Toner Fixation via Abrupt Storage Elastic Modulus Drop
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Solution Overview
Problem
In electrophotography, the shrinkage or deformation of recording media due to heat during fixation poses challenges, particularly in achieving high paper registration accuracy, as existing toners do not maintain stable fixation quality and glossiness across a wide temperature range.
Innovation Solution
Developing toner particles with specific properties, including a storage elastic modulus that abruptly lowers at a prescribed temperature, allowing for stable fixation at low temperatures and preventing deformation during fixation, achieved by using a urethane-modified polyester resin with a urethane group concentration between 0.5% and 5% and a melting point between 50°C and 90°C, and applying a pressure of 200 kPa to 800 kPa during fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fixation temperature is increased to improve fixation quality and glossiness, then fixation quality improves, but recording medium shrinkage and deformation increase
Solution Approach 1:
The patent changes the physical and chemical parameters of the toner particles, specifically designing them with a storage elastic modulus that abruptly decreases at a prescribed temperature (Expression 1: G′(T0)/G′(T0+10)≥10, where 40≤T0≤60). This parameter change allows the toner to deform sufficiently for good fixation and glossiness only within a specific temperature range, while remaining stable outside this range, thus preventing both cold offset and high-temperature recording medium deformation.
2Stability of the object's composition
If toner storage elastic modulus is kept high to prevent deformation, then storage stability improves, but fixation quality and glossiness deteriorate
Solution Approach 1:
The patent implements a temperature-dependent parameter change in the toner's storage elastic modulus. The toner is designed to maintain high storage elastic modulus at temperatures below T0 for storage stability, but exhibits an abrupt decrease in storage elastic modulus at the prescribed temperature T0 (Expressions 1-3) during fixation, enabling sufficient deformation for high-quality fixation and excellent glossiness. This resolves the contradiction by making the toner's mechanical properties dynamically responsive to temperature changes.
3Shape
If fixation temperature is reduced to prevent recording medium shrinkage, then recording medium deformation decreases, but fixation quality and glossiness deteriorate
Solution Approach 1:
The patent enables precise temperature control for fixation by designing toner with an abrupt storage elastic modulus decrease at a specific temperature range (Expressions 1-3). This allows fixation to be performed at optimized temperatures within 70°C to 100°C, where the toner achieves the right balance between maintaining structural integrity and deforming sufficiently for high-quality fixation, thus preventing both recording medium deformation and fixation quality deterioration.
4Manufacturing precision
If toner deformability is increased to improve glossiness, then surface finish improves, but storage stability decreases
Solution Approach 1:
The patent achieves this contradiction resolution by designing the toner's storage elastic modulus to be temperature-dependent with an abrupt decrease at a prescribed temperature (Expression 1: G′(T0)/G′(T0+10)≥10). At storage temperatures below T0, the high storage elastic modulus ensures toner stability and prevents deformation. During fixation at temperatures at or above T0, the abrupt decrease in storage elastic modulus allows sufficient toner deformation for excellent glossiness and fixation quality, thus resolving the contradiction between storage stability and glossiness.
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 solution ensures stable fixation quality and excellent glossiness across a wide temperature range, preventing cold offset and high-temperature offset, while maintaining desired elasticity and preventing toner particle deformation.
Implementation Method 1
toner desirably has such characteristics that a storage elastic modulus abruptly lowers at a prescribed temperature
Implementation Method 2
the step of fixing the toner particles contained in the electrostatic latent image developer transferred to the recording medium to the recording medium includes the steps of heating the recording medium
Data Source
AI summary
An image formation method includes a step of preparing an electrostatic latent image developer, a transferring step, and a fixation step. The step of preparing an electrostatic latent image developer includes a step of preparing an electrostatic latent image developer containing toner particles having prescribed viscoelasticity characteristics. The fixation step includes steps of heating a recording medium and fixing the toner particles to the recording medium at a pressure not lower than 200 kPa and not higher than 800 kPa.