Developer Set with Strontium Titanate for Image Quality
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Solution Overview
Problem
Image forming apparatuses face challenges in maintaining desired image density in low-temperature and low-humidity environments and preventing fogging in high-temperature and high-humidity environments due to issues with toner charge stability and carrier degradation.
Innovation Solution
A developer set comprising a first and second developer, where the first developer includes toner particles with spacer particles and strontium titanate-coated carrier particles, and the second developer lacks strontium titanate particles, with both containing barium titanate particles in their coat layers to enhance electrostatic charging and stability, preventing excessive toner charging and fogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-type developer is used, then the device complexity is reduced, but the image quality consistency across different environments deteriorates
Solution Approach 1:
The developer system is segmented into two distinct types: a first developer containing strontium titanate particles for low-temperature/low-humidity environments, and a second developer without strontium titanate particles for high-temperature/high-humidity environments. This segmentation allows each developer type to be optimized for specific environmental conditions, resolving the contradiction between simplicity and environmental adaptability.
Solution Approach 2:
The invention implements a dynamic developer selection mechanism where the system automatically switches between the first and second developers based on detected environmental conditions (temperature and humidity). This dynamic adaptation enables the system to maintain optimal image quality across varying environments without requiring manual intervention or complex reconfiguration.
2Manufacturing precision
If strontium titanate particles are added to carrier particles, then image density is improved in low-temperature environments, but fogging increases in high-temperature environments
Solution Approach 1:
The invention applies local quality by creating two distinct carrier particle formulations: first carrier particles coated with strontium titanate particles for low-temperature environments where image density is critical, and second carrier particles without strontium titanate coating for high-temperature environments where fogging prevention is priority. Each carrier type is locally optimized for its specific operational environment.
Solution Approach 2:
The invention changes the compositional parameter of the carrier particles based on environmental conditions. The first carrier particles include strontium titanate coating (0.01-5 mass%) to enhance charge stability and image density in cold conditions, while the second carrier particles exclude this coating to prevent excessive charging and fogging in hot conditions. This parameter change resolves the contradiction between image density and fogging.
3Manufacturing precision
If toner particles are charged to high density, then image density is improved, but carrier degradation accelerates
Solution Approach 1:
The invention changes the charge density parameter of toner particles by controlling the carrier-to-toner mass ratio and the amount of strontium titanate particles on carriers. In low-temperature environments, the first developer uses optimized ratios to achieve sufficient charge for good image density while the strontium titanate coating prevents excessive charging. This parameter optimization resolves the contradiction between achieving high image density and preventing carrier degradation.
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 developer set ensures consistent image density in low-temperature and low-humidity conditions and reduces fogging in high-temperature and high-humidity environments by stabilizing toner charge and inhibiting carrier degradation, extending the life of carrier particles and maintaining image quality.
Implementation Method 1
The coat layers contain a coating resin and barium titanate particles. The barium titanate particles have a number average primary particle diameter of at least 100 nm and no greater than 500 nm.
Implementation Method 2
The first carrier particles each include a first carrier mother particle and strontium titanate particles attached to a surface of the first carrier mother particle.
Data Source
AI summary
A developer set includes a first developer and a second developer. The first developer contains a first toner containing first toner particles and a first carrier containing first carrier particles. The second developer contains a second toner containing second toner particles and a second carrier containing second carrier particles. The first toner particles and the second toner particles each include a toner mother particle and external additive particles attached to the surface of the toner mother particle. The external additive particles include spacer particles. The spacer particles have a number average primary particle diameter of at least 32 nm and no greater than 145 nm. The first carrier particles each include a first carrier mother particle and strontium titanate particles attached to the surface of the first carrier mother particle.