Nitrogen-Adsorbed Silica Additives for Toner Charge Stability

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Solution Overview

Problem

Existing electrostatic charge image developing toners using silica particles as external additives suffer from fogging, toner scattering, and deterioration of fine line reproducibility due to wide charge distribution and excessive negative charging.

Innovation Solution

The toner incorporates silica particles with a nitrogen element-containing compound, having specific NMR spectral characteristics and extraction amounts, adsorbed into the silica particles' pores, to narrow the charge distribution and stabilize the charge balance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If silica particles are used as external additives in toner, then toner流动性 and charge control are improved, but fogging and toner scattering occur due to wide charge distribution and excessive negative charging

Engineering Contradiction:

Improvetoner flowabilityVSAvoidfogging and toner scattering

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical parameters of silica particles by controlling the C/D ratio (0.05-0.80) of specific silicon environments detected by 29Si NMR, and controls the extraction amount of nitrogen element-containing compound (0.03-5.0 mass%). These parameter changes narrow the charge distribution and prevent excessive negative charging, thereby suppressing fogging and toner scattering while maintaining good flowability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure by adsorbing nitrogen element-containing compounds onto silica particles. This composite material combines the flowability benefits of silica particles with the charge control properties of nitrogen-containing compounds, achieving both good toner flowability and suppressed fogging through the synergistic effect of the composite structure.

Inventive Principle:

Principle #40Composite materials

2Reliability

If silica particles with high negative charge are used, then charge control is enhanced, but fine line reproducibility deteriorates due to excessive negative charging

Engineering Contradiction:

Improvecharge controlVSAvoidfine line reproducibility

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent optimizes the C/D ratio parameter (0.05-0.80) to control the distribution of silicon environments in silica particles. This parameter change narrows the charge distribution and prevents excessive negative charging, thereby maintaining reliable charge control while achieving excellent fine line reproducibility by eliminating the harmful over-charging effect.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional silica particles are used, then production cost is reduced, but fogging occurs during repeated image formation due to wide charge distribution

Engineering Contradiction:

Improveproduction costVSAvoidfogging during repeated image formation

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of silica particles by controlling the nitrogen element-containing compound content (0.03-5.0 mass%) and its extraction characteristics. These parameter changes narrow the charge distribution without significantly increasing production cost, thereby suppressing fogging during repeated image formation while maintaining cost-effectiveness.

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

This configuration effectively suppresses fogging, toner scattering, and maintains fine line reproducibility by stabilizing the charge distribution, even under high humidity conditions.

Implementation Method 1

silica particles which are added to an exterior of the toner particles and contain a nitrogen element-containing compound

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

electrostatic charge image developing toner

Methodology Applied

Scientific EffectElectrostatic charge: Electrostatics

Data Source

PatentUS12455515B2Electrostatic charge image developing toner, electrostatic charge image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method

Publication Date: 2025.10.28 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An electrostatic charge image developing toner has toner particles and silica particles that are added to an exterior of the toner particles, contain a nitrogen element-containing compound, have a ratio C/D of 0.10 or more and 0.75 or less where C represents an integral value of signals observed in a range of chemical shift of −50 ppm or more and −75 ppm or less in a 29Si solid-state nuclear magnetic resonance (NMR) spectrum obtained by a cross-polarization/magic angle spinning (CP/MAS) method and D represents an integral value of signals observed in a range of chemical shift of −90 ppm or more and −120 ppm or less in the same spectrum, have an extraction amount X of the nitrogen element-containing compound by a mixed solution of ammonia/methanol of 0.1% by mass or more, and satisfy Expression: Y/X<0.3 where X represents an extraction amount of the nitrogen element-containing compound by a mixed solution of ammonia/methanol and Y represents an extraction amount of the nitrogen element-containing compound by water.