Toner Composition for Fixing, Bleed Resistance, and Stable Charge
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Solution Overview
Problem
Conventional toners face issues with release agent bleeding in high-temperature and high-humidity environments, leading to print failures such as fogging, and charge fluctuations due to mechanical stress in large toner cartridges, affecting printing quality and efficiency.
Innovation Solution
A toner formulation using two kinds of positively-chargeable charge control resins with specific functional group amounts and a polar resin with controlled acid value, combined with a fatty acid ester release agent, to suppress release agent bleeding and maintain stable charge levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a release agent is added to improve low temperature fixability, then the toner can be fixed at lower temperatures, but the release agent bleeds out in high-temperature and high-humidity environments causing print failures
Solution Approach 1:
The patent changes the molecular weight parameter of the release agent to 500-2000 (optimizing it below the conventional 2000), and adjusts the content ratio to 2-20 parts by mass per 100 parts by mass of binder resin. These parameter optimizations enable the release agent to function effectively at low temperatures while reducing its tendency to bleed in high-temperature environments.
Solution Approach 2:
The patent uses a composite formulation combining the optimized release agent (fatty acid ester with Mn=500-2000) with specific binder resins and colorants. This composite material approach creates a balanced system where the release agent provides low-temperature fixability while the overall composition prevents excessive bleeding in high-temperature storage conditions.
2Ease of operation
If the release agent content is increased to improve releasability, then low temperature fixability is enhanced, but the bleeding of release agent increases causing fogging
Solution Approach 1:
The patent optimizes the release agent content parameter to a specific range of 2-20 parts by mass per 100 parts by mass of binder resin, and controls the molecular weight to 500-2000. This parameter optimization achieves the right balance where sufficient release agent is present to provide good releasability, but not so much that it causes excessive bleeding and fogging.
3Loss of time
If conventional toner is stored in high-temperature and high-humidity environment, then the release agent transfers to toner surface faster, but print failures occur due to bleeding
Solution Approach 1:
The patent changes the molecular weight parameter of the release agent to a lower range (500-2000) compared to conventional toners, and optimizes the content ratio. This parameter change reduces the mobility and volatility of the release agent, thereby suppressing its transfer to the toner surface during high-temperature and high-humidity storage, and preventing print failures.
4Productivity
If large amount of toner is filled in cartridge for continuous printing, then productivity is improved, but charge amount decreases due to mechanical stress
Solution Approach 1:
The patent uses a composite material formulation with optimized release agent (Mn=500-2000) and binder resin combination that provides mechanical stability. This composite structure maintains the charge control properties even when large amounts of toner are subjected to mechanical stress during continuous printing operations.
Solution Approach 2:
The patent optimizes the molecular weight parameter of the release agent to 500-2000, which provides the right balance between flexibility and structural integrity. This parameter optimization ensures that the toner particles maintain their charge properties even under the mechanical stress of continuous printing with large toner volumes.
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 effectively prevents release agent bleeding and print failures in high-temperature and high-humidity conditions, maintains consistent charge levels, and supports continuous printing in both low- and high-humidity environments, ensuring high-quality image output.
Implementation Method 1
a toner formulation using two kinds of positively-chargeable charge control resins with specific functional group amounts and a polar resin with controlled acid value, combined with a fatty acid ester release agent, to suppress release agent bleeding and maintain stable charge levels
Implementation Method 2
The release agent improves the releasability of the toner from a fixing roller, it is effective in improving the low temperature fixability of the toner
Data Source
AI summary
To provide a toner having the following properties: the release agent is less likely to bleed out even in a high-temperature and high-humidity environment; a print failure is less likely to occur even when the toner is used after long-time storage in a high-temperature and high-humidity environment; in both a low-temperature and low-humidity environment and a high-temperature and high-humidity environment, continuous printing can be carried out while suppressing a print failure; and a fluctuation in the charge amount of the toner, which is involved in temperature and humidity changes, is suppressed. A toner comprising colored resin particles, which contain a binder resin, a colorant, a positively-chargeable charge control resin and a release agent, and an external additive, wherein the positively-chargeable charge control resin comprises a copolymer A, which contains a functional group-containing monomer unit in an amount of 1.50% by mass or more and 6.00% by mass or less, and a copolymer B, which contains a functional group-containing monomer unit in an amount of 0.10% by mass or more and less than 1.50% by mass, and wherein the colored resin particles further contain a polar resin having an acid value of 0.5 mgKOH/g or more and 8.0 mgKOH/g or less.