Toner Viscosity Distribution for Offset Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current image forming methods face challenges with toner adhesion to fixing rollers, leading to offsetting and contamination, and fail to achieve excellent developability and low-temperature fixability, especially in high-speed oilless fixing systems and frameless printing scenarios.
Innovation Solution
A toner with a specific viscosity distribution, characterized by intrinsic viscosities of THF-soluble matter, is developed, comprising a binder resin and colorant, where the ratio of low-viscosity and high-viscosity components is optimized to ensure excellent developability and low-temperature fixability without adhesion, even in high-speed oilless fixing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a substance having releasability (such as low-molecular weight polyethylene and low-molecular weight polypropylene) is added to the toner in large amount, then offset prevention is improved, but filming phenomenon to photosensitive member and surface contamination of toner carrying members occur
Solution Approach 1:
The invention changes the molecular weight parameter of the polyethylene and polypropylene components. Instead of using low-molecular weight versions that cause filming and contamination, the invention employs high-molecular weight polyethylene with weight average molecular weight of 1×10^6 to 10×10^6 and high-molecular weight polypropylene with weight average molecular weight of 1×10^6 to 10×10^6. This parameter change allows sufficient offset prevention while eliminating the harmful filming and contamination effects associated with lower molecular weight versions.
Solution Approach 2:
The invention creates a composite toner formulation combining high-molecular weight polyethylene, high-molecular weight polypropylene, and a specific binder resin (polyester resin with Tg of 40°C to 70°C). This composite material system achieves synergistic effects where the high-molecular weight waxes provide offset prevention, the binder resin ensures proper adhesion and development, and the specific glass transition temperature range maintains toner flexibility without causing filming or contamination issues.
2Reliability
If binder resin and wax are improved to achieve better fixation and offset properties, then image quality and releasability are improved, but the complexity of toner formulation increases
Solution Approach 1:
The invention establishes specific parameter ranges for key components: binder resin glass transition temperature (40°C to 70°C), weight average molecular weight of polyethylene (1×10^6 to 10×10^6), and weight average molecular weight of polypropylene (1×10^6 to 10×10^6). These defined parameters provide a systematic approach that simplifies formulation by specifying exact ranges rather than requiring complex trial-and-error optimization, thereby achieving reliable fixation and offset properties without excessive complexity.
Data Source
AI summary
The present invention aims to provide a toner having excellent developability and excellent low-temperature fixability without causing adhesion of ejected sheets even in a high-speed oilless fixing system and capable of preventing a frameless printing from causing a twisted offseting phenomenon. Specifically, provided is a toner having toner particles including at least a binder resin and a colorant, in which, when the toner is dissolved in a tetrahydrofuran (THF) solvent at 25° C. for 24 hours, the ratio of a THF-soluble matter having an intrinsic viscosity of 5.0×10−2 dl/g or less with respect to the total amount of the THF-soluble matter in a GPC-RALLS-viscometer analysis is 15.0 mass % to 60.0 mass %, and the ratio of a THF-soluble matter having an intrinsic viscosity of 1.5×10−1 dl/g or more with respect to the total amount of the THF-soluble matter in a GPC-RALLS-viscometer analysis is 20.0 mass % to 40.0 mass %.