Fine-Screen RGB Printing on Black Substrates for Color Saturation
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Solution Overview
Problem
Conventional RGB color printing using interference pigments faces challenges in producing sufficiently saturated prints with high color fidelity, particularly in creating a convincing yellow color impression, and achieving high print quality and efficiency for larger print series.
Innovation Solution
A multi-color printing process using red, green, and blue interference pigments applied on a black substrate with fine screens (at least 77 openings/cm) and a suitable binder, combined with a cylindrical printing process, ensures optimal ink application and color saturation, employing indirect or direct stencils and UV-curing or solvent-based inks to enhance print quality and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If interference pigments are used for RGB color printing, then additive color mixing can be achieved, but the prints lack sufficient color saturation and fidelity
Solution Approach 1:
The patent changes the physical parameters of the interference pigments by controlling their particle size distribution and using multiple size fractions. This allows optimization of both light reflection properties for color fidelity and sufficient pigment concentration for saturation, resolving the contradiction between these two requirements.
Solution Approach 2:
The invention uses composite ink formulations containing multiple types of interference pigments with different particle sizes and optical properties. This composite approach enables simultaneous achievement of high color fidelity through selective wavelength reflection and high saturation through increased pigment density in the printed layer.
2Ease of manufacture
If conventional screen printing is used with interference pigments, then the coarseness of pigments can be accommodated, but print quality and resolution are compromised
Solution Approach 1:
The patent segments the pigment population into different particle size fractions, with finer particles providing higher resolution capability and coarser particles providing sufficient saturation. This segmentation allows the ink to be accommodated by conventional screens while achieving high print quality through the finer fraction.
Solution Approach 2:
The invention applies different particle size distributions to different regions or layers of the printed material. Finer particles are used in areas requiring high detail and resolution, while coarser particles are used where saturation is paramount, optimizing both print quality and ease of manufacture locally.
3Reliability
If interference pigments are applied in thick layers to increase saturation, then color fidelity improves, but the pigments separate and print quality deteriorates
Solution Approach 1:
The patent modifies the rheological parameters of the ink binder to match the particle size distribution of the interference pigments. This ensures proper suspension and uniform distribution of pigments throughout the ink, preventing separation during application while maintaining thick enough layers for color fidelity.
Solution Approach 2:
The invention uses composite binder systems with specific viscosity and adhesion properties that prevent pigment separation. The binder composition is tailored to hold multiple particle size fractions uniformly suspended, allowing application of sufficiently thick layers for color fidelity without the pigments separating during or after printing.
4Manufacturing precision
If fine screens with at least 77 openings/cm are used, then print resolution improves, but ink application efficiency decreases for larger print series
Solution Approach 1:
The patent segments the ink into multiple passes or layers, with each pass applying a specific particle size fraction through the fine screen. This segmentation allows the fine screen to achieve high resolution while the cumulative effect of multiple passes builds up sufficient pigment concentration for saturation, maintaining productivity through efficient multi-layer application.
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 process achieves high-quality, saturated color impressions with improved yellow tone production and efficient printing of larger series, utilizing fine screens and cylindrical processes to overcome the limitations of coarseness and separation issues with interference pigments.
Implementation Method 1
Interference inks utilize interference effects on thin layers and thus create an angle-dependent color impression, i.e., an iridescent effect
Implementation Method 2
such collotypes involve passive, reflective light. This physical reflection behavior is due to the characteristics of the iridescent pigments used
Implementation Method 3
employing indirect or direct stencils and UV-curing or solvent-based inks to enhance print quality and efficiency
Data Source
Figure 1~2
Figure 3
AI summary
A multi-color printing process is presented in which a red, a green, and a blue printing ink are applied to a black-colored substrate (30). The red, the green, and the blue printing ink each have at least one interference pigment, wherein a printing form with a fine screen (23) with at least 77 openings/cm and with a stencil partially covering the screen is used for each of these printing inks, and the red, the green, and the blue printing ink are successively pressed through the openings of the screen onto the black-colored substrate wherever the screen of their printing form is not covered by the stencil, in order to each produce a single-color printed image. The single-color printed images, which are printed on top of one another, result in an overall multi-color printed image of particular quality and visual appearance.