Toner Particle Production via Melt Atomization and Wax Encapsulation
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Solution Overview
Problem
Conventional methods for producing toner, such as pulverization and chemical methods, face challenges in controlling wax dispersion, leading to issues with fixing temperature range, durability, and environmental concerns like organic solvent use and effluent treatment.
Innovation Solution
A method involving melting a mixture of binder resin and additives with lower melting points, followed by atomization and controlled cooling to form resinous particles that encapsulate the additives, eliminating the need for organic solvents and effluent treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pulverization method is used to produce toner, then the production process is relatively simple, but the wax content is limited to only 3% to 6% and the fixing temperature range is narrow
Solution Approach 1:
The invention changes the fundamental production parameter from solid-state pulverization to liquid-state atomization. By melting the binder resin and additives together to form a molten mixture, then atomizing it to form particles, the method enables encapsulation of wax content exceeding 10% while achieving a wide fixing temperature range. This parameter change resolves the contradiction by allowing high wax content without limiting the fixing temperature adaptability.
Solution Approach 2:
The invention utilizes phase transitions of the binder resin and additives. The binder resin is heated to melt (solid to liquid transition), allowing thorough mixing with wax and other additives in the molten state. During atomization and cooling, the mixture undergoes liquid to solid transition, encapsulating the additives within the resin matrix. This phase transition approach enables high wax content encapsulation while maintaining particle integrity and broadening the fixing temperature range.
2Adaptability or versatility
If the chemical method is used to produce toner with high wax content, then the fixing temperature range can be widened, but organic solvents and effluent treatment are required
Solution Approach 1:
The invention extracts and eliminates the harmful organic solvents from the chemical method. By using a melt atomization process where the binder resin is heated to melting point and atomized in a molten state, the method achieves high wax content encapsulation and wide fixing temperature range without requiring organic solvents. This extraction of the harmful element (organic solvent) while retaining the beneficial outcomes (high wax content, wide temperature range) resolves the contradiction.
Solution Approach 2:
The invention converts the potential harm of high wax content (which can cause staining and durability issues) into a benefit by using controlled atomization. The molten mixture is atomized into fine droplets that solidify into particles with uniformly distributed wax encapsulated within the resin matrix. This converts the harmful effect of high wax content into a beneficial feature, achieving wide fixing temperature range without the drawbacks of staining or poor durability, and without requiring organic solvents.
3Reliability
If wax is finely dispersed in binder resin to improve low temperature offset, then the dispersion control becomes difficult and production complexity increases
Solution Approach 1:
The invention performs preliminary mixing of wax and binder resin in the molten state before atomization. By heating the binder resin to melting point and thoroughly mixing the wax and other additives in this liquid state, uniform dispersion is achieved before the particle formation step. This preliminary action in the molten state simplifies the overall process by ensuring uniform distribution without requiring complex dispersion control mechanisms during atomization, thus improving low temperature offset resistance while reducing production complexity.
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 method produces toners with improved wax encapsulation, enhanced durability, and a wider fixing temperature range while reducing environmental impact by avoiding organic solvents and effluent treatment.
Implementation Method 1
melting a mixture containing a binder resin and at least one additive having a melting point which is lower than T1/2 of the binder resin
Implementation Method 2
atomizing resinous particles from the molten material in an atmosphere having a temperature which is higher than a glass transition temperature of the binder resin and is lower than 3 times of T1/2 of the binder resin
Implementation Method 3
cooling and solidifying the resinous particles
Data Source
AI summary
There is provided a method for producing resinous particles, containing: melting a mixture containing a binder resin and at least one additive having a melting point lower than T1/2 of the binder resin so as to prepare a molten material; atomizing resinous particles from the molten material in an atmosphere having a temperature higher than Tg of the binder resin and lower than 3 times of T1/2 of the binder resin; retaining the resinous particles in an atmosphere having a temperature higher than Tg of the binder resin, and lower than 1.5 times of T1/2 of the binder resin for 1 s to 15 s; and cooling and solidifying the resinous particles. There is also provided a method for producing resinous particles containing: melting the mixture so as to prepare a molten material; increasing a specific surface of the molten material in an atmosphere having a temperature higher than Tg of the binder resin, and lower than 3 times of T1/2 of the binder resin, so as to form a precursor; retaining the precursor in an atmosphere having a temperature higher than Tg of the binder resin, and lower than 1.5 times of T1/2 of the binder resin for 1 ms to 10 ms; cooling and solidifying the precursor; and atomizing resinous particles from the precursor.