Ribbon Feeder Torque Dampers for Printer Tension Control
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Solution Overview
Problem
Conventional ribbon feeders in printers using transfer film ribbons face issues with ribbon tension variability, leading to wrinkles and compromised print quality, especially with wide ribbons, due to the need for extended tension arms and lack of effective wrinkle removal mechanisms.
Innovation Solution
The ribbon feeder incorporates torque dampers in the form of coil springs between motor shafts and feed/take-up rolls, with integrated ribbon tension detecting means that include movable members and a smoothing function to maintain accurate tension control and prevent wrinkles, utilizing stepping motors for quick tension adjustments and shock absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a long tension arm is used to remove looseness from the ribbon effectively, then the ribbon tension control is improved, but the installation space is reduced and the mechanism becomes more complex
Solution Approach 1:
The patent extracts the tension control function from the mechanical tension arm and relocates it to the torque damper component. The torque damper absorbs ribbon looseness through its inherent damping characteristics without requiring a long mechanical arm, thereby simplifying the overall mechanism while maintaining effective tension control.
Solution Approach 2:
The torque damper is designed to perform multiple functions: it provides shock absorption during motor operation, removes ribbon looseness, and contributes to tension standardization. This multi-functionality eliminates the need for separate tension control mechanisms, reducing device complexity while improving reliability.
2Reliability
If a conventional tension arm with ribbon retainer portion is used, then the ribbon engagement is achieved, but wrinkles on the ink ribbon cannot be removed
Solution Approach 1:
The patent changes the operational parameters of the torque damper to enable wrinkle removal. By adjusting the damping characteristics and operational range, the torque damper not only absorbs looseness but also applies sufficient force to smooth out wrinkles in the ribbon, thereby eliminating harmful factors while maintaining reliable engagement.
3Productivity
If the ribbon feed motor and take-up motor operate with pulsating rotation, then the ribbon is fed and wound, but shocks are generated that affect tension stability
Solution Approach 1:
The torque damper is positioned in the power transmission path between the motor and the ribbon winding mechanism to provide beforehand cushioning. It absorbs shocks generated by pulsating motor rotation before they reach the ribbon, thereby maintaining tension stability while allowing the motor to operate at high productivity.
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 configuration allows for compact design, precise tension control, and effective wrinkle elimination, ensuring high print quality by independently managing ribbon tension on both sides of the platen and absorbing shocks from motor pulsations.
Implementation Method 1
The torque dampers are formed of coil springs such that they are rewound on the ribbon feed roll side as the ribbon feed motor rotates and are tightened on the ribbon take-up roll side as the ribbon take-up motor rotates
Data Source
AI summary
Ribbon tension detecting means (20, 21), which are formed of a plate-like lever body (35) each, are located individually on the upstream side and the downstream side of a platen (7) with respect to its travel. The plate-like lever body (35) has first and second rollers (47, 48) on the upstream and downstream sides with respect to travel of a ribbon, and swings around an axis of rotation of the second roller (48), depending on a tension of the ribbon traveling guided by the rollers (47, 48). If the amount of its swing is not less than or not more than a fixed value, a ribbon feed motor (18) or a ribbon take-up motor (19) is driven. Further, the ribbon tension detecting means (20, 21) are provided with a smoothing member which touches the ink ribbon (13) to remove wrinkles from the ink ribbon (13).