Toner Formulation for Low-Temperature Fixing and Hot Offset
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Solution Overview
Problem
Current toner technologies face challenges in achieving high gloss, low temperature fixability, and storage stability while maintaining hot offset resistance, particularly due to the conflicting requirements of melting point, molecular weight distribution, and the use of cross-linkable monomers which affect the toner's fluidity and surface smoothness.
Innovation Solution
A toner formulation with a polyester resin binder, a monoester wax releasing agent, and a tri- or higher metal salt, having a weight average molecular weight of 7,000 to 10,000, a molecular weight ratio of 5 or less, and an acid value of 6 to 12 mgKOH/g, which provides excellent gloss, low temperature fixability, and hot offset resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the melting point of toner is lowered to enable low temperature fixing, then low temperature fixability is improved, but storage stability deteriorates
Solution Approach 1:
The invention changes the molecular weight parameters of the binder resin (Mw: 7,000-10,000, Mw/Mn ratio: 5 or less) and controls acid value (6-12 mgKOH/g) to achieve low temperature fixability while maintaining storage stability. This parameter optimization allows the toner to melt at lower temperatures without compromising its stability during storage.
Solution Approach 2:
The invention uses a composite binder resin system combining polyester resin with specific molecular weight characteristics and acid value range, creating a material that exhibits both low temperature melting behavior and long-term storage stability. The composite nature of the resin system allows simultaneous achievement of conflicting properties.
2Object-affected harmful factors
If cross-linkable monomer is introduced to improve hot offset resistance, then hot offset resistance is improved, but fluidity deteriorates
Solution Approach 1:
The invention optimizes the molecular weight (Mw: 7,000-10,000) and molecular weight distribution (Mw/Mn ≤ 5) parameters of the binder resin to achieve a balance between fluidity and hot offset resistance. The controlled acid value (6-12 mgKOH/g) further modulates the resin's reactivity and flow characteristics, allowing good fluidity during fixing while maintaining adequate hot offset resistance without requiring cross-linkable monomers.
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 achieves high gloss comparable to photographs over a wide temperature range, excellent low temperature fixability, and good storage stability while maintaining hot offset resistance, addressing the limitations of existing toner formulations.
Implementation Method 1
the toner has a weight average molecular weight (Mw) of from 7,000 to 10,000, a ratio of the weight average molecular weight (Mw) to a number average molecular weight (Mn) of 5 or less, and an acid value of from 6 mgKOH/g to 12 mgKOH/g... excellent low temperature fixability
Implementation Method 2
the toner is required to have a better hot offset resistance... the toner achieves high gloss comparable to photographs over a wide temperature range, excellent low temperature fixability, and good storage stability
Implementation Method 3
To impart a good hot offset resistance to toner, a cross-linkable monomer is in general introduced into a resin to obtain a wide molecular weight distribution, thereby preventing occurrence of hot offset. However, if such a cross-linkable monomer is introduced, hot offset can be prevented but fluidity is not demonstrated because of elastic components.
Implementation Method 4
the releasing agent is a monoester wax... excellent low temperature fixability, and good storage stability while maintaining hot offset resistance
Data Source
AI summary
Toner contains a binder resin, a releasing agent, and a tri- or higher metal salt, wherein the toner has a weight average molecular weight (Mw) of from 7,000 to 10,000, a ratio of the weight average molecular weight (Mw) to a number average molecular weight (Mn) of 5 or less, and an acid value of from 6 mgKOH/g to 12 mgKOH/g, wherein the binder resin is a polyester resin, wherein the releasing agent is a monoester wax.