Sheet Feeding Apparatus Roller Reversal for Jam Prevention
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Solution Overview
Problem
Conventional sheet feeding apparatuses experience sheet jams and damage when the front end of a sheet is halted downstream from the nip position of the paper feed and separation rollers, making it difficult to return the sheet to the load tray during cassette or storage cabinet pull-out.
Innovation Solution
The sheet feeding apparatus incorporates a separation/contact section that brings and separates sheets into contact with a pick-up roller, a separation section that brings and separates the paper feed roller into press-contact with a separation roller, and a control section that executes sheet return operations by rotating the separation roller in a direction different from the feed direction, ensuring safe return of sheets to the storage cabinet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cassette or storage cabinet is pulled out with the front end of the sheet halted downstream from the nip position of the paper feed roller and separation roller, then the sheet cannot be returned to the load tray, but sheet damage and sheet jam occur
Solution Approach 1:
The control section detects whether the sheet front end is positioned downstream from the nip position before the cassette pull-out operation is initiated. If detected, the system preliminarily executes the sheet return operation to retract the sheet to the load tray, preventing the sheet from being damaged or jammed during cassette removal. This preliminary detection and corrective action resolves the contradiction by preparing the system state before the problematic operation occurs.
2Reliability
If the sheet return operation is executed by rotating the separation roller in the sheet return direction, then the sheet is safely returned to the storage cabinet, but the separation roller must reverse rotation direction
Solution Approach 1:
The separation roller is designed to perform multiple functions: it rotates in the sheet feed direction during normal sheet feeding operations and rotates in the sheet return direction during sheet return operations. By making the separation roller multi-functional, the system avoids adding a separate return mechanism, thus resolving the contradiction between reliable sheet return and device complexity through efficient use of existing components.
3Productivity
If the separation roller rotates in the sheet feed direction during normal operation, then sheets are fed efficiently, but the sheet cannot be returned if halted downstream
Solution Approach 1:
The separation roller's rotation direction is made dynamic rather than fixed. The control section adjusts the rotation direction based on the operational phase: rotating in the sheet feed direction during normal feeding for high productivity, and rotating in the sheet return direction when sheet return is required. This dynamic adaptability resolves the contradiction by allowing the system to switch between efficient feeding mode and return capability mode as needed.
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
This solution effectively prevents sheet jams and damage by ensuring the sheet is returned to the storage cabinet without being caught between the paper feed and separation rollers, maintaining the integrity of the sheets and the apparatus.
Implementation Method 1
a friction separation scheme is widely known which is comprised of a paper feed roller that rotates in a feed direction of the sheet, and a separation roller that is brought into press-contact with the paper feed roller
Data Source
AI summary
A sheet feeding apparatus is provided with a pick-up roller that contacts sheets loaded on a load tray to pick up, a paper feed roller that feeds a picked-up sheet, and a separation roller brought into press-contact with the paper feed roller to separate the sheet, where the sheets are separated from the pick-up roller, the separation roller is rotated in a sheet return direction different from a sheet feed direction, and subsequently, the paper feed roller is separated from the separation roller. It is possible to prevent damage to a sheet and sheet jam from occurring in pulling out the load tray loaded with sheets to the front side.