Roll Paper Conveyance Torque Control for Skew Prevention
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Solution Overview
Problem
Conventional printing apparatuses face challenges in maintaining stable back tension during roll paper conveyance, leading to issues such as sheet slippage, skewed conveyance, and reduced conveyance accuracy due to inadequate torque control during acceleration and deceleration phases.
Innovation Solution
A printing apparatus with a conveyance system that includes a feed motor and a conveyance motor, where the torque applied by each motor is dynamically controlled across different phases of the conveyance operation (acceleration, steady, and deceleration) to maintain optimal back tension and prevent sheet slippage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a large force is applied to pull out the sheet portion from the heavy roll paper, then the sheet can be conveyed, but the sheet may be torn
Solution Approach 1:
The pulling force is segmented into two independent components: the conveyance motor drives the conveyance roller to pull the sheet, while the roll paper motor independently rotates the roll paper. This segmentation allows each motor to contribute appropriately to the overall pulling force, preventing excessive force on the sheet while ensuring adequate conveyance capability.
Solution Approach 2:
The system dynamically coordinates the operation of two motors based on real-time conditions. The control unit adjusts the driving forces of both the conveyance motor and roll paper motor during acceleration, steady conveyance, and deceleration phases, optimizing the force distribution to prevent sheet damage while maintaining conveyance efficiency.
2Stability of the object's composition
If the sheet portion is always given a tension to prevent skewed conveyance, then conveyance stability improves, but the sheet may slip on the conveyance roller and conveyance accuracy decreases
Solution Approach 1:
The back tension is dynamically adjusted according to the conveyance phase. During acceleration, a larger back tension stabilizes the sheet; during steady conveyance, the back tension is reduced to prevent slippage and maintain accuracy. This dynamic adjustment resolves the contradiction between stability and precision.
Solution Approach 2:
The system changes the back tension parameter based on operational requirements. By varying the torque applied by the roll paper motor according to the conveyance phase (acceleration, steady, deceleration), the system optimizes both conveyance stability and accuracy for each phase.
3Ease of operation
If conventional torque control is used during acceleration and deceleration, then the system is simple to operate, but back tension varies and conveyance accuracy decreases
Solution Approach 1:
The control system dynamically adjusts torque based on the conveyance phase without requiring complex manual intervention. The control unit automatically implements different torque strategies for acceleration, steady conveyance, and deceleration, maintaining high precision while keeping the operation simple for the user.
Solution Approach 2:
The system uses feedback from encoders and current detectors to monitor the actual conveyance state and adjusts the motor torques accordingly. This closed-loop control maintains conveyance accuracy during acceleration and deceleration while keeping the system easy to operate through automatic adjustment.
Data Source
AI summary
This invention has been made to cause a printing apparatus for conveying roll paper and performing printing to simultaneously attain a stable conveyance accuracy and prevent skewed conveyance independently of LF roller driving conditions and disturbance conditions that variously change as the roll paper state changes. For this purpose, a feed motor is used as a load generator for the roll paper. A section from a conveyance operation by the LF roller to the next conveyance operation is divided into a plurality of sub-sections. A feed mechanism is controlled by switching between a feeder load generation section and a feeder load zero section for each sub-section.