Continuous Sheet Conveyance Control for Stable Recording Tension
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Solution Overview
Problem
Existing recording apparatuses experience significant variations in sheet tension during speed changes, leading to increased time to stabilize tension and resulting in wasted sheets (broke) due to inefficient control methods.
Innovation Solution
A recording apparatus with a control unit that controls the speeds of first and second conveyance rollers, starting with the second roller at a first speed while the first roller is stopped, then increasing the second roller to a second speed and the first roller to a third speed, which is slower than the second, to stabilize sheet tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the infeed roller is reversely rotated to remove sheet slack before acceleration, then the sheet tension is applied before recording start, but a variation in sheet tension increases for transition from reverse rotation to normal rotation
Solution Approach 1:
The invention applies preliminary action by removing sheet slack through reverse rotation of the infeed roller before acceleration, but improves upon this by carefully controlling the transition phase. The control unit manages the acceleration process to minimize tension variation during the transition from reverse to normal rotation, allowing the sheet to reach a predetermined tension value faster while maintaining stability.
2Speed
If the speed of the infeed roller is increased to the recording speed, then recording can be performed, but it takes a longer time for the speed to settle down to a predetermined tension value
Solution Approach 1:
The invention applies dynamics by implementing a multi-stage acceleration control strategy. The control unit increases the infeed roller speed in controlled increments rather than a single abrupt change, allowing the sheet tension to stabilize at each stage. This dynamic approach enables faster overall acceleration while maintaining tension stability, reducing the time to reach predetermined tension values.
3Stability of the object's composition
If torque lower limit restriction is imposed on clutch control, then hunting of tension can be suppressed, but it takes a longer time to reach a prescribed tension value
Solution Approach 1:
The invention applies parameter changes by dynamically adjusting the torque control parameters of the clutch based on the operational phase. During the acceleration phase, the control unit temporarily modifies the torque lower limit restriction to allow faster tension establishment, then transitions to stricter control once the predetermined tension value is approached. This parameter adaptation enables both faster response and tension stability.
Data Source
AI summary
With a recording apparatus for performing recording onto a continuous sheet to be conveyed, for starting conveyance of the continuous sheet, control is started so that with a first conveyance roller for conveying the continuous sheet on the upstream side of a recording portion in a conveyance path of a continuous sheet being stopped, the speed of a second conveyance roller for conveying the continuous sheet on the downstream side of the recording portion in the conveyance path becomes a first speed, and control is changed so that the speed of the second conveyance roller becomes a second speed faster than the first speed, and moreover control of the first conveyance roller is started so that the speed of the first conveyance roller may become a third speed faster than the first speed and slower than the second speed.