Sea-Island Toner for Rough Sheet Offset Control
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Solution Overview
Problem
In the electrophotographic process, achieving high-quality printing on rough sheets with large projections and recesses is challenging due to issues like minute white spots, hot offsetting, and uneven glossiness, which are caused by inadequate heat and pressure transmission and release agent bleeding.
Innovation Solution
The development of an electrostatic charge image developing toner with a sea-island structure, containing a binder resin and a release agent, where the toner has specific melt viscosity and flow activation energy ranges, and a controlled distribution of eccentricity B, ensuring sufficient release agent bleeding and preventing excessive melting or bleeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the release agent content is increased to prevent minute white spots on rough sheets, then the white spots are reduced, but hot offsetting occurs due to excessive release agent bleeding
Solution Approach 1:
The toner employs a sea-island structure where the release agent is localized in specific island regions rather than being uniformly distributed. This local concentration allows sufficient release agent to be present at the toner surface for preventing minute white spots on rough sheets, while the overall controlled distribution prevents excessive bleeding that causes hot offsetting.
Solution Approach 2:
The invention optimizes specific parameters including the release agent content (5-20 parts by weight per 100 parts binder resin), melt viscosity (4,000-200,000 Pa·s at 100°C), and flow activation energy (18,000-80,000 J/mol). These parameter changes ensure proper release agent bleeding behavior that prevents both minute white spots and hot offsetting.
2Object-affected harmful factors
If the toner melting is enhanced to improve heat transmission on rough sheets, then the image quality improves, but excessive melting causes uneven glossiness
Solution Approach 1:
The invention carefully controls the melt viscosity within 4,000-200,000 Pa·s at 100°C and flow activation energy within 18,000-80,000 J/mol. These parameter ranges ensure sufficient melting for heat transmission on rough sheets while preventing excessive melting that would cause uneven glossiness.
Solution Approach 2:
The sea-island structure creates local regions with different properties: the sea portion provides the base melting characteristics while the island portions containing release agent modify the local melting and bleeding behavior, ensuring uniform glossiness while maintaining adequate heat transmission.
3Ease of operation
If the release agent distribution is increased toward the toner surface to improve release agent bleeding, then the bleeding is enhanced, but the structural stability of the toner decreases
Solution Approach 1:
The sea-island structure localizes the release agent in island regions within the toner matrix. This localization ensures the release agent is positioned to bleed effectively during fixation while the surrounding binder resin matrix maintains the structural stability of the toner particle.
Solution Approach 2:
The toner is formulated as a composite material with binder resin (sea portion) and release agent (island portions). This composite structure combines the benefits of both components: the binder resin provides structural stability while the release agent ensures adequate bleeding, achieving both requirements simultaneously.
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 effectively reduces minute white spots and uneven glossiness, maintaining high-quality image formation on rough sheets during high-speed printing by ensuring proper melting and release agent distribution, preventing hot offsetting and maintaining image quality.
Implementation Method 1
ensuring sufficient release agent bleeding and preventing excessive melting or bleeding
Implementation Method 2
caused by inadequate heat and pressure transmission
Implementation Method 3
ensuring sufficient release agent bleeding
Data Source
AI summary
An electrostatic charge image developing toner includes a toner particle which has a sea portion containing a binder resin and an island portion containing a release agent, wherein a melt viscosity at 100° C. of the toner is from 4,000 to 200,000 Pa·s, a flow activation energy of the toner is 18,000 to 80,000 J·mol−1, a maximum frequent value in distribution of eccentricity B of the island portion is from 0.75 to 0.98, a skewness in the distribution of the eccentricity B is from −1.10 to −0.50, and the eccentricity B is expressed by 2d/D, wherein D indicates an equivalent circle diameter (μm) of the toner in an observation of a cross-section of the toner, and d indicates a distance (μm) from a centroid of the toner to a centroid of the island portion containing the release agent in the observation of a cross-section of the toner.