Positively Chargeable Toner Domain Control for Charging Stability
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Solution Overview
Problem
Existing positively chargeable toners for electrostatic image development face issues with initial triboelectric charging capacity and stability, leading to problems like image fog, scattering, and insufficient image density, especially when used for extended periods in development devices.
Innovation Solution
A positively chargeable toner is developed by dispersing a quaternary ammonium salt functional group-containing resin into a polyester resin binder, forming domains with a specific size distribution to enhance charging capacity and durability, ensuring that at least 98% of the charge control resin domains have diameters between 0.01 μm and 0.3 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If positively chargeable charge control resin is merely adhered to the surface of toner mother particles, then initial triboelectric charging capacity is improved, but charge stability deteriorates during prolonged use
Solution Approach 1:
The patent merges the charge control resin with the binder resin to form an integrated composite resin structure. The charge control resin and binder resin are combined in specific ratios (charge control resin: 1-20 parts by mass, binder resin: 80-99 parts by mass) to create a unified material that maintains both excellent initial charging capacity and stable charge properties during prolonged use, eliminating the need for separate adhesion layers.
Solution Approach 2:
The patent employs composite materials by creating a composite resin consisting of charge control resin and binder resin. This composite structure leverages the electrostatic charge generation capability of the charge control resin while the binder resin provides structural stability and durability, resulting in a toner that maintains consistent charging properties over extended periods without charge control resin drop-off.
2Productivity
If charge control resin is adhered to toner surface, then initial development property is improved, but toner scattering increases after prolonged stirring
Solution Approach 1:
The patent combines the charge control resin with the binder resin to form an integrated composite resin structure. This merging eliminates the interface between separate materials, preventing charge control resin drop-off during prolonged stirring in development devices, thereby eliminating the root cause of toner scattering while maintaining excellent initial development properties.
Solution Approach 2:
Instead of adhering charge control resin to the external surface of toner particles, the patent inverts the approach by incorporating charge control resin within the toner particle matrix itself through the composite resin structure. This internal integration ensures the charge control resin remains firmly embedded and cannot drop off, preventing toner scattering while maintaining surface charge functionality.
3Reliability
If charge control resin is used to improve charging capacity, then initial rise of triboelectric charging capacity is improved, but durability deteriorates
Solution Approach 1:
The patent creates a composite resin material combining charge control resin and binder resin in optimized ratios. The charge control resin provides high triboelectric charging capacity while the binder resin contributes structural integrity and durability. This composite structure maintains excellent charging capacity from the first use through prolonged operation, achieving both high initial performance and long-term durability.
Solution Approach 2:
The patent optimizes the mass ratio parameters of charge control resin to binder resin (specifically 1-20:80-99) to achieve the最佳 balance between initial charging capacity and durability. By precisely controlling these compositional parameters, the toner achieves both rapid initial charge buildup and sustained performance over extended periods without 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 toner exhibits excellent initial triboelectric charging capacity and development properties, preventing scattering and maintaining image quality even after prolonged use, with improved durability and consistent charging performance.
Implementation Method 1
an initial rise of triboelectric charging capacity of the toner is important such that the toner can be stably charged to a desired charged amount in a short time
Data Source
AI summary
Domains of a charge control resin are formed by dispersing a charge control resin containing a quaternary ammonium salt functional group-containing resin of a copolymer of an addition-polymerizable monomer having a quaternary ammonium salt functional group and a styrene and/or acrylic monomer into a polyester resin as binder resin, and the proportion of the number of domains of the charge control resin with a domain diameter of no less than 0.01 μm to less than 0.3 μm versus the number of domains of the charge control resin with a domain diameter of no less than 0.01 μm, which is measured by a predetermined method, is adjusted to no less than 98% by number.