Toner Additive Formulation for Flow and Charge Control
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Solution Overview
Problem
Current toner compositions, particularly those using the emulsion aggregation process, face challenges such as poor toner flow, toner blocking, charge issues, and high costs due to the use of additives like titania. There is a need for improved toners with performance characteristics similar to or better than existing compositions while reducing or eliminating titania.
Innovation Solution
A toner composition comprising a parent toner particle made of a combination of first and second amorphous polyesters and a crystalline polyester, along with optional colorants and waxes. The toner includes a surface additive formulation featuring medium and large silica particles, and a positive charging surface additive, either titanium dioxide or a non-titanium dioxide metal oxide, to enhance charging characteristics and flow properties without relying on titania.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If titania is used as a positive charging surface additive, then charging characteristics are improved, but cost increases and health concerns arise
Solution Approach 1:
The patent replaces expensive titania with cheaper metal oxide alternatives such as aluminum oxide, silicon oxide, or zinc oxide that provide the same positive charging function without the health concerns and cost issues associated with titania
Solution Approach 2:
The patent changes the chemical composition parameter of the positive charging additive from titania to other metal oxides, while adjusting particle size (8-30 nanometers) and surface area coverage (5-15 percent) to maintain optimal charging characteristics
2Ease of operation
If conventional toner additives are used, then toner flow and charge are improved, but toner blocking occurs
Solution Approach 1:
The patent segments the surface additive formulation into multiple size classes (small: 8-16 nm, medium: 30-50 nm, large: 80-120 nm) with different functions - small particles for charge, medium particles for flow, and large particles for blocking prevention, creating a balanced formulation that addresses all three issues simultaneously
Solution Approach 2:
The patent creates a composite surface additive formulation combining multiple metal oxides (silica, titania or alternative metal oxides, and other oxides) with complementary properties to achieve optimal toner flow, charge distribution, and blocking resistance without relying on a single additive
3Reliability
If high surface area coverage additives are used, then charge distribution is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by assigning different surface area coverage levels to different particle size classes - small particles (8-16 nm) at 5-75 percent coverage for charge distribution, medium particles (30-50 nm) at 40-100 percent coverage for flow, and large particles (80-120 nm) at 5-29 percent coverage for blocking - optimizing each function independently while maintaining overall formulation simplicity
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 proposed toner composition achieves improved flow, charge distribution, and storage performance under high humidity conditions, while reducing costs by minimizing the use of expensive additives like titania. The surface additive formulation ensures optimal toner performance without titania, addressing issues of toner flow, blocking, and charge stability.
Implementation Method 1
at least one positive charging surface additive, wherein the at least one positive charging surface additive is: (a) a titanium dioxide surface additive having an average primary particle size of 15 to 40 nanometers
Implementation Method 2
the at least one medium silica provided at a surface area coverage of 40 to 100 percent of the parent toner particle surface area
Data Source
AI summary
A toner including a parent toner particle comprising at least one resin, in combination with an optional colorant, and an optional wax; and a surface additive formulation comprising at least one medium silica surface additive; at least one large silica surface additive; at least one positive charging surface additive, wherein the at least one positive charging surface additive is (a) a titanium dioxide surface additive; and wherein the parent toner particles further contain a small silica; or (b) a non-titanium dioxide positive charging metal oxide surface additive; and wherein the parent toner particles further optionally contain a small silica; and wherein a total surface area coverage of all of the surface additives combined is 100 to 140 percent of the parent toner particle surface area.