Toner with Rectangular Inorganic Particles for Roller Contamination
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Solution Overview
Problem
Existing electrophotographic toners face a trade-off between high transferability and charging roller contamination, with silica particles of large diameter improving transferability but causing charging failures and image defects due to adherence to the charging roller.
Innovation Solution
Incorporating inorganic fine particles of a rectangular parallelepiped shape into the toner, controlling their separation amount, and matching the triboelectric series of these particles with the binder resin to reduce charging roller contamination while maintaining low non-electrostatic attachment forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If silica particles having a large particle diameter are used to cover toner particles, then transferability is improved, but charging roller contamination occurs and causes image defects
Solution Approach 1:
The invention uses a composite structure where silica particles with large particle diameter (improving transferability) are combined with inorganic fine particles (controlling contamination). This composite approach allows both functions to coexist: the large silica particles reduce non-electrostatic attachment force for better transfer, while the inorganic fine particles prevent charging roller contamination by interfering with silica particle adhesion.
Solution Approach 2:
The invention applies different properties to different components: silica particles with large particle diameter are used specifically for reducing non-electrostatic attachment force on the toner surface, while inorganic fine particles are used specifically for preventing charging roller contamination. Each component has a localized function that addresses a specific aspect of the contradiction.
2Object-generated harmful factors
If inorganic fine particles are added to scrape silica particles off charging roller, then charging roller contamination is reduced, but transferability is not improved sufficiently due to increased electrostatic attachment force
Solution Approach 1:
The invention carefully controls the particle diameter parameter of inorganic fine particles (0.1 μm to 10 μm) and their content ratio (0.1 parts by mass to 10 parts by mass per 100 parts by mass of silica particles). By optimizing these parameters, the inorganic fine particles effectively reduce charging roller contamination while the large silica particles (0.1 μm to 10 μm, with D50 of 3 μm to 8 μm) maintain low non-electrostatic attachment force for good transferability.
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 solution achieves excellent transferability with reduced charging roller contamination, breaking the trade-off relationship and ensuring high image quality by effectively scraping off silica particles and managing electrostatic attachment forces.
Implementation Method 1
the inorganic fine particles have an effect of scraping the silica particles off the charging roller
Implementation Method 2
the electrostatic attachment force is increased by the local charge generation on the surface of the toner particle due to triboelectric charging of the toner and the inorganic fine particles transferred to the carrier
Implementation Method 3
the force of an electric field that each toner particle receives from a transfer bias be greater than the attachment force between the toner and the electrostatic latent image bearing member
Implementation Method 4
The attachment force can be generally classified into a non-electrostatic attachment force represented by van der Waals force
Data Source
AI summary
A toner comprises a toner particle including a binder resin, and inorganic fine particles A and silica particles B, wherein the inorganic fine particle A has a rectangular parallelepiped shape; an amount of the inorganic fine particles A is 0.3 to 3.0 mass parts per 100 mass parts of the toner particles; a number average particle diameter of the silica particles B is 80 to 200 nm; a fixing ratio of the inorganic fine particle A is 25% to 70%; where a separation amount of the inorganic fine particles A is denoted by YA (mg), and a separation amount of the silica particles is denoted by YB (mg), YA is 3.00 to 18.0, YA and YB satisfy the following formula,YA/YB>0.75, anda surface potential difference C in a rubbing test using the inorganic fine particle A and the binder resin is −70 V to +70 V.