Ink Circulation System with Independent Degassing Flow Control

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Solution Overview

Problem

The existing ink circulation and degassing systems for ink jet printing apparatuses face limitations in controlling the ink flow rate through the degassing unit, leading to potential re-introduction of gas into the ink during intermediate storage and reduced efficiency due to hydrostatic pressure limitations and dependency on the number of print heads and tubing length.

Innovation Solution

An improved ink circulation system that independently controls the ink flow rate through the degassing unit by using separate circulation pumps and a 3-way valve, allowing for optimal degassing at the location of the intermediate storage before supplying ink to the print heads, thereby ensuring consistent and high-quality ink delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a through-flow ink degassing unit is mounted inline with the ink circulation, then gas removal from ink is improved, but the ink flow rate through the degassing unit cannot be independently controlled and may be insufficient for optimal degassing

Engineering Contradiction:

Improvegas removal efficiencyVSAvoidflow rate control independence

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The ink circulation system is segmented into a main circulation loop (supply tank → print heads → waste tank) and a separate degassing circulation loop (supply tank → degassing unit → supply tank). This segmentation allows independent control of degassing flow rate from printing flow rate, enabling optimal degassing performance without affecting print head supply.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system merges the degassing circulation loop with the main circulation loop at the supply tank, allowing the degassed ink to rejoin the main supply. This combining ensures that the ink receives both degassing treatment and maintains continuous circulation for printing operations.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If ink is stored in an intermediate storage tank, then ink supply to multiple print heads is facilitated, but gas may be reintroduced into the degassed ink during storage

Engineering Contradiction:

Improveink supply flexibilityVSAvoidink degassing quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary degassing action by circulating ink through the degassing unit continuously before the ink reaches the print heads. The degassing unit is positioned in the circulation path such that ink is constantly being degassed, preventing gas reintroduction that would occur with intermediate storage tanks.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The degassing process operates continuously as ink circulates through the closed-loop system. The circulation pump maintains constant ink flow through the degassing unit, ensuring uninterrupted degassing action and preventing gas accumulation that would occur with batch storage and transfer operations.

Inventive Principle:

Principle #20Continuity of useful action

3Device complexity

If hydrostatic pressure difference is used to drive ink circulation, then system simplicity is maintained, but flow rate is limited and dependent on tubing length and number of print heads

Engineering Contradiction:

Improvecirculation system simplicityVSAvoidink flow rate

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The system replaces the passive hydrostatic pressure mechanism with an active circulation pump. This substitution provides controllable, consistent flow rate independent of tubing length and print head quantity, while maintaining relatively simple system architecture through a single pump unit.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 allows for independent control of the ink flow rate through the degassing unit, ensuring optimal operating conditions and preventing gas reintroduction, resulting in improved ink quality and efficiency by degassing the ink just before it is supplied to the print heads.

Implementation Method 1

a circulation pump that circulates the ink at a flow rate that is higher than the flow rate through the ink jet print head

Methodology Applied

Scientific EffectHydraulic pump: Pump

Implementation Method 2

an ink circulation system with a through-flow ink degassing unit mounted inline with the ink circulation

Methodology Applied

Scientific EffectGas removal through membrane: Semipermeable Membrane

Data Source

PatentUS8157365B2Ink degassing for circulating ink supply systems in ink jet printers

Publication Date: 2012.04.17 AGFA NV

AI summary

An ink circulation system includes a supply subtank for supplying ink to an ink jet print head and a return subtank returning the ink not ejected by the ink jet print head. A print circulation path links the supply subtank with the ink jet print head and the return subtank for providing a print flow of ink from the supply subtank to the ink jet print head, the return subtank, and back to the supply subtank. A degas circulation path links the supply subtank with a through-flow degassing unit for providing a degas flow of ink from the supply subtank to the through-flow degassing unit and back to the supply subtank. The ink circulation system improves the degassing quality of the ink supplied to the ink jet print head of a printing apparatus is provided.