Sheet Feeder Shield Linkage for Photosensor Light Interference
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Solution Overview
Problem
Existing sheet feeders face issues with false light detection due to external light interference, affecting the accuracy of photosensor operations in detecting sheet presence or absence.
Innovation Solution
A sheet feeder design incorporating a movable shield connected to a pivotable contact element via a linkage, which positions itself between a light emitter and receiver to either allow or block light transmission, reducing external light impact on the photosensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light shield is added to cover the photosensor, then false light detection is reduced, but device complexity increases
Solution Approach 1:
The light shield is merged with the contact element, which is a pre-existing component in the sheet feeder. By integrating the light-shielding function into the contact element that already pivots to detect sheet presence, the patent avoids adding a separate light shield component, thus improving detection accuracy while minimizing increases in device complexity
Solution Approach 2:
The contact element serves dual functions: it detects sheet presence through pivoting motion and simultaneously acts as a light shield by blocking external light from reaching the photosensor. This multi-functionality resolves the contradiction by eliminating the need for a dedicated light shield component
2Measurement precision
If a movable shield is introduced to block external light, then photosensor accuracy improves, but device complexity increases
Solution Approach 1:
The light-shielding capability is made dynamic by utilizing the existing pivoting motion of the contact element. As the contact element pivots in response to sheet presence, it dynamically adjusts its position to either block or allow light from reaching the photosensor, providing adaptive light shielding without requiring additional dynamic components
Solution Approach 2:
The contact element performs self-service by simultaneously executing its primary detection function and providing light shielding. The same mechanical motion that detects sheet presence also automatically adjusts the light blocking position, eliminating the need for separate actuation mechanisms for light shielding
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
This configuration effectively minimizes false light detection, enhancing the accuracy of sheet presence detection by shielding the photosensor from external light, thereby improving the reliability of the sheet feeder's operation.
Implementation Method 1
The photosensor includes a light emitter for emitting a light and a light receiver for receiving the emitted light
Implementation Method 2
The shield at the light shield position shields the light receiver from the light emitted from the light emitter
Data Source
AI summary
A sheet feeder includes a sheet tray, a feed roller, a sheet feed frame, a contact element, a guide frame, a photosensor, a shield, and a linkage. The feed roller feeds a sheet on the sheet tray. The sheet feed frame holds the feed roller. The contact element is pivotable relative to the sheet feed frame. The guide frame is disposed below the sheet feed frame. The photosensor includes a light emitter and a light receiver. The shield is movable between a light transmission position and a light shield position. The linkage connects the contact element and the shield such that the shield is movable as the contact element pivots. The light receiver receives the light emitted from the light emitter when the shield is at the light transmission position. The shield at the light shield position shields the light receiver from the light emitted from the light emitter.