Pickup Roller Positioning for Full Sheet Stacks
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Solution Overview
Problem
When the feeding cassette is inserted into an image forming apparatus with a full stack of sheets, the pickup roller may come into contact with the uppermost sheet, causing position deviation and potential paper jams due to insufficient distance between the pickup roller and the sheets.
Innovation Solution
A control unit, such as a CPU, controls a motor to temporarily move the pickup roller to a second position, separating it from the sheets, and then back to a first position for contact, using a switching unit to adjust the positional relationship between the pickup roller and the stacking member based on the sheet height, ensuring proper alignment and preventing deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the feeding cassette is inserted with a full stack of sheets, then the stacking capacity is maximized, but the pickup roller may come into contact with the uppermost sheet causing position deviation
Solution Approach 1:
The stacking plate is designed to be movable between a first position (lowered) and a second position (raised). When the feeding cassette is inserted with a full stack, the stacking plate is raised to create sufficient distance between the uppermost sheet and the pickup roller, preventing contact and position deviation. This dynamic adjustment resolves the contradiction by adapting the structure to the loading condition.
Solution Approach 2:
The system performs a preliminary action by raising the stacking plate before the feeding operation begins. This preliminary position adjustment ensures that even with a full stack of sheets, the pickup roller maintains proper clearance and will only contact sheets at the correct feeding position, thereby preventing position deviation from the outset.
2Productivity
If the pickup roller is positioned close to the sheets for efficient feeding, then the feeding speed is improved, but the sheet position may deviate when the stack is full
Solution Approach 1:
The stacking plate's movable design allows the system to dynamically adjust the vertical distance between the sheets and the pickup roller. When the stack is full, the plate raises to prevent premature contact, maintaining alignment accuracy. During feeding operations, the plate can lower to enable efficient pickup, thus resolving the contradiction between feeding efficiency and alignment accuracy.
3Volume of moving object
If the distance between the pickup roller and the uppermost sheet is reduced for compact design, then the apparatus size is minimized, but the sheet may not be properly positioned during insertion
Solution Approach 1:
The movable stacking plate enables the apparatus to maintain a compact overall design while dynamically creating sufficient clearance when needed. The plate can be raised during insertion with full stacks to ensure proper sheet positioning, and lowered during normal operation to maintain compact dimensions, thus resolving the contradiction between compactness and positioning accuracy.
Data Source
AI summary
A feeding apparatus includes a stacking member provided to a feeding cassette, a feeding member, a contact portion provided on a regulating member provided on the feeding cassette, a movement unit, and a switching unit. The movement unit raises the feeding member when the feeding cassette is pulled out and lowers the feeding member when the feeding cassette is inserted. The switching unit switches a positional relationship between the feeding and stacking member. After the feeding member is lowered and before the feeding member performs a sheet feeding operation, the switching unit switches the relationship to the second positional relationship from the first. When a stacked sheet amount is equal to or more than a predetermined amount, the contact portion is disposed in contact with the stacked sheets and when the amount is smaller than the predetermined amount, the contact portion is disposed not in contact with the stacked sheets.