Hybrid Developing Apparatus for Image Memory Suppression

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Solution Overview

Problem

Existing image forming apparatuses face challenges in maintaining long-term image quality and extending the life-span of developers due to carrier deterioration, image memory phenomena, and uneven consumption of reverse polarity chargeable particles, particularly in hybrid and two-component developing methods.

Innovation Solution

An image forming apparatus is designed with a developer container containing toner, carrier, and reverse polarity particles that are electrically chargeable with a reverse polarity to the toner, featuring a toner carrying member, a supply-developer carrying member, and a recovery-developer carrying member. The apparatus applies specific voltage configurations to enhance the ability to move reverse polarity particles from the toner carrying member to the supply-developer carrying member, while recovering toner and reducing particle consumption, thereby stabilizing the electrically charged toner amount and preventing image memory.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If one component type developing method is used, then apparatus simplicity and size are improved, but toner surface quality deteriorates and life-span becomes shorter

Engineering Contradiction:
Improveapparatus simplicityVSAvoidlife-span
Core Design Contradiction:
Device complexityVSDuration of action of stationary object

Solution Approach 1:

The patent combines the advantages of one-component simplicity with two-component durability by introducing carrier particles into the toner mixture. The developing apparatus integrates a toner supply unit and a developer supply unit that work together, merging the simplicity of one-component systems with the extended life-span benefits of two-component systems through synergistic interaction between toner and carrier.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a composite developer system combining toner particles and carrier particles. The carrier particles serve as charge-providing members while toner particles form the image, creating a composite material system that maintains the simplicity of single-component apparatus while achieving extended life-span through the protective role of carrier particles in reducing toner surface stress and degradation.

Inventive Principle:
Principle #40Composite materials

2Strength

If two component type developing method is used, then toner degradation is reduced, but carrier pollution occurs and life-span is limited

Engineering Contradiction:
Improvetoner degradation resistanceVSAvoidlife-span
Core Design Contradiction:
StrengthVSDuration of action of stationary object

Solution Approach 1:

The patent implements a recovery mechanism that captures and recovers carrier particles that become polluted or deteriorated during operation. The developing apparatus includes a recovery unit that separates and recovers carrier particles from the developer mixture, allowing them to be reused and preventing the accumulation of polluted carrier that would otherwise limit system life-span.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The patent incorporates feedback control mechanisms that monitor the condition of carrier particles and adjust the developing process parameters accordingly. The system detects carrier pollution or deterioration and modifies toner-to-carrier ratios, voltage levels, or recovery rates to maintain optimal performance throughout the extended operational life-span.

Inventive Principle:
Principle #23Feedback

3Reliability

If carrier is replaced to suppress deterioration, then electrically charged amount is maintained, but device complexity increases

Engineering Contradiction:
Improveelectrically charged amount stabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a self-service mechanism where the developing apparatus automatically manages carrier replacement and recovery without external intervention. The recovery unit continuously captures and recovers carrier particles, and the system automatically adjusts toner supply and developer composition to maintain stable electrically charged amount, eliminating the need for manual carrier replacement and reducing operational complexity.

Inventive Principle:
Principle #25Self-service

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 carrier deterioration, stabilizes the electrically charged toner amount, and prevents image memory phenomena, enabling long-term high-quality image formation with reduced reverse polarity particle consumption and extended developer life.

Implementation Method 1

a first voltage applying section to apply a first voltage between the toner carrying member and the first developer carrying member; and a second voltage applying section to apply a second voltage between the toner carrying member and the second developer carrying member

Methodology Applied
Scientific EffectElectrostatic force: Electrostatics

Implementation Method 2

the ability to move the reverse polarity particles from the toner carrying member to the first developer carrying member is larger than the ability to move the reverse polarity particles from the second developer carrying member to the toner carrying member

Methodology Applied
Scientific EffectElectrophoresis: Electrophoresis

Implementation Method 3

reverse polarity particles electrically chargeable with a reverse polarity against the electrically charged polarity of the toner

Methodology Applied
Scientific EffectElectrical charge: Electrostatics

Implementation Method 4

in the two component type developing method, since toner is electrically charged with triboelectrification when the toner is mixed with carrier

Methodology Applied
Scientific EffectTriboelectrification: Triboelectric Effect

Data Source

PatentEP1967913B1Developing device and image forming apparatus
Publication Date: 2019.06.26 KONICA MINOLTA BUSINESS TECH INC
  • EP1967913B1 patent drawingFigure 1
  • EP1967913B1 patent drawingFigure 2
  • EP1967913B1 patent drawing

AI summary

An image forming apparatus provided with an image carrying member to carry an electrostatic latent image, a toner carrying member to develop the electrostatic latent image on the image carrying member with toner; a first developer carrying member to carry developer containing toner, carrier, reverse polarity particles and to supply toner to the toner carrying member; and a second developer carrying member to carry developer and to recover toner on the toner carrying member, wherein an ability to move the reverse polarity particles from the toner carrying member to the first developer carrying member is larger than an ability to move the reverse polarity particles from the second developer carrying member to the toner carrying member.