectors (331) of corresponding at least two of the plurality of sub tanks (300) detect different upper limits of the remaining amounts of liquid in the at least two of the plurality of sub tanks (300).