Ink Delivery System Backpressure Control via Recirculation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current ink delivery systems for printing modules face challenges with backpressure control and flow uniformity, particularly with pigmented inks, leading to potential pigment precipitation and clogging issues, and often require a large number of pumps and sensors.

Innovation Solution

A closed-loop ink recirculation system with a pressure regulating chamber, vacuum discharge circuit, and backpressure generating circuit, which includes a vacuum pump, Pirani sensor, and adjustable needle valve, to maintain stable backpressure and prevent air bubbles, using a lesser number of pumps and sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a closed-loop ink recirculation circuit is implemented to prevent pigment precipitation, then ink mixing effectiveness is improved, but system complexity increases due to additional pumps and sensors

Engineering Contradiction:
Improveink composition uniformityVSAvoidnumber of pumps and sensors
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent combines the recirculation pump and backpressure control function into a single integrated system. The recirculation pump is configured to simultaneously maintain ink flow through the closed-loop circuit and regulate backpressure at the printing module, eliminating the need for separate dedicated components for each function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The recirculation pump serves multiple functions: it circulates ink through the closed-loop circuit to prevent pigment precipitation, maintains stable backpressure at the printing module, and controls ink flow rate. This multi-functionality reduces the overall number of components needed in the ink delivery system.

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

2Reliability

If vacuum discharge circuit is added to eliminate air bubbles, then printing reliability is improved, but device complexity increases

Engineering Contradiction:
Improveprinting reliabilityVSAvoidsystem components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The vacuum discharge circuit is integrated into the existing recirculation circuit by utilizing the return conduit. The vacuum pump is positioned to create negative pressure in the return conduit, allowing air bubbles to be removed from the ink circuit without requiring a completely separate vacuum system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The vacuum pump acts as an intermediary device that creates negative pressure to draw air bubbles out of the ink circuit. The vacuum pressure serves as a mediating force that enables reliable ink delivery while preventing air bubble formation in the printing module.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If backpressure control is improved to maintain stable pressure, then ink flow uniformity is improved, but measurement and control difficulty increases

Engineering Contradiction:
Improveink flow uniformityVSAvoidbackpressure control precision
Core Design Contradiction:
Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The system employs a feedback control mechanism where a pressure sensor monitors the actual backpressure at the printing module. The controller receives the pressure signal and adjusts the recirculation pump operation accordingly to maintain the desired backpressure level, ensuring stable ink flow.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical backpressure control mechanisms with an electronically controlled system. The recirculation pump is driven by a motor controlled through electronic feedback from a pressure sensor, substituting mechanical adjustments with electronic control for more precise and easier-to-measure pressure regulation.

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

Ensures regular ink flow and low backpressure fluctuations, reducing pigment precipitation and clogging, while enhancing the reliability of the printing equipment by eliminating air from the ink and improving fluidic circuit replenishment.

Implementation Method 1

a vacuum discharge circuit connected to the second ink conduit through a valve, the vacuum discharge circuit configured to produce a vacuum condition in the at least one printing module

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

a recirculation pump arranged in the second ink conduit; wherein the ink delivery system further comprises a vacuum discharge circuit connected to the second ink conduit through a valve

Methodology Applied
Scientific EffectPumping: Pump

Implementation Method 3

using a lesser number of pumps and sensors

Methodology Applied
Scientific EffectPirani effect:

Data Source

PatentEP3829880B1Ink delivery system for a printing module and method for delivering ink
Publication Date: 2022.06.29 SICPA HOLDING SA
  • EP3829880B1 patent drawingFigure 1
  • EP3829880B1 patent drawingFigure 2~3
  • EP3829880B1 patent drawingFigure 4a~4b

AI summary

An ink delivery system for at least one printing module comprising a closed-loop ink recirculation circuit and a vacuum discharge circuit, which is configured to produce a vacuum condition in the at least one printing module. A method for delivering ink to the at least one printing module is also disclosed.