Printer Table Shim Layer for Print Gap Control
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Solution Overview
Problem
Existing methods for maintaining a uniform print gap in large inkjet printers face challenges due to irregularities in the substrate support surface and misalignment of the printhead, leading to variations in print quality and difficulty in achieving tight tolerances, which result in visible print artefacts and inefficiencies.
Innovation Solution
A method involving the measurement of the print gap using sensors and the application of a shim layer, printed with UV-curable ink or other materials, to mitigate variations in the print gap, ensuring a consistent distance between the printhead and the substrate, thereby improving print quality and reducing the need for frequent recalibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If heavy granite or thick rigid materials are used for the printer table to ensure rigidity and flatness, then the structural stability and flatness are improved, but the weight and cost increase significantly
Solution Approach 1:
Instead of making the entire printer table uniformly heavy and thick, the patent applies localized compensation by printing shim layers only at specific positions where gap variations occur. This allows the table to remain lightweight overall while achieving the required flatness and stability at critical locations through targeted material deposition.
Solution Approach 2:
The patent uses composite material structures by combining the base printer table (which can be lightweight materials like aluminium, carbon fibre or thin ceramic) with printed shim layers (UV-curable ink or other materials). This composite approach allows the lightweight base structure to achieve the required rigidity and flatness when combined with the compensating shim layers.
2Manufacturing precision
If the print gap is reduced to increase print resolution, then the print quality is improved, but the sensitivity to print gap variations increases leading to visible artefacts
Solution Approach 1:
The patent implements a feedback mechanism where the print gap is measured at multiple positions across the printing area, and the measured variations are used to generate compensation data. This feedback loop allows the system to detect and correct gap variations, enabling reduced print gaps to be used without producing visible artefacts.
Solution Approach 2:
The patent performs preliminary measurement of the print gap variations before actual printing. Based on these measurements, shim layers are printed in advance to compensate for anticipated gap variations. This preliminary compensation ensures that when the actual printing occurs at reduced gaps, uniform print quality is maintained without artefacts.
3Manufacturing precision
If tight tolerances on the print gap are imposed to maintain uniform print quality, then the print quality is improved, but the difficulty and cost of building the machine increases
Solution Approach 1:
The patent enables the printer to self-correct its own print gap variations by measuring the actual gaps and printing compensating shim layers. This self-service approach eliminates the need for complex mechanical adjustment mechanisms and precision manufacturing tolerances, as the system automatically compensates for variations through the printing process itself.
Solution Approach 2:
The patent changes the approach from maintaining fixed mechanical parameters (rigid table structure, precise alignment) to dynamic parameter adjustment through printed shim layers. The thickness and position of these layers are varied based on measured gap variations, allowing tight print gap tolerances to be achieved through material deposition rather than mechanical precision.
4Measurement precision
If the focal length is varied to accommodate table topography variations, then the focus accuracy is improved, but the process time increases and efficiency decreases
Solution Approach 1:
The patent performs preliminary measurement and compensation by printing shim layers to create a uniform print gap surface before the actual focused processing (laser treatment, imaging, etc.). This preliminary topography correction eliminates the need for frequent focal length adjustments during subsequent processing, maintaining both focus accuracy and high productivity.
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 approach significantly reduces print gap variations to less than 0.5mm, enhancing the smoothness and accuracy of the printing surface, leading to improved print quality and efficiency by maintaining a constant print gap across the printing area.
Implementation Method 1
The ink is UV-curable and is printed in a first area to form a first shim having a first thickness and printed in a second area to form a second shim having a second thickness
Data Source
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AI summary
Methods for adjusting the topography of a surface, such as for making a support surface substantially flat, e.g. for mitigating variations in a print gap, are described. The topography of the surface is first measured, and then a shim layer is printed to approximate the topography to a reference topography, the thickness of the layer being calculated using the measurements. For example the print gap comprising the distance between the surface of a printer table and printing means, such as a printhead. The print gap is first measured before at least one layer of ink is printed, using the printing means, at a selected position based on the measured print gap. The thickness of the layer of ink is selected to mitigate the variations in the print gap. In some embodiments, a substrate support surface may then be arranged over the printer table, so that the printed layer is disposed between the printer table and the substrate support surface. The apparatus can compensate for variations in the print gap due both to irregularities in the printer table surface and misalignment in mounting of the printing means. Also described is a printer table produced according to the methods described.