Ribbon Tension Control via Dynamic Braking and Dancer Roller
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Solution Overview
Problem
In thermal transfer printing systems, rapid changes in print ribbon tension due to varying torque applied by the windup spindle can lead to blurry or incomplete images, as the unwind spindle spins uncontrollably and the ribbon tension becomes unstable.
Innovation Solution
A ribbon tension control system utilizing a cam lobe, dancer roller, tension control member, articulating arm, and brake to adjust the path of the print ribbon and vary the braking force applied to the unwind spindle, maintaining tension within designated limits by resisting lateral movement of the dancer roller and altering the braking force in response to changes in torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the windup spindle applies varying torque to pull the ribbon through the printing system, then the printing process can be controlled, but the ribbon tension changes rapidly causing the unwind spindle to spin uncontrollably
Solution Approach 1:
The system uses a tension control apparatus that continuously monitors ribbon tension and provides feedback control. When tension exceeds predetermined limits, the apparatus automatically adjusts the braking force applied to the unwind spindle to maintain tension within acceptable ranges, preventing uncontrollable spinning while allowing controlled printing operation.
Solution Approach 2:
The system dynamically changes the braking parameter applied to the unwind spindle based on real-time tension conditions. The tension control apparatus adjusts the braking force magnitude and duration in response to varying ribbon tension, allowing the system to adapt to different printing conditions and maintain stable tension despite varying torque application.
2Speed
If the ribbon tension changes rapidly, then the printing speed can be adjusted, but the images printed become blurry or incomplete
Solution Approach 1:
The tension control apparatus applies preliminary braking action to the unwind spindle before rapid tension changes can affect image quality. By anticipating and counteracting tension fluctuations through controlled braking, the system prevents the ribbon from going too tight or too loose during high-speed printing, thereby maintaining image quality while allowing speed adjustment.
3Force
If a friction brake is used to control the unwind spindle, then the ribbon tension can be controlled, but the brake must handle rapid torque changes without causing uncontrollable spinning
Solution Approach 1:
The system employs a dynamic braking control mechanism where the braking force is continuously adjusted based on real-time tension conditions. Rather than using a static brake setting, the tension control apparatus dynamically modulates the braking force to match varying torque application, ensuring reliable control under changing operating conditions and preventing uncontrollable spinning.
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 stabilizes print ribbon tension, preventing uncontrollable spinning of the unwind spindle and ensuring consistent image quality by maintaining tension within predefined limits, thereby preventing issues like blurriness or incomplete prints.
Implementation Method 1
The brake is coupled with the articulating arm and is configured to engage at least one of an unwind spindle or a flange coupled to the unwind spindle to apply a braking force to the unwind spindle
Data Source
AI summary
A ribbon tension control system for a printing system includes a ribbon tension control apparatus. The ribbon tension control apparatus is configured to engage a print ribbon that extends through the printing system for applying one or more inks in the print ribbon to one or more target objects as the print ribbon is pulled from an unwind spindle to a windup spindle in the printing system. The ribbon tension control apparatus also is configured to control tension in the ribbon in response to change in a torque applied to the windup spindle that is used to pull the ribbon through the printing system.