Liquid Cartridge Prism Positioning for Splash Detection

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Solution Overview

Problem

Existing liquid cartridges face issues with precise detection of remaining liquid amounts due to ink splashes onto the remaining amount detecting portion during cartridge removal or attachment, leading to incorrect readings.

Innovation Solution

The liquid cartridge design includes a liquid supply port positioned below a third wall, with a prism located above this wall and between two main walls, reducing the risk of ink splashes and incorrect detection. Additionally, a differential pressure regulating valve and buffer chambers help prevent air intrusion and ensure accurate detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the liquid supply port and remaining amount detecting portion are both disposed at the front of the cartridge, then the structure is compact and easy to manufacture, but ink splashes during cartridge removal may contaminate the detecting portion causing incorrect detection

Engineering Contradiction:
Improveease of manufactureVSAvoidmeasurement precision
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies dimensional separation by positioning the remaining amount detecting portion above the third wall in the upward direction, while the liquid supply port remains below the third wall. This vertical separation in the upward/downward dimension prevents ink splashes from the supply port from reaching the detecting portion, while both components remain at the front of the cartridge for compactness

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If the prism is positioned closer to the liquid supply port for compact design, then the cartridge structure is simplified, but the risk of ink splash contamination increases

Engineering Contradiction:
Improvedevice complexityVSAvoidreliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent uses vertical positioning above the third wall to separate the prism from the liquid supply port horizontally. This creates spatial separation in the upward direction without significantly increasing overall cartridge complexity, as the prism remains within the front portion of the cartridge structure

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The third wall acts as an intermediary barrier between the liquid supply port and the prism. By positioning the prism above the third wall and the supply port below it, the wall structure itself serves as a protective element that prevents direct exposure of the prism to ink splashes from the supply port

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration enhances the precision of liquid remaining amount detection, reduces the risk of incorrect readings, and maintains accurate liquid level assessment in the cartridge.

Implementation Method 1

light emitted toward the remaining amount detecting portion is refracted at an ink layer in the remaining amount detecting portion

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

all the light is reflected from an inner wall of the remaining amount detecting portion

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3753737B1Liquid cartridge
Publication Date: 2023.04.05 BROTHER KOGYO KK
  • EP3753737B1 patent drawingFigure 1
  • EP3753737B1 patent drawingFigure 2
  • EP3753737B1 patent drawingFigure 3

AI summary

The present invention relates to a liquid cartridge (30) storing liquid therein and configured to be mounted on a cartridge mounting portion, the liquid cartridge comprises a liquid supply port (71), a third wall (133) extending between upper end portions of first and second walls (128, 129); and a prism (78) having an irradiated surface (78A) configured to receive light emitted from a light emitting portion included in the cartridge mounting portion and change the state of received light in response to a level of stored liquid, wherein the liquid supply port (71) is positioned below the third wall in a downward direction; and the irradiated surface is positioned above the third wall in an upward direction and positioned between the first and second walls (128, 129).