Electrostatic Toner With Crystalline Polyester And Composite Wax
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Solution Overview
Problem
Existing electrostatic image developing toners face challenges in achieving low-temperature fixability while maintaining high-temperature offset resistivity and uniform gloss, particularly when handling thin papers, due to issues with crystalline resin sizes and viscosity changes during the heat fixing process.
Innovation Solution
The development of an electrostatic image developing toner comprising a binder resin with an amorphous vinyl resin and crystalline polyester resin, along with a releasing agent containing ester wax and microcrystalline wax, where the content and melting points of these components are specifically controlled to ensure optimal fixing-separation and gloss uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a crystalline polyester resin is introduced in the binder resin to improve low-temperature fixability, then the melting point is reduced and low-temperature fixability is improved, but the viscosity rapidly decreases during heat fixing causing image breaking and high-temperature offset
Solution Approach 1:
The invention changes the chemical composition parameters of the binder resin by incorporating specific ratios of amorphous vinyl resin (50-80 mass%) and crystalline polyester resin (20-50 mass%), and adjusts releasing agent composition (ester wax 40-98 mass%, microcrystalline wax 2-60 mass%). This parameter optimization allows the toner to maintain appropriate viscosity during heat fixing while achieving low-temperature fixability, preventing image breaking and offset.
2Ease of operation
If releasing agents are added to improve fixing-separation property, then separation from fixing member is improved, but gloss uniformity deteriorates due to diverse crystalline sizes
Solution Approach 1:
The invention uses a composite releasing agent system combining ester wax and microcrystalline wax in specific proportions (ester wax 40-98 mass%, microcrystalline wax 2-60 mass%). This composite approach creates a synergistic effect where the two waxes work together to provide both excellent fixing-separation property and uniform gloss, overcoming the limitations of using single releasing agents or diverse crystalline size mixtures.
3Temperature
If the content of crystalline polyester resin is increased to enhance low-temperature fixability, then fixing temperature is reduced, but high-temperature offset resistivity deteriorates
Solution Approach 1:
The invention optimizes the crystalline polyester resin content within 20-50 mass% of the binder resin, preventing excessive crystalline content that would cause rapid viscosity decrease and offset. This parameter control, combined with the amorphous vinyl resin matrix and specific releasing agent composition, maintains high-temperature offset resistivity while achieving low-temperature fixability.
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
This toner achieves excellent fixing-separation and uniform gloss while maintaining low-temperature fixability and high-temperature offset resistivity, by controlling the crystal size and distribution of the crystalline polyester resin and releasing agents, thereby improving the heat melting process and adhesion properties.
Implementation Method 1
the crystalline component of the crystalline polyester resin will be melted when the temperature of the heat fixing process is above the melting point of the crystalline polyester resin
Implementation Method 2
the releasing agent contains a first releasing agent component containing an ester wax and a second releasing agent component containing a microcrystalline wax
Data Source
AI summary
Provided is an electrostatic image developing toner having toner mother particles containing a binder resin and a releasing agent, wherein the binder resin contains an amorphous vinyl resin and a crystalline polyester resin; the releasing agent contains a first releasing agent component containing an ester wax and a second releasing agent component containing a microcrystalline wax; a content of the first releasing agent component in the releasing agent is in the range of 40 to 98 mass %; a content of the second releasing agent component in the releasing agent is in the range of 2 to 60 mass %; and a content of the crystalline polyester resin in the binder resin is in the range of 5 to 20 mass %.