Inkjet Printing on Nonabsorbent Substrates with Water-Based Ink
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Solution Overview
Problem
Printing non-absorbent substrates with water-based ink using inkjet technology faces challenges such as ink spreading and poor wettability due to hydrophobic surfaces, leading to blurry or unusable images, especially on metallic substrates with surface tensions lower than the ink.
Innovation Solution
Increasing the surface tension of non-absorbent substrates to match or exceed that of the water-based ink, followed by immediate shock-like drying to prevent ink spreading, using pre-treatment methods like corona, plasma, or chemical processes, and employing inkjet printing with precise temperature control and air flow to fix ink drops in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If water-based ink is applied to non-absorbent substrate with hydrophobic surface, then environmental benefits and cost advantages are achieved, but ink spreading and poor wettability occur leading to blurry images
Solution Approach 1:
The patent applies preliminary surface treatment (corona, plasma, or chemical processes) to increase the surface tension of non-absorbent substrates before inkjet printing. This pretreatment modifies the substrate surface to achieve good wettability with water-based inks, preventing ink spreading and ensuring sharp print images while maintaining environmental benefits of water-based solvents.
2Manufacturing precision
If surface treatment is applied to increase surface tension, then good wettability is achieved, but possible negative effects on printed substrates may occur
Solution Approach 1:
The patent employs different surface treatment methods (corona discharge, plasma treatment, or chemical processes) that can be adjusted in intensity and duration to increase surface tension to the optimal range for water-based ink wettability. By controlling treatment parameters, the method achieves good wettability while avoiding excessive treatment that could damage the substrate or interfere with subsequent printing quality.
3Adaptability or versatility
If inkjet printing is performed on metallic substrates with low surface tension, then printing capability is maintained, but ink spreading occurs due to surface tension mismatch
Solution Approach 1:
The patent applies surface treatment specifically tailored for metallic substrates to increase their surface tension before inkjet printing. This preliminary modification of the metal surface creates optimal wettability conditions, allowing water-based inks to be deposited with precise droplet positioning without spreading, thereby maintaining printing versatility while improving image sharpness on metallic surfaces.
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
Achieves high-quality prints with complete wettability, low relief formation, high gloss, and environmental benefits, meeting packaging industry requirements while preventing disruptive abrasion and allowing for overpainting.
Implementation Method 1
the surface tension of the substrate to be printed is increased by a device (03) for pretreating the substrate (01) to be printed, in particular by a corona process, a plasma process, a chemical process, flame treatment or UV irradiation
Implementation Method 2
the surface tension of the substrate to be printed is increased by a device (03) for pretreating the substrate (01) to be printed, in particular by a corona process, a plasma process, a chemical process, flame treatment or UV irradiation
Implementation Method 3
the surface tension of the substrate to be printed is increased by a device (03) for pretreating the substrate (01) to be printed, in particular by a corona process, a plasma process, a chemical process, flame treatment or UV irradiation, wherein the increased surface tension of the substrate corresponds to at least the surface tension of the ink to be applied
Implementation Method 4
the workpiece carrier (04) is heated and the substrate (01) supported by the workpiece carrier (04) is heated within a very short time, in particular in the range of less than 1 second, wherein the ink applied to the substrate (01) is heated as a consequence
Implementation Method 5
the ink applied to the substrate (01) is dried within a very short time, in particular within 1 second, by heat input into the substrate (01) and/or into the applied ink
Implementation Method 6
the vapor layer which has formed above the liquid phase of the ink is transported away and thereby removed
Data Source
Figure 1
AI summary
The invention relates to a method for printing on a surface of a nonabsorbent substrate (01) with an ink to be applied by an inkjet printing device (02), wherein: an ink containing water as a solvent is used to print on the substrate (01), an ink having a water proportion of at least 70% being used; the substrate (01) to be printed on is supported by a workpiece support (04) and is moved relative to the inkjet printing device (02); during this relative movement, ink is applied by the inkjet printing device (02) to the surface of the substrate (01) to be printed on; the ink applied to the surface of the substrate (01) is heated to a temperature that lies above the temperature of the air surrounding the substrate (01) and below the boiling temperature of the of the solvent contained in the ink; a vapor layer consisting of the solvent contained in the ink is formed above a liquid phase of the ink; the vapor layer formed above the liquid phase of the ink is transported away by means of an air flow discharged from at least one blowing nozzle unit (06; 07); the air output by the blowing nozzle unit (06; 07) in question is heated and/or dehumidified beforehand. The invention further relates to a digital printing machine for carrying out said method.