Unwind Roller Speed Feedback for Print Media Tension Control
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Solution Overview
Problem
In print apparatuses, maintaining optimal print media tension between the unwind roller and the print zone is crucial to prevent image defects such as banding, wrinkling, and jamming, which can occur due to variations in media tension that are not within a target range.
Innovation Solution
A closed-loop system is employed to measure print media tension in real-time using a load sensor and a PID controller to adjust the rotational speed of the unwind roller, ensuring the tension remains within a target range by correcting deviations through a servomotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotational speed of the unwind roller is increased to advance the print media faster, then the productivity is improved, but the media tension increases causing image defects such as banding and wrinkling
Solution Approach 1:
A load sensor measures the actual media tension in real-time, and this measurement is fed back to a controller that adjusts the unwind roller speed to maintain tension within a target range, allowing high-speed printing without image defects
Solution Approach 2:
The system dynamically changes the rotational speed parameter of the unwind roller based on measured tension conditions, adjusting speed within a range that maintains both high productivity and acceptable media tension for quality printing
2Reliability
If the media tension is increased to prevent slack and jamming, then the reliability is improved, but the media may become too taut causing image defects such as banding
Solution Approach 1:
The load sensor provides continuous feedback on media tension, enabling the controller to maintain tension within an optimal range that prevents both slack/jamming and excessive tautness, ensuring both reliability and image quality
3Manufacturing precision
If a load sensor and closed-loop control system is added to measure and control media tension, then the image quality is improved, but the device complexity increases
Solution Approach 1:
A load sensor measures media tension and feeds this information back to a controller that adjusts the unwind roller speed, creating a closed-loop system that automatically maintains optimal tension and prevents image defects
Solution Approach 2:
The system replaces manual or open-loop mechanical tension control with an automated electro-mechanical control system using a load sensor and servo motor, reducing the need for complex mechanical tensioning mechanisms
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 maintains consistent media tension, reducing image defects by ensuring the media is neither too taut nor too slack, thereby enhancing print quality and reducing errors.
Implementation Method 1
a sensor to measure the tension of the print media in a region between the unwind roller and the print zone
Implementation Method 2
a controller to control a rotational speed of the unwind roller based on the print media tension measured by the sensor
Data Source
AI summary
In one example, the tension in a print media may be determined in a region between a roller for unwinding the print media and a print zone. In this example, the rotational speed of the roller may be controlled based on the determined tension of the print media.