Document Feeding Unit Stopper Restriction Mechanism
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Solution Overview
Problem
Conventional document conveying devices experience positional displacement of the stopper and feeding unit due to excessive pressure, leading to double feeding or skew feeding of document sheets, as the stopper is inadvertently brought into a fixing released state when users forcibly align the stack of document sheets.
Innovation Solution
A document conveying device with a swingably supported feeding unit and stopper, where the stopper is restricted from swinging by an engagement piece and restriction surface, preventing displacement even under excessive pressure, ensuring stable operation and accurate alignment of document sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the stopper is configured to be swingable for aligning document sheets, then the ease of operation is improved, but the reliability deteriorates due to unintended displacement
Solution Approach 1:
The engagement piece and restriction surface are designed to preemptively counteract the downward force applied when users align document sheets. The restriction surface is positioned to engage the engagement piece before excessive force can cause displacement, creating a preliminary counter-action that prevents the stopper from moving to the fixing released state during normal alignment operations.
Solution Approach 2:
The engagement piece acts as an intermediary element between the stopper and the restriction surface. This intermediary mechanism allows the stopper to be swingable for alignment while the restriction surface provides a controlled interface that prevents unintended displacement, mediating between the need for movement and the need for stability.
2Ease of operation
If the stopper is made swingable to allow document sheet passage, then the ease of operation is improved, but the device complexity increases due to additional restriction mechanisms
Solution Approach 1:
The stopper control mechanism is segmented into distinct functional elements: the stopper body with document restriction portion, the engagement piece protruding from the support shaft, and the restriction surface on the main body. This segmentation allows each element to perform its specific function independently while working together as a unified system, making the overall mechanism easier to understand and maintain despite the added functionality.
Solution Approach 2:
Instead of using a complex locking mechanism to prevent stopper displacement, the invention inverts the approach by using a simple restriction surface that passively engages the engagement piece. The restriction surface is stationary and uses the geometry of the engagement piece's movement path to naturally prevent excessive displacement, eliminating the need for active control mechanisms.
3Ease of operation
If the feeding unit is swingably supported to enable paper feeding, then the ease of operation is improved, but the stability deteriorates under excessive pressure
Solution Approach 1:
The restriction surface is designed to engage the engagement piece in advance, creating a preliminary counter-action that prevents the feeding unit from displacing under excessive pressure. This engagement occurs before the feeding unit can move to an incorrect position, ensuring that even when users apply force to align document sheets, the feeding unit remains stable at the standby position.
Data Source
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AI summary
A document conveying device (27) of the present disclosure includes a document stacking tray (29), a feeding unit (50), a stopper (63), and a restriction surface (70). The feeding unit (50) is swingably supported on a first swinging fulcrum (57) on a main body side of the document conveying device (27) and is disposed selectively at a paper feeding position or at a retracted position. The stopper (63) is swingably supported on a second swinging fulcrum provided on a swingable end side of the feeding unit (50), and has a document restriction portion (67) that becomes opposed to tip ends of a stack of document sheets stacked on the document stacking tray (29) and an engagement piece (68) that is provided to protrude in the opposite direction to the document restriction portion (67). The restriction surface (70) is provided on the main body side of the document conveying device (27), and extends downward from a position coinciding with a first trajectory, along which the engagement piece (68) moves as the stopper (63) is swung about the second swinging fulcrum, toward an inner side of the first trajectory, while extending downward from a position coinciding with a second trajectory, along which the engagement piece (68) moves as the feeding unit (50) is swung about the first swinging fulcrum (57), toward an inner side of the second trajectory. When the feeding unit (50) is at the retracted position, the engagement piece (68) is engaged with the restriction surface (70), and thus an opposedly fixed state is brought about where swinging of the stopper (63) is restricted, and when the feeding unit (50) is at the paper feeding position, the engagement between the engagement piece (68) and the restriction surface (70) is released.