Developing Device Air Exhaust System for Image Quality

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Solution Overview

Problem

The existing developing devices in image forming apparatuses face challenges in managing internal pressure and preventing developer leakage, which can lead to contamination and uneven image density due to inadequate air exhaust and developer circulation mechanisms.

Innovation Solution

A developing device is designed with a developer carrier, a transport member, and a conveying member that includes magnets to hold and stir the developer, along with an exhaust system using a sirocco fan and a filter to manage air pressure and prevent leakage by exhausting air and ensuring consistent developer distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a developing device is used in an image forming apparatus, then image formation is enabled, but internal pressure increases and developer leakage occurs

Engineering Contradiction:

Improveprevention of developer leakageVSAvoidinternal pressure

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The patent extracts and removes excess air from the developing device through a dedicated exhaust port and exhaust fan system. The exhaust port is positioned to allow air extraction from the interior of the developing device, and the exhaust fan actively draws air out, reducing internal pressure and preventing developer leakage caused by pressure buildup.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses pneumatic principles by implementing an exhaust fan that creates negative pressure to draw air out of the developing device. This pneumatic system manages internal pressure by continuously exhausting air, preventing pressure accumulation that would otherwise cause developer leakage.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Manufacturing precision

If air is not exhausted from the developer container, then internal pressure builds up, but developer circulation and image quality deteriorate

Engineering Contradiction:

Improveimage density uniformityVSAvoidinternal pressure

Core Design Contradiction:

Manufacturing precisionVSStress or pressure

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the pressure parameter inside the developing device by introducing an exhaust system that actively reduces internal pressure. This parameter change ensures optimal conditions for developer circulation and prevents pressure-related issues while maintaining uniform image density.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If the exhaust port is positioned at the top of the developing device, then air exhaust is simplified, but developer may leak through the exhaust port

Engineering Contradiction:

Improveair exhaust efficiencyVSAvoiddeveloper leakage

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a mesh screen as an intermediary component at the exhaust port. This mesh screen acts as a barrier that allows air to pass through while blocking developer particles, thus maintaining effective air exhaust while preventing developer leakage through the exhaust port.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses a mesh screen, which is a porous material, at the exhaust port. This porous structure allows air molecules to pass through while blocking larger developer particles, achieving both efficient air exhaust and prevention of developer leakage.

Inventive Principle:

Principle #31Porous materials

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 effectively reduces internal pressure, prevents developer leakage, and ensures consistent developer distribution, leading to improved image quality and reduced maintenance needs by maintaining filter cleanliness and preventing clogging.

Implementation Method 1

a conveying member that is disposed on the transport member and that conveys air in the developer container toward an exhaust port

Methodology Applied

Scientific EffectMagnetic force: Magnetic Field

Implementation Method 2

a filter member that removes air particles from the air to be exhausted

Methodology Applied

Scientific EffectFiltration: Filter (physical)

Data Source

PatentUS10289027B2Image forming apparatus and developing device that conveys air to exhaust port

Publication Date: 2019.05.14 FUJIFILM BUSINESS INNOVATION CORP

AI summary

A developing device includes a developer carrier that rotates while holding a developer, a developer container that supports the developer carrier and contains the developer, a transport member that is supported in the developer container and that transports the developer by rotating, and a conveying member that is disposed on the transport member and that conveys air in the developer container toward an exhaust port, which enables the air in the developer container to be exhausted outside, along with rotation of the transport member.