Toner Container Magnetic Shielding for Accurate Level Sensing

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Solution Overview

Problem

Existing image forming devices lack an effective system for measuring the remaining toner level in replaceable units, leading to potential device damage and user inconvenience due to empty toner cartridges.

Innovation Solution

A toner container with a rotatable paddle and magnet system, where a shield moves between blocking and unblocking positions relative to a magnetic sensor, allowing detection of the magnet's field to indicate toner levels based on paddle rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a magnetic sensor is used to detect toner levels, then measurement capability is improved, but the risk of contamination from toner particles increases

Engineering Contradiction:

Improvetoner level measurementVSAvoidtoner contamination

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A magnetic field is introduced as an intermediary between the sensor and toner particles. The magnetic field carries information about toner level without requiring direct contact between the sensor and toner, thus enabling measurement while preventing contamination.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical contact between the sensor and toner with a magnetic field-based detection system. This substitution eliminates the need for physical contact while maintaining measurement capability, thereby preventing contamination.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If electrical connections are made outside the container for sensing, then detection capability is improved, but the risk of contamination and device damage increases

Engineering Contradiction:

Improvetoner level detectionVSAvoiddevice reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The magnetic field serves as an intermediary that transmits information about toner level without requiring electrical connections to extend outside the container. This maintains system reliability while enabling detection.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces electrical connections with a magnetic field-based sensing system. This substitution eliminates exposure points for contamination while preserving detection functionality, thereby improving reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If no toner level measurement system is implemented, then device complexity is reduced, but the risk of printing with empty cartridges increases

Engineering Contradiction:

Improvesystem complexityVSAvoidprevention of device damage

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent uses a magnetic field-based system that is simpler than traditional mechanical or electrical contact-based sensing systems. This substitution reduces device complexity while maintaining the ability to prevent printing with empty cartridges.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Accurately determines toner levels without electrical or mechanical connections outside the container, reducing contamination risks and preventing device damage by signaling when toner is low.

Implementation Method 1

A magnet having a magnetic field is rotatably coupled to one of the paddle and the drive member

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

A shield is rotatably coupled to the other of the paddle and the drive member such that the shield is movable between a blocking position for attenuating the magnetic field of the magnet to block detection of the magnetic field by a magnetic sensor

Methodology Applied

Scientific EffectMagnetic shielding: Magnetic Reluctance

Data Source

PatentUS12468238B2Toner container having a magnet for toner level sensing

Publication Date: 2025.11.11 LEXMARK INTERNATIONAL INC

AI summary

A toner container for use in an image forming device includes a housing having a reservoir for storing toner, a paddle positioned within the reservoir, and a rotatable drive member positioned to push the paddle in a first rotational direction. The paddle is free to rotate ahead of the drive member in the first rotational direction. A magnet is rotatably coupled to one of the paddle and the drive member. A shield is rotatably coupled to the other of the paddle and the drive member such that the shield is movable between a blocking position for attenuating a magnetic field of the magnet to block detection of the magnetic field by a magnetic sensor and an unblocking position for unblocking the magnetic field of the magnet to permit detection of the magnetic field by the magnetic sensor based on a rotational position of the paddle relative to the drive member.