Ceramic Inkjet Inks for Glass Substrates
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Solution Overview
Problem
Existing ceramic inkjet inks for glass surfaces face challenges such as ink splattering, spreading, and dust contamination leading to defects like fish-eyes and craters due to high solid content, shear thinning viscosity, and non-porous substrate issues, requiring clean room environments for printing.
Innovation Solution
Development of hybrid thermoplastic and photo-sensitive ceramic inkjet inks with viscosity ranging from 8-20 mPa.s at jetting temperature that significantly increase to over 100 mPa.s upon landing on the substrate, using frits, inorganic pigments, and solvents to maintain ink stability and prevent spreading, with additives for image retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high solid content ceramic ink is used, then ink coverage and color intensity are improved, but viscosity becomes too high for reliable jetting and causes nozzle blockage
Solution Approach 1:
The patent changes the temperature parameter of the ink from room temperature to elevated temperature (40-80°C) to reduce viscosity. This parameter change allows high solid content ink (40-60 wt%) to achieve jettable viscosity levels, resolving the contradiction between high solid content and jetting reliability
Solution Approach 2:
The patent introduces temperature as a dynamic control parameter for viscosity management. The ink viscosity is dynamically adjusted by controlling ink temperature during storage, jetting, and drying processes, enabling the system to adapt between high viscosity (for stability) and low viscosity (for jetting)
Solution Approach 3:
The patent applies preliminary heating to the ink before jetting to reduce viscosity to the optimal range (8-20 mPa.s). This preliminary action ensures the ink is in the correct rheological state for reliable jetting before it is deposited on the substrate
2Reliability
If ink viscosity is reduced for jetting, then jetting reliability is improved, but ink spreading and splattering increase after landing
Solution Approach 1:
The patent employs a two-stage drying process with different temperature phases: initial room temperature drying to prevent spreading, followed by elevated temperature drying to complete solvent evaporation. This periodic temperature action resolves the contradiction between low viscosity for jetting and high viscosity for image definition
Solution Approach 2:
The patent changes the temperature parameter dynamically: low temperature during initial drying to maintain high viscosity and prevent spreading, then elevated temperature to complete drying. This parameter change sequence allows the ink to exhibit different viscosity characteristics at different stages
3Use of energy by stationary object
If printing is performed at room temperature, then energy consumption is reduced, but dust contamination and image defects increase
Solution Approach 1:
The patent changes the temperature parameter of the drying process from room temperature to elevated temperature (40-80°C). This parameter change accelerates solvent evaporation and reduces drying time, thereby minimizing the window for dust contamination while maintaining energy efficiency through optimized drying cycles
4Reliability
If ink temperature is increased for jetting, then viscosity is reduced for better jetting, but ink stability and particle sedimentation worsen
Solution Approach 1:
The patent introduces temperature as a dynamic parameter that is elevated only during jetting operations and returned to room temperature for storage and transport. This dynamic temperature control allows the system to achieve jettable viscosity temporarily while maintaining ink stability during non-jetting periods
Solution Approach 2:
The patent applies preliminary heating to the ink system before jetting to ensure optimal viscosity, then rapidly cools or maintains at jetting temperature only during the brief jetting window. This preliminary and controlled heating action minimizes the time ink is exposed to elevated temperatures, preserving overall ink stability
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 inks provide high ink stability, reduce printhead drive voltage, eliminate ink splattering and spreading, and minimize dust-induced defects, allowing reliable printing on glass without external heating and maintaining image definition.
Implementation Method 1
the viscosity of the inks at the jetting temperature of 33-50°C is 8-20 mPa.s and increase substantially to more than a factor of 5 (greater than 100 mPa.s) after landing on the substrate
Data Source
Figure 1(a)~1(b)
Figure 2(a)~3(b)
AI summary
Ceramic inkjet inks for non-porous substrates (such as glass, metals) whereby the viscosity of the inks at the jetting temperature of 33-50°C is 8-20 mPa.s and increase substantially to more than a factor of 5 (greater than 100 mPa.s) after landing on the substrate. The invention also relates to processing/formulating steps and tuning of the bulk and dynamic properties suitable for (i) inkjet printing in the printhead channel and (ii) desirable high viscosity after landing on the glass substrate. The ink comprises: Glass Frit composition which is in the form of particles having a volume particle size distribution Dv90 of less than 1.5 µm, carriers (30-50wt %) and additives (0-10%). The ceramic ink mitigate ink splattering, spreading during and after landing, eliminate/reduce image defects because of dust contaminations from the environment on wet inks after printing