Positive Toner Composition for Stable Charging and Clean Release
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Solution Overview
Problem
Existing positively chargeable toner experiences issues with mechanical stress-induced changes in external additives, such as sinking-in or coming-off, leading to charging-induced faults like fogging, particularly when silica is used as a spacer particle.
Innovation Solution
The toner composition includes a combination of first and second resin fine particles and a cleaning auxiliary particle, where the first resin fine particles have a smaller size and cover 10-20% of the toner surface, the second resin fine particles cover 5-12%, and the cleaning auxiliary particles have a larger size, all formed from silicone modified acrylic resin, to stabilize charging and prevent additive slipping-through during cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If silica particles are used as spacer particles to reduce sinking-in and coming-off of external additives, then the mechanical stability of external additives is improved, but charging-induced faults (fogging) occur because silica particles themselves need to be positively charged
Solution Approach 1:
The patent uses resin fine particles as intermediary spacer particles instead of silica particles. These resin particles serve as a mediator that provides mechanical stability without requiring positive charging, thereby preventing fogging while maintaining the spacing function between toner particles
Solution Approach 2:
The patent changes the material parameter of spacer particles from inorganic silica to organic resin fine particles. This parameter change allows the spacer particles to achieve both mechanical stability and charging compatibility without causing fogging, as the resin particles can be charged without the same issues as silica
2Object-generated harmful factors
If large particle size resin fine particles are used as spacer particles to avoid charging-induced faults, then fogging is prevented, but the cleaning properties of toner against photosensitive drum deteriorate
Solution Approach 1:
The patent segments the spacer particle population into multiple size classes (first resin fine particles with smaller size and second resin fine particles with larger size). This segmentation allows different particle sizes to perform different functions: smaller particles maintain spacing without causing fogging, while larger particles contribute to cleaning properties
Solution Approach 2:
The patent applies different particle size qualities to different functional requirements. Smaller resin fine particles (30-50 nm) are used where spacing and anti-fogging are critical, while larger resin fine particles (80-120 nm) are used where cleaning effectiveness is needed, creating local optimization of particle properties
3Reliability
If inorganic fine particles are used as cleaning auxiliary particles, then cleaning efficiency is improved, but the complexity of toner composition increases
Solution Approach 1:
The patent creates a composite toner system that combines organic resin fine particles for spacing and charging functions with inorganic fine particles for cleaning functions. This composite approach allows each material type to specialize in its optimal function, achieving high cleaning efficiency while maintaining overall system compatibility
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 configuration enhances charging stability and suppresses additive slipping-through, maintaining high-quality image formation over time by preventing agglomeration and improving cleaning efficiency with the cleaning blade.
Implementation Method 1
The first resin fine particles have a number average primary particle size of 30 nm or more but 50 nm or less, and the ratio of coverage of the surface region of the toner base particle with the first resin fine particles is 10% or more but 20% or less. The second resin fine particle has a number average primary particle size of 80 nm or more but 120 nm or less, and the ratio of coverage of the surface region of the toner base particle with the second resin fine particles is 10% or more but 20% or less.
Implementation Method 2
The cleaning auxiliary particle has a number average primary particle size of 100 nm or more but 300 nm or less
Data Source
AI summary
Positively chargeable toner has toner particles including a toner base particle and an external additive attached to its surface. The external additive includes first and second resin fine particles of silicone modified acrylic resin and a cleaning auxiliary particle. The first resin fine particle has a number average primary particle size of 30 nm or more but 50 nm or less, and the ratio of its coverage of the surface region of the toner base particle is 10% or more but 20% or less. The second resin fine particle has a number average primary particle size of 80 nm or more but 120 nm or less, and the ratio of its coverage of the surface region of the toner base particle is 10% or more but 20% or less. The cleaning auxiliary particle has a number average primary particle size of 100 nm or more but 300 nm or less.