Discharge Treatment for Analog Printed Surfaces

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Solution Overview

Problem

Existing methods for printing additional variable data on surfaces previously printed by analog methods, such as gravure or flexographic printing, face challenges with ink-jet printing due to hydrophobic properties of the analog ink components, leading to poor adhesion and hiding power, and often require additional layers or UV-curable inks that increase environmental concerns and reduce productivity.

Innovation Solution

A process involving discharge treatment of the image-bearing surface with specific conditions, followed by ink-jet printing using a water-based ink, enhances the surface's wettability and adhesion properties without the need for additional layers or environmentally harmful inks, allowing for high productivity and improved image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If analog printing is used to print characters or images on a recording medium, then productivity and cost efficiency are improved, but the image-bearing surface becomes hydrophobic due to polymer components in the analog printing ink, causing poor adhesion and hiding power for subsequent ink-jet printing

Engineering Contradiction:
ImproveproductivityVSAvoidadhesion properties
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies discharge treatment (corona or plasma) to the image-bearing surface before ink-jet printing to modify the surface properties. This preliminary action introduces polar groups that increase surface energy and wettability, enabling water-based inks to adhere properly to the analog-printed surface without compromising the analog printing productivity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the surface energy parameters of the image-bearing surface through discharge treatment. By increasing the surface free energy from typically low values (making it hydrophobic) to higher values (making it hydrophilic), the surface becomes compatible with water-based inks while maintaining the original analog printing process

Inventive Principle:
Principle #35Parameter changes

2Reliability

If additional layers or UV-curable inks are used to improve ink-jet printing adhesion on analog printed surfaces, then adhesion properties are improved, but environmental concerns increase and productivity decreases due to additional processing steps

Engineering Contradiction:
Improveadhesion propertiesVSAvoidproductivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent extracts and eliminates the need for additional adhesive layers or UV-curable ink systems by directly modifying the image-bearing surface properties through discharge treatment. This removes the extra processing steps and materials while maintaining improved adhesion for water-based inks

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive UV-curable inks and additional adhesive layers with a simple, inexpensive discharge treatment process. The treatment creates a permanent surface modification that enables water-based inks to adhere without requiring costly alternative materials or processes

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If UV-curable inks are used for ink-jet printing on analog printed surfaces, then adhesion properties are improved, but environmental impact increases due to harmful chemicals in UV-curable inks

Engineering Contradiction:
Improveadhesion propertiesVSAvoidenvironmental impact
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the hydrophobic nature of analog printing surfaces, which is initially a harmful property preventing ink adhesion, into a beneficial property by applying discharge treatment. The treatment transforms the surface chemistry to be hydrophilic, enabling water-based (environmentally friendly) inks to adhere without requiring harmful UV-curable chemicals

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent replaces environmentally harmful UV-curable inks with simple water-based inks. The discharge treatment creates a surface that is compatible with water-based inks, eliminating the need for toxic chemicals while maintaining or improving adhesion properties

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 process achieves excellent hiding power and adhesion properties for ink-jet printed images on analog printed surfaces, maintaining high productivity and reducing environmental impact by using water-based inks, even at high printing speeds.

Implementation Method 1

subjecting an image-bearing surface of a printed recording medium 1' on which characters or images are formed by analog printing to discharge treatment under the following conditions to obtain a printed recording medium 1

Methodology Applied
Scientific EffectDischarge treatment (corona or plasma): Plasma

Implementation Method 2

a surface free energy (wetting tension) of the image-bearing surface of the printed recording medium 1 obtained in the step 1

Methodology Applied
Scientific EffectSurface free energy modification: Surface Tension

Implementation Method 3

enhances the surface's wettability and adhesion properties without the need for additional layers or environmentally harmful inks

Methodology Applied
Scientific EffectWetting: Wetting

Data Source

PatentEP3584084B1Method for manufacturing printed matter
Publication Date: 2024.06.12 KAO CORP

AI summary

The present invention relates to [1] a process for producing a printed material, including step 1 of subjecting an image-bearing surface of a printed recording medium 1' on which characters or images are formed by analog printing to discharge treatment under specific conditions to obtain a printed recording medium 1, and step 2 of further forming characters or images on the image-bearing surface of the printed recording medium 1 by ink-jet printing using a water-based ink to obtain the printed material, [2] an ink-jet printing method including the step of ejecting a water-based ink onto a printed recording medium 1 by an ink-jetting method to form characters or images thereon, in which the printed recording medium 1 has an image-bearing surface on which characters or images are formed by analog printing, and the image-bearing surface is subjected to discharge treatment under the specific conditions, [3] a recording medium for ink-jet printing, including an image-bearing surface on which characters or images are formed by analog printing and which is subjected to discharge treatment, in which a surface free energy of the image-bearing surface after being subjected to the discharge treatment is not less than 30 mN/m, and [4] a printed material including an image-bearing surface on which characters or images are formed by analog printing and then on at least a part of which characters or images are further formed by ink-jet printing using a water-based ink, in which the image-bearing surface after forming the characters or images thereon by the analog printing is subjected to discharge treatment, and a surface free energy of the image-bearing surface after being subjected to the discharge treatment is not less than 30 mN/m.