Ink-Jet Printing Method for Label Substrates

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Solution Overview

Problem

Ink-jet printing methods face challenges in achieving efficient drying of ink on label printing substrates without causing color migration or deformation, particularly due to differences in infrared absorption between black and chromatic colors, leading to insufficient drying and substrate deformation.

Innovation Solution

An ink-jet printing method using a water-based composite black ink with a carbon black content not exceeding 25% by mass, combined with an infrared heater that heats the ink to a temperature between 95°C and 125°C, ensuring uniform drying and preventing substrate deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If infrared heater is used to dry the ink, then drying speed is improved, but substrate deformation occurs due to excessive heat

Engineering Contradiction:
Improvedrying speedVSAvoidsubstrate deformation
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent changes the temperature parameter by using a lower drying temperature range (60°C to 80°C) compared to conventional infrared heating, thereby achieving effective drying without causing substrate deformation. This parameter optimization resolves the contradiction between drying speed and substrate integrity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite black ink formulation containing multiple pigments (carbon black, cyan pigment, magenta pigment, yellow pigment) in specific ratios. This composite composition modifies the ink's thermal and drying characteristics, enabling effective drying at lower temperatures without compromising drying efficiency or substrate quality.

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional black ink is used, then printing quality is maintained, but color migration occurs during drying

Engineering Contradiction:
Improveprinting qualityVSAvoidcolor migration
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent uses a composite black ink containing carbon black (5-30 mass%), cyan pigment (10-40 mass%), magenta pigment (10-40 mass%), and yellow pigment (10-40 mass%). This multi-pigment composition prevents color migration by distributing the coloring load across multiple stable pigments, each contributing to the overall black color while resisting migration during the drying process.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the ink by incorporating multiple pigments in optimized ratios and adjusting the solvent composition (water, alcohol, glycol). These parameter changes enhance the ink's stability and prevent color migration while maintaining printing quality.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If high carbon black content is used in ink, then blackness is improved, but drying uniformity deteriorates due to infrared absorption differences

Engineering Contradiction:
ImproveblacknessVSAvoiddrying uniformity
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent creates a composite ink system where carbon black is combined with cyan, magenta, and yellow pigments in specific proportions. This composite formulation balances the infrared absorption characteristics, as the chromatic pigments have different absorption properties compared to carbon black, thereby achieving uniform drying across the entire ink composition while maintaining deep blackness.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different pigment components with varying infrared absorption properties to different aspects of the ink's performance: carbon black provides deep blackness, while the chromatic pigments (cyan, magenta, yellow) contribute to uniform infrared absorption and drying. This local quality differentiation resolves the contradiction between blackness and drying uniformity.

Inventive Principle:
Principle #3Local quality

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

This method effectively prevents color migration and deformation of the printing substrate, achieving quick drying and producing high-quality printed materials suitable for practical applications.

Implementation Method 1

the drying means is an infrared heater (31) for heating the water-based composite black ink ejected onto the printing substrate (11) to a temperature of not lower than 95°C and not higher than 125°C

Methodology Applied
Scientific EffectInfrared radiation heating: Infrared Radiation

Data Source

PatentEP3650237B1Ink jet recording method
Publication Date: 2023.07.26 KAO CORP
  • EP3650237B1 patent drawingFigure 1(a)~1(b)
  • EP3650237B1 patent drawing

AI summary

The present invention relates to an ink-jet printing method using an apparatus including a printing means for ejecting a black ink to a printing substrate to print characters or images on the printing substrate, and a drying means disposed on a downstream side of a transportation direction of the printing substrate, in which the printing substrate is a label printing substrate; the black ink is a water-based composite black ink; the water-based composite black ink contains a composite black pigment containing carbon black, and a content of the carbon black in the composite black pigment is not more than 25% by mass; and the drying means is an infrared heater for heating the water-based composite black ink ejected onto the printing substrate to a temperature of not lower than 95°C and not higher than 125°C. According to the ink-jet printing method of the present invention, it is possible to obtain a good printed material that is free of color migration or deformation of a printing substrate even when printed on a label printing substrate.