Black Toner with Polyester Resin for Low-Temperature Fixing
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Solution Overview
Problem
Conventional black toners face issues with high water absorption, decreased charge amount, scattering, fogging, and transfer defects due to increased carbon black content, leading to poor low-temperature fixability and image quality.
Innovation Solution
A black toner formulation incorporating a polyester resin as the main component, carbon black, and a fine inorganic particle, with specific glass transition temperature and light absorbance ratios, and an aliphatic diol unit in the polyester to control water absorption and dispersibility, ensuring excellent low-temperature fixability and charging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the content of carbon black in the toner is increased to improve coloring power and reduce toner consumption, then the coloring power increases and toner consumption decreases, but water absorption increases, charge amount decreases, and scattering and fogging occur
Solution Approach 1:
The patent introduces a specific polyester resin as an intermediary substance between the carbon black colorant and the toner matrix. This polyester resin with controlled hydroxyl group value (15-50 mg KOH/g) acts as a mediator that disperses carbon black uniformly while preventing excessive water absorption and maintaining charge stability, thus resolving the contradiction between coloring power and charge reliability
Solution Approach 2:
The patent changes the chemical parameter of the polyester resin by controlling its hydroxyl group value within a specific range (15-50 mg KOH/g). This parameter control allows the toner to achieve high coloring power with adequate carbon black content while preventing excessive water absorption and maintaining stable charging performance, thereby resolving the contradiction
2Quantity of substance
If the content of carbon black in the toner is increased to improve coloring power and reduce toner consumption, then the coloring power increases and toner consumption decreases, but scattering and fogging during developing occur
Solution Approach 1:
The polyester resin with controlled hydroxyl group value serves as a dispersing intermediary that prevents carbon black aggregation. This intermediary substance ensures uniform distribution of carbon black particles, achieving high coloring power while preventing scattering and fogging, thus maintaining image quality
Solution Approach 2:
By controlling the hydroxyl group value of the polyester resin within 15-50 mg KOH/g, the patent optimizes the dispersion characteristics of carbon black. This parameter control allows the toner to achieve high coloring power without scattering and fogging, resolving the contradiction between coloring power and image quality
3Quantity of substance
If the content of carbon black in the toner is increased to improve coloring power and reduce toner consumption, then the coloring power increases and toner consumption decreases, but transfer defects occur due to decreased resistance
Solution Approach 1:
The polyester resin acts as an intermediary that maintains appropriate electrical resistance in the toner. By controlling its hydroxyl group value, the resin prevents excessive water absorption that would decrease resistance, thereby preventing transfer defects while allowing high carbon black content for improved coloring power
Solution Approach 2:
The patent controls the hydroxyl group value of the polyester resin to maintain optimal electrical resistance. This parameter control prevents excessive water absorption and resistance decrease, ensuring reliable transfer performance while achieving high coloring power through adequate carbon black content
4Temperature
If a polyester resin with low glass transition temperature is used to achieve low-temperature fixability, then the fixing temperature can be reduced, but the heat-resistant storage stability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the polyester resin by controlling its hydroxyl group value (15-50 mg KOH/g) and using specific diol components. This parameter optimization allows the resin to have appropriate glass transition temperature for low-temperature fixing while maintaining sufficient heat-resistant storage stability through controlled water absorption characteristics
Solution Approach 2:
The patent creates a composite toner system combining polyester resin with controlled hydroxyl group value and carbon black colorant. This composite structure allows the polyester to provide low-temperature fixability while the controlled composition prevents excessive water absorption, maintaining heat-resistant storage stability
5Manufacturing precision
If the toner particle size is reduced to improve resolution and definition, then the image quality improves, but the fluidity and transfer efficiency may deteriorate
Solution Approach 1:
The patent controls the particle size parameters within an optimized range (3-8 μm weight average diameter) and adjusts the chemical composition of the polyester resin. This parameter optimization maintains appropriate fluidity for small particles while achieving high resolution, preventing the deterioration of transfer efficiency
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 high offset resistance, excellent charging performance, and high-quality image production with reduced water absorption, minimizing scattering and fogging, and maintaining image quality under high-humidity conditions.
Implementation Method 1
a polyester which uses an aliphatic diol unit having 4 to 12 (inclusive thereof) carbon atoms as a diol unit
Implementation Method 2
interfacial polymerization of the compound having the isocyanate group is carried out at the droplet interface
Implementation Method 3
carbon black
Implementation Method 4
a wax
Data Source
AI summary
A black toner has a toner particle including at least a resin (a) having a polyester as a main component, carbon black, and a wax, and a fine inorganic particle. When the Tgs of the black toner measured by DSC at temperature rise rate of 0.5 °C/min and 4.0 °C/min are defined as Tg(0.5) and Tg(4.0) respectively, Tg(0.5) is 35.0 to 60.0 °C and the difference between Tg(4.0) and Tg(0.5) is 2.0 to 10.0 °C. When preparing a solution of which the black toner is dissolved in ethyl acetate and defined the concentration thereof as Cb1 (mg/mL) and the light absorbance thereof at 600 nm wavelength as A600, A600/Cb1 is less than 0.15. When preparing a solution of which the black toner is dissolved in chloroform and defined the concentration thereof as Cb2 (mg/mL) and the light absorbance thereof at 600 nm wavelength as A600, A600/Cb2 is 2.00 to 6.55.