Sheet Folding Apparatus Roller Rotation Control
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Solution Overview
Problem
Conventional sheet folding apparatuses face challenges in achieving accurate second folding positions due to slipping issues when the pushing member contacts the moving sheet, leading to inconsistent folding accuracy.
Innovation Solution
The apparatus employs a control unit that manages the rotation and movement of rollers and pushing members to perform first and second foldings, including pausing the rollers during the second folding to ensure precise alignment and reactivation timing based on sheet count, using a stepping motor and encoder for precise control, and incorporating a crease marking unit for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pushing member moves forward to push the sheet in the second nip while the rollers are rotating, then the folding operation can be performed continuously, but the pushing member slips on the moving sheet surface causing inaccurate folding position
Solution Approach 1:
The roller rotation is periodically controlled: rotated during sheet conveyance and first folding, then stopped during the second folding operation. This periodic action allows the pushing member to contact the sheet at a controlled position without slipping, as the sheet is stationary relative to the roller during the second folding push.
Solution Approach 2:
The system dynamically adjusts the roller rotation state based on the folding stage. The roller rotates during sheet conveyance and first folding, then stops during the second folding operation. This dynamic control enables the pushing member to accurately position and push the sheet without slipping, while maintaining continuous overall operation capability.
2Speed
If the pushing member speed is increased to compensate for sheet conveyance speed, then the folding operation remains continuous, but the pushing member still slips on the moving sheet surface
Solution Approach 1:
Instead of increasing pushing member speed continuously, the system uses periodic roller rotation control. The roller stops during the second folding operation, creating a controlled stationary condition that eliminates slipping regardless of pushing member speed, thereby achieving accurate folding position.
3Manufacturing precision
If the roller rotation is stopped during the second folding operation, then the pushing member can accurately contact the sheet, but the sheet conveyance is interrupted
Solution Approach 1:
The roller rotation is implemented periodically: rotated during sheet conveyance and first folding operations, then stopped during the second folding operation. This periodic action allows accurate second folding while maintaining overall continuous operation capability through the rotation-conveyance-rotation pattern.
Solution Approach 2:
The sheet is conveyed and positioned using roller rotation before the second folding operation. By stopping the roller during the second folding, the sheet is already in the correct position, allowing accurate folding without interrupting the overall conveyance process.
Data Source
AI summary
Disclosed is a sheet folding apparatus which performs a first folding and a second folding on one or a plurality of sheets including a first roller which is one of rollers that form a first nip which performs the first folding, a second roller which forms the first nip with the first roller, a third roller which forms a second nip with the second roller which performs the second folding, a roller drive unit which operates the first, second and third rollers, a first pushing member which pushes a sheet in the first nip, a first push drive unit which operates the first pushing member, a second pushing member which pushes the sheet in the second nip, a second push drive unit which operates the second pushing member, and a control unit which controls the roller driver unit, the first push drive unit and the second push drive unit.