Toner Level Detection Using Magnetic Sensor and Lifter Mechanism
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Solution Overview
Problem
In full-color electrophotographic image formation apparatuses, magnetic noise from the motor affects reed switches, leading to incorrect detection of remaining toner levels, resulting in unnecessary toner supply operations and premature replacement of toner cartridges.
Innovation Solution
An image formation apparatus with a magnetic sensor system that includes a magnet and reed switch, a lifter to periodically lift the magnet out of the detection area, an ON-edge detector to identify valid detection points, and a misdetection determiner to prevent false ON-edge detection, ensuring accurate toner level monitoring and reducing unnecessary toner supply operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a reed switch is used to detect toner level, then the device can be downsized and cost reduced, but magnetic noise from the motor causes false detection
Solution Approach 1:
The system performs preliminary actions by lifting the magnet before and after the detection period to eliminate magnetic noise interference from the motor. This preliminary positioning ensures that any detection signal during the detection period is caused solely by the magnet's position relative to the reed switch, not by external magnetic noise.
Solution Approach 2:
The magnet is lifted periodically at specific timing intervals before and after the detection period. This periodic lifting action creates a controlled magnetic environment where the reed switch can detect toner level accurately without interference from continuous motor operation, effectively separating the detection function from the noise-generating function.
2Measurement precision
If the magnet is continuously in detection area, then toner level can be monitored, but magnetic noise causes false ON-edge detection
Solution Approach 1:
The system performs preliminary actions by lifting the magnet before and after the detection period to eliminate magnetic noise interference from the motor. This preliminary positioning ensures that any detection signal during the detection period is caused solely by the magnet's position relative to the reed switch, not by external magnetic noise.
Solution Approach 2:
The system converts the harmful magnetic noise from the motor into a beneficial timing signal. By lifting the magnet at specific intervals before and after detection, the system uses the motor's operational rhythm to define precise detection windows, transforming the noise source into a synchronization mechanism that improves detection accuracy.
3Productivity
If motor operates continuously, then toner supply function is maintained, but magnetic noise interferes with reed switch detection
Solution Approach 1:
The system segments the motor operation into distinct phases: a detection period when the magnet is lifted for accurate sensing, and operational periods when the magnet is in position for toner supply. This temporal segmentation allows the motor to operate continuously for productivity while creating noise-free detection windows for accurate toner level monitoring.
Solution Approach 2:
The magnet is lifted periodically at specific timing intervals before and after the detection period. This periodic lifting action creates a controlled magnetic environment where the reed switch can detect toner level accurately without interference from continuous motor operation, effectively separating the detection function from the noise-generating function.
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
Prevents misdetected toner levels, reducing unnecessary toner supply operations and extending the life of toner cartridges by accurately determining remaining toner amounts, thus enhancing the reliability and efficiency of the image formation process.
Implementation Method 1
using a reed switch to detect the position of a magnet attached to a detection plate placed on the surface of the toner
Implementation Method 2
a magnet and a reed switch that determines whether the magnet is within a detection area thereof, one of which is fixed to a predetermined position, and the other of which is configured to move downwards as a surface level of toner stored in a toner storage of the hopper decreases
Data Source
AI summary
An image formation apparatus including: a toner cartridge storing toner; a developer; a hopper temporarily storing toner supplied from the toner cartridge and supplying the developer with the toner; a magnetic sensor including a magnet and a reed switch that determines whether the magnet is within a detection area thereof, one of which is fixed to a predetermined position, and the other of which is configured to move downwards as a surface level of toner stored in a toner storage of the hopper decreases and thus serves as a surface level detector for detecting the surface level; a lifter configured to periodically lift the surface level detector above the surface level such that the magnet goes out of the detection area; and an ON-edge detector configured to detect ON-edges each indicating a point in time when the magnet has entered the detection area.