Ink Cartridge Negative Pressure Control via Capillary Filter

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Solution Overview

Problem

Existing ink storage containers in ink jet printing apparatuses face issues where air can remain inside filters, leading to a loss of meniscus and uncontrolled negative pressure, which can cause ink leakage and disrupt ink supply to the print head.

Innovation Solution

A liquid storage container with a communication portion, a negative pressure generation unit, and a limiting member that allows air to enter the container when negative pressure exceeds a certain level, maintaining a balanced negative pressure through a filter and capillary grooves to prevent ink leakage and ensure consistent ink supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a filter is provided to allow air to enter the bag member when negative pressure exceeds a predetermined level, then the negative pressure can be kept at a predetermined level, but air may remain inside the filter causing loss of meniscus and uncontrolled negative pressure

Engineering Contradiction:

Improvenegative pressure controlVSAvoidair remaining in filter

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the harmful air trapped in the filter by providing a specific structure where the filter is positioned and configured to allow air to be removed from the filter cavity. The filter is arranged such that air can escape through designated pathways while maintaining the necessary filtration function, thereby eliminating the harmful air accumulation that causes meniscus loss and uncontrolled negative pressure.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary mechanism involving the filter's specific positioning and structural configuration. The filter acts as a mediator that controls air flow into the bag member while preventing air from remaining trapped inside. The filter's arrangement with the bag member and communication portions creates a controlled environment where air can be managed effectively, preventing both excessive negative pressure and air accumulation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the filter is positioned high in the liquid storage chamber, then air can easily enter the bag member, but the filter may be exposed to air and cause uncontrolled air entry

Engineering Contradiction:

Improveair entry controlVSAvoiduncontrolled air entry

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies a dynamic positioning approach where the filter's location is strategically determined based on the liquid level and air pressure conditions. The filter is positioned at a height that allows it to effectively control air entry into the bag member while remaining below the liquid level under normal operating conditions. This dynamic consideration ensures the filter maintains proper function across varying operational states, preventing both excessive air entry and loss of negative pressure control.

Inventive Principle:

Principle #15Dynamics

3Productivity

If the liquid level is low in the liquid storage chamber, then air can enter the bag member more easily, but the filter may be exposed to air causing loss of meniscus

Engineering Contradiction:

Improveink supply efficiencyVSAvoidfilter exposure to air

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements preliminary protective measures by positioning the filter at a specific height that anticipates potential air exposure risks. The filter's location is predetermined to remain below the liquid level under normal operating conditions, preventing air from reaching the filter before it can cause harm. This preliminary positioning ensures that even when liquid levels fluctuate, the filter maintains its protective function and prevents air-induced meniscus loss.

Inventive Principle:

Principle #10Preliminary action

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 maintains a stable negative pressure within the ink storage container, preventing ink leakage and ensuring reliable ink supply to the print head, thereby maintaining print quality and preventing air from entering the container unnecessarily.

Implementation Method 1

a negative pressure generation unit configured to generate a negative pressure in the liquid storage chamber

Methodology Applied

Scientific EffectNegative pressure: Pressure Gradient

Implementation Method 2

allowing air to pass from the outside to the inside of the liquid storage chamber depending on the negative pressure in the liquid storage chamber

Methodology Applied

Scientific EffectPressure balance: Pressure Gradient

Implementation Method 3

maintaining a balanced negative pressure through a filter and capillary grooves to prevent ink leakage

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS9333758B2Liquid storage container and liquid ejection apparatus

Publication Date: 2016.05.10 CANON KK

AI summary

There is provided a liquid storage container capable of keeping a negative pressure therein more reliably. An ink cartridge includes a negative pressure generation unit configured to generate a negative pressure in an ink storage chamber and a filter attached to an atmosphere communication channel opening and allowing air to pass from the outside to the inside of the liquid storage chamber depending on the negative pressure in the ink storage chamber. The ink cartridge has a capillary groove configured to supply ink from a portion in which ink is stored in the ink storage chamber to the filter.