Printer Paper Carriage Mechanism with Movable Subframe for Backlash Control
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Solution Overview
Problem
Conventional printers used in POS terminals, cash registers, photocopiers, and facsimiles experience pitch fluctuations and instability in gear backlash due to varying belt lengths and complex structures, which affect printing quality.
Innovation Solution
A paper carrying mechanism with a base frame, upper frame, platen pulley, subframe, reduction gear, belt pulley, drive gear, and a spring that applies tension to a drive belt between the pulleys, maintaining constant engagement and reducing backlash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a first drive system with multiple reduction gears is used, then torque transmission is achieved, but the distances between gear shafts are not maintained constant causing unstable backlash and pitch fluctuations
Solution Approach 1:
The subframe is made movable relative to the upper frame, allowing the positions of the reduction gears and belt pulley to adjust dynamically. This maintains constant distances between gear shafts during operation, ensuring stable backlash while preserving torque transmission capability.
2Reliability
If a second drive system with tension roller is used, then belt tension is maintained constant, but the structure becomes complicated and backlash problem is not solved
Solution Approach 1:
Instead of adding a tension roller, the invention makes the subframe movable to dynamically adjust belt tension through position changes. This simplifies the structure by eliminating the tension roller while maintaining constant belt tension through the movable configuration.
3Manufacturing precision
If the subframe is made movable to maintain constant gear shaft distances, then backlash is stabilized, but the structure becomes more complex
Solution Approach 1:
The movable subframe serves multiple functions simultaneously: it maintains constant distances between gear shafts for stable backlash, adjusts belt tension, and positions the platen pulley correctly. This multi-functionality avoids adding separate components, thereby simplifying rather than complicating the overall structure.
4Adaptability or versatility
If belt length varies, then adaptability is improved, but maintaining constant tension becomes difficult
Solution Approach 1:
The movable subframe allows the belt length to vary dynamically while automatically maintaining constant tension through position adjustments. As the subframe moves, it compensates for belt length variations, ensuring reliable tension without requiring additional tensioning mechanisms.
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 stabilizes the paper carrying process, eliminates pitch fluctuations, and simplifies the structure by maintaining consistent gear engagement and belt tension, ensuring stable printing.
Implementation Method 1
a spring (23) attached between the upper frame (21) and the subframe (22), the spring (23) applying tension to the drive belt (25)
Data Source
AI summary
In a printer including a base frame, an upper frame rotatably coupled to the base frame, and a platen and a platen pulley both rotatably supported by the upper frame, a subframe is attached to the upper frame rotatably and movably in one direction. A reduction gear and a belt pulley both are rotatably supported by the subframe. A drive gear is rotatably supported by the base frame and engaged with the reduction gear. A drive belt is stretched between the platen pulley and the belt pulley. A spring is attached between the upper frame and the subframe. The base frame has a guiding portion concentric with the drive gear. The subframe has a guided portion opposite the guiding portion. The spring applies tension to the drive belt and brings the guided portion into contact with the guiding portion.