Pickup Roller Swing Mechanism for Sheet Feeding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Medium feeding apparatuses in office automation machines, such as scanners and printers, often experience issues where the second sheet gets curled and stuck due to the delayed movement of the pickup roller away from the first sheet, leading to inefficiencies in the feeding process.
Innovation Solution
The apparatus includes a pickup roller, a support member that swings between feeding and non-feeding positions, and a separation roller, controlled by a motor and sensor system to detect the rotation or edge passage of sheets, ensuring timely withdrawal of the pickup roller to prevent curling and sticking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pickup roller moves away from the first sheet after it is nipped by feed rollers, then the second sheet is prevented from curling and sticking, but the response time is delayed because the sheet detector is positioned downstream
Solution Approach 1:
The patent applies preliminary action by using the rotation sensing section to detect the first sheet's passage and trigger the pickup roller's withdrawal before the sheet actually leaves the transport rollers. The control section monitors the rotation state of the separation roller and initiates the pickup roller's movement away from the sheet in advance, based on predicted sheet position and movement characteristics, thereby eliminating the time delay inherent in downstream detection systems.
2Reliability
If the pickup roller maintains contact with the medium to ensure stable feeding, then feeding reliability is improved, but the second sheet may be curled and stuck when the first sheet is processed
Solution Approach 1:
The patent applies dynamics by making the pickup roller's contact state with the medium variable rather than fixed. The support member swings the pickup roller between a feeding position (where it contacts the medium for stable feeding) and a non-feeding position (where it withdraws to prevent curling). This dynamic adjustment allows the system to adapt its contact state based on the processing stage, eliminating the harmful effect of curling while maintaining feeding stability when needed.
3Device complexity
If a sheet detector is positioned downstream to detect the first sheet's edge, then the detection function is simplified, but the pickup roller cannot respond quickly enough to prevent second sheet curling
Solution Approach 1:
The patent introduces an intermediary mechanism - the rotation sensing section that detects sheet passage through the rotation state of the separation roller. This intermediary provides real-time information about sheet movement without requiring direct line-of-sight detection downstream. The control section uses this intermediate detection to calculate sheet position and trigger pickup roller withdrawal in advance, achieving fast response while keeping the detection system relatively simple.
Data Source
AI summary
A medium feeding apparatus includes a pickup roller that feeds a medium from a medium mount section. A support member supports a pickup roller and swings around a swing axis to switch between a feeding position and a non-feeding position. A separation roller separates the medium from other media. A feed roller feeds the medium toward the downstream end. The separation and feed rollers are disposed downstream of the pickup roller. A control section controls a position of the support member. After the pickup roller and the feed roller start rotating, when the control section determines that the separation roller stops rotating or returns the medium by rotating in a reverse direction, based on a detection signal from a rotation sensing section configured to detect rotation of the separation roller, the control section causes the support member to switch from the feeding position to the non-feeding position.