Toner Viscoelasticity Control for Low-Temperature Fixing and Gloss Uniformity
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Solution Overview
Problem
Existing electrostatic latent image developing toners face challenges in achieving low-temperature fixability and controlling image glossiness across a wide range of fixing speeds, often resulting in uneven gloss and increased heat requirements during the image fixing process.
Innovation Solution
The development of an electrostatic latent image developing toner comprising a mother particle with a coloring agent, release agent, and binder resin, where an inorganic particle is added to the surface, and the dynamic viscoelastic properties are optimized to satisfy specific relaxation time and relaxation modulus conditions, including a maximum relaxation time t1 and minimum relaxation time t2, to control stress relaxation and glossiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If crystalline resins low in melting temperature are used as binder resins to lower toner fixing temperature, then low-temperature fixability is improved, but image glossiness control deteriorates resulting in uneven gloss and glossiness rise
Solution Approach 1:
The invention changes the viscoelastic parameters of the toner by controlling the relaxation time and relaxation modulus to satisfy specific mathematical relationships. This allows the toner to maintain appropriate viscosity at low fixing temperatures while controlling stress relaxation to prevent glossiness rise and unevenness, thereby resolving the contradiction between low-temperature fixability and image glossiness control
Solution Approach 2:
The invention uses a composite binder resin system comprising specific types of resins (e.g., polyester resin, polyamide resin) with controlled molecular weight distributions and functional groups. This composite material approach enables simultaneous achievement of low melting temperature for easy fixing and controlled viscoelastic properties for uniform image glossiness
2Temperature
If conventional toner formulations are used to achieve low-temperature fixability, then fixing temperature is reduced, but adaptability to various fixing speeds deteriorates
Solution Approach 1:
The invention makes the toner's viscoelastic properties dynamic by controlling the relaxation time spectrum to span a wide range. This allows the toner to adapt its flow and stress relaxation characteristics to match different fixing speeds, enabling compatibility from low to high fixing speeds while maintaining low-temperature fixability
Solution Approach 2:
The invention optimizes multiple parameters including relaxation time (t1, t2), relaxation modulus (G(t1), G(t2)), and their mathematical relationships to create a toner formulation that responds appropriately to varying fixing conditions, thereby achieving broad speed adaptability
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 approach reduces glossiness rise and unevenness in fixed images, maintains low-temperature fixability, and allows for compatibility with various fixing speeds, ensuring both suitable fixability and gloss control across a wide range of speeds from low to high.
Implementation Method 1
an inorganic particle that is added to the surface of the mother particle
Implementation Method 2
a relation between a relaxation time t and a relaxation modulus G(t) which are determined from the dynamic viscoelasticity measurement made on the toner
Implementation Method 3
control stress relaxation and glossiness
Data Source
AI summary
An electrostatic latent image developing toner includes a mother particle which contains a coloring agent, a release agent and a binder resin; and an inorganic particle which is added to the surface of the mother particle, and wherein a relation between a relaxation time t and a relaxation modulus G(t) which are determined from the dynamic viscoelasticity measurement made on the toner satisfies the following equations (1) and (2); G(t1)<100 Pa(1) 515<(G(t2)-G(t1))/(log(t1)-log(t2))<1,230(2) wherein t1 represents the maximum relaxation time and t2 represents the minimum relaxation time.