Pivotable Magnet Toner Level Detection
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Solution Overview
Problem
Existing image forming devices lack an effective method to accurately measure the remaining toner level in replaceable units, leading to potential damage and inefficiencies in the printing process.
Innovation Solution
A toner level detection assembly that includes a rotatable shaft with a pivotable magnet, where a magnetic sensor measures the orientation or magnitude of the magnetic field to estimate the toner level based on the magnet's position and motion within the toner reservoir.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnet is positioned at a fixed radial distance from the rotation axis, then the magnetic field measurement is simple, but the measurement precision of toner level is insufficient
Solution Approach 1:
The magnet is positioned at a variable radial distance from the rotation axis, allowing its position to dynamically change during rotation. This dynamic positioning enables the magnetic field strength at the sensor to vary with the magnet's angular position, creating a measurable signal that correlates with toner level while maintaining a relatively simple device structure.
Solution Approach 2:
The solution introduces a radial dimension variable by positioning the magnet at a distance that varies with angular position. Instead of using multiple sensors at different fixed positions, the system varies the magnet's radial distance to encode toner level information, effectively using angular position to control radial distance and thus magnetic field strength.
2Measurement precision
If multiple magnetic sensors are used to measure toner level, then the measurement precision improves, but the device complexity and cost increase
Solution Approach 1:
Rather than using multiple sensors simultaneously, the system segments the measurement function into temporal segments by rotating a single magnet past a single sensor multiple times. Each rotation provides a new measurement opportunity, and the varying radial distance creates distinct magnetic field patterns that encode different toner level information.
Solution Approach 2:
The system uses periodic rotation of the magnet to repeatedly present the magnetic field to the sensor. The periodic variation in radial distance during each rotation creates a characteristic magnetic field pattern that can be analyzed to determine toner level, replacing the need for multiple simultaneous sensors with a single sensor performing periodic measurements.
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 allows for precise monitoring of toner levels, preventing damage and ensuring continuous operation by accurately determining when toner units need to be refilled or replaced.
Implementation Method 1
A magnetic sensor is positioned to sense a magnetic field of the magnet at a point in a rotational path of the magnet
Data Source
AI summary
A toner level detection assembly for an electrophotographic image forming device according to one example embodiment includes a magnet connected to a rotatable shaft and rotatable with the shaft around an axis of rotation of the shaft. The magnet is pivotable independent of the shaft about a pivot axis that is spaced radially from the axis of rotation. A magnetic sensor is positioned to sense a magnetic field of the magnet at a point in a rotational path of the magnet and is configured to measure an orientation of the magnetic field of the magnet at the point in the rotational path of the magnet. Processing circuitry in communication with the magnetic sensor is configured to determine an estimate of an amount of toner in a toner reservoir correlating with the measured orientation of the magnetic field of the magnet at the point in the rotational path of the magnet.