Sheet Feed Detection Lever Layout for Reliable No-Sheet Sensing
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Solution Overview
Problem
Existing sheet feeding apparatuses face issues with inaccurate detection of sheet presence or absence due to improper engagement of mechanical components caused by foreign objects, warping from injection molding, and detachment of sheet stacking portions, leading to potential damage and feed failures.
Innovation Solution
A sheet feeding apparatus with a detection unit that includes a movable detection lever with a contact portion inside a through hole, an optical sensor, and a posture holding mechanism to accurately detect sheet presence or absence, while minimizing interference with feeding rollers and compensating for warping and foreign objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rack is provided at a position which is exposed in the case where no sheet is present in the sheet stacking portion, then the sheet stacking portion can be discharged when no sheet is present, but the position of the rack becomes higher than expected when a foreign object is present or when warping occurs, causing improper engagement and detection failure
Solution Approach 1:
The patent replaces the mechanical rack and idler gear engagement system with an optical sensor system. The optical sensor detects the presence or absence of sheets without mechanical contact, eliminating the problem of position shifts caused by foreign objects or warping. The detection unit uses light reflection or interruption to determine sheet presence, providing reliable detection independent of mechanical component positioning.
2Adaptability or versatility
If the sheet stacking portion is made detachable to allow lever operation when detached, then the lever can detect sheets placed directly in the space, but this causes improper sheet conveyance and feed failures such as double feed and non-feed
Solution Approach 1:
The patent extracts the detection function from the mechanical lever system and implements it as a separate optical sensor system. This allows the detection unit to independently detect sheet presence without requiring the sheet stacking portion to be attached, while the feeding roller system maintains proper engagement only when the sheet stacking portion is correctly installed, preventing feed failures.
3Measurement precision
If the contact portion is positioned to detect sheets accurately, then sheet presence detection precision is improved, but the detection unit may interfere with the feeding roller operation
Solution Approach 1:
The patent replaces the mechanical contact portion that physically touches sheets with an optical sensor system. The optical sensor detects sheets through light reflection or interruption without mechanical contact, achieving high detection precision while completely eliminating interference with the feeding roller's mechanical operation.
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
Enables precise detection of sheet presence or absence, preventing damage and feed failures by ensuring proper engagement of mechanical components and maintaining accurate sheet feeding operations.
Implementation Method 1
an optical sensor, and a posture holding mechanism to accurately detect sheet presence or absence
Data Source
AI summary
A sheet feeding apparatus includes a detection unit provided to be movable with respect to a sheet stacking portion and configured to detect a sheet by causing a contact portion to come into contact with an uppermost sheet stacked on a stacking surface. A bottom portion of the sheet stacking portion forms a part of a bottom portion of the sheet feeding apparatus, the sheet stacking portion is provided with a through-hole configured to be exposed in the case where no sheet is stacked on the stacking surface, the through-hole penetrates the stacking surface to a bottom surface of the sheet stacking portion, and the contact portion is positioned inside the through-hole in the case where no sheet is stacked on the stacking surface.