Developer Gas Vent Layout for Longer-Life Image Forming Filters

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Solution Overview

Problem

The internal pressure increase in developing devices of image forming apparatuses can lead to a shortened service life of filters due to developer leakage at pressure relief openings, and the provision of gas discharge openings above developer flow paths results in excessive developer flow, necessitating complex filter replacements.

Innovation Solution

The image forming apparatus is designed with gas openings positioned upstream or offset from the developer flow path, reducing developer flow towards the openings and simplifying filter replacement by using removable bodies with integrated filters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If an opening for relieving internal pressure is provided in the developing device, then internal pressure can be relieved, but developer is more likely to reach the opening leading to shortened filter service life

Engineering Contradiction:
Improveinternal pressureVSAvoidfilter service life
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The gas discharge opening is extracted from the developing device and relocated to the supply device. This separates the pressure relief function from the developer storage location, allowing pressure to be relieved without developer contamination. The opening in the supply device is positioned away from the developer flow path, further preventing developer from reaching the opening while maintaining effective pressure relief.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary structure (the supply device) between the developing device and the external environment for gas discharge. This intermediary allows pressure relief while filtering out developer particles through its structural design, where the opening is positioned in a region not directly exposed to developer flow, thus protecting the filter system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Extent of automation

If an opening for discharging gas is provided directly above the developer flow path, then gas can be discharged, but a large amount of developer flows toward the opening resulting in shorter filter service life

Engineering Contradiction:
Improvegas dischargeVSAvoidfilter service life
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The opening is positioned asymmetrically relative to the developer flow path. Instead of being directly above the flow path (symmetrical positioning), the opening is located at an offset position where gas can escape but developer particles are less likely to reach. This asymmetric placement creates a directional separation between gas discharge and developer flow.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent changes the spatial dimension of the opening position from directly above the flow path (vertical alignment) to an offset position that combines horizontal and vertical displacement. This dimensional change allows gas to discharge effectively while reducing developer exposure to the opening by utilizing three-dimensional space more strategically.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of repair

If a filter is provided at a device not designed for frequent attachment and detachment, then filter replacement is possible, but the replacement process becomes complex requiring specific tasks

Engineering Contradiction:
Improvefilter replacementVSAvoidreplacement process
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The filter is merged with the removable body (container) rather than being a separate component. This integration means that when the container is removed or replaced, the filter is automatically replaced as well. This eliminates the need for separate filter replacement procedures and reduces the complexity of maintenance tasks.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system enables self-service filter replacement through the removable body design. When the container is detached, the filter is automatically removed with it, and a new container comes with a new filter already installed. This self-service mechanism eliminates the need for manual filter installation procedures and reduces maintenance complexity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4685571A1Image forming apparatus and removable body
Publication Date: 2026.01.28 FUJIFILM BUSINESS INNOVATION CORP
  • EP4685571A1 patent drawingFigure 1
  • EP4685571A1 patent drawingFigure 2
  • EP4685571A1 patent drawingFigure 3

AI summary

An image forming apparatus includes an image carrier, at least one developing device that applies a developer to the image carrier, and a transport device that transports a developer discharged from the developing device, the transport device having at least one gas opening that is an opening to be used to discharge a gas that has flowed from the developing device to the transport device.