Substrate Transport Grippers for Variable Pitch Printing
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Solution Overview
Problem
Existing substrate transport systems in printing machines face challenges such as substrate deformation, inkjet printhead suction issues, and inflexibility in handling substrates of varying sizes and thicknesses, leading to inaccurate printing and cumbersome adjustments.
Innovation Solution
A substrate transport system with adjustable gripping means and motorized guides that can adapt to different substrate sizes and thicknesses, allowing for variable pitch printing and precise tensioning to accommodate various substrates, while minimizing contact with printheads to prevent suction and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If suction belts are used to transport substrates, then substrates can be maintained and tensioned against moving belts, but air movements and pressure gradients cause deformation of large substrates and affect printing accuracy
Solution Approach 1:
The invention removes the suction belt system from the transport mechanism and replaces it with a mechanical gripper system. This extraction eliminates the source of air movements and pressure gradients that caused substrate deformation, while maintaining the ability to tension and transport substrates through direct mechanical gripping at multiple points along the transport path.
Solution Approach 2:
The invention introduces intermediary gripping elements (grippers) that contact the substrate at multiple discrete points along the transport path. These intermediaries provide localized support and tensioning without creating the continuous air pressure differentials that deform substrates, thereby maintaining printing accuracy while preserving substrate stability.
2Productivity
If suction belts are used for substrate transport, then substrates can be conveyed, but inkjet printheads become unprimed due to accidental suction of ink
Solution Approach 1:
The invention extracts the suction-based transport mechanism and replaces it with a mechanical gripper system that does not create negative pressure. This eliminates the accidental suction of ink from printheads, preventing depriming while maintaining continuous substrate conveyance through mechanical gripping and transport.
Solution Approach 2:
The invention replaces the pneumatic suction system with a mechanical gripping system. The mechanical grippers physically hold and transport substrates without creating pressure differentials that would otherwise suction ink from the printheads, thus preserving printhead reliability while maintaining productivity.
3Manufacturing precision
If cylinders with grippers are used to transport substrates, then substrate movement precision is improved, but inkjet heads must be arranged in orbital manner around large dimension cylinder requiring tedious adjustments
Solution Approach 1:
The invention segments the substrate transport into discrete gripping points along a linear or simple curved path rather than requiring a large orbital cylinder. Multiple grippers are distributed along the transport path, each providing localized control, which simplifies the overall geometry and reduces the complexity of printhead arrangement while maintaining precision.
Solution Approach 2:
Instead of arranging printheads in an orbital manner around a large cylinder, the invention inverts the approach by using a simpler transport geometry where printheads can be positioned more directly. This inversion of the transport mechanism simplifies the printhead arrangement from complex orbital positioning to more straightforward configurations.
4Device complexity
If fixed print pitch is used in cylinder systems, then substrate transport is simplified, but print rate remains the same regardless of substrate size requiring stopping for adjustments
Solution Approach 1:
The invention introduces dynamic adjustability to the transport system through independently controllable grippers that can adapt their positioning and spacing according to substrate size. This dynamic capability allows the system to maintain simplicity in its basic mechanism while gaining the versatility to handle various substrate sizes without stopping, as the gripper configuration can be adjusted during operation.
Solution Approach 2:
The invention enables parameter changes in the transport system by allowing adjustment of gripper positions and spacing based on substrate dimensions. This parameter adaptability permits the same transport mechanism to accommodate different substrate sizes by modifying operational parameters rather than requiring physical reconfiguration or stopping, thereby enhancing versatility while maintaining operational simplicity.
Data Source
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AI summary
The invention relates to a novel device and a novel method for transporting printable substrates in a precise manner, suitable for various types, sizes and thicknesses of substrate. The invention is also suitable for printing machines that do not come into contact with the substrate, such as ink-jet printing machines.