Core-Shell Resin Particles for Charge Stability and Low-Temperature Fixing
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Solution Overview
Problem
Existing recycled toners face challenges in achieving both charge stability and low-temperature fixability due to excessive presence of sulfo groups, which affect viscoelasticity and melting properties, and uniform sulfo-derived shells are difficult to control.
Innovation Solution
A resin particle with a core-shell structure is developed, where the sulfo component is laminated with a specific gradient, ensuring the largest amount is at the outermost surface and gradually decreases towards the interior, using an emulsion aggregation method to control the lamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform sulfo-derived shell is formed on recycled toner particles, then charge stability is improved, but low-temperature fixability deteriorates due to excessive presence of sulfo groups affecting viscoelasticity and melting properties
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of sulfo groups within the resin particle. The shell layer contains a higher concentration of sulfo groups at the outer surface to ensure charge stability, while the inner core has progressively fewer sulfo groups to maintain low-temperature fixability. This gradient structure allows different regions of the same particle to have different functional properties, resolving the contradiction between charge stability and low-temperature fixability.
Solution Approach 2:
The resin particle is segmented into multiple layers with different sulfo group concentrations. The particle structure is divided into a core region with lower sulfo content and a shell region with higher sulfo content at the surface. This segmentation allows the particle to simultaneously achieve charge stability (from the high-sulfo shell) and low-temperature fixability (from the low-sulfo core), as each segment contributes its specific functional property.
2Object-affected harmful factors
If plant-derived resin or recovered polyethylene terephthalate is introduced as binder resin to reduce environmental load, then environmental sustainability is improved, but control over sulfo group distribution and particle structure becomes more difficult
Solution Approach 1:
The patent applies preliminary action by pre-forming resin particles with controlled sulfo group distribution using plant-derived resin or recovered polyethylene terephthalate before incorporating them into the toner formulation. The emulsion aggregation method is used in advance to create particles with the desired gradient structure, ensuring that the environmental sustainability benefits are achieved without compromising the precision of sulfo group distribution in the final toner product.
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 resin particle achieves improved charge stability and low-temperature fixability while minimizing environmental impact by precisely controlling the sulfo component distribution.
Implementation Method 1
in a depth profile of a surface of the resin particle measured by time-of-flight secondary ion mass spectrometry
Data Source
AI summary
A resin particle having a core-shell structure is provided that includes a binder resin and an organic compound having a sulfo group, in which Formula (1), I(100)<I(t)<I(0), and Formula (2), 0.005<I(100), are satisfied in a range of 0<t<100. I(t) represents, in a depth profile of a surface of the resin particle measured by time-of-flight secondary ion mass spectrometry, a secondary ion intensity derived from the sulfo group at t (nm) in depth from an outermost surface of the resin particle.