Developer Unit Magnetic Body Layout for Space-Saving Level Detection

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Solution Overview

Problem

Existing image forming apparatuses with a movable magnetic body inside the developer accommodation portion reduce the available space for developer storage due to the presence of the moving member, limiting the amount of developer that can be accommodated.

Innovation Solution

The image forming apparatus reduces the need for a moving member by incorporating a rotary main body that supports developing units and toner cartridges, allowing them to be detachably attached and slidably moved, thus optimizing space utilization and enabling efficient developer replenishment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a moving member is installed inside the accommodation portion to move the magnetic body relative to the developer, then the magnetic body can be moved to detect developer levels, but the amount of developer that can be accommodated is decreased

Engineering Contradiction:
Improvedeveloper level detectionVSAvoiddeveloper storage capacity
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The moving member is extracted from inside the accommodation portion and relocated to the exterior. The magnetic body is moved by the moving member when it protrudes from the accommodation portion, eliminating the space occupation issue while maintaining the developer level detection capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The magnetic body serves as an intermediary that can be positioned in two locations: inside the accommodation portion for developer level detection, or protruding from the accommodation portion to be moved by the moving member. This intermediary approach allows the system to achieve both detection precision and adequate developer storage capacity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a moving member is placed inside the accommodation portion to move the magnetic body, then developer level can be detected, but the device complexity increases

Engineering Contradiction:
Improvedeveloper level detectionVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The moving member is extracted from the interior of the accommodation portion and positioned on the exterior. This extraction simplifies the internal structure of the accommodation portion, allowing it to be a simple container without internal moving components, while the moving member operates from outside to manipulate the magnetic body.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If the magnetic body is moved inside the accommodation portion to detect developer levels, then accurate detection is achieved, but the available space for developer is reduced

Engineering Contradiction:
Improvedeveloper remaining level detectionVSAvoidaccommodation portion volume
Core Design Contradiction:
Measurement precisionVSVolume of stationary object

Solution Approach 1:

The magnetic body is preliminarily positioned inside the accommodation portion at the bottom. When developer level needs to be detected, the magnetic body is moved to protrude from the accommodation portion. This preliminary positioning allows the system to maintain accurate detection capability while minimizing space occupation during non-detection periods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The moving member that would otherwise occupy space inside the accommodation portion is extracted and positioned outside. The magnetic body is temporarily extracted from the accommodation portion during detection operations, allowing the accommodation portion to be fully utilized for developer storage without internal obstructions.

Inventive Principle:
Principle #2Taking out (Extraction)

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 configuration enhances developer storage capacity and facilitates easy toner replenishment, improving operational efficiency and usability without compromising the detection of developer levels.

Implementation Method 1

detects a magnetic field produced by the magnetic body

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP4647845A1Image forming apparatus
Publication Date: 2025.11.12 CANON KK
  • EP4647845A1 patent drawingFigure 1
  • EP4647845A1 patent drawingFigure 2
  • EP4647845A1 patent drawingFigure 3

AI summary

The present invention is directed to reducing moving members for moving a magnetic body (101) relative to a developer. An image forming apparatus includes a developing unit including an accommodation portion (53), a developing member, and a magnetic body unit, the magnetic body unit being located inside the accommodation portion (53) and supported to be movable relative to the accommodation portion (53) in a moving direction, a rotary, and a magnetic sensor (102). A rotation period for the rotary to make one rotation includes a first period. In the first period, the moving direction includes a vertically downward direction. The first period includes a contact period during which the magnetic body unit is received by a developer. The contact period includes timing at which a rotation center (Rm) of the rotary (90), the magnetic body unit (103), and the magnetic sensor (102) are aligned on a straight line in a radial direction of rotation of the rotary (90).