Sheet Conveying Apparatus Loop Control for Wrinkle Prevention
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Solution Overview
Problem
Conventional sheet conveying systems fail to prevent wrinkles in sheets due to torsion and shear forces generated during skew feeding correction, especially in sheets with low rigidity and long conveying distances, leading to kinking and wrinkle formation when passing through registration rollers.
Innovation Solution
A sheet conveying apparatus with a controller that switches between two control modes: one where the loop formed during skew feeding correction is maintained, and another where the loop is dissolved, allowing the sheet to be conveyed without back tension, thereby preventing torsion and shear forces from causing wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a loop is formed between two pairs of rollers to perform skew feeding correction, then the head side of the sheet is corrected, but torsion is generated in the loop and the tail side remains in skew feeding position
Solution Approach 1:
The patent applies dynamics by making the roller pair configuration changeable between two states: a first configuration where rollers form a loop for skew correction, and a second configuration where rollers are positioned closer to convey sheets without forming a loop. This dynamic reconfiguration allows the system to adapt between skew correction mode and normal conveyance mode, preventing torsion while maintaining correction capability when needed.
2Manufacturing precision
If the sheet is conveyed in a loop state, then skew feeding correction is maintained, but shear force increases and causes kinking
Solution Approach 1:
The system dynamically switches between loop formation mode and direct conveyance mode by repositioning the roller pairs. During skew correction, the loop configuration is used temporarily, then the system transitions to the second configuration where rollers are positioned closer together, eliminating the loop and reducing shear force to prevent kinking while maintaining conveyance function.
3Productivity
If the distance between two pairs of rollers is shortened, then response to various media is improved, but wrinkle generation is increased
Solution Approach 1:
The patent employs dynamic reconfiguration of the roller pair system, allowing it to operate in two distinct modes: a first mode with larger roller spacing optimized for skew feeding correction of various media types, and a second mode with reduced spacing that minimizes wrinkle generation during high-speed conveyance. The controller selects the appropriate configuration based on the operational requirements.
Data Source
AI summary
A sheet conveying apparatus includes a pair of first conveying rollers, a pair of second conveying rollers provided at a downstream of the pair of first conveying rollers in a conveying direction of a sheet, a loop being formed in the sheet when a head of the sheet conveyed by the pair of first conveying rollers butts against the pair of second conveying rollers, and a controller which executes a first control mode in which the sheet is conveyed by the pair of first conveying rollers and the pair of second conveying rollers without dissolving the loop formed in the sheet, or a second control mode in which the loop formed in the sheet is dissolved, and the sheet nipped by the pair of first conveying rollers and the pair of second conveying rollers is conveyed.