Pivotable Magnet Toner Level Detection via Magnetic Field Orientation

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Solution Overview

Problem

There is a need for an effective system to measure the remaining toner level in replaceable units of electrophotographic image forming devices to prevent damage and notify users when toner levels are low, as existing systems lack reliable and accurate methods for monitoring toner levels.

Innovation Solution

A toner level detection assembly that includes a rotatable shaft with a pivotable magnet, where a magnetic sensor measures the orientation and magnitude of the magnetic field to estimate the toner level based on the magnet's position and angle, correlating this data with the amount of toner present in the reservoir.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a magnetic sensor measures the magnetic field to determine toner level, then measurement precision is improved, but device complexity increases due to the pivotable magnet mechanism

Engineering Contradiction:

Improvetoner level measurement precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

A magnetic field is introduced as an intermediary between the toner level (object to be measured) and the sensor. The pivotable magnet's orientation changes in response to toner level, and this magnetic field variation is detected by the magnetic sensor, providing indirect but precise measurement of toner level without direct contact or complex mechanical linkages to the toner itself.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical measurement mechanisms with a magnetic field-based sensing system. Instead of using mechanical sensors that would require physical contact with toner or complex linkages to the toner reservoir, a magnetic field is used to transmit information about toner level to the sensor, reducing mechanical complexity while maintaining measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If the magnet is pivotable about a pivot axis spaced radially from the rotation axis, then measurement precision is improved by varying magnet orientation, but device complexity increases

Engineering Contradiction:

Improvemagnet orientation measurement precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a second degree of freedom by allowing the magnet to pivot about an axis spaced radially from the rotation axis. This creates a varying orientation in a different dimension that provides additional measurement information about toner level, enhancing precision by utilizing spatial variation in multiple dimensions rather than simple radial rotation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If a magnetic sensor measures magnetic field orientation and magnitude, then toner level detection accuracy is improved, but loss of information is reduced by correlating multiple parameters

Engineering Contradiction:

Improvetoner level detection accuracyVSAvoidinformation loss

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The system measures both the orientation and magnitude of the magnetic field, and correlates these measurements with known toner level states to determine the current toner level. This feedback mechanism uses multiple measured parameters (orientation and magnitude) to cross-validate and accurately determine toner level, preventing information loss by using redundant measurement data.

Inventive Principle:

Principle #23Feedback

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 system accurately detects the toner level by analyzing the magnetic field's orientation and magnitude, allowing for timely notification of low toner levels and preventing device damage, thereby ensuring continuous and efficient printing operations.

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 around the axis of rotation and is configured to measure an orientation of the magnetic field of the magnet at the point in the rotational path of the magnet

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentUS10451997B1Toner level detection measuring an orientation of a rotatable magnet having a varying orientation relative to a pivot axis

Publication Date: 2019.10.22 LEXMARK INTERNATIONAL INC

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.