Intermediate Reservoir Bubble Management via Inverted Communication Pipes

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Solution Overview

Problem

Inkjet printers face issues with bubbles entering the ejection head through the second communication passage, leading to defective ink ejection due to the location of the second communication passage inlet below the first communication passage inlet, causing bubbles to flow into the filter chamber along with the ink.

Innovation Solution

The design of an intermediate reservoir with a first communication pipe located downward from the second communication pipe and an airflow pipe, creating a hydraulic head difference that prevents bubbles from entering the ejection head by discharging them through a mechanism that adjusts pressure loss and flow resistance to restrict bubble entry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the second communication passage inlet is located below the first communication passage inlet, then the device structure is simplified and manufacturing is easier, but bubbles enter the filter chamber together with ink causing defective ejection

Engineering Contradiction:

Improveease of manufactureVSAvoidreliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent inverts the conventional arrangement by positioning the second communication passage inlet above the first communication passage inlet instead of below. This inversion causes bubbles to rise away from the inlet openings rather than being drawn in, thereby preventing bubble contamination while maintaining the simplified structural layout

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent utilizes the natural buoyancy of bubbles (which normally causes them to rise and potentially enter the system) by positioning the inlet above the filter chamber. This converts the harmful upward movement of bubbles into a beneficial feature where bubbles naturally rise away from the inlet, preventing them from entering the filter chamber while still allowing ink flow

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Device complexity

If the second communication passage inlet is positioned below the first, then the communication passages are easier to route, but bubbles are drawn into the filter chamber causing ejection defects

Engineering Contradiction:

Improvedevice complexityVSAvoidharmful factors

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent counteracts the harmful effect of bubble buoyancy by positioning the inlet above the filter chamber. This creates a configuration where the upward buoyant force of bubbles directs them away from the inlet rather than toward it, effectively using gravity and buoyancy opposition to prevent bubble entry while keeping the passage routing simple

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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 effectively restricts the entrance of bubbles into the ejection head, reducing defective ink ejection and maintaining stable ink flow by adjusting pressure and flow resistance, thereby improving printing quality and reducing maintenance frequency.

Implementation Method 1

a first communication pipe located downward from the second communication pipe in the gravitational direction, the hydraulic head difference between ink in the ink storage chamber and ink in the filter chamber being greater than or equal to a length in the gravitational direction of the filter chamber

Methodology Applied

Scientific EffectHydraulic head difference: Pressure Gradient

Implementation Method 2

the first communication pipe located downward from the second communication pipe in the gravitational direction

Methodology Applied

Scientific EffectGravitation: Gravitation

Data Source

PatentEP3263343B1Liquid discharge device and intermediate retaining body

Publication Date: 2020.11.04 SEIKO EPSON CORP

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AI summary

In the present invention, a liquid discharge device is provided with a discharge head that discharges a liquid, a liquid supply path that supplies the liquid to the discharge head, and an intermediate retaining body disposed in the liquid supply path. The intermediate retaining body comprises a first retaining chamber, a second retaining chamber disposed upstream of the first retaining chamber, an upper communication path that communicates between the first retaining chamber and the second retaining chamber, and a lower communication path that communicates between the first retaining chamber and the second retaining chamber below the upper communication path. The lower communication path has a lower communication opening that opens into the second retaining chamber, the upper communication path has an upper communication opening that opens into the second retaining chamber, and the lower communication opening is smaller than the upper communication opening.