Developer Retainer Gap Configuration for Toner Scattering

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Solution Overview

Problem

Existing image forming devices face challenges in suppressing toner scattering due to air pressure increases within the developing device, which affects the efficiency and quality of toner distribution and image formation.

Innovation Solution

The design incorporates a developer retainer with specific gap configurations between the developer carrier, image carrier, and container, along with an air circulation path, to manage air flow and prevent toner scattering by optimizing air suction and discharge, including the use of a brush to reduce toner concentration in air flows.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If air flow is increased to remove toner, then toner scattering is suppressed, but air pressure increase causes toner scattering

Engineering Contradiction:
Improvetoner scattering suppressionVSAvoidair pressure
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The developing device is divided into multiple sealed chambers (first developing chamber, second developing chamber, third developing chamber) separated by partition walls. Each chamber has independent air flow control with dedicated suction ports and discharge ports, allowing localized air pressure management without causing overall pressure increase that would scatter toner.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A brush member is introduced as an intermediary component in the air flow path. The brush member reduces toner concentration in the air flow by removing excess toner particles, thereby suppressing toner scattering while maintaining necessary air flow for developer circulation and heat dissipation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If air suction is increased to maintain air flow, then toner scattering is suppressed, but developer distribution is affected

Engineering Contradiction:
Improvetoner scattering suppressionVSAvoiddeveloper distribution
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

Different regions of the developing device have different air flow characteristics tailored to their specific functions. The first, second, and third developing chambers have optimized air suction and discharge arrangements that locally balance air flow rates to maintain appropriate developer distribution in each region while collectively suppressing toner scattering.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The air flow control system operates as a feedback mechanism where air is continuously circulated through the developing chambers, suctioned at controlled rates, and discharged through designated ports. This cyclic air flow maintains stable developer distribution while removing scattered toner, creating a self-regulating system that balances developer circulation with toner scattering suppression.

Inventive Principle:
Principle #23Feedback

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 suppresses toner scattering, maintaining optimal air flow and toner distribution, thereby enhancing the quality and efficiency of the image forming process.

Implementation Method 1

a brush to reduce toner concentration in air flows

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

an air circulation path, to manage air flow and prevent toner scattering by optimizing air suction and discharge

Methodology Applied
Scientific EffectAir flow: Convection

Data Source

PatentEP3598238B1Image forming system with developer retainer
Publication Date: 2020.09.30 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3598238B1 patent drawingFigure 1
  • EP3598238B1 patent drawingFigure 2
  • EP3598238B1 patent drawingFigure 3

AI summary

An image forming system includes: an image carrier to rotate; a developer carrier to rotate; a container to contain the developer carrier; and a developer retainer separated from the rotatable developer carrier by a first gap of closest proximity, separated from the rotatable image carrier by a second gap of closest proximity, and separated from the container by a third gap of closest proximity. The first gap is smaller than the second gap and the third gap.