Infrared Drying for Inkjet Printers
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Solution Overview
Problem
Conventional inkjet printing methods using evaporation drying ink face challenges such as nozzle clogging and reduced print quality due to high heating temperatures, especially when using heaters or far infrared light for drying, which can also heat the medium excessively, leading to smearing and blurred images.
Innovation Solution
A printing device with an ejection head and an infrared irradiating member that uses near-infrared light (wavelength ≤ 3 µm) to selectively heat the ink, allowing it to dry without excessively raising the medium's temperature, thereby preventing nozzle clogging and maintaining high print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the heating temperature of the heater is raised to sufficiently dry the ink before smearing occurs, then the drying effectiveness is improved, but the medium temperature increases causing nozzle clogging and reduced print quality
Solution Approach 1:
An infrared light-absorbing substance is introduced as an intermediary component in the ink formulation. This substance selectively absorbs infrared radiation and converts it to heat, enabling direct heating of the ink solvent without significantly heating the medium or nozzle. The absorbing substance acts as a mediator that transfers infrared energy to the ink, achieving rapid drying while preventing nozzle clogging and medium damage
Solution Approach 2:
The invention changes the thermal parameters by using infrared radiation with specific wavelengths (2.7-4.0 μm) that are selectively absorbed by the ink solvent and infrared light-absorbing substance. This selective wavelength approach allows precise control of heat generation in the ink layer, achieving rapid evaporation of the solvent while maintaining the medium temperature below damaging levels, thus preventing nozzle clogging and preserving print quality
2Productivity
If a heater is used to heat the medium for drying, then the ink drying is improved, but the medium temperature rises excessively causing smearing and blurred images
Solution Approach 1:
The infrared light-absorbing substance serves as an intermediary that enables selective heating of the ink layer. When infrared radiation is applied, this substance absorbs the energy and converts it to heat locally within the ink, accelerating solvent evaporation without significantly heating the underlying medium. This prevents the smearing and image blurring that occur with conventional medium heating methods
Solution Approach 2:
The invention applies local quality by concentrating the heating effect specifically in the ink layer through the use of infrared-absorbing substances. The heat generation is localized to where the ink is deposited, creating a temperature gradient that facilitates rapid drying at the ink-medium interface while keeping the bulk medium temperature low, thereby maintaining sharp print edges and preventing smearing
3Productivity
If far infrared light is used to heat the ink, then the ink drying is improved, but the medium is also heated excessively causing nozzle clogging
Solution Approach 1:
The invention changes the wavelength parameter of the infrared radiation from conventional far-infrared (8-14 μm) to a shorter range (2.7-4.0 μm). This wavelength adjustment is critical because it matches the absorption characteristics of the ink solvent and infrared light-absorbing substance, enabling selective heating of the ink layer. The medium, having different absorption characteristics in this wavelength range, remains relatively cool, preventing nozzle clogging while achieving rapid ink drying
4Object-affected harmful factors
If the heating temperature is lowered to prevent nozzle clogging, then the medium safety is improved, but the ink drying speed reduces making high speed printing difficult
Solution Approach 1:
The infrared light-absorbing substance acts as a mediator that enables decoupling of ink drying speed from medium temperature. By absorbing infrared energy and converting it to localized heat, this substance accelerates solvent evaporation from the ink layer without significantly heating the medium or nozzle. This allows high-speed printing to be achieved while maintaining safe operating temperatures that prevent nozzle clogging
Solution Approach 2:
The invention employs periodic or pulsed infrared irradiation that is synchronized with the ink ejection and drying process. Short bursts of infrared energy are applied at optimal intervals to accelerate solvent evaporation during the critical drying phase, while allowing the system to cool between pulses. This periodic action achieves rapid drying kinetics without sustaining high temperatures that would cause nozzle clogging
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 solution effectively dries the ink before smearing occurs while preventing temperature-related issues, allowing for high-quality printing with reduced nozzle clogging and maintaining medium temperature below 50°C, thus enhancing printing speed and quality.
Implementation Method 1
an infrared irradiating member that irradiates an infrared light in which a wavelength is smaller than or equal to 3 μm with respect to the ink on the medium
Implementation Method 2
the ejection head ejects the ink containing a solvent that generates heat by absorbing the infrared light
Implementation Method 3
the infrared irradiating member volatilizes and removes at least one part of the solvent in the ink by irradiating the infrared light with respect to the ink on the medium
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
There is provided a printing device (10) that carries out printing with respect to a medium (50); the printing device (10) including inkjet heads (102c-k), which are ejection heads that eject an ink to the medium (50); and an infrared irradiating member (104) that irradiates an infrared light in which a wavelength is smaller than or equal to 3 µm with respect to the ink on the medium (50); where the inkjet heads (102c-k) eject the ink containing a solvent that generates heat by absorbing the infrared light; and the infrared irradiating member (104) volatilizes and removes at least one part of the solvent in the ink by irradiating the infrared light with respect to the ink on the medium (50).