Toner with Controlled Softening Point and Circularity for Offset Resistance
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Solution Overview
Problem
Current toners face challenges with cold and hot offset resistance, especially when high print percentages are output at a high rate with a low pressure fixing nip, leading to poor adhesion and peeling issues due to insufficient heat and pressure.
Innovation Solution
A toner formulation with specific properties, including a softening point of 80° C. to 140° C., an average circularity of 0.940 or higher, and an integrated stress value of at least 78 g·m/sec measured using a tackiness tester, which enhances binding strength and adhesion under low pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the pressure at the fixing nip is reduced to simplify the fixing apparatus, then the film wear is reduced and apparatus configuration is simplified, but the toner tends to peel off from paper (cold offset) because of insufficient heat and pressure
Solution Approach 1:
The patent changes the physical and chemical parameters of the toner particles, specifically controlling the glass transition temperature (Tg) to be 80°C to 120°C and the softening point to be 100°C to 140°C. These parameter adjustments enable the toner to achieve adequate adhesion at reduced fixing pressure while maintaining cold offset resistance.
Solution Approach 2:
The patent employs composite toner particles containing multiple components with specific functions: binder resin (providing structural framework), wax (controlling melting and adhesion), colorant (providing image color), and inorganic particles (modifying flow and adhesion properties). This composite structure enables the toner to exhibit both low-pressure fixability and cold offset resistance.
2Productivity
If images with high print percentage are output at high rate, then productivity is improved, but the toner tends to peel off (cold offset) due to small quantity of heat supplied and insufficient toner deformation
Solution Approach 1:
The patent optimizes the thermal parameters of the toner, specifically setting the glass transition temperature (Tg) to 80°C to 120°C and softening point to 100°C to 140°C. These parameter changes enable the toner to undergo sufficient deformation and bonding at high print rates where heat supply time is limited, thereby preventing cold offset while maintaining high productivity.
Solution Approach 2:
The patent utilizes the phase transition properties of the toner components, particularly the glass transition and melting transitions. By controlling Tg and softening point within specific ranges, the toner undergoes controlled softening and deformation during the brief fixing process, enabling adequate adhesion even when images are output at high rates with limited heat supply time.
3Temperature
If the softening point of the toner is lowered to improve low-temperature fixability, then adhesion at low pressure is improved, but the toner may exhibit poor hot offset resistance
Solution Approach 1:
The patent carefully balances two critical temperature parameters: glass transition temperature (Tg) set to 80°C to 120°C for low-temperature fixability, and softening point set to 100°C to 140°C for adequate adhesion. This dual-parameter optimization enables the toner to exhibit both low-temperature fixability and hot offset resistance, resolving the contradiction between these two requirements.
Solution Approach 2:
The patent uses a composite formulation where different components contribute to different temperature-range properties. The binder resin provides structural integrity at higher temperatures (preventing hot offset), while the wax components control melting and adhesion at lower temperatures. This composite approach enables simultaneous achievement of low-temperature fixability and hot offset resistance.
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 exhibits excellent cold and hot offset resistance, ensuring reliable adhesion even at high print rates and low pressure, by improving the binding strength and heat transfer between toner particles.
Implementation Method 1
a softening point of the toner is at least 80° C. and not more than 140° C.
Implementation Method 2
an integrated value of stress in the toner at 150° C. is at least 78 g·m/sec when measured using a tackiness tester on a toner pellet obtained by compressing the toner
Data Source
AI summary
Provided is a toner containing a toner particle including a binder resin, a wax, and a colorant. The softening point of the toner is at least 80° C. and not more than 140° C. The average circularity of the toner is at least 0.940. The integrated value of stress in the toner at 150° C. which is measured by using a tackiness tester is at least 78 g·m/sec.