Automatic Document Feeder Optical Lifting Detection
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Solution Overview
Problem
Existing automatic document feeders in image forming apparatuses face accuracy issues in detecting the lifting of the document feeder, leading to potential paper jams, especially when thin books are left behind, due to low detection accuracy of open/close sensors and angle sensors.
Innovation Solution
An automatic document feeder with a movable document guiding member and a detecting unit using a light interrupting portion and optical sensor to accurately detect the relative position of the guiding member with respect to the document reading surface, preventing paper jams by stopping the feeder when the lifting exceeds a permissible height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an open/close sensor is disposed near the hinge to detect lifting of the automatic document feeder, then the occurrence of paper jam can be prevented, but the accuracy in detecting the lifting is low causing false stopping
Solution Approach 1:
The patent replaces the mechanical open/close sensor system with an optical detection system. A light source emits light that passes through a light-receiving window, and a photodetector detects the light intensity. When the automatic document feeder is properly closed, the optical path is blocked; when lifted, the light reaches the photodetector, providing accurate detection of the lifting state without the inaccuracies of mechanical sensors.
Solution Approach 2:
The patent introduces an optical intermediary (light beam) between the detection system and the automatic document feeder. The light beam serves as a mediator that translates the physical position of the feeder into detectable optical signals, enabling precise detection of lifting states that mechanical sensors cannot accurately detect.
2Difficulty of detecting and measuring
If an angle sensor is used to detect lifting of the automatic document feeder, then detection capability is improved, but it still cannot detect thin books that would not cause paper jam
Solution Approach 1:
The patent replaces angle sensors with an optical detection system that directly measures the lifting position. The optical system uses a light source and photodetector arrangement that can detect even minimal lifting distances, providing the precision needed to distinguish between thin books that won't cause paper jams and thicker materials that will.
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
Enhances the accuracy of detecting the lifting of the document feeder, allowing thin books to be read without causing paper jams, making the image forming apparatus more user-friendly and preventing operational interruptions.
Implementation Method 1
a detecting unit for detecting a relative position of the document guiding member with respect to the automatic document feeder main body when the automatic document feeder main body is set in the reading posture
Data Source
AI summary
An automatic document feeder (10) includes an automatic document feeder main body (11) arranged openable and closeable relative to the document reading surface (2b) and feeding the document to the document reading surface (2b) when closed to be set to a reading posture, a document guiding member (20) so supported by the automatic document feeder main body (11) as to be movable relative to the automatic document feeder main body (11), and a detecting unit for detecting a relative position of the document guiding member (20) with respect to the automatic document feeder main body (11) when the automatic document feeder main body (11) is set in the reading posture.