Core-Shell Toner for Offset Resistance and Fixability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing toner manufacturing methods face challenges in achieving a balance between low-temperature fixability, thermostable preservability, hot offset resistance, structure control, resistance to contaminating image forming members, and environmental resistance, while also minimizing energy consumption in the fixing process.
Innovation Solution
A toner composition comprising a core with a colorant, release agent, and a binder resin (A) with a polyester skeleton, and a shell of vinyl copolymer resin (B), where the weight ratio of the shell to the core is between 0.05 and 0.5, and the toner has a volume average particle diameter of 3 to 8 μm, manufactured using a method involving dispersion in an organic solvent followed by addition of a particulate vinyl copolymer resin in an aqueous medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large amount of release agent is used to prevent offset, then hot offset resistance is improved, but toner filming and blocking problems occur
Solution Approach 1:
The invention applies local quality by creating a core-shell structure where the release agent is concentrated in the core portion while the shell portion has different composition. This allows the release agent to function locally where needed (preventing offset) without causing harmful effects (filming and blocking) on the toner surface.
Solution Approach 2:
The toner particle is segmented into core and shell portions with different compositions. The core contains the release agent mixed with binder resin and colorant, while the shell has a different resin composition. This segmentation allows the release agent to be contained and controlled, preventing it from migrating to the surface and causing filming problems.
2Reliability
If polyester resin is used as binder resin to achieve low-temperature fixability and thermostable preservability, then fixability is improved, but it is difficult to use with suspension polymerization or emulsion aggregation methods
Solution Approach 1:
The invention uses an organic solvent as an intermediary to dissolve the polyester binder resin and disperse the colorant and release agent, forming a homogeneous mixture that can then be emulsified in aqueous medium. This intermediary step enables the use of polyester resin with aqueous-based manufacturing methods like suspension polymerization or emulsion aggregation.
Solution Approach 2:
The invention changes the physical state and solubility parameters of the polyester resin by dissolving it in an organic solvent first, then emulsifying the solution in aqueous medium. This parameter transformation allows the resin to be processed through aqueous-based polymerization methods while maintaining its essential properties for low-temperature fixability and thermostable preservability.
3Reliability
If high-molecular-weight resin is used to improve thermostable preservability, then thermal stability is improved, but the solution viscosity becomes too large for good granulation ability
Solution Approach 1:
The organic solvent acts as an intermediary that reduces the viscosity of high-molecular-weight polyester resin, making it suitable for granulation. The solvent dissolves the resin to form a low-viscosity solution that can be easily emulsified and granulated, while the high molecular weight of the resin is preserved in the final dried toner particles, maintaining thermostable preservability.
4Ease of manufacture
If conventional pulverization method is used to manufacture toner, then manufacturing simplicity is maintained, but release agent migrates to surface causing filming and blocking problems
Solution Approach 1:
The invention creates local quality differences between core and shell portions, concentrating the release agent in the core and preventing its migration to the surface. The shell portion acts as a barrier that contains the release agent, allowing conventional manufacturing methods to be used while preventing the harmful effects of release agent migration.
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 toner achieves good low-temperature fixability, thermostable preservability, hot offset resistance, and environmental resistance, while minimizing energy consumption and preventing toner film formation on image forming members, ensuring stable image production and reduced operational costs.
Implementation Method 1
a binder resin (A) comprising a resin having a polyester skeleton... the binder resin (A) comprises a resin having a polyester skeleton, the binder resin (B) includes a vinyl copolymer resin... having both low-temperature fixability and thermostable preservability
Implementation Method 2
a shell comprising a binder resin (B)... the binder resin (B) includes a vinyl copolymer resin... hot offset resistance... environmental resistance
Implementation Method 3
the emulsion aggregation method in which emulsion polymerization particles are aggregated in an aqueous medium... Toners manufactured by these polymerization methods
Implementation Method 4
a release agent serving as an offset inhibitor... a part of the toner is adhered to the heating member... resulting in occurrence of the offset problem
Data Source
AI summary
A toner having a core containing a colorant, a release agent and a binder resin (A), and a shell containing a binder resin (B), the shell overlying the core, wherein the binder resin (A) contains a resin having a polyester skeleton, the binder resin (B) contains a vinyl copolymer resin, and a weight ratio of the shell to the core is from 0.05 to 0.5, and wherein the toner has a volume average particle diameter of from 3 to 8 μm; a toner manufacturing method of such the toner can be used in an image forming apparatus and in a process cartridge.