Web Conveyance Apparatus Tension Control via Speed Feedback
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Solution Overview
Problem
In printing apparatuses, maintaining a constant web tension without a tension detector is challenging, leading to potential ink landing position deviations and decreased print quality due to changes in web tension and conveyance speed.
Innovation Solution
A conveyance apparatus with a conveyance roller, motor, back tension roller, brake, and controller that adjusts the motor's drive control parameter and braking force to maintain target speed and tension without direct tension detection, using a base brake and adjustment brake to finely control braking force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a tension detector is installed to detect web tension and control the brake to maintain constant tension, then web tension stability is improved, but device complexity increases and conveyance failure risk increases
Solution Approach 1:
The patent removes the tension detector from the system and instead uses the conveyance speed detector output to indirectly control web tension. The controller calculates required braking force based on conveyance speed feedback, eliminating the need for direct tension detection while maintaining tension stability.
Solution Approach 2:
The patent introduces the conveyance speed detector output as an intermediary parameter to control web tension. Instead of directly detecting tension, the system uses conveyance speed as a mediator to infer and control tension state through the relationship between speed, torque, and tension.
2Manufacturing precision
If motor control is performed to maintain fixed conveyance speed, then ink landing position accuracy is improved, but web tension changes causing vibration and distance variation
Solution Approach 1:
The patent implements a feedback control system where the conveyance speed detector continuously monitors web speed, and the controller adjusts the brake output based on speed deviations. This feedback loop simultaneously maintains conveyance speed for print quality and stabilizes web tension by coordinating brake control with speed feedback.
Solution Approach 2:
The patent changes the control parameter from direct tension control to speed-based indirect control. By monitoring and controlling conveyance speed rather than directly controlling tension, the system achieves both speed stability for print quality and tension stability as a secondary effect.
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 solution allows for stable web tension and conveyance speed control, suppressing tension changes and oscillations, thus maintaining print quality without the need for a tension detector, simplifying the apparatus configuration and brake control.
Implementation Method 1
a brake connected to the back tension roller, and the back tension roller applies tension to the web by receiving the braking force of this brake
Implementation Method 2
a conveyance motor configured to drive the conveyance roller
Data Source
AI summary
A conveyance apparatus includes a conveyance roller, a conveyance motor, a back tension roller, a conveyance speed detector, a brake, and a controller. The controller is configured to: based on a conveyance speed of a web detected by the conveyance speed detector, control a value of a drive control parameter of the conveyance motor such that the conveyance speed of the web is equal to a target speed; and, based on an output torque of the conveyance motor corresponding to the value of the drive control parameter, adjust a braking force of the brake applied to the back tension roller which applies a tension to the web such that the tension of the web is equal to a target tension.