Liquid Developer Toner Recrystallization for Density and Gloss
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Solution Overview
Problem
Liquid developers containing carbon black face challenges in achieving high image density while maintaining desired gloss and preventing document offset, as increased carbon black content can lead to lower gloss and image density variability.
Innovation Solution
A liquid developer formulation with toner particles containing a crystalline polyester resin, carbon black, and nigrosine, where the mass ratio of the coloring agent to toner particles is optimized within specific ranges to achieve a peak temperature in the DSC curve between 30°C and 50°C, ensuring high image density and gloss without document offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the content of carbon black is increased to achieve higher image density, then image density may improve, but the degree of gloss decreases due to the filler effect of carbon black
Solution Approach 1:
The patent employs a composite coloring agent system combining carbon black (inorganic pigment) with nigrosine (organic dye). This composite approach allows the carbon black to provide image density while the nigrosine compensates for gloss reduction, achieving both high density and maintained glossiness simultaneously
Solution Approach 2:
The patent optimizes the mass ratio parameters of the coloring agent components (carbon black and nigrosine) relative to the toner particles. By controlling these compositional parameters within specific ranges, the system achieves the desired balance between image density and gloss without requiring excessive carbon black content
2Quantity of substance
If the content of coloring agent is increased to achieve higher image density, then image density improves, but image density varies depending on the degree of gloss
Solution Approach 1:
The composite coloring agent system of carbon black and nigrosine provides complementary functions: carbon black ensures consistent base density while nigrosine modulates the density-gloss relationship. This combination stabilizes image density across varying gloss conditions, preventing the variability that occurs with single-agent systems
Solution Approach 2:
By controlling the mass ratio of coloring agent to toner particles and the composition ratio between carbon black and nigrosine, the patent establishes optimal parameter ranges that ensure consistent image density regardless of gloss variations, achieving reproducible results
3Loss of substance
If toner particles are used in liquid developer to reduce adhesion amount, then cost per page decreases, but image density may be reduced
Solution Approach 1:
The composite coloring agent system enhances the color strength per unit mass of toner. The synergistic combination of carbon black and nigrosine provides higher pigmentary efficiency, allowing reduced toner adhesion while maintaining or improving image density, thus resolving the contradiction between lower CPP and sufficient density
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 optimized formulation achieves high image density, excellent glossiness, and prevents document offset by maintaining the toner particles in a state suitable for recrystallization, ensuring effective fixation and image quality.
Implementation Method 1
The toner particles have a peak at not lower than 30° C. and not higher than 50° C. in a differential scanning calorimetry (DSC) curve in temperature decrease
Data Source
AI summary
A liquid developer includes an insulating liquid and toner particles which are dispersed in the insulating liquid and contain a resin and a coloring agent. The resin contains a first resin which is a resin containing a component derived from a crystalline polyester resin. The coloring agent contains carbon black and nigrosine. The toner particles have a peak at not lower than 30° C. and not higher than 50° C. in a DSC curve in temperature decrease.