Cationic Ink Jet Printer Using UV LEDs and Heating for Fast Curing
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Solution Overview
Problem
UV curing ink jet printers are inconvenient due to the use of mercury lamps, which are slow to heat up and cool down, and can release toxic mercury, and cationic ink jet inks are slow to cure, making them unsuitable for wide commercial acceptance.
Innovation Solution
An ink jet printer that uses a cationic UV curing ink with a heating means to elevate the ink temperature before and during curing, utilizing UV radiation, and incorporates UV LEDs or IR radiation to enhance curing speed without the need for mercury lamps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mercury lamps are used to generate UV radiation for curing UV curable inks, then high dose UV radiation can be achieved for rapid curing, but the lamps take time to heat up and cool down and can release toxic mercury
Solution Approach 1:
The patent extracts and eliminates the harmful mercury lamp component from the UV curing system. Instead of using mercury lamps that release toxic mercury, the invention employs alternative UV LED arrays that provide the necessary UV radiation without the harmful byproducts, thereby maintaining curing effectiveness while removing the toxic element.
Solution Approach 2:
The patent replaces long-lived but harmful mercury lamps with shorter-lived but environmentally friendly UV LEDs. While UV LEDs may have shorter operational lifetimes compared to mercury lamps, they eliminate mercury contamination risks and can be replaced more easily, representing a trade-off that prioritizes environmental safety over component longevity.
2Speed
If mercury lamps are used to generate UV radiation for curing UV curable inks, then high dose UV radiation can be achieved for rapid curing, but the lamps are inconvenient to use because they take time to heat up and cool down
Solution Approach 1:
The patent removes the heating-up and cooling-down phases inherent to mercury lamp operation by extracting the thermal mass and thermal inertia characteristics of mercury lamps. UV LEDs provide instantaneous UV radiation output without requiring warm-up time, and can be turned off immediately without cooling delays, thereby eliminating the operational inconveniences associated with mercury lamps.
Solution Approach 2:
The patent substitutes the thermal-mechanical system of mercury lamps (which require heating filaments and cooling periods) with an electronic-optical system using UV LEDs. This replacement eliminates the thermal cycles and mechanical wear associated with mercury lamps, providing a more convenient and responsive curing system that can be activated and deactivated instantaneously.
3Object-affected harmful factors
If cationic ink jet inks are used, then lower odour and lower skin irritancy are achieved, but the inks are slower to cure than free radical ink jet inks
Solution Approach 1:
The patent changes the chemical parameters of the cationic ink formulation to enhance its reactivity and curing speed. By modifying the cationic monomer structure, photoinitiator selection, and ink composition, the patent accelerates the curing reaction of cationic inks while preserving their environmental benefits of low odour and skin irritancy, thereby resolving the speed disadvantage of cationic inks.
Solution Approach 2:
The patent employs composite ink formulations that combine cationic monomers with specific photoinitiators and co-monomers to create a synergistic system. This composite approach allows the ink to maintain the low odour and skin irritancy characteristics of cationic inks while achieving faster curing speeds through the combined chemical actions of multiple components working together under UV irradiation.
4Speed
If higher levels of reactive monomers such as dioxetane are included in cationic inks to improve cure speed, then curing speed increases, but the resulting films of cured ink tend to be brittle and therefore lack durability
Solution Approach 1:
The patent carefully adjusts the concentration and type of reactive monomers in the cationic ink formulation to achieve optimal curing speed without excessive brittleness. By controlling the monomer-to-polymer ratio and selecting specific monomer types with balanced reactivity and flexibility, the patent achieves fast curing while maintaining film durability and preventing brittleness.
Solution Approach 2:
The patent uses composite ink systems that combine reactive monomers with flexible polymer matrices and crosslinking agents. This composite structure allows the cured film to achieve both fast curing speed and adequate durability by distributing stress across multiple components, preventing the brittleness that would result from using high levels of single reactive monomers like dioxetane.
5Reliability
If the printer is made too large and complex to accommodate UV curing components, then UV curing capability is achieved, but the printer becomes unsuitable for home or high street printer market
Solution Approach 1:
The patent segments the UV curing system into compact, modular UV LED arrays that can be integrated directly onto or near the print head assembly. This segmentation allows the UV curing components to be distributed throughout the printer in small, manageable units rather than requiring a single large curing chamber, thereby maintaining UV curing capability while reducing overall printer size and complexity.
Solution Approach 2:
The patent merges the printing and UV curing functions into a closely integrated system where UV LED arrays are positioned immediately adjacent to the print head. This merging eliminates the need for separate, large-scale UV curing chambers and transport mechanisms, allowing the printer to perform both printing and curing in a compact configuration suitable for home and high street printer markets.
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
Significantly increases the curing speed of cationic ink jets, allowing immediate handling and stacking of printed products, while being more environmentally friendly and reducing odour and skin irritancy compared to free radical inks.
Implementation Method 1
a heating means for heating the ink on the substrate
Implementation Method 2
a source of radiation for curing the heated ink
Implementation Method 3
incorporates UV LEDs or IR radiation to enhance curing speed
Implementation Method 4
incorporates UV LEDs or IR radiation to enhance curing speed
Data Source
AI summary
An ink jet printer for printing a cationic ink jet ink is provided. The printer comprises a print head for printing the ink onto a substrate, a heating means for heating the ink on the substrate, and a source of radiation for curing the heated ink.