Crystalline Toner Composition for Low-Temperature Fixing Stability
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Solution Overview
Problem
Existing toners struggle to achieve both low-temperature fixability and heat-resistant storage stability while maintaining excellent release properties and fixed image rubfastness, as they often exhibit poor adhesion to paper and release agent interactions.
Innovation Solution
A toner comprising a binder resin with a crystalline resin A, derived from (meth)acrylic acid esters with 18 to 36 carbon atoms, and a release agent, where specific DSC parameters (50≤Tp≤70, 20≤ΔH≤70, and 0.00≤ΔHTp-3/ΔH≤0.30) are satisfied to optimize long chain alkyl group interactions and ensure sharp melt properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the glass transition temperature (Tg) of the binder resin is lowered to enable low-temperature fixing, then low-temperature fixability is improved, but heat-resistant storage stability deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the binder resin by incorporating specific monomer units with defined glass transition temperatures and functional groups. The binder resin comprises a specific combination of monomer units including those with Tg of -50°C to 0°C (for low-temperature flexibility) and those with Tg of 50°C to 100°C (for heat-resistant stability), resolving the contradiction between low-temperature fixability and heat-resistant storage stability through controlled compositional parameters
Solution Approach 2:
The invention creates a composite binder resin system by combining multiple types of monomer units with different thermal properties and functional characteristics. The composite structure includes monomer units contributing to low-temperature softening, monomer units providing heat resistance, and monomer units enhancing paper adhesion, achieving synergistic effects that simultaneously satisfy low-temperature fixability and heat-resistant storage stability requirements
2Speed
If plasticizers are added to increase softening speed while maintaining Tg value, then low-temperature fixability is improved, but the toner softening process becomes limited by the plasticizer melting step
Solution Approach 1:
The invention extracts and eliminates the need for separate plasticizer components by incorporating plasticizing functionality directly into the binder resin molecular structure through specific monomer units. This removes the limiting plasticizer melting step while maintaining the desired softening behavior, thereby improving fixing efficiency without sacrificing softening speed
Solution Approach 2:
The invention integrates multiple functional monomer units into a unified binder resin composite that simultaneously provides plasticizing effects, adhesion promotion, and thermal stability. This composite structure eliminates the need for separate plasticizer addition while achieving enhanced softening speed and overall fixing efficiency through the synergistic interaction of different monomer unit types
3Temperature
If long chain alkyl groups are used to achieve crystallinity and sharp-melt properties, then low-temperature fixability is improved, but adhesion between fixed toner and paper deteriorates due to high hydrophobicity
Solution Approach 1:
The invention applies local quality differentiation by incorporating specific monomer units with polar functional groups (carboxyl, hydroxyl, amine groups) at strategic locations within the binder resin structure. These localized polar regions provide strong paper adhesion through hydrogen bonding and electrostatic interactions, while the overall crystalline structure maintained by long chain alkyl groups provides sharp-melt properties and low-temperature fixability
Solution Approach 2:
The invention creates a composite molecular structure combining hydrophobic long chain alkyl groups for crystallinity with hydrophilic polar functional groups for adhesion. This composite architecture at the molecular level allows simultaneous achievement of sharp-melt behavior (from crystalline regions) and strong paper bonding (from polar functional groups), resolving the contradiction between melting properties and adhesion
4Reliability
If high content of long chain alkyl groups is used to achieve crystallinity, then heat-resistant storage stability is improved, but release properties deteriorate due to high affinity for release agents
Solution Approach 1:
The invention changes the quantitative composition parameters by precisely controlling the content of long chain alkyl group-containing monomer units within specific ranges (1-50 mass%, preferably 5-30 mass%). This controlled parameter adjustment maintains sufficient crystallinity for heat-resistant storage stability while limiting excessive long chain alkyl content that would cause harmful interactions with release agents, thereby improving release properties
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 achieves excellent low-temperature fixability, heat-resistant storage stability, and improved release properties with enhanced fixed image rubfastness by controlling the crystalline resin's peak temperature, endothermic quantity, and interaction with the release agent.
Implementation Method 1
Crystalline vinyl resins have the property of hardly softening at all up to the melting point because the side chains in the molecule are regularly arranged. Crystals also melt suddenly at the melting point, accompanied by a rapid drop in viscosity.
Implementation Method 2
an endothermic peak appears in DSC measurement when a crystalline resin component is included
Data Source
AI summary
A toner comprising a toner particle comprising a binder resin and a release agent, wherein the binder resin comprises a crystalline resin A, the crystalline resin A comprises a monomer unit derived from a monomer (a), the monomer (a) is at least one selected from the group consisting of (meth)acrylic acid esters having an alkyl group with 18 to 36 carbon atoms, the peak temperature and endothermic quantity at an endothermic peak derived from the crystalline resin A in DSC measurements using the toner satisfy specific relationships, and the release agent is at least one selected from the group consisting of hydrocarbon-based waxes and ester waxes.