Paper-Length Detection via Rotating Magnet and Angle Sensor
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Solution Overview
Problem
Existing paper-length detection methods in image forming apparatuses are inefficient for irregularly sized paper, as they rely on encoders that struggle to accurately measure paper length with precision and flexibility.
Innovation Solution
A paper-length detection device comprising a bottom plate, first and second regulatory members, a rotating magnet, and an angle sensor, where the magnet rotates based on the movement of the regulatory members relative to each other, allowing for precise detection of paper length by outputting an absolute angle corresponding to the distance between the members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an encoder is used to detect paper length, then the detection method can handle irregular sized paper, but the measurement precision and flexibility are insufficient
Solution Approach 1:
The patent replaces the mechanical encoder system with a magnetic field-based detection system. A magnet attached to the movable regulatory member generates a magnetic field that is detected by a magnetic sensor, eliminating the need for mechanical encoders and their associated precision limitations while maintaining adaptability for various paper sizes.
Solution Approach 2:
The patent changes the detection parameter from mechanical position encoding to magnetic field strength variation. By detecting changes in magnetic field strength as the regulatory members move, the system achieves higher precision measurement without compromising flexibility for different paper dimensions.
2Device complexity
If direct contact and sliding mechanisms are used for detection, then the detection structure is simple, but the lifetime of the sensor is reduced due to wear
Solution Approach 1:
The patent eliminates direct mechanical contact between the sensor and moving parts by using a magnetic field-based detection system. The magnet moves with the regulatory member while the magnetic sensor remains stationary, detecting position through magnetic field changes without physical contact, thus avoiding wear and extending sensor lifetime.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the moving regulatory member and the stationary sensor. The magnet attached to the movable member creates a magnetic field that mediates the transmission of position information to the sensor without requiring direct mechanical contact.
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 accurate and flexible detection of paper length, supporting both fixed and irregular paper sizes, and maintains the lifetime of the angle sensor by avoiding direct contact and sliding, thus ensuring reliable operation.
Implementation Method 1
The magnet rotates while an S pole and an N pole are parallel to the bottom plate. The moving mechanism causes the magnet to rotate in accordance with the movement of the first regulatory member closer to or further from the second regulatory member.
Implementation Method 2
The angle sensor faces the magnet and outputs a signal corresponding to an absolute angle with the magnet.
Data Source
AI summary
According to an embodiment, a paper-length detection device includes: a moving mechanism and an angle sensor. The moving mechanism supports a magnet. The moving mechanism causes a first regulatory member to move closer to or further from a second regulatory member in accordance with movement of the first regulatory member. The moving mechanism further causes the magnet to rotate in accordance with the movement of the first regulatory member closer to or further from the second regulatory member. The angle sensor faces the magnet and outputs a signal corresponding to an absolute angle with the magnet.