Liquid Cartridge Sealing Member with Third Protrusion

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Solution Overview

Problem

The existing ink cartridges face issues with ink leakage due to the detachment of the sealing member from the cap when the ink needle is inserted, compromising the sealability and leading to ink loss.

Innovation Solution

The design incorporates a third protrusion with a tapered shape that contacts the cap, a second sealing surface inclined relative to the axis, and a valve to close the liquid supply hole, ensuring the sealing member remains attached to the cap and preventing ink leakage. Additionally, a needle valve in the cartridge attachment section opens to allow ink flow only when the cartridge is attached, maintaining seal integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the ink needle is inserted into the through hole of the sealing member, then ink supply to the recording head is enabled, but the sealing member may be pulled off the cap by friction, compromising sealability

Engineering Contradiction:
ImprovesealabilityVSAvoidink needle insertion
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The sealing member is divided into multiple functional parts: a cylindrical portion with a through hole for ink supply, and a third protrusion extending from the cylindrical portion. The third protrusion acts as a separate engagement feature that interfaces with the cap, while the cylindrical portion interfaces with the ink needle. This segmentation allows the ink needle to pass through without directly interacting with the cap-engagement features, preventing the pulling-off problem while maintaining sealability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The third protrusion serves as an intermediary element between the sealing member and the cap. It provides a dedicated engagement interface that transfers the holding force from the cap to the sealing member, independent of the ink needle insertion process. This intermediary structure ensures that the sealing member remains securely attached to the cap during ink needle insertion and operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the sealing member is securely attached to the cap, then ink leakage is prevented, but the structure becomes more complex with additional protrusions and sealing surfaces

Engineering Contradiction:
Improveink leakage preventionVSAvoidsealing member structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealing member incorporates localized sealing features at specific positions: the first sealing portion at the tip of the first protrusion, the second sealing portion at the tip of the second protrusion, and the third sealing portion at the tip of the third protrusion. Each sealing portion is positioned precisely where needed to prevent leakage at critical interfaces, rather than using a complex overall structure. This localized approach maintains reliability while minimizing structural complexity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3603980B1Liquid cartridge and liquid supplying device using the same
Publication Date: 2021.05.05 BROTHER KOGYO KK
  • EP3603980B1 patent drawingFigure 1
  • EP3603980B1 patent drawingFigure 2
  • EP3603980B1 patent drawingFigure 3

AI summary

A liquid cartridge includes a liquid supply tube, a sealing member, and a cap. The sealing member seals an opening of the liquid supply tube. The sealing member includes a cylindrical portion, a first protrusion, a second protrusion, and a third protrusion. The first protrusion protrudes radially inward. The first protrusion has a first protruding end defining a first sealing surface facing an axis of the cylindrical portion. The second protrusion protrudes radially outward to have a second protruding end in a direction away from the axis. The second protrusion has a second sealing surface in contact with the liquid supply tube. The third protrusion protrudes along the axis to have a third protruding end. The third protrusion has a contacting surface inclined relative to the axis to face the axis. The contacting surface is in contact with the cap.