Toner Core-Shell Structure for Fixing and Stress Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current toners face challenges in achieving both low-temperature fixability and stress resistance, with existing solutions either lacking sufficient thermal storability or exhibiting image defects due to degradation during high-speed printing.
Innovation Solution
A toner with a core-shell structure is developed, where the binder resin contains a crystalline polyester segment and an amorphous resin, and the shell phase is formed using a resin B with a crystalline polyester segment, optimized for rheological properties to ensure high melting rate under pressure and resistance to deformation under low pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a binder resin containing crystalline polyester is used to achieve low-temperature fixability, then the sharp melting characteristic is improved, but the stress resistance deteriorates causing toner deformation during continuous printing
Solution Approach 1:
The binder resin is segmented into distinct functional components: a crystalline polyester component (providing sharp melting at 50-90°C for low-temperature fixing) and an amorphous resin component (providing stress resistance and elasticity). This segmentation allows each component to perform its specialized function without compromising the other, resolving the contradiction between low-temperature fixability and stress resistance
Solution Approach 2:
The invention uses a composite binder resin system combining crystalline polyester and amorphous resin in specific ratios (crystalline polyester 20-80 wt%, amorphous resin 20-80 wt%). This composite structure integrates the advantages of both materials: the crystalline portion provides sharp melting behavior for low-temperature fixing, while the amorphous portion provides stress resistance and elastic recovery to prevent toner deformation during continuous high-speed printing
2Productivity
If continuous printing for a large number of sheets is performed at high speed, then productivity is improved, but the toner degradation increases causing contamination and image defects
Solution Approach 1:
The invention optimizes the rheological parameters of the binder resin by controlling the glass transition temperature (Tg) of the amorphous resin component to be 40-100°C and adjusting the molecular weight and composition ratios. These parameter changes ensure the toner maintains appropriate viscosity and elasticity under high-speed printing conditions, preventing degradation and contamination while enabling continuous printing of large numbers of sheets
3Temperature
If the toner easily deforms under pressure load during fixing, then low-temperature fixability is improved, but the toner strength against light pressure load decreases causing contamination in development device
Solution Approach 1:
The invention applies local quality by creating different mechanical properties in different contexts: under high pressure and temperature (fixing conditions), the crystalline polyester melts and enables easy deformation for good fixability; under light pressure and ambient conditions (development device operations), the amorphous resin maintains sufficient strength and elasticity to prevent contamination. This context-dependent behavior resolves the contradiction between easy deformation for fixing and strength for contamination 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 low-temperature fixability and stress resistance, maintaining thermal storability and preventing image defects during high-speed printing by controlling the melting rate and deformation characteristics.
Implementation Method 1
Crystalline polyester has molecular chains that are regularly arranged and, as a result, does not clearly undergo glass transition, does not soften in a temperature range lower than the crystalline melting point, but melts at a temperature slightly higher than the melting point.
Implementation Method 2
when a pressure of 5.0 MPa is applied to the sample with the piston, a temperature at which a displacement of the piston reaches 2.0 mm after 10 seconds from initiation of an application of the pressure is defined as T(5)
Data Source
AI summary
Provided is a toner that is excellent in terms of low-temperature fixability and hot offset resistance, has a wide fixing temperature range from a low-temperature region to a high-temperature region, and has high thermal storability.When the toner is measured with a capillary rheometer,t(1) is 60 seconds or more and t(5) is 30 seconds or less andthe toner satisfies the following formulae (1) and (2)65.0[° C.]≦T(5)≦90.0[° C.] (1)4.5≦t(1)/t(5)≦10.0 (2).