Web Tension Control in Multicolor Printing Presses
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Solution Overview
Problem
Multicolor rotary printing machines often produce waste or images of reduced quality due to changes in web tension between inking units, which can take a long time to stabilize, leading to unsteady web running conditions and register errors.
Innovation Solution
A device and method that use measuring means to record web tension values between inking units and adjust the tension based on those measurements, with a control device controlling the adjustment process to achieve a stationary web running state, involving prepositioning of cylinders and adjusting their angular position relative to each other to maintain longitudinal register and reduce waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If settings are changed on multicolor rotary printing machines (such as adjusting printing rollers or changing printing speed), then the printing parameters can be adapted to different requirements, but the web tension between inking units becomes unstable and print quality deteriorates
Solution Approach 1:
The patent implements a feedback control system where web tension is continuously measured between inking units and the measured values are fed back to a control device. The control device automatically adjusts printing parameters (such as printing roller positions or printing speed) to maintain stable web tension, thereby preserving print quality while allowing parameter changes. This closed-loop feedback mechanism resolves the contradiction by automatically compensating for the destabilizing effects of parameter adjustments.
2Manufacturing precision
If web tension is allowed to stabilize naturally after setting changes, then print quality can be maintained, but a long period of waste printing is required
Solution Approach 1:
The continuous web tension measurement and feedback control system enables real-time monitoring and adjustment, allowing the system to actively manage the transition to stable web tension rather than passively waiting. This reduces or eliminates the waste printing period while maintaining print quality.
Solution Approach 2:
The system performs preliminary adjustments based on predicted web tension changes before actual print quality deteriorates. By anticipating tension instability and making proactive corrections, the system prevents waste printing while maintaining quality standards.
3Stability of the object's composition
If web tension fluctuations occur during unsteady web running conditions, then the longitudinal register changes and register errors occur, but automatic adjustment processes take a very long time
Solution Approach 1:
The real-time web tension measurement and feedback control system enables immediate detection and correction of web tension fluctuations. This active control dramatically accelerates the stabilization process compared to natural self-adjustment, reducing the time loss while maintaining web running stability.
Solution Approach 2:
The patent replaces the slow natural mechanical self-adjustment process with an active control system that uses measurement feedback to drive rapid corrections. This substitution of passive mechanical adjustment with active controlled adjustment significantly reduces the stabilization time.
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 shortens the duration of unsteady web running states, reduces the amount of poor-quality prints, and minimizes waste by actively controlling web tension changes to reach a stable state more quickly.
Implementation Method 1
Devices for measuring web tension on printing machines include measuring rollers, in which the force that the web tension exerts on the axis of the roller can be measured.
Implementation Method 2
it has also become known to influence the web tension that exists in a printing press during printing by controlling the winding and unwinding or the feed-in and pull-out
Data Source
Figure 1
Figure 2~2c
Figure 3~3b
AI summary
The invention discloses a device for measuring and setting the web tension on a printing press (8) with several inking stations (Dn), in which measuring devices (Mm n) for measuring the web tension, and setting devices (Fn) for setting the web tension, are provided, with which the web tension can be actively set in the case of unsteady web tension conditions. The invention is characterized in that at least one measuring device (Mm n) and at least one setting device (Fn) is arranged such that the web tension can be measured and set between the print areas of two inking stations. A control device is hereby available that controls the at least one setting device based on the measured values of the at least one measuring device (Mm n).