Toner Release Agent Recrystallization for Folding and Stacking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electrophotographic processes, toner images with release agents can crack upon folding due to large release agent domains, and stacking occurs when recording media are not cooled sufficiently, leading to adhesion issues and image degradation.
Innovation Solution
A toner formulation with toner particles containing a binder resin and a release agent, where the ratio of the half-width of the exothermic peak to the endothermic peak, determined by differential scanning calorimetry, is between 1.5 and 4, enhancing the dispersion and recrystallization of release agent domains, thereby improving folding resistance and reducing stacking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a release agent is included in the toner to prevent stacking, then stacking resistance is improved, but the release agent crystallizes and forms large domains that cause cracking when the toner image is folded
Solution Approach 1:
The patent changes the physical and chemical parameters of the release agent by controlling its molecular weight distribution (Mw/Mn ratio of 2.0 or more) and selecting specific types (polyethylene wax, polypropylene wax, Fischer-Tropsch wax, or mixtures). This parameter optimization allows the release agent to maintain small domain sizes that prevent cracking while still providing adequate stacking resistance through controlled recrystallization behavior.
Solution Approach 2:
The patent uses composite material strategies by combining multiple wax types or mixing different release agents with specific molecular weight distributions. This composite approach creates a synergistic effect where the release agent provides both sufficient stacking resistance and maintains small domain sizes to prevent folding cracks, resolving the contradiction between the two opposing requirements.
2Productivity
If the recording media are stacked immediately after fixing without sufficient cooling, then productivity is improved by continuous processing, but the binder resin remains softened causing the recording media to bond together (stacking)
Solution Approach 1:
The release agent acts as an intermediary substance between the toner image and the recording medium. During stacking, the release agent recrystallizes and forms a barrier that prevents direct contact and bonding between the binder resin of adjacent toner images, enabling high-speed continuous processing without stacking defects.
Solution Approach 2:
The patent exploits the phase transition behavior of the release agent, which recrystallizes from liquid to solid state during the cooling process. This phase transition occurs at controlled temperatures and rates, creating a protective crystalline structure that prevents stacking while allowing rapid processing. The specific molecular weight distribution ensures optimal recrystallization timing and morphology.
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 formulation achieves high folding resistance and reduces stacking by ensuring uniform dispersion and recrystallization of release agent domains, maintaining image quality and integrity.
Implementation Method 1
the release agent may crystallize and form domains in the toner image
Implementation Method 2
determined in a first cooling step by differential scanning calorimetry
Data Source
AI summary
A toner for developing an electrostatic image includes toner particles that each include a binder resin and a release agent. The ratio B/A of a half-width B of an exothermic peak Tc resulting from the release agent which is determined in a first cooling step by differential scanning calorimetry to a half-width A of an endothermic peak Tm resulting from the release agent which is determined in a first heating step prior to the first cooling step by differential scanning calorimetry is 1.5 or more and 4 or less.