Toner Matrix Silica Coverage for Drum Adhesion Control
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Solution Overview
Problem
The slipping-through phenomenon occurs in image-forming apparatuses when toner with crystalline polyester resin is used, as the adhesiveness to the photoconductive drum is high, leading to insufficient collection by the cleaning blade, especially in low-humidity environments.
Innovation Solution
A toner with a toner matrix particle containing crystalline polyester resin and associated silica, where the associated silica has a coverage of 1% to 30% and adherence strength of 20% to 90%, and is hydrophobized with hexamethyldisilazane, to increase contact points and areas with the toner matrix particle, facilitating scraping by the cleaning blade and reducing adhesiveness to the photoconductive drum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If crystalline polyester resin is blended in toner matrix particle to achieve low-temperature fixation, then fixation temperature is reduced, but adhesiveness to photoconductive drum increases causing slipping-through phenomenon
Solution Approach 1:
The patent applies local quality by creating uneven distribution of silica particles on the toner surface, concentrating them in specific regions (cavities) rather than uniform distribution. This localized concentration at adhesion points provides sufficient grip for collection while maintaining low-temperature fixation capabilities elsewhere in the toner matrix.
Solution Approach 2:
The patent changes the particle size parameter of silica from conventional small sizes to large particle sizes (1-10 μm), and controls the coverage ratio at 3-20%. This parameter change reduces overall adhesiveness while providing localized grip points, resolving the contradiction between low-temperature fixation and reliable collection.
2Reliability
If spherical large particle-sized silica is used as external additive to reduce adhesiveness, then slipping-through is prevented, but silica distributes unevenly into cavities exposing toner matrix surface
Solution Approach 1:
The patent intentionally creates non-uniform local distribution of silica particles, concentrating them in cavity regions on the toner surface. This local quality approach ensures silica is present where needed for collection reliability while accepting that distribution is not uniform across the entire surface.
Solution Approach 2:
The patent utilizes the spherical shape of large silica particles to roll them across the toner surface, allowing them to naturally settle into cavity regions. The curvature and rolling motion facilitate their migration to low-points on the surface, achieving the desired localized distribution pattern.
3Stability of the object's composition
If associated silica is used instead of spherical large particle-sized silica, then silica distribution becomes more uniform, but contact area with cleaning blade decreases reducing scraping effectiveness
Solution Approach 1:
The patent employs spherical large particle-sized silica whose curved surfaces provide optimal contact geometry with the cleaning blade. The spherical shape ensures point contact that concentrates force effectively, improving scraping effectiveness compared to irregularly shaped associated silica.
Solution Approach 2:
The patent changes the particle size parameter to large dimensions (1-10 μm) while maintaining spherical shape, and controls coverage at 3-20%. This parameter combination ensures sufficient particle size for effective blade contact while controlling overall adhesiveness to prevent slipping-through.
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 solution effectively suppresses the slipping-through phenomenon by enhancing the silica's ability to be caught by the cleaning blade and reducing adhesiveness to the photoconductive drum, even in low-humidity environments, while maintaining charge stability in high-humidity conditions.
Implementation Method 1
the adherence strength of the associated silica to the toner matrix particle is 20% or more to 90% or less
Implementation Method 2
the associated silica is hydrophobized with hexamethyldisilazane
Implementation Method 3
a cleaning blade (e.g., a mark 61 in FIG. 2) collect toner remaining on a photoconductive drum
Implementation Method 4
facilitating catching on the cleaning blade and allowing toner remaining on a photoconductive drum to be successfully scraped off
Data Source
AI summary
The toner has a toner matrix particle containing a crystalline polyester resin. Associated silica including two or more of primary particles is present on the surface of the toner matrix particle. The coverage with associated silica onto the toner matrix particle is 1% or more to 30% or less, and the adherence strength of associated silica to the toner matrix particle is 20% or more to 90% or less.