Ribbon Drive Assembly Torque Control for Constant Tension
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Solution Overview
Problem
Conventional thermal transfer printers face challenges in maintaining constant ribbon tension due to fluctuating spindle radii, requiring mechanical systems like springs and clutches, and are not adaptable for coated side in or out ribbons without reconfiguration, leading to varying tension and operational instability.
Innovation Solution
A ribbon drive assembly with independently controlled supply and take-up spindles, each equipped with motors, gears, and rotary encoders, connected to a control processor that continuously adjusts torque based on real-time data to maintain constant tension, allowing for electronic selection of tension values and compatibility with various ribbon types and orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical systems with springs and clutches are used to maintain constant ribbon tension, then tension stability is improved, but device complexity increases
Solution Approach 1:
The patent replaces conventional mechanical tensioning systems (springs and clutches) with an electronic control system that uses motors with encoders to control spindle rotation. The control processor continuously adjusts motor torque based on encoder feedback and radius calculations, eliminating complex mechanical components while maintaining constant ribbon tension through electronic regulation of supply and take-up spindles.
2Adaptability or versatility
If mechanical reconfiguration is performed to support different ribbon types, then adaptability is improved, but ease of operation deteriorates
Solution Approach 1:
The patent implements dynamic control where the system automatically adapts to different ribbon types through electronic parameter adjustment rather than mechanical reconfiguration. The control processor dynamically calculates required torque based on real-time radius measurements from encoders and adjusts motor output accordingly, allowing the same mechanical system to handle various ribbon widths, compositions, and wind directions without physical changes.
Solution Approach 2:
The system changes operational parameters (motor torque, rotation speed, tension force) through electronic control to accommodate different ribbon types. By continuously monitoring spindle radius via encoders and adjusting torque parameters in real-time, the system adapts to various ribbon characteristics without requiring mechanical reconfiguration, thereby improving ease of operation while maintaining versatility.
3Device complexity
If spindle torque is kept constant, then device complexity is reduced, but manufacturing precision deteriorates
Solution Approach 1:
The patent employs feedback control where rotary encoders on both supply and take-up spindles continuously measure the actual radius of ribbon rolls. The control processor uses this feedback to calculate the current radius and adjusts motor torque accordingly to maintain constant ribbon tension. This closed-loop feedback system ensures precise tension control while using relatively simple motor and encoder components.
Data Source
AI summary
A ribbon drive assembly for optimizing the tension across a ribbon supply in a thermal transfer printer comprising a supply spindle and a take up spindle operable for cooperating with each other such that the ribbon supply is fed from the supply spindle through a print station and metered onto the take up spindle. Each spindle is provided with and connected to a motor, a plurality of gears, and a rotary encoder such that the spindles may be independently controlled by a control processor. The control processor is operable for monitoring, detecting, and controlling the operation of the motors and spindles. During operation and in order to maintain a constant ribbon tension, the torque on the motors are continuously adjusted in accordance with various data provided by the printer's processor.