Two-component developer with barium titanate carrier coating
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Solution Overview
Problem
The existing positively chargeable cyan developer lacks improvement in fog resistance, stable image density, and prevention of image defects caused by cleaning failures.
Innovation Solution
A two-component developer is designed with toner particles having external additive resin particles and carrier particles with a coat layer containing barium titanate particles, which provide high charge retention and prevent detachment, ensuring stable image formation and reduced fog.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin coat is provided on carrier core particles with 60-90% coverage, then toner charging is inhibited, but fog resistance and image density stability deteriorate
Solution Approach 1:
The carrier particle surface is coated with a composite material consisting of a resin coat (60-90% coverage) combined with barium titanate particles (1-10 wt%). This composite structure combines the charge-control function of the resin with the fog-reduction properties of barium titanate, achieving both stable toner charging and improved fog resistance simultaneously.
Solution Approach 2:
The patent optimizes the coverage rate parameter of the resin coat to 60-90% (not 100% coverage) and introduces barium titanate particles at 1-10 wt% concentration. These parameter changes allow the carrier to maintain controlled charging while reducing fog, resolving the contradiction between charging stability and image quality.
2Manufacturing precision
If barium titanate particles are made smaller than 100 nm, then coating uniformity improves, but particle stability and prevention of detachment worsen
Solution Approach 1:
The patent specifies a number average primary particle diameter of 100 nm or more for barium titanate particles. This parameter threshold ensures sufficient particle stability and resistance to detachment during handling and processing, while still providing effective fog reduction. The size parameter is optimized to balance coating uniformity with particle stability.
3Object-affected harmful factors
If barium titanate content is increased beyond 45 parts by mass per 100 parts resin, then fog resistance improves, but coating uniformity and particle stability worsen
Solution Approach 1:
The patent optimizes the barium titanate content parameter to 1-45 parts by mass per 100 parts resin. This range allows sufficient fog reduction (improving at higher concentrations) while maintaining coating uniformity and particle stability (deteriorating at excessive concentrations). The optimal balance is achieved within this specific range.
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 achieves excellent fog resistance, stable image density, and minimizes image defects from cleaning failures by maintaining consistent toner charging and preventing barium titanate particle detachment.
Implementation Method 1
The barium titanate particles have a number average primary particle diameter of at least 100 nm and no greater than 500 nm. The barium titanate particles have a content of at least 4 parts by mass and no greater than 45 parts by mass relative to 100 parts by mass of the coating resin.
Implementation Method 2
The external additive particles include resin particles. The resin particles contain a thermoplastic resin.
Implementation Method 3
The coat layers contain a coating resin and barium titanate particles. The coating resin includes a silicone resin.
Data Source
AI summary
In a two-component developer, external additive particles of toner particles include resin particles containing a thermoplastic resin. Coat layers of carrier particles contain a coating resin and barium titanate particles. The coating resin includes a silicone resin. The barium titanate particles have a number average primary particle diameter of 100-500 nm. The barium titanate particles have a content of 4-45 parts by mass relative to 100 parts by mass of the coating resin. The rate of the mass of the coat layers to the mass of the carrier cores is 0.10-4.90% by mass. The average of coverage rates of the carrier cores is at least 80.0% and less than 100.0%.