Drive Roller Positioning for Sheet Curl Prevention
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Solution Overview
Problem
Conventional sheet post-processing devices experience issues with sheet curling and alignment failures due to the front end portion of the sheet being curled downward and contacting the paper discharge tray, leading to paper jams.
Innovation Solution
A sheet post-processing device with a paper discharge roller pair that includes a driven roller and a drive roller, which can be moved between a nip position and a maximum separate position, with a drive controller managing their separation and contact to prevent excessive curling by aligning the sheets with a reference plate after the back edge passes through the supply roller pair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drive roller is placed at the maximum separate position to allow sheet transport onto the post-processing tray, then the sheet can be supplied to the post-processing path, but the front end portion of the sheet contacts the paper discharge tray and causes excessive curling
Solution Approach 1:
The drive roller is designed to dynamically change its position between the maximum separate position (for sheet supply) and the nip position (for alignment). This dynamic adjustment allows the system to optimize roller separation based on the operational phase, preventing sheet curling while maintaining efficient sheet supply to the post-processing tray
Solution Approach 2:
The drive roller is moved to the nip position in advance before sheet alignment is required. This preliminary action ensures that the roller is in the correct position to prevent sheet curling before the sheet reaches the critical area, thereby maintaining alignment reliability
2Manufacturing precision
If the drive roller is moved to the nip position to align sheets with the reference plate, then sheet alignment is achieved, but the front end portion of the sheet may be pressed against the paper discharge tray
Solution Approach 1:
The drive roller dynamically adjusts its position to the nip position only when needed for alignment, and returns to the maximum separate position when sheet supply is required. This dynamic control prevents the roller from continuously pressing sheets against the discharge tray, thereby eliminating excessive curling while maintaining alignment precision when needed
Solution Approach 2:
The drive roller alternates between the maximum separate position and the nip position in a periodic manner, corresponding to the sheet supply and alignment cycles. This periodic action ensures that the roller applies pressure only during the brief alignment phase, preventing continuous contact that would cause sheet curling
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents excessive curling and alignment failures by ensuring the front end of the sheet does not contact the paper discharge tray, thereby reducing paper jams and improving the reliability of the sheet alignment process.
Implementation Method 1
a nip portion is formed between the drive roller and the driven roller
Implementation Method 2
the drive roller is rotated in a positive rotation direction, and thus the stack of sheets is discharged to a paper discharge tray
Implementation Method 3
The paper discharge tray is inclined toward the upper side from an upstream side to a downstream side in a paper discharge direction
Data Source
AI summary
In a sheet post-processing device, the front end portion of a sheet (P) transported onto a post-processing tray makes contact with a paper discharge tray, and thus it is possible to prevent the sheet (P) from being curled excessively. When the first sheet (P) in a stack of sheets to be subjected to post-processing in a post-processing portion is transported onto the paper discharge tray, the standby position of a drive roller forming a paper discharge roller pair is set between the maximum separate position and a nip position on a driven roller.