Substrate Alignment Tension Control for Fast De-Skew Printing
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Solution Overview
Problem
Current automatic de-skew processes in large format printers are time-consuming and prone to creating substrate wrinkles due to slow convergence and the need for decoupling pinch wheels, which affects image quality.
Innovation Solution
A controller-based system that applies an initial alignment tension greater than the printing tension to rapidly align the substrate, allowing slippage between pinch rollers and substrate to correct skew, followed by transitioning to printing tension to prevent wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If long loading advances are used to align substrate, then substrate skew is reduced, but alignment time increases and productivity decreases
Solution Approach 1:
The system performs preliminary substrate alignment before printing by advancing the substrate a predetermined distance and applying tension to straighten skew. This preliminary alignment action ensures the substrate is properly positioned before the printing process begins, resolving the contradiction by preparing the substrate in advance rather than during printing operations.
Solution Approach 2:
The pinch roller assembly is designed to dynamically adjust between engaged and disengaged states. During alignment, the pinch rollers engage to apply tension and reduce skew. During printing, they disengage to prevent wrinkles. This dynamic adjustment allows the system to optimize for alignment precision when needed and for productivity during printing.
2Manufacturing precision
If pinch wheels are engaged during substrate advance, then substrate control is improved, but wrinkles are created on the substrate
Solution Approach 1:
The pinch roller assembly dynamically transitions between engaged and disengaged positions based on the operational phase. During substrate loading and alignment, the pinch rollers are engaged to provide control and tension. During the printing phase, they are disengaged to eliminate the harmful effect of wrinkles while maintaining substrate control through other means.
Solution Approach 2:
The substrate handling process is segmented into distinct phases: alignment phase where pinch rollers are engaged for control, and printing phase where they are disengaged to prevent wrinkles. This segmentation allows the system to apply different control strategies appropriate for each phase, eliminating the contradiction between control precision and wrinkle prevention.
3Object-generated harmful factors
If pinch wheels are raised between loading advances, then wrinkles are released, but the de-skew process becomes slower
Solution Approach 1:
The system performs wrinkle prevention as a preliminary action by disengaging the pinch rollers before the substrate advance occurs. Rather than allowing wrinkles to form and then releasing them (which wastes time), the system proactively prevents wrinkle formation by adjusting the pinch roller state in advance, thereby eliminating both the harmful factor and the time loss.
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
Rapid alignment reduces substrate skew and eliminates wrinkles, ensuring high-quality printing by minimizing substrate distortions and improving print efficiency.
Implementation Method 1
A predetermined pinch roller force less than a printing pinch roller force is applied to the substrate during the forward motion
Data Source
AI summary
Example implementations provide a controller comprising circuitry to align a substrate; the controller comprising: circuitry to control varying the tension of an unspooled portion of the substrate between a spool bearing the substrate and a pinch roller; said circuitry comprising circuitry to control varying the pinch load exerted by the pinch roller on the unspooled portion of the substrate.