Toner Composition with Eutectic Structure for Stable Charging
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Solution Overview
Problem
Existing toners face challenges in maintaining stable image quality and low-temperature fixability in diverse environmental conditions, particularly with the use of talc paper in cleanerless systems, where high humidity and temperature fluctuations affect charging performance and image quality.
Innovation Solution
A toner composition featuring a binder resin with specific monomer units and an ester compound, optimized to provide stable positive charging performance and low-temperature fixability, utilizing a resin A with a long-chain acrylate unit and resin B with a quaternary ammonium salt group, along with an ester compound, to form a eutectic structure that inhibits moisture adsorption and promotes charge stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a positive charge control resin containing a quaternary ammonium salt group is used to improve charging characteristics, then charging performance is improved, but hygroscopicity increases causing charging performance to decline in high-temperature, high-humidity environments
Solution Approach 1:
The patent changes the chemical structure parameters of the charge control resin by incorporating aromatic carboxylic acid groups (such as benzoic acid, naphthoic acid) instead of or in combination with quaternary ammonium salts. This structural modification reduces hygroscopicity while maintaining positive charging characteristics, enabling stable charging performance in high-temperature, high-humidity environments.
Solution Approach 2:
The patent uses composite charge control resins that combine multiple functional groups (aromatic carboxylic acid groups, quaternary ammonium salts, sulfonic acid groups) within a single resin system. This composite approach allows balancing charging performance with reduced moisture sensitivity by leveraging the complementary properties of different functional groups.
2Temperature
If a styrene-acrylic resin with specific monomer units is used to improve low-temperature fixability, then melting characteristics are improved, but charging stability in extreme environments deteriorates
Solution Approach 1:
The patent modifies the binder resin composition by incorporating specific monomer units (acrylonitrile, vinylidene chloride, carboxylic acid groups) that adjust the glass transition temperature and melting characteristics. These compositional changes enable low-temperature fixability while the associated charge control resin components maintain charging stability across extreme temperature and humidity conditions.
Solution Approach 2:
The patent creates a composite toner system where the binder resin (styrene-acrylic with specific monomers) works synergistically with the charge control resin (containing aromatic carboxylic acid groups). This composite structure allows the binder to provide low-temperature melting properties while the charge control resin ensures stable charging performance in varying environmental conditions.
3Manufacturing precision
If talc content in paper is high to improve print quality, then image quality is improved, but talc transfer to the photosensitive drum causes charging reduction and image fogging
Solution Approach 1:
The patent converts the harmful effect of talc transfer into a beneficial outcome by using a positive-charging toner with reduced hygroscopicity. The positive charge attracts negatively charged talc particles, and the low-hygroscopicity charge control resin prevents moisture-induced charge loss, thereby maintaining effective charging even when talc is present on the photosensitive drum.
Solution Approach 2:
The patent applies preliminary anti-action by designing a charge control resin with aromatic carboxylic acid groups that inherently resists moisture adsorption before environmental humidity can degrade charging performance. This preliminary protection ensures stable positive charging capability even when talc transfer occurs during printing operations.
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 toner exhibits improved charging stability and low-temperature fixability in both high-temperature, high-humidity and low-temperature, low-humidity environments, reducing image fogging and nontransfer fogging, and maintaining consistent image quality during extended printing durations.
Implementation Method 1
utilizing a resin A with a long-chain acrylate unit and resin B with a quaternary ammonium salt group, along with an ester compound, to form a eutectic structure that inhibits moisture adsorption and promotes charge stability
Implementation Method 2
a positive charge control resin that contains a unit derived from styrene and a unit derived from a quaternary ammonium salt group
Data Source
AI summary
A toner comprising a toner particle comprising a binder resin and an ester compound, wherein:the binder resin comprises a resin A comprising a specific amount of a long-chain acrylate unit and a styrene-based monomer unit, and a resin B comprising a specific monomer unit in a specific amount;the ester compound has an alkyl chain with a specific chain length,a content of the resin A in the chloroform-soluble portion of the toner particles is 60% by mass or more; andusing SPm (J/cm3)1/2 for a SP value of the long-chain acrylate unit and using SPw (J/cm3)1/2 for a SP value of the ester compound,SPm is 18.00 to 19.00, andSPm and SPw satisfy formula (a).|SPm−SPw|≤1.50 (a)