Two-Stage UV Inkjet Curing for Film Strength and Image Quality
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Solution Overview
Problem
Inkjet recording methods using ultraviolet-curable aqueous inks face challenges with weak coating film strength and insufficient image quality, particularly when using ink sets of two or more colors, and existing solutions do not adequately address these issues.
Innovation Solution
An inkjet recording method involving simultaneous application of an inkjet ink containing a polymerizable compound and polymerization initiator with an active energy ray, followed by adjusted irradiation in two stages with varying light amounts and irradiances to enhance curing and improve film strength and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ultraviolet-curable aqueous ink is used for inkjet recording, then environmental and safety properties are improved, but coating film strength becomes weak
Solution Approach 1:
The curing process is divided into two distinct stages: a first irradiation step with lower energy parameters and a second irradiation step with higher energy parameters. This segmentation allows the ink to first form a preliminary cured film with good adhesion, then achieve full crosslinking and maximum strength in the second step, resolving the contradiction between environmental safety and film strength.
Solution Approach 2:
The first irradiation step performs preliminary curing of the ultraviolet-curable aqueous ink before the second irradiation step. This preliminary action creates a stable film structure that prevents ink migration and ensures good adhesion, while the subsequent second irradiation step completes the crosslinking to achieve maximum coating film strength.
2Object-affected harmful factors
If ultraviolet-curable aqueous ink is used for inkjet recording, then environmental and safety properties are improved, but image quality becomes insufficient
Solution Approach 1:
The image formation process is segmented into two irradiation steps with different energy parameters. The first step with lower irradiance prevents ink migration and maintains sharp edges, while the second step with higher irradiance ensures complete curing for optimal image quality, thus resolving the contradiction between environmental safety and image quality.
Solution Approach 2:
Different regions of the ink layer receive different irradiation intensities at different times. The first irradiation step provides uniform low-intensity exposure across the entire ink layer for preliminary curing, while the second step provides high-intensity exposure to ensure complete crosslinking, achieving both environmental safety and high image quality.
3Productivity
If simultaneous printing with mixed-color ink set is performed, then productivity is improved, but image quality becomes insufficient
Solution Approach 1:
The first irradiation step performs preliminary curing of all ink colors simultaneously during the printing process, preventing ink migration and maintaining color accuracy. This preliminary action enables high-speed simultaneous printing while the second irradiation step ensures complete curing for optimal image quality, resolving the contradiction between productivity and image 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
The method achieves a printed coating film with sufficient strength and good image quality, enabling high-quality printed images even with mixed-color ink sets, while maintaining environmental and safety properties.
Implementation Method 1
applying an inkjet ink containing at least a polymerizable compound, a polymerization initiator, and water to a recording medium and irradiating the recording medium with an active energy ray simultaneously with the application of the inkjet ink; and irradiating the inkjet ink applied to the recording medium with an active energy ray
Data Source
AI summary
An inkjet recording method including (1) applying an inkjet ink containing at least a polymerizable compound, a polymerization initiator, and water to a recording medium and irradiating the recording medium with an active energy ray simultaneously with the application of the inkjet ink; and (2) irradiating the inkjet ink applied to the recording medium with an active energy ray.