Toner Particle Production via Centrifugal Condensation
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Solution Overview
Problem
Toner performance is compromised due to adhesiveness issues between binder resin and materials in toner particles, particularly at low temperatures and high humidity, leading to fogging, development streaks, and reduced durability in electrophotographic processes.
Innovation Solution
A method involving a decanter-type centrifugal separator is used to treat toner slurry under specific conditions of centrifugal force (500 G to 4000 G) and temperature (Tg−10°C to Tg+10°C) to enhance adhesiveness, using a crystalline material like ester wax or crystalline polyester to improve toner durability and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sudden temperature changes are applied to return toner from high temperature to normal temperature, then productivity is improved by shortening cooling time, but adhesiveness between materials and binder resin deteriorates due to thermal expansion differences
Solution Approach 1:
The invention changes the temperature parameter during the cooling process, specifically maintaining temperature within Tg±10°C range of the binder resin to prevent thermal shock and maintain adhesiveness while still achieving productivity improvement
Solution Approach 2:
The invention addresses thermal expansion differences between magnetic powder and binder resin by controlling the temperature change rate, preventing cracking and chipping that would occur with sudden temperature changes
2Manufacturing precision
If contact development system is used to achieve high-definition images, then image quality is improved, but toner durability deteriorates due to increased pressure and load on toner
Solution Approach 1:
The invention uses composite materials including binder resin, magnetic powder, and crystalline materials to create toner particles that can withstand the pressure and load of contact development systems while maintaining high-definition image quality
Solution Approach 2:
The invention changes the physical and chemical parameters of toner materials, including glass transition temperature and crystalline structure, to enhance toner toughness and durability under contact development conditions
3Productivity
If toner is produced in aqueous medium using suspension polymerization, then productivity is improved by achieving high yield and sharp particle size distribution, but adhesiveness between materials and binder resin deteriorates under low temperature and low humidity conditions
Solution Approach 1:
The invention changes the temperature parameter control during production and use, maintaining temperature within specific ranges to prevent adhesiveness deterioration while preserving the high yield benefits of suspension polymerization
Solution Approach 2:
The invention uses composite materials with specific glass transition temperatures and crystalline structures to maintain adhesiveness in the aqueous medium production method, preventing fogging and development streaks under low temperature and humidity conditions
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 toner with improved adhesiveness and durability, preventing fogging and development streaks, even under low-temperature, low-humidity conditions, while maintaining high image density and productivity.
Implementation Method 1
a treatment step of treating a raw slurry containing an aqueous medium and colored particles each containing a binder resin and a colorant, wherein the treatment step includes a step of condensing the raw slurry by using a decanter-type centrifugal separator
Implementation Method 2
using a crystalline material like ester wax or crystalline polyester to improve toner durability and image quality
Data Source
AI summary
Provided is a method for producing a toner particle including a step of condensing a raw slurry by using a decanter-type centrifugal separator, in an aqueous medium. The step of condensing the raw slurry is carried out under following conditions: a centrifugal force is at least 500 G and less than 4000 G and a temperature is at least Tg−10° C. and not more than Tg+10° C. And a ratio of a colored particles in condensed slurry is within a prescribed range.