Positively-Charged Liquid Developer Using Polymeric Dispersant
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Solution Overview
Problem
It is challenging to develop a positively-charged liquid developer using polyester resin, as polyester resins are naturally negatively-charged, and adding charge control agents does not provide sufficient positive charging, leading to issues with ozone generation and environmental concerns with negatively-charged developers.
Innovation Solution
A positively-charged liquid developer is created by dispersing toner particles with a polyester resin matrix and a positively-charged polymeric dispersant in an insulation liquid, where the polymeric dispersant has an amino group and ester structure, adhering firmly to the toner particles to enhance positive charging and compatibility, and using a plant oil as the insulation liquid to improve dispersibility and prevent peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a negatively-charged liquid developer is used, then excellent color development and fixing characteristics are achieved, but ozone is generated causing environmental problems and adverse effects to peripheral components
Solution Approach 1:
The invention changes the electrical charge parameter of the liquid developer from negative to positive by using a polymeric dispersant with positive charging capability instead of conventional negative charge control agents, thereby eliminating ozone generation while maintaining developer performance
Solution Approach 2:
The invention converts the harmful effect of negative charge (ozone generation) into a beneficial outcome by using positive charge control through polymeric dispersant, which not only eliminates ozone but also provides excellent dispersibility and charge stability
2Reliability
If a polyester resin is used as binder resin, then high transparency and excellent color development are achieved, but the resin is negatively-charged making it difficult to create positively-charged toner particles
Solution Approach 1:
The invention introduces a polymeric dispersant as an intermediary substance that adsorbs onto the polyester resin particles and provides positive charge, acting as a mediator between the negatively-charged resin and the requirement for positive charging without compromising the resin's transparency and color development properties
Solution Approach 2:
The invention creates a composite structure where polyester resin particles are combined with polymeric dispersant molecules that have positive charge groups, forming a composite material that exhibits both the optical properties of polyester resin and the positive charging characteristics of the polymeric dispersant
3Object-generated harmful factors
If a charge control agent is added to polyester resin to achieve positive charging, then some positive charge is obtained, but sufficient positive toner charging cannot be achieved
Solution Approach 1:
The invention changes from using conventional small-molecule charge control agents to using a polymeric dispersant with higher molecular weight and multiple positive charge groups per molecule, significantly increasing the positive charge density and achieving sufficient positive toner charging
Solution Approach 2:
The invention concentrates positive charge groups at the surface of toner particles through the use of polymeric dispersant that adsorbs onto the particle surface, creating a localized high-density positive charge layer that ensures sufficient positive charging for liquid developer operation
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 achieves stable positive charging and excellent fixing characteristics of toner particles, preventing aggregation and ensuring high dispersibility and environmental sustainability by effectively adhering the polymeric dispersant to the toner particles, thus improving image development and storage stability.
Implementation Method 1
a positively-charged polymeric dispersant adhering to the surface of the toner matrix particle
Implementation Method 2
the polymeric dispersant is of the type that an amino group is contained in its molecule... since the polymeric dispersant having such an amino group has a high positively-charged property
Data Source
AI summary
A liquid developer of the type that is positively-charged is provided. The liquid developer includes an insulation liquid, and toner particles dispersed in the insulation liquid, wherein each of the toner particles includes a toner matrix particle mainly made of a polyester resin and a positively-charged polymeric dispersant adhering to the surface of the toner matrix particle. The polymeric dispersant is preferably of the type that an amino group is contained in its molecule, or of the type that an ester structure is contained in its molecule. Further, the polyester resin is preferably of the type that a —SO3− group is contained in its molecule. The liquid developer has excellent positively-chargeable charging characteristics and fixing characteristics.