Toner Composition Narrow Particle Distribution via Polymerization

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Solution Overview

Problem

Conventional toner preparation methods, such as the grinding method, often result in wide particle diameter distributions, limiting control over toner characteristics like fixing and durability, which are crucial for high printing performance and image quality in electrophotography.

Innovation Solution

A toner composition including latex, a colorant, and a releasing agent, with specific molecular weight ranges and crossover temperatures, is developed using a polymerization method that involves mixing, agglomeration, and heating to achieve controlled particle sizes and distributions, enhanced durability, and improved fixing properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the grinding method is used to prepare toner, then the manufacturing process is simple, but the particle diameter distribution becomes wide

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidparticle diameter distribution

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the fundamental parameter of toner preparation from mechanical grinding to chemical polymerization. By controlling polymerization conditions (monomer composition, initiator type, reaction temperature, and use of suspension agents), the invention achieves narrow particle diameter distribution (GSD ≤ 1.2) while maintaining manufacturing feasibility through a standardized chemical process.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical grinding system with a chemical polymerization system. Instead of mechanically reducing particle size through grinding and classification, the toner particles are formed directly through controlled polymerization of monomers in suspension, eliminating the need for mechanical size reduction and classification equipment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If the grinding method is used to prepare toner, then the manufacturing process is straightforward, but the control over toner structure and characteristics is limited

Engineering Contradiction:

Improvemanufacturing process straightforwardnessVSAvoidcontrol over toner characteristics

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent enables comprehensive control over toner characteristics by adjusting multiple polymerization parameters: monomer composition (styrene-butadiene-acrylic acid ratios), initiator concentration and type, suspension agent selection, reaction temperature, and particle size control agents. This allows optimization of toner properties including particle diameter, glass transition temperature, durability, and fixing characteristics.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates composite toner particles through polymerization of multiple monomers (styrene, butadiene, acrylic acid) with suspended colorant particles and releasing agents. This composite structure integrates multiple functional components into a single particle system, enabling simultaneous optimization of durability, colorfastness, and fixing properties.

Inventive Principle:

Principle #40Composite materials

3Manufacturing precision

If polymerization method is used to prepare toner, then particle size can be controlled easily without classifying process, but additional process steps for agglomeration are required

Engineering Contradiction:

Improveparticle diameter controlVSAvoidprocess steps

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the polymerization and agglomeration steps into a unified process. The polymerization reaction is conducted in the presence of suspension agents and colorant particles, allowing simultaneous formation of polymer matrix and incorporation of colorant. The agglomeration occurs in-situ during polymerization, eliminating the need for separate classification equipment and reducing overall process complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 provides toners with improved durability, fixing performance, and high glossiness, while maintaining narrow particle diameter distributions, thus enhancing image quality and printing performance.

Implementation Method 1

heating the primary agglomerated toner to a temperature that is equal to or higher than the glass transition temperature of the latex particle to coalesce the primary agglomerated toner

Methodology Applied

Scientific EffectCoalescence: Cohesion

Implementation Method 2

adding an agglomerating agent to the mixture to form a primary agglomerated toner

Methodology Applied

Scientific EffectAgglomeration: Coagulation

Data Source

PatentUS8663891B2Toner for developing electrostatic latent image and method of preparing the same

Publication Date: 2014.03.04 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

Disclosed are a toner for developing an electrostatic latent image and a method of preparing the same. The toner may include latex, a pigment and a releasing agent. The lowest crossover temperature of the toner at which the storage modulus (G′) and the loss modulus (G″) of the toner are substantially equal to each other may be in the range of about 65 to about 80° C. The weight average molecular weight (Mw) of the toner may be in the range of about 65,000 to about 75,000. The z-average molecular weight (Mz) of the toner may be in the range of about 110,000 to about 220,000.