toner
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Solution Overview
Problem
Existing technologies have not adequately addressed the challenges of achieving low-temperature fixability and durability in toner particles containing crystalline polyester-based resins, which are prone to hot offset and low durability in the presence of fogging and a decrease in uniformity of image density over time.
Innovation Solution
A toner formulation comprising amorphous and crystalline polyester-based resins, titanium oxide particles treated with a hydrophobizing agent, and a wax, which enhances dispersibility and stability, ensuring low-temperature fixability and resistance to hot offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a crystalline polyester-based resin is added to enhance low-temperature fixability, then the melting temperature is lowered and fixing at lower temperature becomes possible, but hot offset is likely to occur and durability is lowered
Solution Approach 1:
The patent uses a composite resin system combining amorphous polyester-based resin (70-90 mass%) with crystalline polyester-based resin (10-30 mass%). The amorphous resin provides durability and hot offset resistance, while the crystalline resin enables low-temperature fixing. This composite approach allows the toner to achieve both low-temperature fixability and sufficient hot offset resistance by leveraging the complementary properties of each resin type.
2Reliability
If metal oxide particles surface-treated with hydrophobizing agent are externally added to stabilize charging property, then charge amount is stabilized, but charge amount distribution becomes non-uniform over time due to burying of external additive
Solution Approach 1:
The patent introduces a silane coupling agent as an intermediary substance that coats the metal oxide particles before they are added to the toner. This silane layer acts as a protective barrier that prevents the metal oxide particles from being buried in the toner particle surface over time, while still allowing them to function as charge control agents. This intermediary layer maintains both the stability of charging property and the uniformity of charge distribution throughout the toner's service life.
3Temperature
If crystalline polyester-based resin is used to lower melting temperature, then low-temperature fixing is achieved, but image density uniformity decreases due to external additive embedding
Solution Approach 1:
The patent employs a composite resin system where amorphous polyester-based resin (70-90 mass%) provides structural integrity and prevents additive embedding, while crystalline polyester-based resin (10-30 mass%) lowers the melting temperature for low-temperature fixing. This composite structure maintains image density uniformity even at reduced fixing temperatures by preventing the embedding of external additives into the toner particle surface.
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 exhibits improved hot offset resistance, suppresses fogging, and maintains uniform image density over a long period by optimizing charge distribution and resin compatibility.
Implementation Method 1
the metal oxide particles are surface-treated with a hydrophobizing agent containing a linear alkyl group having 6 or more carbon atoms
Data Source
AI summary
A toner including toner particles containing an amorphous polyester-based resin, a crystalline polyester-based resin, and a wax has the following constitution. The toner particles contain metal oxide particles having a number-average particle size of 60 nm or less. The metal oxide particles are surface-treated with a hydrophobizing agent containing a linear alkyl group having 6 or more carbon atoms. The content of the metal oxide particles in the toner particles is 0.02 mass % or more and 2 mass % or less.