Electrostatic Latent Image Developer Colorant Dispersant
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Solution Overview
Problem
The challenge is to maintain proper image density and fixation strength in electrostatic latent image developers with high concentrations of colorants, as increased colorant concentration leads to aggregation and poor dispersibility, resulting in decreased fixation strength and image quality.
Innovation Solution
Incorporating a colorant dispersant with a specific structure, comprising a first polymer compound derived from 4-vinylpyridine, n-butyl acrylate or n-butyl methacrylate, and a monomer with a (CH2CH2O)nCH3 or (CH2CH2O)nCH2CH3 group, along with a second polymer compound containing a constitutional unit from ε-caprolactone, to enhance colorant dispersion and fixation strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the concentration of colorant in toner particles is increased to maintain image density, then image density is preserved, but the colorant aggregates and dispersibility deteriorates
Solution Approach 1:
A colorant dispersant comprising a first polymer compound and a second polymer compound is introduced as an intermediary substance. The first polymer compound contains constitutional units from 4-vinylpyridine, n-butyl acrylate, or n-butyl methacrylate, while the second polymer compound contains constitutional units from ε-caprolactone. This dispersant mediates between the colorant and resin, preventing aggregation even at high colorant concentrations (30-60 mass%) while maintaining uniform dispersion and stability.
2Quantity of substance
If the ratio of colorant in toner particles is increased, then image density is maintained, but fixation strength decreases due to reduced resin ratio
Solution Approach 1:
The colorant dispersant acts as a bridging intermediary between colorant and resin components. By incorporating both the first polymer compound (with 4-vinylpyridine, n-butyl acrylate, or n-butyl methacrylate units) and the second polymer compound (with ε-caprolactone units), the system maintains strong interfacial adhesion even when colorant constitutes 30-60 mass% of toner particles, thereby preserving fixation strength despite high colorant loading.
Solution Approach 2:
The toner particle is designed as a composite material system comprising resin, colorant, and a composite dispersant structure. The dispersant itself is a composite of two polymer compounds with different functional units, creating a multi-component composite structure that simultaneously achieves high colorant loading (30-60 mass%), uniform dispersion, and maintained fixation strength through synergistic interactions among components.
3Quantity of substance
If the concentration of colorant is increased to achieve proper color phase, then color saturation is improved, but uniform dispersion becomes difficult
Solution Approach 1:
The colorant dispersant serves as a mediating agent that enables uniform dispersion of colorant at high concentrations (30-60 mass%). The first polymer compound (containing 4-vinylpyridine, n-butyl acrylate, or n-butyl methacrylate constitutional units) and second polymer compound (containing ε-caprolactone constitutional units) work together to prevent colorant aggregation during manufacturing, ensuring uniform distribution and consistent color phase throughout the toner particles.
Data Source
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AI summary
An electrostatic latent image developer of the present invention includes a resin, a colorant and a colorant dispersant, wherein the colorant dispersant contains a first polymer compound containing a constitutional unit derived from a monomer A, a constitutional unit derived from a monomer B and a constitutional unit derived from a monomer C, the monomer A is 4-vinylpyridine, the monomer B is CH2=CR1-COOR2 (where R1 represents hydrogen or a methyl group; and R2 represents an alkyl group having 1 to 10 carbon atoms), and the monomer C is CH2=CR3-COOR4 (where R3 represents hydrogen or a methyl group; R4 represents (CH2CH2O)nCH3 or (CH2CH2O)nCH2CH3; and n represents an integer of 12 to 18).