Toner Particle Surface Modification for Image Uniformity
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Solution Overview
Problem
Current toner manufacturing processes for electrophotography face challenges in achieving high-quality images with favorable transferability, cleaning ability, and stability, as they often result in uneven particle distribution, residual toner issues, and inadequate low-temperature fixing properties.
Innovation Solution
The development of a toner with a controlled quantity of external additives, where large and small diameter particles are balanced to prevent aggregate immersion and ensure stable flowability and charge stability over prolonged periods, using a specific method to measure and adjust the particle distribution to maintain image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pulverization process is used to manufacture toner particles, then toner can be produced with acceptable properties, but the distribution of particle diameters becomes wide spread and yield is extremely low
Solution Approach 1:
The patent changes the manufacturing process from pulverization to suspension polymerization, fundamentally altering the parameters of particle formation. This enables precise control over particle diameter distribution while maintaining manufacturing feasibility, directly resolving the contradiction between ease of manufacture and manufacturing precision.
Solution Approach 2:
The patent replaces the mechanical pulverization system with a chemical polymerization system. Instead of mechanically crushing toner materials, the invention uses suspension polymerization to grow toner particles from monomers, achieving narrow particle diameter distribution without the drawbacks of mechanical size reduction.
2Shape
If suspension polymerization is used to manufacture toner particles, then particle shape becomes spherical, but cleaning ability becomes poor and residual toner accumulates on photoconductor
Solution Approach 1:
The patent introduces surface modification to create local quality differences on toner particles. By controlling surface properties while maintaining spherical shape, the invention enables both good transferability and cleaning ability, preventing residual toner accumulation on the photoconductor surface.
Solution Approach 2:
The patent uses composite toner particles consisting of polymer particles with specifically controlled surface properties. The composite structure combines the benefits of spherical shape for uniform coverage with surface characteristics that prevent excessive adhesion and facilitate cleaning, resolving the contradiction between shape and cleaning ability.
3Ease of manufacture
If emulsion polymerization is used to form toner particles, then resin fine particles can be associated, but residual surfactants remain inside particles causing background smear and reducing environmental stability
Solution Approach 1:
The patent extracts and eliminates harmful residual surfactants from the toner particle system. By using suspension polymerization instead of emulsion polymerization, the invention avoids incorporating surfactants into the particle structure, thereby preventing background smear and improving environmental stability of toner charge.
Solution Approach 2:
The patent replaces the use of surfactants with alternative dispersing mechanisms that do not leave harmful residues. The suspension polymerization process uses minimal or no surfactant, and any residual dispersing agents are easily removable, effectively eliminating the source of background smear problems.
4Manufacturing precision
If toner particles are made smaller with narrow distribution to improve image quality, then resolution and fineness improve, but transferability and cleaning ability deteriorate
Solution Approach 1:
The patent optimizes the particle diameter parameters to a specific range (0.5-5 μm with narrow distribution) and combines this with controlled surface properties. This parameter optimization enables simultaneous achievement of high image quality through narrow distribution and reliable transferability/cleaning ability through appropriate particle size and surface characteristics.
Solution Approach 2:
The patent employs composite toner particles with optimized internal structure and surface composition. The composite nature of the particles allows small size for high resolution while maintaining surface properties that ensure good transferability and cleaning ability, resolving the contradiction between image quality and reliability.
5Ease of operation
If external additives are increased to improve flowability, then flowability improves initially, but aggregates of external additives immerse into toner and cause image nonuniformity over time
Solution Approach 1:
The patent uses a controlled, moderate amount of external additives rather than excessive quantities. This partial action approach provides sufficient flowability improvement while preventing aggregate formation and immersion into toner particles, thereby maintaining image uniformity over extended periods.
Solution Approach 2:
The patent ensures uniform local distribution of external additives on the toner particle surface. By controlling the local quality and dispersion of additives, the invention prevents aggregate formation and subsequent immersion into toner, maintaining both flowability and image uniformity over time.
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 approach enables the production of high-quality images with sustained transferability and cleaning ability, preventing photoconductor filming and image nonuniformity, while maintaining flowability and charge stability over extended use.
Implementation Method 1
A latent electrostatic image is formed on a photoconductor, to which toner is attached
Implementation Method 2
The toner is transferred to a transfer material, and then fixed to the transfer material by heat to form a toner image
Data Source
AI summary
It is an object of the present invention to provide a toner that can sustain favorable transferability and cleaning ability for prolonged periods; prevent photoconductor filming; exhibit no variation in image nonuniformity or external additive immersion induced by developer agitation at the time of use; excels in stability with flowability and charge stability over prolonged periods. Therefore, provided is the toner of which the quantity of aggregate of residual external additives found on the sieve of 635-mesh and 452 cm2 of mesh area, after 0.2 g of the toner on the sieve is blasted with air at a blow pressure of 0.2 MPa from 160 mm above the sieve while being air-suctioned at a suction force of 5 mmHg, and then air-suctioned at a suction force of 20 mmHg, is 4,500 or less and 5 or more.