UV Curable Phase Change Ink Two-Step Curing Method
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Solution Overview
Problem
UV curable phase change inks used in printing processes face challenges such as incomplete curing and print artifacts due to temperature-induced fluidization, which affects the gloss level and coalescence of the ink, making it difficult to achieve a fully cured and artifact-free image.
Innovation Solution
A method involving a two-step curing process using a first beam of UV radiation with controlled intensity to pre-cure and a second beam with higher intensity to post-cure the ink, ensuring the ink remains below its phase transition temperature during pre-curing to prevent fluidization, while completely curing the ink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UV radiation is applied to cure UV curable phase change ink, then the ink is cured, but the temperature increase causes the ink to fluidize and creates print artifacts
Solution Approach 1:
The curing process is divided into two distinct stages: a first curing step using a first UV radiation source, and a second curing step using a second UV radiation source. This segmentation allows the curing process to be controlled in phases, preventing excessive temperature rise and ink fluidization while ensuring complete curing.
Solution Approach 2:
The invention changes the parameters of the curing process by using two different UV radiation sources with different characteristics (wavelengths, intensities, or types). This allows optimization of each curing step to avoid ink fluidization while ensuring complete curing, addressing the contradiction between curing effectiveness and artifact prevention.
2Reliability
If high intensity UV radiation is used to cure thick ink layers, then curing is more effective, but the temperature rise causes ink fluidization and coalescence
Solution Approach 1:
The curing process is divided into two distinct stages: a first curing step using a first UV radiation source, and a second curing step using a second UV radiation source. This segmentation allows the curing process to be controlled in phases, preventing excessive temperature rise and ink fluidization while ensuring complete curing.
Solution Approach 2:
The first UV radiation source performs a partial curing action that is sufficient to prevent ink fluidization but not complete curing. The second UV radiation source then completes the curing process. This partial action approach prevents the harmful effects of excessive temperature rise while achieving the desired curing effectiveness.
3Ease of operation
If the ink is jetted at elevated temperature to maintain fluid state, then the ink can be properly applied, but the ink may fluidize on the receiving medium causing print artifacts
Solution Approach 1:
The ink is pre-cooled to a temperature below its melting point before being jetted onto the receiving medium. This preliminary cooling action ensures that the ink remains in a stable, non-fluidized state during application and curing, preventing print artifacts while still allowing proper ink jetting and application.
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 approach ensures complete curing of the ink without print artifacts, maintaining the ink's immobilized state and preventing fluidization, resulting in a stable and visually appealing image with controlled gloss.
Implementation Method 1
UV curable phase change inks may be fluid at elevated temperature and may be solid or semi-solid at lower temperatures. This type of ink may be jetted as a fluid at elevated temperate and may cool down after it has been applied onto the receiving medium, thereby transforming into a solid or semi-solid.
Implementation Method 2
pre-curing the deposited droplets of ink by irradiating the droplets of ink with a first beam of UV radiation, the first beam having a first intensity; wherein: pre-curing is done before post-curing; and the intensity of the first beam is controlled such that at least in the pre-curing step, the temperature of the ink does not exceed T1
Implementation Method 3
post-curing the deposited ink by irradiating the droplets of ink with a second beam of UV radiation, the second beam having a second intensity; wherein: the second intensity is higher than the first intensity
Data Source
Figure 1A~1B
Figure 2~3
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AI summary
The invention relates to a method for applying an image onto a receiving medium using an ultraviolet curable phase change ink. The method comprises the steps of pre-curing the ultraviolet curable ink and post-curing the ultraviolet curable ink. The invention further relates to an ink jet apparatus configured to perform the above mentioned method.