UV Ink Print Preparation via Pre-heating
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Solution Overview
Problem
Conventional ink-jet recording methods using UV curable ink face issues with image wear resistance, gloss evenness, and image density evenness, particularly due to rapid solidification of ink droplets leading to uneven dot formation and potential contamination of rollers during printing.
Innovation Solution
A print preparation method involving the ejection of actinic energy radiation curable ink containing a polymerizable compound, photo-polymerization initiator, and gelling agent, where the recording medium is exposed to electromagnetic waves with a longer wavelength than the absorption wavelength of the photo-polymerization initiator before actinic energy radiation exposure to control ink viscosity and dot formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If actinic energy radiation curable ink is used to prevent bleed, then bleed prevention is improved, but image wear resistance and gloss evenness deteriorate due to rapid solidification and uneven dot formation
Solution Approach 1:
The patent applies preliminary heating to the recording medium before ink ejection. This pre-heating action prepares the recording medium surface to control ink solidification speed, preventing rapid solidification that causes uneven dot formation. The heated surface allows ink to spread uniformly before curing, improving image wear resistance and gloss evenness while maintaining bleed prevention properties of UV curable ink.
Solution Approach 2:
The patent changes the temperature parameter of the recording medium by heating it to a specific temperature range before ink deposition. This parameter change controls the viscosity and solidification behavior of the ink, allowing for uniform dot formation and improved image quality. The temperature control prevents rapid solidification while maintaining the ink's ability to prevent bleed through UV curing.
2Ease of operation
If ink viscosity is reduced for ejection, then ejection property is improved, but bleed increases due to lower viscosity ink spreading more
Solution Approach 1:
The patent utilizes phase transition of the ink from liquid to solid state through UV radiation curing. The ink is ejected in liquid form with low viscosity for good ejection properties, then rapidly cured by UV radiation to prevent bleed. This phase transition approach allows the ink to exhibit low viscosity during ejection but high stability after deposition, resolving the contradiction between ejection property and bleed prevention.
Solution Approach 2:
The patent employs a two-stage process: first ejecting ink with low viscosity for good ejection properties, then applying UV radiation to cure the ink and prevent bleed. This periodic action sequence allows the system to benefit from both low viscosity (during ejection) and high stability (after curing), effectively resolving the contradiction between ease of ejection and bleed prevention.
3Manufacturing precision
If heat pressure is applied after printing to improve gloss, then gloss evenness is improved, but roller contamination and image quality deterioration occur
Solution Approach 1:
The patent replaces the mechanical heat-pressure system with a UV radiation curing system. Instead of using heated rollers that cause contamination and image quality issues, the patent uses UV light to cure the ink and achieve the desired gloss and image quality. This substitution eliminates the harmful effects of mechanical contact while maintaining the ability to control surface properties and achieve even gloss.
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 results in prints with improved image wear resistance, gloss evenness, and image density evenness by reducing liquid migration and dot elevation, enhancing the durability and quality of the printed images.
Implementation Method 1
an actinic energy radiation curable monomer and a photo-polymerization initiator are added into ink, and the resulting one is exposed to actinic energy radiation after depositing it onto a recording medium to cure the ink
Implementation Method 2
the recording medium is exposed to electromagnetic waves having a longer wavelength than a wavelength of an absorption wavelength of the photo-polymerization initiator contained in the actinic energy radiation curable type ink-jet ink
Data Source
AI summary
Provided is a print preparation method possessing an ejection step in which liquid drops of actinic energy radiation curable type ink-jet ink each containing a polymerizable compound, a photo-polymerizable initiator and a gelling agent are injected from an ink-jet recording head to supply the actinic energy radiation curable type ink-jet ink onto a recording medium, and an actinic energy radiation exposure step, wherein the print preparation method further comprises step (A) in which the recording medium is exposed to electromagnetic waves having a longer wavelength than a wavelength of an absorption wavelength of the photo-polymerization initiator contained in the actinic energy radiation curable type ink-jet ink from a side of a surface on which the image is formed, before conducting the actinic energy radiation exposure step, the print preparation method by which a print having images exhibiting excellent image wear resistance, gloss evenness and image density evenness is provided.