Sheet Feeding Device Pickup Roller Elevation Control
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Solution Overview
Problem
Conventional image forming apparatuses face issues with variance in distancing positions between the sheet conveying tray and the pickup roller, leading to potential image defects due to prolonged contact, which existing solutions attempt to address but with increased complexity.
Innovation Solution
A sheet feeding device with a sheet loading portion and a feeding member that can elevate between contact and distanced positions, controlled by a control portion to maintain consistent distancing without additional position detection means, reducing variance in distancing positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pickup roller remains in contact with the sheet after feeding operation, then the sheet loading tray can be kept at a lower position, but image defects occur due to prolonged contact causing oil seepage and press marks
Solution Approach 1:
The pickup roller is raised to the distanced position before the sheet loading tray descends to its lower position. This preliminary action ensures that the roller and sheet are separated in advance, preventing any prolonged contact that could cause image defects, while allowing the tray to be positioned at a lower level for compactness.
Solution Approach 2:
The system dynamically adjusts the relative positions of the pickup roller and sheet loading tray based on operational state. During feeding operations, the roller contacts the sheet; after feeding completes, the roller elevates to a distanced position while the tray can descend. This dynamic positioning resolves the contradiction between maintaining image quality and simplifying tray control.
2Manufacturing precision
If the sheet loading tray is lowered from the contact state to reduce variance in distancing positions, then positioning precision improves, but the structure becomes more complex requiring additional control mechanisms
Solution Approach 1:
The pickup roller's elevation mechanism serves dual purposes: it performs the feeding function during operations and automatically establishes the precise distanced position after feeding completes. The roller is raised to a predetermined distanced position that self-adjusts to maintain consistent spacing from the sheet, eliminating the need for additional position-detecting means or complex control mechanisms.
Solution Approach 2:
The pickup roller elevation mechanism is designed to perform multiple functions: feeding sheets during operations and maintaining precise distancing after operations. By making the roller position adjustable between contacting and distanced positions, a single mechanism achieves both feeding reliability and positioning precision without requiring separate control systems.
3Measurement precision
If additional position detecting means are added to control the distancing of the feeding member, then distancing precision improves, but the device complexity and cost increase
Solution Approach 1:
The pickup roller elevation mechanism is designed to perform multiple functions: feeding sheets during operations and automatically establishing the precise distanced position after feeding completes. The roller is raised to a predetermined distanced position that self-adjusts to maintain consistent spacing from the sheet, eliminating the need for additional position-detecting means or complex control mechanisms.
Data Source
AI summary
A sheet feeding device includes a sheet loading portion which is capable of elevating operation and on which a sheet is loaded, a feeding member for feeding the sheet loaded on the sheet loading portion, the feeding member being capable of elevating movement between a contacting position in contact with the sheet and a distanced position distanced upward from the sheet, and a control portion that controls the elevating operation of the sheet loading portion and the elevating movement of the feeding member. When the feeding member at the contacting position moves to the distanced position, the feeding member is distanced upward from the sheet loaded on the sheet loading portion after the sheet loading portion starts a descending operation.