Silane Surface Treated Core Shell Toner for 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 affect 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 surface energy and enhancing charge stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional surface treatments are used to modify toner surface energy, then surface energy changes occur, but the silane becomes embedded inside the toner shell resin, negating the positive effect
Solution Approach 1:
The patent applies preliminary action by first forming the core shell toner structure with specific functional groups on the outer shell surface, then subsequently applying the silane surface treatment. This sequence ensures the silane bonds to the pre-formed shell surface rather than being embedded during toner formation, thereby achieving both proper positioning and desired surface energy modification for charge stability
Solution Approach 2:
The patent uses the outer shell resin as an intermediary layer between the core toner and the silane surface treatment. The outer shell resin with specific functional groups acts as a mediator that enables controlled bonding of the silane to the toner surface, preventing direct embedding while facilitating the desired surface modification for improved charge stability
2Reliability
If direct interaction methods are used to bond silane to toner surface, then bonding may occur, but the hydrophobicity mismatch prevents effective bonding
Solution Approach 1:
The patent applies parameter changes by modifying the chemical parameters of the surface treatment process, specifically using sol-gel chemistry and hydrolytic deposition conditions that enable the silane to interact effectively with the functional groups on the toner surface despite hydrophobicity differences. This changes the bonding mechanism from direct hydrophobic interaction to hydrolysis-driven condensation bonding
Solution Approach 2:
The patent replaces direct physical adsorption (Van der Waals forces) with a chemical bonding mechanism through sol-gel hydrolysis. Instead of relying on mechanical/physical interaction that is hindered by hydrophobicity mismatch, the silane undergoes hydrolytic deposition to form covalent bonds with the toner surface functional groups, achieving effective bonding through chemical substitution
3Reliability
If toner charge is not maintained at adequate level, then toner particles can be contained in reservoir, but toner dusting and fuming occur
Solution Approach 1:
The patent converts the potential harm of charge loss into a benefit by using the controlled surface energy modification through silane treatment to prevent charge neutralization in the first place. The modified surface energy creates electrostatic conditions that maintain charge stability during storage, thereby preventing the harmful effects of toner dusting and fuming that would otherwise occur
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 improves charge stability, leading to enhanced print quality and reduced toner fuming in hot and humid conditions.
Implementation Method 1
by using a the sol-gel technique in situ, in particular a hydrolytic deposition process as the surface treatment, an alkyloxysilane can be used to interact with the functional groups found on the outer surface of the toner particle via the hydrolytic deposition
Implementation Method 2
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
Implementation Method 3
This silane surface treatment on the outer surface of the toner changes the surface energy of the toner thereby generating an improved 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 chemically prepared toner composition according to one example embodiment includes a core including a first polymer binder, a colorant and a release agent; a shell that is formed around the core that includes a second polymer binder; and a borax coupling agent between the core and the shell and an alkoxysilane hydrocarbon or combination of different alkoxysilane hydrocarbons that are bonded to the outer surface of the shell using a hydrolytic deposition process. This successful alkoxysilane hydrocarbon surface treatment on the outer surface of the toner particle results in attaining a desirable charge stability in hot and humid environments and ultimately improving the quality of the toner, especially by reducing toner dusting, toner fuming and ultra-fine particles generation.