Ink Recirculation System for Printheads with Compact Dual-Chamber Design

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Solution Overview

Problem

Existing recirculation systems for inkjet printheads are not compact, difficult to interchange, and lack effective temperature control, leading to issues with constant flow and maintenance complexity, especially when handling high-speed and high-acceleration applications.

Innovation Solution

A compact recirculation system with two chambers, pressure sensors, a vacuum generator, and a pressure generator, allowing for easy interchangeability and precise temperature control, ensuring a constant flow and easy maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the recirculation system uses long tube lengths and large ink volumes, then the system can handle high-speed and high-acceleration applications, but the temperature control becomes imprecise and the system size increases

Engineering Contradiction:
Improvecarriage speedVSAvoidtemperature control precision
Core Design Contradiction:
SpeedVSTemperature

Solution Approach 1:

The system divides the ink recirculation into two separate chambers (first chamber for supply, second chamber for return) with distinct functions. This segmentation allows each chamber to be optimized independently - the first chamber can be compact for temperature control while the second handles the recirculation flow, resolving the contradiction between speed handling and temperature precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a vertical dimension by stacking chambers and using vertical tube connections rather than horizontal extensions. This reduces the horizontal footprint and tube length while maintaining the necessary ink volume and flow characteristics for high-speed operation, thereby improving temperature control without sacrificing speed capability

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If the recirculation system is designed to be compact, then the system occupies less space and is easier to interchange, but the temperature control precision may be compromised

Engineering Contradiction:
Improvesystem volumeVSAvoidtemperature control precision
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The patent nests the vacuum generator and pressure generator within the housing structure, and places the heating element directly within or adjacent to the first chamber. This nesting approach maximizes the use of available space, allowing compact design while maintaining effective temperature control through proximal heating elements that don't require large tube lengths

Inventive Principle:
Principle #7Nested doll (Nesting)

3Measurement precision

If the system uses ink level control sensors in contact with the ink, then the ink level can be monitored, but the cleaning complexity increases

Engineering Contradiction:
Improveink level measurementVSAvoidcleaning complexity
Core Design Contradiction:
Measurement precisionVSEase of repair

Solution Approach 1:

The patent extracts the ink level control sensors from direct contact with the ink by positioning them in the housing walls or in separate compartments that can be accessed without draining the ink. This allows continuous monitoring of ink levels while simplifying maintenance, as sensors can be cleaned or replaced without the complexity of dealing with ink-contaminated components

Inventive Principle:
Principle #2Taking out (Extraction)

4Productivity

If the recirculation system uses suction means only, then the ink can be recirculated, but the system becomes complex and requires multiple components

Engineering Contradiction:
Improveink recirculation capabilityVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the vacuum generator and pressure generator into a single integrated system with coordinated control. The vacuum generator draws ink from the printhead, and the pressure generator pushes it back, creating a complete recirculation loop. By combining these functions and controlling them together, the system achieves effective ink recirculation while reducing overall complexity compared to separate suction-only systems

Inventive Principle:
Principle #5Merging (Combining)

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 achieves a compact design that allows easy interchangeability and precise temperature control, ensuring a constant flow and reducing maintenance complexity, enabling efficient operation at high speeds and with multiple colors.

Implementation Method 1

a vacuum generator and a pressure generator

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

a vacuum generator and a pressure generator

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 3

a heating element, positioned inside the first chamber

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 4

a cooling element, positioned inside the second chamber

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP3517305B1Recirculation system for recirculating print heads
Publication Date: 2025.05.21 TECGLASS
  • EP3517305B1 patent drawingFigure 1

AI summary

An ink recirculation system for recirculating printheads comprising a housing in the interior of which two chambers, a series of pressure sensors, a vacuum generator and a pressure generator are disposed; the container has two entrances for transmitting signals towards the pressure sensors, a first feed connection to the printhead, a second flow connection to the printhead, a third ink feed connection, a fourth connection for returning the ink to the main tank and means for connecting and supporting the vacuum generator and the pressure generator. A compact assembly is achieved that can be mounted on a moving printing carriage, wherein it can be mounted in an easy and simple manner.