Induction Heating Anilox Roller for Flexographic Printing

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Solution Overview

Problem

Flexographic printing machines experience unpredictable decay in printing density and colorimetric parameters as printing speed increases, leading to reduced print quality due to ineffective ink transfer, and existing solutions are either complex or costly, such as adjusting roller distance or heating systems.

Innovation Solution

A magnetic induction coil is used to heat the anilox roller by generating a magnetic field that induces parasitic currents in the ferromagnetic material, improving ink transfer efficiency and print quality, with a simple and cost-effective setup that adjusts the magnetic field based on measured printing parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the rotation speed of the printing rollers is increased to improve productivity, then the printing speed increases, but the ink transfer effectiveness deteriorates leading to unpredictable decay of printing parameters

Engineering Contradiction:
Improveprinting speedVSAvoidprinting parameters
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by heating the anilox roller to a controlled temperature range (typically 40-80°C) to modify the viscosity and flow characteristics of the ink. This temperature parameter change ensures consistent ink transfer effectiveness across varying printing speeds, preventing the decay of printing parameters that occurs at higher speeds.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The heating of the anilox roller is performed in advance before the actual printing process begins and is maintained throughout operation. This preliminary thermal preparation of the anilox ensures that the ink achieves optimal transfer properties before and during high-speed printing, rather than attempting to correct transfer issues after they occur.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the mutual distance between the printing rollers is adjusted to improve ink transfer effectiveness, then the printing parameters can be maintained, but the device complexity increases due to additional control systems

Engineering Contradiction:
Improveprinting parametersVSAvoidcontrol system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical adjustment system (motors, sensors, and control algorithms required to dynamically adjust roller distances) with a thermal field system. Instead of mechanically moving rollers to control ink transfer, the invention uses electromagnetic induction heating to control ink viscosity and transfer properties, significantly reducing mechanical and electronic complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces thermal energy as an intermediary between the anilox roller and the ink. The heating element transfers thermal energy to the anilox, which then transfers heat to the ink, modifying its rheological properties to ensure consistent transfer. This thermal intermediary simplifies the control mechanism compared to direct mechanical adjustment of roller gaps.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If the pressure between the roller and support is increased to improve ink transfer, then the printing density can be maintained, but the printing quality deteriorates due to deformation of the plastic printing plate

Engineering Contradiction:
Improveprinting densityVSAvoidprinting defects
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

Instead of changing the pressure parameter to maintain printing density, the patent changes the temperature parameter of the anilox roller. This temperature modification alters the ink's viscosity and transfer characteristics, allowing consistent printing density to be achieved at lower, non-damaging pressures that do not deform the plastic printing plate.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If known heating systems using heat carrier fluids or electrical resistances are used to heat the anilox, then the ink transfer can be improved, but the structural complexity and cost increase

Engineering Contradiction:
Improveink transfer effectivenessVSAvoidheating system structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical heating systems (heat carrier fluid circulation pumps, heat exchangers, or resistance heating elements requiring electrical connections and cooling systems) with an electromagnetic induction heating system. The induction heating coil generates an alternating magnetic field that directly induces eddy currents in the conductive anilox roller, heating it efficiently without mechanical moving parts or complex fluid systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The anilox roller serves a dual function: it is both the printing element and the heating element. The conductive material of the anilox itself generates heat through induced eddy currents when exposed to the alternating magnetic field from the induction coil. This self-heating capability eliminates the need for separate heating mechanisms, reducing structural complexity.

Inventive Principle:
Principle #25Self-service

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 solution maintains consistent printing quality across varying speeds by heating the anilox roller, enhancing ink transfer and reducing the need for complex adjustments, while being applicable to existing printing units and cost-effective.

Implementation Method 1

A magnetic induction coil 6 is used to heat the anilox roller by generating a magnetic field that induces parasitic currents in the ferromagnetic material

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A magnetic induction coil is used to heat the anilox roller by generating a magnetic field that induces parasitic currents in the ferromagnetic material, improving ink transfer efficiency and print quality

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Data Source

PatentEP3439882B1A device and method for heating an anilox by induction in printing machines
Publication Date: 2020.02.26 BOBST FIRENZE
  • EP3439882B1 patent drawingFigure 1
  • EP3439882B1 patent drawingFigure 2~3
  • EP3439882B1 patent drawingFigure 4

AI summary

The present invention concerns a device and a method for controlling and adjusting printing parameters such as printing density and colorimetric parameters in printing machine, in particular flexographic printing machines. The printing parameters are modified by controlling the ink viscosity with an inductive heater (6) added to the anilox roller (10).