Heated Gas Nozzle Drying for High-Speed Inkjet Printing
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Solution Overview
Problem
Existing inkjet printers face challenges in rapidly evaporating solvents from ink deposits, particularly in high-speed applications, leading to inefficiencies and safety concerns with high volatile solvents, and existing drying solutions are not suitable for small printheads or production line integration.
Innovation Solution
A small size dryer mechanism using a heated gas stream with controlled velocity and shape is applied downstream of the printhead to enhance solvent evaporation, utilizing low volatile solvents like water, and incorporating features such as gas amplifiers and Coanda effect to optimize drying time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If high volatile solvents (MEK, methanol) are used to speed up drying, then drying time is reduced, but safety and regulatory compliance deteriorate
Solution Approach 1:
The invention changes the drying mechanism from relying on solvent volatility to using external thermal energy input. By applying heated gas streams with controlled temperature and velocity parameters, the system achieves rapid drying of low volatile solvents without requiring the solvents to be highly volatile, thus resolving the safety-compliance issue while maintaining fast drying times
Solution Approach 2:
The invention replaces the natural evaporation mechanism (passive) with an active thermal field (heated gas stream). This substitution allows control over drying rate through gas temperature and velocity parameters rather than relying on solvent vapor pressure, enabling use of safer low volatile solvents
2Loss of time
If conventional drying solutions (heaters, high intensity light sources) are used, then drying speed is improved, but device size and complexity increase
Solution Approach 1:
The invention uses pneumatic principles by employing gas streams (typically air) as the drying medium. The gas is delivered through nozzles that create focused jets or sheets, utilizing fluid dynamics to concentrate thermal energy on the ink deposit. This approach avoids bulky heating elements or light sources while achieving rapid drying through controlled gas flow parameters
Solution Approach 2:
The invention applies drying energy locally and selectively to the ink deposit area rather than heating the entire substrate or environment. Gas nozzles are positioned to deliver heated gas precisely where needed, creating a localized thermal field that speeds drying without requiring large-scale heating infrastructure
3Productivity
If high-speed printing is implemented, then productivity increases, but drying completeness deteriorates
Solution Approach 1:
The invention applies preliminary heating action to the ink deposit immediately after printing. The heated gas stream is introduced right behind the printhead, providing thermal energy to the solvent before the substrate moves away. This preliminary thermal treatment ensures complete drying even at high line speeds where the substrate passes through the drying zone quickly
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 reduces drying time to match high volatile solvent-based inks, allowing for high-speed printing without production line speed reductions and enabling the use of low volatile solvents that comply with safety regulations.
Implementation Method 1
The solvent flows away due to an evaporation mechanism meaning that the solvent is changing its thermodynamic state from liquid to gas
Implementation Method 2
a small size dryer mechanism comprising an efficient gas stream... using a heated gas stream on or over the printed pattern
Implementation Method 3
incorporating features such as gas amplifiers and Coanda effect to optimize drying time
Data Source
AI summary
An arrangement in communication with a printer. The printer includes at least a print-head configured to deposit liquid ink on an area on a surface of a substrate. The liquid ink comprises a solvent portion and a dry content. The arrangement comprises at least one nozzle configured to generate a stream of gas over said area with a gas stream velocity and/or gas stream shape, such that an evaporation rate of the solvent portion of the liquid ink is increased and a rate of change of velocity of the gas stream propagation increases with a distance normal to a direction of a gas flow and is maximized over the surface of the substrate and the deposited ink.