Silane Surface Treated Core Shell Toner Charge Stability
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Solution Overview
Problem
Chemically prepared toners for electrophotography face challenges in maintaining charge stability, particularly in hot and high humidity environments, leading to toner dusting and fuming, which negatively impact print quality.
Innovation Solution
Surface treating the outer surface of core shell toner particles with silanes using a hydrolytic deposition process, specifically bonding alkyloxysilanes to the toner's functional groups, thereby modifying the toner's surface energy and improving charge stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional surface treatment methods are used, then the silane may embed into the toner shell, but this negates the positive effect of surface treatment on charge stability
Solution Approach 1:
The patent applies preliminary action by first forming a borax coupling agent layer on the toner surface before adding the silane solution. This pre-prepared coupling agent layer creates ready-to-react sites that guide the silane to bond properly on the surface rather than embedding into the shell, thus preventing the worsening effect while maintaining the charge stability improvement.
Solution Approach 2:
The borax coupling agent acts as an intermediary between the toner shell and the silane. It provides a mediating layer that facilitates controlled interaction, allowing the silane to bond to the surface through the coupling agent without penetrating into the shell interior, thus resolving the contradiction between achieving surface treatment and preventing embedding.
2Reliability
If hydrocarbonsilane is used for surface treatment, then the surface energy changes positively, but the hydrophobicity mismatch prevents effective bonding
Solution Approach 1:
The borax coupling agent serves as an intermediary that bridges the hydrophobicity gap between the hydrocarbonsilane and the toner surface functional groups. It creates a compatible interface that enables effective bonding despite the hydrophobicity mismatch, thus resolving the contradiction between achieving positive surface energy change and maintaining bonding efficiency.
Solution Approach 2:
The patent changes the chemical parameters of the surface by introducing the borax coupling agent layer, which modifies the surface chemistry to be compatible with hydrocarbonsilane. This parameter change enables the hydrophobic hydrocarbonsilane to bond effectively to the toner surface, resolving the bonding efficiency issue while maintaining the charge stability benefit.
3Reliability
If silane is embedded inside the outer shell resin, then the surface treatment is complete, but the charge stability improvement is lost
Solution Approach 1:
By preliminarily forming the borax coupling agent layer on the surface before silane addition, the patent creates a stable surface composition that directs silane bonding to remain on the surface. This preliminary preparation ensures that the surface composition remains stable with silane located where it can exert its charge stability benefit, rather than embedding into the shell.
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 silane surface treatment effectively reduces toner dust generation and fuming, enhancing the toner's performance and print quality by maintaining charge stability in demanding environmental conditions.
Implementation Method 1
bonding the silane or combination of silanes to the outer surface of the core shell toner particle through a hydrolytic deposition process
Implementation Method 2
bonding alkyloxysilanes to the toner's functional groups
Implementation Method 3
The silane is surface treated on the outer surface of the toner using a sol-gel technique in situ, in particular a hydrolytic deposition process. This silane surface treatment on the outer surface of the toner changes the surface energy of the toner
Implementation Method 4
The magnetic particles are also used to charge the toner particles in a triboelectric manner. The normal triboelectric charge exchange between toner particles and the magnetic carriers is moderated by the moisture content in air.
Data Source
AI summary
A method for producing core shell toner for electrophotography according to one embodiment, includes surface treating the outer surface of a core shell toner particle with a alkoxysilane hydrocarbon or combination of different alkoxysilane hydrocarbons using a hydrolytic deposition process after the core shell toner particle is fully formed. This method results in the bonding of the alkoxysilane hydrocarbon or combination of different alkoxysilane hydrocarbons to the outer surface of the core shell toner particle. In an alternative method, the outer surface of the toner is surface treated with the alkoxysilane hydrocarbon solution and then fused to form toner particles. The alkoxysilane hydrocarbon surface treated core shell toner also can be mixed with magnetic carrier beads to form a developer mix to be used in a dual component development electrophotographic printer.