Crystalline Polyester Toner Production via Recrystallization
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Solution Overview
Problem
Conventional toner production methods using kneading and pulverization processes result in toners with indeterminate shapes, large energy consumption for fixation, and unsatisfactory performance due to interfacing spaces filled with wax, while polymerization processes struggle to produce stable low-temperature fixing and anti-hot offset properties with downsized particle diameters.
Innovation Solution
A method involving dispersing an oil phase containing crystalline and amorphous polyester resins in an aqueous medium, followed by recrystallization and mechanical pulverization to achieve a crystalline polyester dispersion with a volume average particle diameter of 0.1 μm to 1.0 μm, enhancing low-temperature fixing ability and anti-hot offset properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If kneading and pulverization process is used to produce toner, then production is straightforward, but particle shapes become indeterminate and particle diameter distribution becomes statistically dispersed
Solution Approach 1:
The invention changes the fundamental production parameter from mechanical kneading and pulverization to solution polymerization. This parameter change enables precise control over particle formation, producing spherical particles with narrow size distribution (standard deviation of 0.5 μm or less) instead of indeterminate shapes and dispersed distributions.
Solution Approach 2:
The invention replaces the mechanical kneading and pulverization system with a chemical polymerization system. By conducting polymerization in a solution state and then precipitating the polymer, the process achieves precise particle morphology control without mechanical force, eliminating the indeterminate shapes and size dispersion caused by mechanical processing.
2Ease of manufacture
If kneading and pulverization process is used, then production is feasible, but large amounts of energy are required for fixation
Solution Approach 1:
The invention changes the particle morphology parameter from irregular cracked shapes to uniform spherical shapes. This parameter change improves flowability and packing efficiency, enabling lower fixation temperatures and reduced energy consumption during the fixing process.
Solution Approach 2:
The invention utilizes controlled phase transition during polymerization to form uniform spherical particles. By precipitating the polymer from solution in a controlled manner, spherical particles are formed that melt uniformly during fixation, reducing the energy required compared to irregular particles with interfacing spaces.
3Length of moving object
If polymerization process is used to downsize particles, then particle diameter can be reduced, but stable low-temperature fixing and anti-hot offset properties cannot be achieved
Solution Approach 1:
The invention changes the resin composition parameters by incorporating specific crystalline polyester resins with controlled melting points (60-150°C) alongside amorphous polyester resins. This dual-resin system maintains particle downsizing while achieving stable low-temperature fixing ability and anti-hot offset properties through the complementary characteristics of crystalline and amorphous phases.
Solution Approach 2:
The invention creates a composite toner system combining crystalline polyester resin and amorphous polyester resin in specific proportions. This composite material approach enables simultaneous achievement of downsized particles, low-temperature fixing stability, and anti-hot offset properties by leveraging the distinct thermal and structural characteristics of each resin type.
4Temperature
If crystalline polyester is introduced using conventional dispersion methods, then low-temperature fixing ability may improve, but only coarse dispersion with particle diameter of several tens to hundreds of micrometers can be produced
Solution Approach 1:
The invention replaces conventional mechanical dispersion methods with solution polymerization followed by controlled precipitation. This substitution enables formation of fine crystalline polyester particles (1.0 μm or less) directly during the polymerization process, avoiding the coarse dispersion (tens to hundreds of micrometers) produced by mechanical methods.
Solution Approach 2:
The invention changes the dispersion mechanism from mechanical force to controlled chemical precipitation. By adjusting polymerization conditions and precipitation parameters, the invention produces ultra-fine crystalline polyester particles with volume average diameter of 1.0 μm or less, enabling both low-temperature fixing and fine particle size.
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 method produces toners with stable low-temperature fixing ability and anti-hot offset properties, achieving excellent heat-resistant storage stability and sharp melting characteristics, which improves the fixation process and image quality.
Implementation Method 1
cooling the solution so as to recrystallize the crystalline polyester resin
Implementation Method 2
removing the organic solvent from the dispersion to obtain the toner
Data Source
AI summary
A method for producing a toner, containing: dispersing, in an aqueous medium, an oil phase which contains an organic solvent, and a binder resin component contained in the organic solvent, where the binder resin component contains a crystalline polyester resin and an amorphous polyester resin; and removing the organic solvent from the dispersion to obtain the toner, in which the dispersing further contains heating and dissolving the crystalline polyester and the amorphous polyester in the organic solvent to obtain a solution, cooling the solution so as to recrystallize the crystalline polyester resin, and mechanically pulverizing the recrystallized crystalline polyester resin so as to obtain a crystalline polyester dispersion.