Toner Production via Amine Salt Aggregation
Solution Overview
Problem
Toner production methods using the aggregation/fusion method face challenges with releasing agents being isolated or exposed due to heat, leading to deteriorated charging properties, and existing solutions like multi-stage emulsification/aggregation methods are insufficient.
Innovation Solution
A process involving the mixing and aggregation of resin particles, releasing agent particles, and a divalent to pentavalent amine salt in an aqueous medium to produce toner particles with improved low-temperature fusing and charging properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the toner is produced by an aggregation/fusion method using a releasing agent, then the low-temperature fusing property is improved, but the charging property deteriorates due to releasing agent exposure
Solution Approach 1:
A shell layer comprising a shell resin and a shell releasing agent is introduced as an intermediary structure between the core toner particles and the external environment. This shell layer acts as a protective mediator that controls the release behavior of the releasing agent, allowing it to be released in a controlled manner during the fusing process rather than being exposed prematurely, thereby maintaining both low-temperature fusing property and charging property
Solution Approach 2:
The toner particles are segmented into a core-shell structure where the core contains the colorant and resin binder, and the shell contains the shell resin and shell releasing agent. This segmentation allows the releasing agent to be contained within the shell structure during the aggregation/fusion process, preventing its exposure and maintaining charging property while still enabling low-temperature fusing when the shell releases the agent during actual fusing
2Reliability
If the multi-stage emulsification/aggregation method is used to form a shell layer, then the releasing agent exposure is reduced, but the charging property remains insufficient
Solution Approach 1:
The invention merges the releasing agent formation with the shell layer formation in a single aggregation/fusion process. Both the core resin particles and shell resin particles are aggregated simultaneously with the releasing agent incorporated into the shell structure, eliminating the need for separate multi-stage emulsification processes while achieving adequate protection of the releasing agent and maintaining charging property
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 process results in toners with enhanced low-temperature fusing and charging properties, ensuring improved optical density and reduced scattering in printing devices.
Implementation Method 1
a step (1) of mixing and aggregating resin particles (A), releasing agent particles and an aggregating agent formed of a divalent to pentavalent amine salt in an aqueous medium to obtain aggregated particles (1)
Implementation Method 2
there occurs such a problem that the releasing agent is isolated from the toner or exposed to a surface of the toner owing to heat generated upon the fusion
Data Source
AI summary
The present invention relates to a process for producing a toner for development of electrostatic latent images which includes a step (1) of mixing and aggregating resin particles (A), releasing agent particles and an aggregating agent formed of a divalent to pentavalent amine salt in an aqueous medium to obtain aggregated particles, and a toner for development of electrostatic latent images obtained by the process.