Sheet Conveyance Roller Separation Timing Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional sheet conveying systems in image forming apparatuses face issues with skew correction, leading to potential wrinkles, scratches, and sheet jams due to conveyance resistance, especially after skew correction, which can worsen image position deviation and sheet conveyance problems.
Innovation Solution
A sheet conveying apparatus with a first pair of rollers for initial conveyance, a second pair for loop formation, a separating mechanism, and a controller to optimize the separation timing based on different conveyance paths, reducing loop reaction forces and conveyance resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the pair of pre-registration rollers is separated immediately after skew correction, then the nipping on the sheet is released to prevent stress, but the conveyance resistance due to slide friction between the sheet and the conveyance guide becomes large, causing skew feeding or turning
Solution Approach 1:
The patent applies dynamics by making the roller separation timing adjustable rather than fixed. The controller dynamically determines when to separate the pre-registration rollers based on detected sheet conveyance state, allowing the system to adapt between maintaining nipping (to reduce friction) and releasing nipping (to prevent stress) depending on real-time conditions.
Solution Approach 2:
The patent changes the parameter of roller separation timing based on conveyance path characteristics. By detecting whether the sheet is conveyed through a path with high or low friction, the controller adjusts the separation timing parameter accordingly, optimizing the balance between preventing sheet stress and maintaining conveyance precision.
2Reliability
If the pair of pre-registration rollers maintains nipping on the sheet after skew correction, then conveyance stability is improved, but the sheet may be stressed causing wrinkles or scratches
Solution Approach 1:
The patent implements feedback by using a detector to monitor the sheet conveyance state and feeding this information back to the controller. The controller then adjusts the roller separation timing based on this feedback, creating a closed-loop control system that balances conveyance stability with sheet protection.
Solution Approach 2:
The system transitions from a static roller separation mechanism to a dynamic one where the separation timing is continuously adjusted based on detected conveyance conditions, allowing optimal performance across different operating scenarios.
3Manufacturing precision
If different separation timings are used for different conveyance paths, then skew feeding is suppressed, but the device complexity increases due to path detection and timing control
Solution Approach 1:
The system uses self-service by employing a detector that automatically identifies the conveyance path and triggers appropriate separation timing without requiring manual intervention or complex external control. The detection and control functions are integrated into the existing sheet conveyance system.
Data Source
AI summary
A sheet conveying apparatus includes: a first pair of conveying rollers for conveying a sheet; a second pair of conveying rollers against which the leading edge of the sheet conveyed by the first pair of conveying rollers is hit and which conveys the sheet together with the first pair of conveying rollers by rotating after a loop is formed on the sheet; a separating portion for separating the first pair of conveying rollers; a first conveyance path for guiding the sheet; a second conveyance path which is a path different from the first conveyance path and guides the sheet; and a controller which changes a separation timing at which the first pair of conveying rollers is separated after the loop is formed on the sheet, depending on whether the sheet is guided by the first conveyance path or by the second conveyance path.