Toner Additive Composition for Stable Low-Humidity Charging

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Toner using silica and titanic acid compound particles experiences deterioration of charging characteristics at low temperature and low humidity, leading to device contamination and fog in non-image areas during intermittent printing.

Innovation Solution

The toner formulation includes silica and titanic acid compound particles with specific peak positions, average circularities, and toner coverages to minimize mutual charging, maintaining stable charging characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If silica particles and titanic acid compound particles are used as external additives in toner, then fluidity and charge uniformity are improved, but charging characteristics deteriorate at low temperature and low humidity

Engineering Contradiction:

Improvecharging characteristicsVSAvoiddevice contamination and fog

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by precisely controlling the particle size distribution of silica particles (peak at 20-80 nm), the circularity of titanic acid compound particles (0.890-0.950), and their respective toner coverages. By optimizing these parameters and ensuring the coverage difference between the two additives is 20 percentage points or less, the toner maintains stable charging characteristics across different environmental conditions, preventing the deterioration that occurs at low temperature and low humidity.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If silica particles with small primary particle size are used, then charge uniformity is improved, but mutual charging between particles increases

Engineering Contradiction:

Improvecharge uniformityVSAvoidmutual charging

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by using silica particles with a specific peak size range (20-80 nm) rather than a single uniform size, and by combining them with titanic acid compound particles of comparable size. This creates a distributed particle size structure where different particle sizes coexist, reducing the mutual charging effect while maintaining good charge uniformity on the toner surface.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses a composite material approach by combining silica particles and titanic acid compound particles as external additives. This composite structure allows the two different materials to work synergistically, where the silica particles provide charge uniformity and the titanic acid compound particles help suppress mutual charging, achieving both benefits simultaneously.

Inventive Principle:

Principle #40Composite materials

3Reliability

If titanic acid compound particles with high circularity are used, then charge stability is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvecharge stabilityVSAvoidparticle circularity control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent specifies a circularity range of 0.890-0.950 for titanic acid compound particles, which balances charge stability with manufacturing feasibility. This parameter range is stringent enough to ensure good charging performance but practical enough for industrial production, avoiding overly tight tolerances that would make manufacturing difficult.

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

Stable charging characteristics are maintained, preventing device contamination and fog, even in low-temperature and low-humidity environments.

Implementation Method 1

electrostatic charge image developing toner containing toner particles, silica particles that are added to an exterior of the toner particles, and titanic acid compound particles that are added to the exterior of the toner particles

Methodology Applied

Scientific EffectElectrostatic charge: Electrostatics

Data Source

PatentUS12529974B2Electrostatic charge image developing toner, electrostatic charge image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method

Publication Date: 2026.01.20 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An electrostatic charge image developing toner contains toner particles, silica particles that are added to an exterior of the toner particles, and titanic acid compound particles that are added to the exterior of the toner particles and have an average circularity of 0.890 or more and 0.950 or less, in which the silica particles include particles having a primary particle size of 80 nm or less, the particles having a primary particle size of 80 nm or less have at least one peak in a range of 20 nm or more and less than 80 nm in a number-based primary particle size distribution curve (hereinafter, silica particles having such a peak will be called “specific silica particles”), the titanic acid compound particles have at least one peak in a range of 20 nm or more and less than 80 nm in a number-based primary particle size distribution curve, a difference between an average circularity of the specific silica particles and the average circularity of the titanic acid compound particles is 0.05 or less, and a difference between a toner coverage of the specific silica particles and a toner coverage of the titanic acid compound particles is 20% points or less.