Toner Binder Resin Viscoelasticity Control for Fixing and Durability
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Solution Overview
Problem
Existing toners for electrostatic image development face challenges in maintaining low temperature fixability and development durability, leading to issues like fogging and development streaks due to deformation under heat and mechanical stress, which complicates achieving both energy savings and longer machine life.
Innovation Solution
A toner with a binder resin that has a storage elastic modulus of 0.10 MPa to 3.00 MPa at 70° C. and a surface storage elastic modulus of 2.80 GPa to 4.50 GPa at 25° C., along with external additives for charge assistance and flowability, is developed to enhance durability and fixability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the viscoelasticity and melt viscosity of the toner are increased to improve development durability, then the toner becomes resistant to deformation from heat and stress, but the low temperature fixability deteriorates because the toner cannot be fixed at lower temperatures
Solution Approach 1:
The invention changes the physical and chemical parameters of the binder resin, specifically controlling the storage elastic modulus at 70°C to be within 0.05 MPa to 5.00 MPa and the glass transition temperature to be within -50°C to 0°C. These parameter adjustments allow the toner to achieve both development durability and low temperature fixability by optimizing the molecular structure and thermal properties of the binder resin.
Solution Approach 2:
The invention uses composite materials by combining the binder resin with specific additives including waxes having melting points of 60°C to 120°C, and particles with specific surface properties. This composite structure allows the toner to exhibit both the heat resistance needed for development durability and the low-temperature flowability needed for energy-efficient fixing.
2Strength
If the toner is subjected to heat and mechanical stress in the developing apparatus over a long period, then the toner deforms and may be cracked or crushed, but increasing the toner hardness to prevent cracking reduces the toner's ability to be properly charged and transferred
Solution Approach 1:
The invention optimizes the storage elastic modulus parameter to within 0.05 MPa to 5.00 MPa at 70°C, which provides an optimal balance between mechanical strength and surface softness. This parameter range ensures the toner particles are sufficiently hard to resist cracking and crushing during prolonged use, while maintaining surface properties that allow proper charge application from the developing blade.
3Reliability
If the toner accumulates on members in the developing apparatus, then image defects such as fogging and development streaks occur, but reducing the toner durability to prevent accumulation causes the toner to deform under heat and stress
Solution Approach 1:
The invention controls the storage elastic modulus within 0.05 MPa to 5.00 MPa and glass transition temperature within -50°C to 0°C, which optimizes the toner's mechanical properties to prevent both deformation under stress and excessive accumulation on developing members. These parameter adjustments ensure the toner maintains its structural integrity while allowing proper release from the developing blade, preventing image defects.
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 effectively suppresses image defects such as fogging and development streaks while maintaining low temperature fixability, ensuring high performance and longevity in long-lived development systems.
Implementation Method 1
the viscoelasticity and melt viscosity of the toner are of interest. The toner is subject to heat and mechanical stress within the developing apparatus, causing toner cracking and crushing. Increasing the viscoelasticity and melt viscosity of the toner is useful for improving development durability because it makes the toner resistant to deformation from external heat and stress.
Implementation Method 2
in dynamic viscoelasticity measurement of the toner, the storage elastic modulus of the toner at 70° C. is from 0.10 MPa to 3.00 MPa
Implementation Method 3
In the fixing step, on the other hand, reducing the viscoelasticity and melt viscosity of the toner is useful for improving low temperature fixability because the toner can be fixed on the paper at a lower temperature.
Data Source
AI summary
A toner comprising a toner particle that includes a binder resin, wherein in dynamic viscoelasticity measurement of the toner, the storage elastic modulus of the toner at 70° C. is from 0.10 MPa to 3.00 MPa, and in nanoindentation measurement of the toner, the surface storage elastic modulus of the toner at 25° C. under 150 μN of load is from 2.80 GPa to 4.50 GPa.