Positively Chargeable Toner Using Polyvinylamine Surface Modification
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Solution Overview
Problem
Existing liquid developers face challenges in achieving stable positive charging properties, especially when using silicone carrier liquids, due to limited options for charge-controlling agents and low solubility, which affects their performance in electrophotography processes.
Innovation Solution
The use of polyvinylamine compound to modify the surfaces of toner particles, creating a proton-receiving layer that enhances positive charging capabilities and stability, even when combined with binder resins like polyester resin, which are not easily positively chargeable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If silicone carrier liquid is used in liquid developer, then developing performance is improved, but positive charging stability deteriorates due to limited charge-controlling agent options and low solubility
Solution Approach 1:
The patent introduces a polyvinylamine compound as an intermediary substance that mediates between the silicone carrier liquid and toner particles. This compound has high solubility in silicone oil and provides excellent positive charging properties, resolving the contradiction by serving as a effective charge-controlling agent that enables stable positive charging in silicone-based liquid developers
Solution Approach 2:
The patent changes the chemical parameter of the charge-controlling agent by using polyvinylamine compound instead of conventional agents. This parameter change (molecular structure, functional groups) enables high solubility in silicone carrier liquid and stable positive charging, thus resolving the limitation of conventional charge-controlling agents in silicone-based systems
2Strength
If polyester resin is used as binder resin, then fixing properties and color developing properties are improved, but positive charging capability deteriorates as polyester resin is easily negatively chargeable
Solution Approach 1:
The patent applies local quality by differentiating the charging characteristics of different parts of the toner system. The binder resin (polyester) provides negative charging tendency for good fixing, while the polyvinylamine compound on toner particle surfaces provides positive charging capability for good development. This local differentiation resolves the contradiction by allowing each component to optimize its local function
Solution Approach 2:
The patent creates a composite toner structure combining polyester binder resin with polyvinylamine compound coating. This composite material integrates the advantages of both components: polyester provides excellent fixing and color properties, while polyvinylamine provides stable positive charging capability, thus resolving the contradiction between fixing performance and positive charging
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 results in toners with excellent positive charging properties, improved adhesive properties to paper, and enhanced fixing properties, while maintaining stability and effectiveness across various toner colors, including color toners.
Implementation Method 1
toner particles of which surfaces are modified by a polyvinylamine compound
Implementation Method 2
causing protons intentionally introduced to the carrier liquid to be adsorbed into proton receiving layers on the surfaces of the toner particles
Data Source
AI summary
A positively chargeable toner includes at least a binder resin, and toner particles of which surfaces are modified by a polyvinylamine compound.