Amorphous Polyester Toner with Low Bisphenol A Content
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Solution Overview
Problem
The existing electrostatic charge image developing toners face issues with image failures such as black spots and fogging, particularly at low temperatures, due to the rigidity of bisphenol A derivatives, which hinder low-temperature fixing and increase heat generation, leading to aggregation and defects.
Innovation Solution
An image forming system using an electrostatic charge image developing toner with amorphous polyester containing a bisphenol A derivative structural unit content of 10 mol% or less, combined with a developing sleeve made of an aluminum alloy with more than 0.6% silicon by mass, to suppress heat generation and improve charge mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the amount of bisphenol A derivative is reduced to improve low-temperature fixing ability, then low-temperature fixing ability is improved, but image failure such as black spots occurs
Solution Approach 1:
The patent precisely controls the content percentage of structural units derived from bisphenol A derivative in the amorphous polyester to be 10 mol% or less, which is a critical parameter threshold. This parameter optimization resolves the contradiction by finding the optimal concentration point where low-temperature fixing ability is sufficient while image quality is maintained.
Solution Approach 2:
The patent uses a composite resin system comprising both amorphous polyester and crystalline polyester binders. The amorphous polyester provides low-temperature fixing ability while the crystalline polyester maintains structural integrity and prevents image failure. This composite approach allows the benefits of reduced bisphenol A derivative content without sacrificing image quality.
2Temperature
If bisphenol A derivative is used to improve resin structure, then heat resistance is improved, but molecule rigidity increases and meltability is inhibited
Solution Approach 1:
The patent optimizes the content percentage of bisphenol A derivative structural units to 10 mol% or less, which is the critical threshold that maintains the balance between heat resistance and meltability. At this concentration, the aromatic rings provide sufficient thermal stability while preventing excessive molecular rigidity that would inhibit melting.
Solution Approach 2:
The combination of amorphous polyester (containing controlled bisphenol A derivative) and crystalline polyester creates a composite binder system where the crystalline component compensates for the reduced meltability caused by aromatic ring structures, enabling both heat resistance and adequate processability.
3Productivity
If printing speed is increased and machine size is reduced, then productivity is improved, but image failure becomes prominent
Solution Approach 1:
The patent sets the bisphenol A derivative structural unit content at 10 mol% or less, which optimizes the toner's thermal and electrical properties for high-speed printing. This parameter control ensures stable charge characteristics and reduced heat generation even under increased printing speeds and in compact machine configurations.
Solution Approach 2:
The dual-polyester binder system (amorphous + crystalline) provides enhanced stability under high-speed printing conditions. The composite structure maintains consistent toner flow and charge properties, preventing image failure such as black spots that typically occur when printing speed increases or machine size is reduced.
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 configuration effectively reduces heat generation on the developing sleeve, preventing image defects like black spots while maintaining low-temperature fixing ability and heat resistance.
Implementation Method 1
the molecule is rigid and very difficult to move, and has a characteristic of inhibiting the meltability of the resin. Therefore, it is disadvantageous for low-temperature fixing, and there remains a concern in terms of environmental load.
Implementation Method 2
a developing sleeve having an aluminum alloy containing more than 0.6% by mass of silicon
Data Source
AI summary
An image forming system includes, an electrostatic charge image developing toner; and a developing sleeve configured to convey the electrostatic charge image developing toner, wherein a toner particle included in the electrostatic charge image developing toner contains an amorphous polyester, the amorphous polyester is a polycondensate of a polyvalent carboxylic acid and a polyhydric alcohol, a content percentage of a structural unit derived from a bisphenol A derivative in the amorphous polyester is 10 mol % or less with respect to all structural units derived from the polyhydric alcohol, and the developing sleeve includes an aluminum alloy including more than 0.6% by mass of silicon.