Toner Production via Casson Yield Value and Temperature Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing toner production methods struggle to control particle size distribution and shape, particularly for spherically shaped toners with small particle diameters, leading to cleaning failures due to rolling friction and uneven shear forces, which affect image fixing and quality.
Innovation Solution
A method involving the preparation of an emulsified dispersion by dispersing a pigment and binder resin in an aqueous medium, with controlled Casson yield value and temperature conditions to form toner base particles, allowing for non-Newtonian flow and precise control of particle shape and size, including the use of inorganic oxide fine particles like organosilica to adjust viscosity and rheological properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spherically shaped toner particles with small particle diameters are used, then dot-reproductivity is improved, but cleaning ability deteriorates due to rolling friction and particle entry into clearance
Solution Approach 1:
The invention changes the shape parameter of toner particles from spherical to ellipsoidal, and controls the particle diameter within a specific range (2 μm to 10 μm). This parameter modification resolves the contradiction by maintaining sufficient dot-reproductivity while preventing particles from entering the cleaning blade clearance, thus preserving cleaning ability.
2Manufacturing precision
If toner particles are made smaller and more spherical, then developing and transferring properties are improved, but cleaning failures occur due to reduced rolling friction
Solution Approach 1:
The invention modifies the shape parameter from spherical to ellipsoidal with specific axial ratio controls, and adjusts particle diameter to 2-10 μm. This prevents the particles from becoming too smooth and spherical, thereby maintaining sufficient rolling friction for effective cleaning while preserving developing and transferring properties.
3Ease of manufacture
If blade cleaning system is used, then cleaning simplicity is achieved, but edge deformation occurs due to frictional resistance
Solution Approach 1:
The invention changes the particle shape parameter from spherical to ellipsoidal with controlled aspect ratios. This shape modification reduces the particles' ability to enter and damage the blade edges during cleaning, thereby reducing edge deformation while maintaining the simplicity of the blade cleaning system.
4Stability of the object's composition
If primary particles are heated to fusion-bond, then particle association is achieved, but particle size distribution widens and productivity decreases
Solution Approach 1:
The invention changes the temperature parameter during particle formation to occur below the glass transition temperature of the resin, avoiding high-temperature fusion-bonding. This allows particle association to occur through controlled cooling and solidification processes, maintaining narrow particle size distribution and high productivity while achieving stable particle composition.
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
This approach enables the production of toners with controlled particle size and shape, improving dot-reproductivity, developing, and transferring properties, while preventing particle coarsening and gelation, resulting in enhanced image fixing and quality.
Implementation Method 1
the Casson yield value of the oil phase in an isolated condition before being emulsified or dispersed in the aqueous medium is 0.5 Pa to 20 Pa
Implementation Method 2
the use of inorganic oxide fine particles like organosilica to adjust viscosity and rheological properties
Data Source
AI summary
The present invention provides a method for producing a toner including preparing an emulsified dispersion which contains emulsion particles by emulsifying or dispersing an oil phase containing at least a pigment and any one of a binder resin and a binder resin precursor in an aqueous medium, and granulating toner base particles by converging the emulsified dispersion, wherein the Casson yield value of the single oil phase before being emulsified or dispersed in the aqueous medium is 0.5 Pa to 20 Pa; and the temperature Tn of the emulsified dispersion in the preparation of the emulsified dispersion, the temperature Ts of the emulsified dispersion in the granulation of the toner base particles, and the glass transition temperature Tg of the toner base particles satisfy the relation Tn<Ts<Tg.