Sulfur-Containing Developing Agent for Charge Stability

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Solution Overview

Problem

Existing two-component developing agents for electrophotography face challenges in maintaining high-quality image production under varying temperature and humidity conditions, leading to issues like fogging and toner scattering due to changes in toner charge, especially in hot and humid environments.

Innovation Solution

A two-component developing agent comprising toner particles with sulfur atoms and carrier particles coated with a resin obtained by polymerizing isobutyl methacrylate monomer, which includes sulfur atoms, enhancing electron transfer and reducing charge variability with environmental changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If carrier particles are coated with a silicone resin coat to avoid toner spent problem, then the coating becomes hard and difficult to wear, but the toner spent problem gradually increases and chargeability deteriorates

Engineering Contradiction:
Improvecoating hardnessVSAvoidchargeability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters of the coating resin by incorporating specific functional groups (carboxyl, hydroxyl, or amine groups) with controlled content ratios. This parameter modification allows the coating to maintain appropriate hardness while preventing toner spent accumulation, thereby preserving chargeability without sacrificing coating strength.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite coating resin system by combining silicone resin with resins containing specific functional groups (carboxyl, hydroxyl, or amine groups). This composite structure integrates the hardness and wear resistance of silicone resin with the toner spent prevention capabilities of functional group-containing resins, achieving both coating durability and chargeability maintenance.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If a copolymer resin of alicyclic methacrylate monomer and linear methacrylate monomer is used to refresh the resin surface, then the resin becomes moderately easy to wear, but toner spent problem is not effectively avoided

Engineering Contradiction:
Improveresin surface refreshabilityVSAvoidtoner spent problem
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The invention modifies the chemical parameters of the coating resin by incorporating resins with specific functional groups (carboxyl, hydroxyl, or amine groups) at controlled content ratios. This parameter change enhances the resin's ability to prevent toner spent adhesion while maintaining surface refreshability, effectively addressing both requirements simultaneously.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies local quality by introducing specific functional groups (carboxyl, hydroxyl, or amine groups) at controlled ratios within the coating resin structure. These localized functional regions provide specific interactions that prevent toner spent adhesion while maintaining the overall wear characteristics of the coating, achieving selective functionality within the material.

Inventive Principle:
Principle #3Local quality

3Object-generated harmful factors

If isobutyl methacrylate monomer polymerized in non-aquatic condition is used to reduce toner spent adhesion, then adhesion force to toner particles decreases, but chemical toner absorbs water and charge amount changes with environmental temperature and humidity

Engineering Contradiction:
Improvetoner spent adhesionVSAvoidcharge stability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters of the coating resin by incorporating resins with specific functional groups (carboxyl, hydroxyl, or amine groups) at controlled content ratios (5-50 mass%). This parameter modification creates a balanced coating that provides both low toner spent adhesion and reduced water absorption, thereby stabilizing toner charge against environmental variations while maintaining effective toner spent prevention.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite coating resin system that combines isobutyl methacrylate polymer with resins containing specific functional groups. This composite structure integrates the low adhesion properties of isobutyl methacrylate with the water resistance and charge stability provided by functional group-containing resins, achieving both reduced toner spent adhesion and improved charge stability simultaneously.

Inventive Principle:
Principle #40Composite materials

4Manufacturing precision

If chemical toner produced by suspension or emulsion polymerization is used to obtain high-resolution images, then image quality improves, but the toner absorbs water and charge amount changes with environmental conditions

Engineering Contradiction:
Improveimage resolutionVSAvoidcharge stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The invention changes the chemical parameters of the coating resin by incorporating resins with specific functional groups (carboxyl, hydroxyl, or amine groups) at controlled content ratios. This parameter modification reduces the hydrophilicity of the coating surface, thereby minimizing water absorption by the chemical toner and stabilizing its charge amount against environmental temperature and humidity changes, while preserving the high-resolution imaging capabilities.

Inventive Principle:
Principle #35Parameter changes

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

The solution effectively reduces fogging and toner scattering, ensuring high-quality image production and durability by stabilizing toner charge across different environmental conditions.

Implementation Method 1

A two-component developing agent comprising toner particles with sulfur atoms and carrier particles coated with a resin obtained by polymerizing isobutyl methacrylate monomer, which includes sulfur atoms, enhancing electron transfer and reducing charge variability with environmental changes

Methodology Applied
Scientific EffectElectron transfer: Triboelectric Effect

Data Source

PatentUS9354536B2Two-component developing agent for developing electrostatic latent image and method for forming electrophotographic image
Publication Date: 2016.05.31 KONICA MINOLTA INC

AI summary

A two-component developing agent for developing an electrostatic latent image includes toner particles composed of toner base particles and an exterior additive attached on the toner base particles, and carrier particles composed of carrier core particles and a coating resin provided on the carrier core particles. The coating resin includes a sulfur atom and a resin obtained by polymerizing an isobutyl methacrylate monomer, and the toner base particles include a sulfur atom.