Printing Apparatus Dynamic Tension Control for Winding Precision
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Solution Overview
Problem
Existing printing apparatuses face issues with irregular wound shapes and distortion of printed characters/graphics due to constant tension application, leading to poor precision and quality in medium winding processes.
Innovation Solution
A printing apparatus that adjusts front tension based on the diameter of the wound roll and offsets changes in tension by adjusting back tension, ensuring a consistent movement amount of the medium and preventing wrinkling and displacement, thereby maintaining high-precision printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If constant tension is applied to the medium during winding, then the medium is easily wound with regular shape, but the wound shape becomes irregular due to meandering movement
Solution Approach 1:
The patent applies dynamics by making the tension adjusting mechanism variable rather than fixed. The tension is dynamically adjusted based on the winding progress and medium state, allowing the system to adapt to changing conditions during the winding process and prevent both irregular winding shapes and meandering movements.
Solution Approach 2:
The patent changes the tension parameter from a constant value to a variable value that is adjusted according to winding conditions. By modifying the tension parameter dynamically, the system achieves both regular wound shape and precise winding position, resolving the contradiction between shape regularity and positioning precision.
2Stability of the object's composition
If smaller tension is applied to the medium, then the medium winds in loosely wound state, but the winding position is easily displaced
Solution Approach 1:
The system dynamically adjusts tension based on the winding state, transitioning from high tension during initial winding to maintain stability, then reducing tension as winding progresses. This dynamic control prevents both excessive displacement and overly tight winding, achieving optimal balance between stability and precision.
Solution Approach 2:
The tension adjusting mechanism incorporates feedback from the winding process, continuously monitoring and adapting tension levels. This feedback control ensures that tension is optimized at each stage of winding, preventing position displacement while maintaining winding stability throughout the entire process.
3Shape
If tension is changed to inhibit irregularity of wound shape, then wound shape regularity improves, but characters and graphics printed on the medium are distorted
Solution Approach 1:
The tension is dynamically adjusted only during the winding process, not during printing. The system applies high tension during winding to ensure regular shape, then maintains appropriate tension levels during printing to prevent distortion. This temporal separation of tension adjustment phases resolves the contradiction between wound shape regularity and printing precision.
Solution Approach 2:
The system performs preliminary tension adjustment during the winding phase before printing occurs. By establishing regular wound shape through preliminary high tension application, the system prepares the medium in advance, then maintains printing precision by avoiding excessive tension changes during the actual printing process.
4Shape
If front tension is adjusted to suppress wrinkling, then wound shape quality improves, but movement amount of medium changes
Solution Approach 1:
The system changes the front tension parameter to suppress wrinkling during winding, while simultaneously adjusting the back tension parameter to compensate for the movement amount change. This coordinated parameter adjustment ensures both high wound shape quality and consistent medium movement through the printing unit.
Solution Approach 2:
The back tension acts as a counterweight to the front tension adjustment. When front tension is increased to prevent wrinkling, the back tension is simultaneously adjusted to offset the resulting movement change, creating a balanced force system that maintains both shape quality and movement consistency.
Data Source
AI summary
A printing apparatus is provided with: a recording head that performs printing on a medium fed out from a transport roller pair; a feeding unit that feeds the medium to the transport roller pair; and a winding unit that winds, into a roll shape, the medium subjected to the printing by the recording head. The winding unit winds the medium while adjusting a front tension acting on the medium between the transport roller pair and the winding unit, depending on a diameter of the medium wound into the roll shape. The feeding unit feeds the medium while adjusting a back tension acting on the medium between the transport roller pair and the feeding unit, depending on changes in the front tension.