Developing Device Insulating Seal Electroconductive Film Toner Control

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Solution Overview

Problem

In existing developing devices, toner can fall onto the developer carrier due to the lack of effective sealing, leading to image quality degradation.

Innovation Solution

A developing device with a sheet-shaped insulating seal member and an electroconductive film is used, where the seal member has one end fixed and the other end in contact with the image carrier, and the electroconductive film underlies the seal member's surface not in contact with the developer, preventing toner from falling onto the developer carrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If only a sheet-shaped insulating seal member is used to seal above the developer carrier, then the structure is simple, but toner falls on the developer carrier causing image quality degradation

Engineering Contradiction:

Improvesealing effectivenessVSAvoidseal member structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The seal member is constructed as a composite structure combining an insulating sheet material with an electroconductive film layer. The insulating portion prevents toner adhesion while the electroconductive film at the contact region with the image carrier provides effective sealing by dissipating static charges, thereby preventing toner fall without requiring complex mechanical structures

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The seal member exhibits different functional properties at different regions: the majority portion is insulating to prevent toner adhesion, while the specific region contacting the image carrier is electroconductive to provide effective sealing. This localized differentiation of material properties achieves reliable sealing precisely where needed without compromising the overall simplicity of the structure

Inventive Principle:

Principle #3Local quality

2Reliability

If the seal member contacts the image carrier to prevent toner fall, then sealing is improved, but the electrostatic latent image may be disturbed

Engineering Contradiction:

Improvesealing effectivenessVSAvoidelectrostatic latent image disturbance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The electroconductive film is positioned only at the region where the seal member contacts the image carrier, while the rest of the seal member remains insulating. This localized electroconductive property provides sealing effectiveness at the contact point without creating widespread electrostatic interference that would disturb the electrostatic latent image across the entire image carrier surface

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The electroconductive film acts as an intermediary layer between the seal member and the image carrier. It provides the necessary electrical contact for sealing while controlling the interaction between the seal member and the electrostatic latent image, preventing direct harmful electrostatic interference while maintaining sealing functionality

Inventive Principle:

Principle #24Intermediary (Mediator)

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 prevents toner from falling onto the developer carrier, maintaining image quality and ensuring reliable sealing without disturbing the electrostatic latent image.

Implementation Method 1

an electroconductive film that underlies an undersurface of the seal member at a portion that is not in contact with the developer held by the developer carrier

Methodology Applied

Scientific EffectElectrostatic charge conduction: Conduction (electrical)

Data Source

PatentUS10831130B2Developing device and image forming apparatus

Publication Date: 2020.11.10 FUJIFILM BUSINESS INNOVATION CORP

AI summary

A developing device includes a developer carrier, a sheet-shaped insulating seal member, and an electroconductive film. The developer carrier holds a developer with which an electrostatic latent image formed on an image carrier is developed. The seal member is disposed above the developer carrier and at a portion that is not in contact with the held developer. The seal member has a first end portion fixed and a second end portion in contact with the image carrier. The electroconductive underlies an undersurface of the seal member at a portion that is not in contact with the developer held by the developer carrier. The electroconductive film has a first end portion connected to the first end portion of the seal member and a second end portion not in contact with the image carrier.