Venturi Ink Circulation for Stable Printhead Pressure

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing printing systems face challenges in maintaining a uniform, constant pressure within a printhead to ensure consistent ink quality, as conventional methods fail to provide a truly constant pressure differential, leading to pressure fluctuations and ink segregation, which affects printing quality.

Innovation Solution

A circulation device using a Venturi tube connected to the external circuit, combined with a diaphragm or propeller pump, circulates ink through the printhead, maintaining a constant pressure gradient without mechanical stirrers, and incorporates a check valve to prevent backflow, ensuring a virtually pulseless flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a mechanical stirrer is used in the ink reservoir, then ink separation is prevented, but the device complexity increases and the airtightness of the reservoir is compromised

Engineering Contradiction:
Improveink mixture stabilityVSAvoidstirrer mechanism complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention extracts the stirring function from the ink reservoir by using an external circulation pump to circulate ink through an external circuit, eliminating the need for mechanical stirrers inside the reservoir and thus preserving airtightness while reducing device complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

An external circulation circuit acts as an intermediary between the ink reservoir and the stirring function, allowing ink to be circulated and mixed outside the sealed reservoir, thereby maintaining reservoir integrity while achieving mixing

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If an actively operated pump device is installed in the inlet line of the printhead, then ink circulation is achieved, but pressure fluctuations occur and the device complexity increases

Engineering Contradiction:
Improveink circulation efficiencyVSAvoidpressure stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The circulation pump automatically maintains constant pressure in the printhead through continuous ink circulation, eliminating the need for additional active pressure control systems or vacuum devices, thus achieving self-regulated pressure stability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention implements continuous ink circulation through the printhead, ensuring constant pressure and preventing the pressure fluctuations that occur with intermittent or actively controlled pump systems

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If two ink reservoirs operating at different internal pressures are used, then ink flow is created, but the device complexity increases and space requirements increase

Engineering Contradiction:
Improveink flow generationVSAvoidink reservoir space
Core Design Contradiction:
ProductivityVSVolume of stationary object

Solution Approach 1:

A single ink reservoir serves multiple functions: it stores ink and provides the reference pressure for circulation, eliminating the need for a second pressure reservoir and reducing space requirements while maintaining effective ink flow

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 system maintains a uniform pressure across the printhead, preventing ink segregation and nozzle blockages, allowing for consistent printing quality without the need for active vacuum control or additional pumps, and is easily retrofittable to existing systems.

Implementation Method 1

a circulation pump that circulates the liquid mixture in the container through an external circuit

Methodology Applied
Scientific EffectCirculation:

Implementation Method 2

A circulation device using a Venturi tube connected to the external circuit

Methodology Applied
Scientific EffectVenturi effect: Venturi Effect

Data Source

PatentEP3863860B1Circulation apparatus for a liquid mixture of substances in a container
Publication Date: 2025.12.03 FRANCK JAN
  • EP3863860B1 patent drawingFigure 1
  • EP3863860B1 patent drawingFigure 2
  • EP3863860B1 patent drawing

AI summary

The invention relates to an apparatus for circulating a liquid mixture of substances, for example a solution, emulsion or suspension, between a container and a pressure-sensitive component which is supplied from the container, for example for circulating an ink between an ink storage container and a print head of a printing system, comprising a pump, which allows the liquid mixture of substances to circulate in the container through an external conduit circuit, a Venturi tube, the main conduit of which is connected into the external conduit circuit, and also a conduit which connects the output connection of the pressure-sensitive component to the suction connection of the Venturi tube.