Domain-Matrix Toner Resolves Heat-Storability and Crease Fixability Trade-offs
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Solution Overview
Problem
Conventional electrophotographic image forming methods face challenges in achieving heat-resistant storability and crease fixability of toner images, with existing solutions either compromising on heat-resistant storability or suffering from poor cold fixability and crease fixability due to issues like hot offset and poor dispersibility of crystalline polyester resin in amorphous styrene-acrylic resin combinations.
Innovation Solution
An electrostatic latent image developing toner with a domain-matrix structure, where the matrix is composed of an amorphous resin with a vinyl resin having an acid group and the domain is formed by combining a vinyl polymerized segment and a polyester polymerized segment, with a crystalline resin content ranging from 3 to 30% by mass, and an ester group concentration within specific ranges to enhance compatibility and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the glass transition point or molecular weight of the binder resin is lowered to reduce melting temperature and melt viscosity, then cold fixability is improved, but heat-resistant storability deteriorates
Solution Approach 1:
The invention uses a composite binder resin system comprising a crystalline polyester resin and an amorphous resin in specific proportions. The crystalline polyester resin provides low melting point for good cold fixability, while the amorphous resin with appropriate Tg contributes to heat-resistant storability. This composite approach allows simultaneous optimization of both properties that cannot be achieved with a single resin type.
Solution Approach 2:
The invention precisely controls the glass transition point of the amorphous resin within 30-80°C and the melting point of the crystalline polyester resin within 60-100°C. By optimizing these thermal parameters within specific ranges and controlling their proportions, the toner achieves both low melting temperature for cold fixability and sufficient heat-resistant storability.
2Temperature
If the glass transition point or molecular weight of the binder resin is lowered to reduce melting temperature and melt viscosity, then cold fixability is improved, but hot offset increases
Solution Approach 1:
The composite binder resin system combines crystalline polyester resin (providing low melting point) with amorphous resin (providing thermal stability). This combination enables the toner to melt at lower temperatures for good cold fixability while maintaining sufficient thermal resistance to prevent hot offset through proper selection of resin components and their ratios.
Solution Approach 2:
The invention optimizes the glass transition point of the amorphous resin to 30-80°C and the melting point of the crystalline polyester resin to 60-100°C. This precise parameter control allows the toner to achieve low melting temperature for cold fixability while maintaining adequate thermal stability to prevent hot offset.
3Temperature
If crystalline polyester resin and amorphous styrene-acrylic resin are used in combination to improve heat-resistant storability and cold fixability, then fixability is improved, but crease fixability deteriorates due to poor dispersibility
Solution Approach 1:
The invention optimizes the molecular weight of the crystalline polyester resin to 5,000-50,000 and controls the ester group concentration within 2.0-5.0 mmol/g. These parameter optimizations improve the dispersibility of crystalline polyester resin in the amorphous resin matrix, enabling good crease fixability while maintaining heat-resistant storability and cold fixability.
Solution Approach 2:
The invention introduces a specific structural feature - the crystalline polyester resin forms discrete domains within the amorphous resin matrix. This local structural arrangement, combined with optimized molecular weight and ester group concentration, creates regions of controlled crystallinity that enhance both the thermal properties and the mechanical strength for crease resistance.
4Use of energy by moving object
If the glass transition point or molecular weight of the binder resin is lowered to reduce melting temperature and melt viscosity, then energy consumption is reduced, but heat-resistant storability deteriorates
Solution Approach 1:
The composite binder resin system combines crystalline polyester resin (providing low melting point for energy efficiency) with amorphous resin (providing thermal stability). This allows the toner to fix at lower temperatures, reducing energy consumption, while the amorphous resin component maintains heat-resistant storability.
Solution Approach 2:
The invention optimizes the glass transition point of the amorphous resin to 30-80°C and the melting point of the crystalline polyester resin to 60-100°C. This parameter optimization enables lower fixation temperature (reducing energy consumption) while maintaining sufficient heat-resistant storability through the synergistic effect of the composite resin system.
Data Source
AI summary
Disclosed is an electrostatic latent image developing toner which contains a toner host particle having a domain-matrix structure. The matrix contains an amorphous resin which contains a vinyl resin having an acid group, the domain contains a crystalline resin which is formed by combining a vinyl polymerized segment and a polyester polymerized segment. A content of the crystalline resin falls within a range from 3 to 30% by mass.