Toner Surface Layer Design for Charging Stability
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Solution Overview
Problem
Existing toners with excellent development durability may not be durable under certain process conditions, leading to density unevenness due to potential fluctuations.
Innovation Solution
A developing device and process cartridge that maintain high charging performance of the developer over a long period by increasing the shear applied to the toner, using a toner with a surface layer including an organosilicon polymer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction resistance of the toner is improved to increase charge quantity, then charging performance is enhanced, but density unevenness occurs due to potential fluctuations over time
Solution Approach 1:
The invention changes the physical and chemical parameters of the toner by incorporating specific additives (silica fine particles, wax particles, amine compounds) and adjusting the surface layer composition. These parameter changes optimize the balance between friction resistance for charging and stability for preventing density unevenness over time.
Solution Approach 2:
The invention uses composite materials by combining multiple components in the toner formulation: organosilicon polymer surface layer, silica fine particles, wax particles, and amine compounds. This composite structure allows the toner to simultaneously achieve high charging performance through friction and long-term stability to prevent potential fluctuations.
2Quantity of substance
If shear applied to the toner is increased to improve charging, then charge quantity increases, but toner durability under process conditions deteriorates
Solution Approach 1:
The invention modifies toner parameters by controlling the hardness and composition of the surface layer (using organosilicon polymer with specific glass transition temperature) and adding functional particles. This allows the toner to withstand increased shear during charging while maintaining durability under process conditions.
Solution Approach 2:
The composite toner structure with organosilicon polymer surface layer, silica particles, and wax particles creates a robust formulation that can handle increased shear forces for improved charging while the cohesive composite structure maintains toner integrity and durability during processing.
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 effectively suppresses density unevenness due to potential fluctuations, maintaining high charging performance and image quality over time.
Implementation Method 1
since the main charging means of the toner is based on friction, where the friction resistance of the toner is improved, the shear (friction opportunity and frictional force) with the charging member can be increased, leading to an increase in the charge quantity of the toner
Implementation Method 2
the present invention suppresses the occurrence of density unevenness due to potential unevenness by maintaining high charging performance of the developer over a long period of time while increasing the shear applied to the toner
Data Source
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AI summary
A developer borne on a developer bearing member includes a toner, the toner has a Martens hardness of at least 200 MPa and not more than 1100 MPa when measured under a condition of a maximum load of 2.0 × 10-4 N, and where a contact pressure of a regulating member that regulates the developer borne on the developer bearing member against the surface of the developer bearing member is denoted by N (gf/mm) and a contact pressure of a supplying member that supplies the developer to the developer bearing member against the surface of the developer bearing member is denoted by D (gf/mm), the following expressions are satisfied: D + 2 × N - 6 ≥ 0, 1.5 ≤ N ≤ 4.5, and 2.0 ≤ D ≤ 4.5.