Liquid Developer Pigment Composite for Image Density and Fixing Strength
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Solution Overview
Problem
Existing liquid developers for electrophotographic image forming struggle to achieve high image density and fixing strength simultaneously due to limitations in pigment dispersion, leading to compromised image quality and increased costs.
Innovation Solution
A liquid developer formulation incorporating a combination of carbon black, nigrosine, and organic pigments, such as phthalocyanine blue, carmine-based, and benzimidazolone-based pigments, dispersed in a polyester resin, which enhances pigment dispersion and maintains a balanced resin content to achieve high image density and fixing strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the content of pigment in toner particle is increased to achieve high image density, then image density is improved, but resin content is relatively decreased resulting in decreased fixing strength
Solution Approach 1:
The patent uses a composite pigment system consisting of carbon black (10-25 mass%), nigrosine (3-15 mass%), and organic pigment (5-20 mass%) within the toner particle. This composite approach allows achieving high image density through synergistic pigment combination while maintaining resin content at adequate levels to ensure fixing strength, resolving the contradiction between pigment concentration and resin content.
2Quantity of substance
If the content of pigment in toner particle is increased to achieve high image density, then image density is improved, but dispersion property of pigment in resin deteriorates
Solution Approach 1:
The patent employs a composite pigment formulation where carbon black, nigrosine, and organic pigment work together to achieve uniform dispersion at high concentrations. The specific combination creates synergistic dispersion effects that prevent aggregation, maintaining pigment distribution stability even at elevated total pigment content (38-60 mass%), thus achieving both high image density and good dispersion property.
3Loss of substance
If the film thickness of image is decreased to reduce toner particle adhesion and achieve low cost, then cost is reduced, but image density needs to be maintained
Solution Approach 1:
The patent changes the pigment composition parameters by incorporating nigrosine and organic pigment alongside carbon black, creating a formulation that achieves higher density per unit mass. This allows the toner particle to maintain sufficient image density even when applied at lower concentrations, reducing overall toner particle adhesion to the recording material while preserving image quality and reducing costs.
Data Source
AI summary
A liquid developer of the present invention includes a toner particle and an insulating liquid, the toner particle including a resin and a pigment, the resin including a polyester resin, the pigment including a first pigment, a second pigment, and a third pigment, the first pigment being a carbon black, 10 to 25 mass % of the first pigment being included in the toner particle, the second pigment being nigrosine, 3 to 15 mass % of the second pigment being included in the toner particle, the third pigment being at least one organic pigment selected from a group consisting of a phthalocyanine blue pigment, a phthalocyanine green pigment, a carmine-based pigment, a naphthol-based pigment, a quinacridon-based pigment, an azo-based pigment, a benzimidazolone-based pigment, and an isoindoline-based pigment, 5 to 20 mass % of the third pigment being included in the toner particle.