Document Tray Foreign Object Detection via Rod Sensor
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Solution Overview
Problem
Existing image reading devices struggle to detect foreign objects intruding between the sheet feed roller and the document tray, especially when the intrusion occurs away from the roller's position, leading to incomplete or failed document reading due to the inability to move the document tray down.
Innovation Solution
An object intrusion detecting device with a rod-like member and optical sensors is implemented, which detects when the rod-like member is pushed to an abnormal height, allowing the controller to determine foreign object presence and control the lifting device to prevent document tray movement if an intrusion is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure sensor is used to detect foreign objects between the sheet feed roller and document tray, then foreign object detection is possible, but detection is incomplete when intrusion occurs away from the roller's position
Solution Approach 1:
The detection system is divided into multiple independent detection points: the pressure sensor detects intrusions near the sheet feed roller, while the rod-like member detects intrusions at other positions on the document tray. This segmentation allows comprehensive coverage of the entire document tray area without requiring a single complex sensor system.
Solution Approach 2:
The rod-like member acts as an intermediary detection element that translates foreign object intrusion into vertical movement, which is then detected by the optical sensor. This intermediary mechanism extends detection capability to areas beyond the direct range of the pressure sensor.
2Ease of operation
If the document tray is allowed to move down automatically when pressure is detected, then newly introduced document sheets can be put in place, but the tray cannot move down when foreign objects are present
Solution Approach 1:
The optical sensor continuously monitors the rod-like member's position in advance to detect foreign objects before they interfere with the document reading process. This preliminary detection allows the system to prevent tray movement before reading errors occur.
Solution Approach 2:
The system uses feedback from both the pressure sensor and optical sensor to control document tray movement. The controller integrates signals from both sensors to make informed decisions about whether to allow tray movement, ensuring both automatic sheet introduction and reading process reliability.
3Measurement precision
If the rod-like member is used to detect foreign objects across the document tray width, then detection coverage is improved, but device complexity increases
Solution Approach 1:
The optical sensor replaces complex mechanical contact sensors or cameras with a non-contact detection method. The system uses optical detection of the rod-like member's position instead of mechanical pressure sensors distributed across the entire document tray, simplifying the overall system while maintaining detection coverage.
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 solution enables proper detection of foreign objects across the document tray width, ensuring smooth document image reading by preventing the document tray from moving up when an intrusion occurs, thus maintaining the reading process integrity.
Implementation Method 1
The object intrusion detecting device includes a rod-like member disposed along a widthwise direction of the document tray and detects that the rod-like member has been pushed up to a predetermined position in a height direction
Data Source
AI summary
In an image reading device, an object intrusion detecting device includes a rod-like member disposed along a widthwise direction of a document tray and detects that the rod-like member has been pushed up to a predetermined position in a height direction. When the object intrusion detecting device detects that the rod-like member has been pushed up to the predetermined abnormal position in the height direction, the controller determines that an object intrusion has occurred.