Magnetic Developing Carrier for Stable Toner Supply
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Solution Overview
Problem
In the two-component developing method, hysteresis occurs due to inappropriate removal of the two-component developer, leading to unstable toner supply and increased resistance in the latent electrostatic image forming process, affecting image density and quality.
Innovation Solution
A latent electrostatic image developing carrier with core particles having specific shape factors and a coating layer containing resin and filler is used, which stabilizes toner supply and prevents resistance increase, even after long-term use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the two-component developer is removed in the removal region with almost 0 magnetic force, then the developer is allowed to freely fall due to gravitational force, but counter charges are generated on the carrier when toner is consumed, forming mirror image force between the carrier and developer bearing member, resulting that the developer cannot normally be removed
Solution Approach 1:
The patent changes the magnetic force parameter in the removal region from almost 0 to a specific range (0.3T to 1.5T). This parameter change allows the developer to be removed effectively while preventing counter charge generation that causes mirror image force, thus resolving the contradiction between ease of operation and reliability
Solution Approach 2:
The patent introduces dynamic control of the magnetic field by adjusting the magnetic force strength within a specific range. This dynamic approach allows the system to adapt to different operational conditions, enabling effective developer removal without generating harmful counter charges, thereby balancing operational ease with system reliability
2Device complexity
If the developer is removed with magnetic force of almost 0, then removal is simple, but the developer in which the concentration of the toner has been lowered is transferred again to the developing region, reducing the developing capability
Solution Approach 1:
The patent changes the magnetic force parameter from 0 to a specific range (0.3T to 1.5T), which enables effective separation of developer components. This prevents low-concentration developer from being transferred back to the developing region, maintaining developing capability without increasing device complexity
Solution Approach 2:
The patent replaces the simple gravitational removal mechanism with a controlled magnetic field system. This substitution allows for more precise control over developer removal, preventing the transfer of low-concentration developer back to the developing region, thus maintaining productivity
3Duration of action of stationary object
If the carrier particles are used for a long period of time, then continuous operation is achieved, but the developing capability of the developer degrades to cause hysteresis where the image density decreases
Solution Approach 1:
The patent optimizes the carrier particle parameters including shape factor SF-2 (115 to 150) and bulk density (1.8 to 2.4 g/cm³). These parameter changes ensure stable toner supply and prevent resistance increase over long periods, maintaining image density stability and eliminating hysteresis effects
Solution Approach 2:
The patent uses composite carrier particles with specific composition and structure. The core particles have magnetism and specific shape factors, covered by a coating layer containing resin and filler. This composite structure prevents toner deposition and resistance increase, maintaining reliable operation over extended periods
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 ensures stable toner supply and prevents resistance increase, maintaining image quality by addressing hysteresis and toner deposition issues in the latent electrostatic image forming process.
Implementation Method 1
core particles each having magnetism; a magnetic roller; a magnetic brush formed by the core particles and the toner in contact with the surface of the latent electrostatic image bearing member
Implementation Method 2
the latent electrostatic image is developed with charged three color toners of yellow, magenta and cyan or with charged four color toners of yellow, magenta, cyan and black to thereby form toner images
Data Source
AI summary
A latent electrostatic image developing carrier including: core particles each having magnetism; and a coating layer covering each of the core particles, wherein the latent electrostatic image developing carrier has a shape factor SF-2 of 115 to 150 and has a bulk density of 1.8 g/cm3 to 2.4 g/cm3, wherein the core particles have a shape factor SF-2 of 120 to 160 and have an arithmetic mean surface roughness Ra of 0.5 μm to 1.0 μm, and wherein the coating layer contains a resin and a filler and an amount of the filler contained in the coating layer is 50 parts by mass to 500 parts by mass per 100 parts by mass of the resin contained in the coating layer.