Toner with Organic-Inorganic Composite Additives for Low-Temperature Fixing
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Solution Overview
Problem
Existing toners for electrophotography face challenges in achieving low-temperature fixability while preventing hot offset and contamination of fixing unit members, as conventional external additives do not effectively improve adhesion and image stability.
Innovation Solution
A toner comprising binder resin and organic-inorganic composite fine particles with specific size, shape, and SP value compatibility, which enhances elasticity and prevents hot offset by thickening the toner surface layer without hindering the releasing agent's oozing, thereby maintaining image density and extending the printer's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If toner particles are designed to be easily softened by heat for low-temperature fixability, then heat fixing temperature is reduced, but external additives are easily embedded in the toner surface leading to hot offset and contamination
Solution Approach 1:
The invention changes the particle size parameter of external additives from conventional large sizes to a specific range of 0.03-0.5 μm, and controls the shape factor SF-2 to 90-130. This parameter optimization allows the toner to maintain low-temperature fixability while preventing external additives from being embedded, thus reducing hot offset and contamination without sacrificing fixing temperature reduction
Solution Approach 2:
The invention uses composite external additives consisting of both organic-inorganic composite fine particles (0.03-0.5 μm) and inorganic fine particles (0.01-0.1 μm). This composite structure provides both the elasticity enhancement needed for low-temperature fixability and the surface protection needed to prevent embedding, resolving the contradiction between temperature reduction and contamination prevention
2Object-affected harmful factors
If conventional external additives with large particle size are used to prevent embedding, then hot offset is reduced, but adhesion and accumulation of molten toner to fixing unit member is not improved
Solution Approach 1:
The invention optimizes the particle size parameter to 0.03-0.5 μm and shape factor SF-2 to 90-130 for external additives. This specific parameter range allows the additives to remain large enough to prevent embedding while being small enough to improve adhesion and accumulation of molten toner to the fixing unit member, resolving the contradiction between hot offset prevention and adhesion improvement
Solution Approach 2:
The invention employs a composite external additive system combining organic-inorganic composite fine particles with inorganic fine particles. This composite structure simultaneously achieves hot offset prevention through appropriate particle size selection and enhances adhesion and accumulation of molten toner, addressing both requirements that conventional single-type additives could not meet
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 excellent low-temperature fixability, suppresses hot offset and contamination, and maintains stable image density even after printing many sheets, ensuring a longer printer lifespan.
Implementation Method 1
enhances elasticity and prevents hot offset by thickening the toner surface layer
Implementation Method 2
a vinyl resin particle containing a vinyl resin, the vinyl resin containing THF-insoluble matter in an amount of 95% by mass or more
Implementation Method 3
the organic-inorganic composite fine particle 1) has a plurality of convexes derived from the inorganic fine particles on the surfaces thereof
Implementation Method 4
the absolute value of a difference between an SP value of the releasing agent and an SP value of the vinyl resin is 0.50 (cal/cm3)1/2 or less
Data Source
AI summary
The toner comprises: toner particles each containing a binder resin and a releasing agent; and an organic-inorganic composite fine particle, wherein: the organic-inorganic composite fine particle comprises: a vinyl resin particle containing a vinyl resin, the vinyl resin containing THF-insoluble matter in an amount of 95% by mass or more; and inorganic fine particles which are exposed at surfaces of the respective organic-inorganic composite fine particles, the organic-inorganic composite fine particle 1) has a plurality of convexes derived from the inorganic fine particles on the surfaces thereof, 2) has a number average particle size of 70-500 nm, and 3) has a shape factor SF-2 as measured at a magnification of 200,000 times of 103-120, and an absolute value of difference between an SP value of the releasing agent and an SP value of the vinyl resin is 0.50 (cal/cm3)1/2 or less.