Electrostatic Image Developer Toner Carrier Composition

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Solution Overview

Problem

Existing electrostatic image developers face challenges in preventing image unevenness, particularly when the ratio of Net intensity of elemental molybdenum to Net intensity of elemental silicon is outside the range of 0.035 to 0.45.

Innovation Solution

The electrostatic image developer comprises a toner with silica particles containing elemental molybdenum and a carrier with a coating resin layer containing inorganic particles, where the ratio of Net intensity of elemental molybdenum to Net intensity of elemental silicon in the silica particles is within the range of 0.035 to 0.45, and the inorganic particles are selected from silica, alumina, strontium titanate, calcium titanate, barium titanate, and titanium oxide.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the ratio of Net intensity of elemental molybdenum to Net intensity of elemental silicon is outside the range of 0.035 to 0.45, then the image unevenness prevention ability is insufficient, but controlling the ratio within this range requires precise composition control

Engineering Contradiction:
Improveimage unevenness prevention abilityVSAvoidcomposition control precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by establishing a specific ratio range (0.035 to 0.45) for molybdenum to silicon content in the silica particles. This quantitative parameter control ensures optimal charge distribution characteristics while preventing image unevenness, transforming the qualitative requirement into a measurable and manufacturable specification.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining silica particles with specific ratios of molybdenum and silicon compounds. This composite approach allows the silica particles to serve multiple functions: providing charge distribution control through the molybdenum-silicon ratio while maintaining the structural integrity and functionality of silica-based charge control agents.

Inventive Principle:
Principle #40Composite materials

2Reliability

If silica particles are added to toner for charge control, then charge distribution is improved, but adhesion of silica particles to carrier causes image unevenness

Engineering Contradiction:
Improvecharge distributionVSAvoidsilica particle adhesion to carrier
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by controlling the chemical composition parameters of the silica particles, specifically the ratio of molybdenum to silicon content. This compositional parameter control modifies the surface properties and charge characteristics of the silica particles, reducing their tendency to adhere to the carrier while maintaining effective charge distribution.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses the molybdenum-silicon compound ratio as an intermediary mechanism to mediate between the silica particles and the carrier. This compositional intermediary controls the interaction forces between silica and carrier surfaces, reducing adhesion while preserving the charge control function.

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 enhances the image unevenness prevention ability by reducing the adhesion of silica particles to the carrier, maintaining a narrow charge distribution, and ensuring good image quality with minimal unevenness.

Implementation Method 1

a carrier B including a core material and a coating resin layer that covers the core material and contains inorganic particles... the inorganic particles selected from the group consisting of silica, alumina, strontium titanate, calcium titanate, barium titanate, and titanium oxide

Methodology Applied
Scientific EffectElectrostatic interaction: Electrostatics

Implementation Method 2

the ratio N Mo /N Si of a Net intensity N Mo of elemental molybdenum that is measured by X-ray fluorescence analysis to a Net intensity N Si of elemental silicon that is measured by the X-ray fluorescence analysis

Methodology Applied
Scientific EffectX-ray fluorescence: X-Ray

Data Source

PatentEP4343440B1Electrostatic image developer, process cartridge, image forming apparatus, and image forming method
Publication Date: 2025.04.23 FUJIFILM BUSINESS INNOVATION CORP
  • EP4343440B1 patent drawingFigure 1
  • EP4343440B1 patent drawingFigure 2
  • EP4343440B1 patent drawing

AI summary

An electrostatic image developer includes: a toner A to which silica particles (A) containing an elemental nitrogen-containing compound containing elemental molybdenum are externally added; and a carrier B including a core material and a coating resin layer that covers the core material and contains inorganic particles. In the silica particles (A), the ratio NMo/NSi of a Net intensity NMo of elemental molybdenum that is measured by X-ray fluorescence analysis to a Net intensity NSi of elemental silicon that is measured by the X-ray fluorescence analysis is from 0.035 to 0.45 inclusive.