Ink Leveling via Rapid Radiant Heating on Porous Substrates
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Solution Overview
Problem
Printing processes face challenges with microbanding and print-through issues on substrates due to ink permeation and freezing, particularly with UV-curable inks on porous substrates like plain paper, which affect image quality and substrate integrity.
Innovation Solution
Irradiating ink on substrates with radiant energy to heat it above the viscosity threshold temperature for lateral flow and leveling, minimizing heat transfer to prevent ink permeation, using a combination of marking and leveling devices with radiant energy sources like tungsten lamps or lasers to achieve rapid thermal reflow without significant substrate heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ink is heated to above viscosity threshold temperature for lateral flow and leveling, then ink leveling is improved, but ink permeation into substrate increases
Solution Approach 1:
The patent applies periodic/pulsed radiant energy heating to the ink, heating it rapidly above the viscosity threshold temperature to enable lateral flow and leveling, then quickly cooling it below the threshold to prevent permeation. This time-varying temperature control allows the ink to level when hot but remain on the substrate surface when cool, resolving the contradiction between leveling quality and ink retention.
Solution Approach 2:
The patent performs preliminary heating of the ink to above the viscosity threshold temperature before the ink can permeate into the substrate. By pre-heating the ink to achieve proper flow characteristics for leveling, then rapidly cooling it, the system ensures leveling occurs first and permeation is prevented subsequently, addressing the contradiction through sequential timing of thermal processes.
2Productivity
If radiant energy is applied to heat ink rapidly, then leveling speed is improved, but heat transfer to substrate increases causing print-through
Solution Approach 1:
The patent uses intense radiant energy to rapidly heat the ink through its critical temperature range for leveling in a very short time, essentially 'rushing through' the heating process before significant heat can conduct to the substrate. This rapid thermal cycle achieves fast leveling while minimizing substrate exposure to harmful heat, resolving the contradiction between productivity and substrate protection.
Solution Approach 2:
The patent replaces conventional slow thermal conduction heating with direct radiant energy heating (optical/thermal radiation). This substitution enables rapid, localized heating of the ink surface without requiring prolonged thermal exposure that would transfer excessive heat to the substrate, thus achieving fast leveling while protecting the substrate from print-through.
3Manufacturing precision
If ink viscosity is reduced for lateral flow, then ink leveling is improved, but ink permeation into substrate increases
Solution Approach 1:
The patent dynamically changes the temperature parameter of the ink, heating it above the viscosity threshold to reduce viscosity and enable lateral flow for leveling, then rapidly cooling it below the threshold to increase viscosity and prevent permeation. This time-dependent parameter control allows the ink to exhibit low viscosity when needed for leveling but high viscosity when needed for substrate protection, resolving the contradiction between leveling quality and substrate integrity.
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 effectively mitigates microbanding and print-through, ensuring high-quality images on various substrates with minimal ink penetration, maintaining substrate integrity and improving optical density while allowing for high-speed printing processes.
Implementation Method 1
irradiating ink disposed on a first surface of a porous substrate with first radiation emitted by at least one first radiant energy source. The first radiation heats the ink to at least a viscosity threshold temperature of the ink
Implementation Method 2
The ink is heated sufficiently rapidly that heat transfer from the ink to the substrate is sufficiently small during the leveling that ink at the substrate interface is cooled to a temperature below the viscosity threshold temperature thereby preventing any significant ink permeation into the substrate
Data Source
AI summary
Methods of leveling ink on substrates and apparatuses useful in printing are provided. An exemplary embodiment of the methods includes irradiating ink disposed on a surface of a porous substrate with radiation emitted by at least one radiant energy source. The radiation heats the ink to at least a viscosity threshold temperature of the ink to allow the ink to flow laterally on the surface to produce leveling of the ink. The ink is heated sufficiently rapidly that heat transfer from the ink to the substrate is sufficiently small during the leveling that ink at the substrate interface is cooled to a temperature below the viscosity threshold temperature thereby preventing any significant ink permeation into the substrate.