Electrostatic Toner Sea-Island Structure for Offset Prevention

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Solution Overview

Problem

Electrophotographic toners face issues with document offset and image defects due to the migration of images to contact surfaces, especially in high-temperature environments, where repeated pressure-contact and separation with resin sheets lead to adherence issues and release failures.

Innovation Solution

The development of an electrostatic image-developing toner with a sea-island structure, where the release agent has a specific distribution of eccentricity degree B, ranging from 0.75 to 1.00, and skewness from -1.30 to -0.50, ensuring the release agent is predominantly on the surface but also distributed with a gradient, allowing controlled bleeding and reduced adherence to contact surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the release agent is uniformly distributed throughout the toner, then the release agent can prevent document offset, but the toner shows gloss unevenness and poor image quality

Engineering Contradiction:

Improvedocument offset preventionVSAvoidimage quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The release agent is distributed non-uniformly with higher concentration at the toner surface and lower concentration in the interior. This local quality variation allows the surface to provide release function while the interior maintains image quality, resolving the contradiction between document offset prevention and gloss unevenness

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The toner is divided into different regions with different release agent concentrations: a surface layer with high concentration for release function, and an interior region with low concentration for image quality. This segmentation allows each region to fulfill its specific function without compromising the other

Inventive Principle:

Principle #1Segmentation

2Reliability

If the release agent concentration is increased to prevent document offset, then release performance improves, but the toner shows excessive bleeding and poor image quality

Engineering Contradiction:

Improverelease performanceVSAvoidimage quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The release agent concentration is varied locally within the toner structure, with high concentration at the surface for release performance and low concentration in the interior to prevent excessive bleeding, thus maintaining both release performance and image quality

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The toner is segmented into a surface region containing release agent for release performance and an interior region with minimal release agent to prevent excessive bleeding, allowing each segment to contribute its specific function without adverse effects

Inventive Principle:

Principle #1Segmentation

3Reliability

If the release agent is placed only at the toner surface, then release function is maximized, but the toner shows poor thermal stability and image defects

Engineering Contradiction:

Improverelease functionVSAvoidthermal stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The release agent is concentrated at the surface where it is needed for release function, while the interior contains minimal release agent to maintain thermal stability, achieving both release function and thermal stability through local quality variation

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The toner is divided into a surface layer with release agent for release function and an interior layer with minimal release agent for thermal stability, allowing each segment to optimize its specific property without compromising the other

Inventive Principle:

Principle #1Segmentation

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 toner configuration effectively prevents document offset and release failures by maintaining release agent presence on the image surface, even under high-temperature conditions, ensuring consistent image quality and reduced gloss unevenness on irregular recording mediums.

Implementation Method 1

the migration of images to contact surfaces, especially in high-temperature environments

Methodology Applied

Scientific EffectMigration:

Implementation Method 2

a release agent having a melting point of 85° C. to 120° C.

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 3

repeated pressure-contact and separation with resin sheets lead to adherence issues

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS9835962B2Electrostatic image-developing toner, electrostatic image developer, and toner cartridge

Publication Date: 2017.12.05 FUJIFILM BUSINESS INNOVATION CORP

AI summary

There is provided an electrostatic image-developing toner containing a binder resin, a coloring agent and a release agent having a melting temperature of 85° C. to 120° C., the toner having a sea-island structure involving a sea part containing the binder resin and an island part containing the release agent, wherein a mode value of the distribution of the eccentricity degree B of the release agent-containing island part, represented by the specific formula, is from 0.75 to 1.00 and a skewness of the distribution of the eccentricity degree B is from −1.30 to −0.50.