Electrophotography Coating Liquid Chelate Titanium Crosslinking
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Solution Overview
Problem
The coating liquid used in electrophotography tends to react with moisture, leading to clouding or precipitation, resulting in uneven coating and non-uniform relative dielectric constants, which affects the charging performance of electrophotographic photosensitive members.
Innovation Solution
A method involving the hydrolysis and condensation of hydrolyzable silane and chelate titanium compounds, followed by crosslinking with an epoxy group, to form a polysiloxane surface layer that suppresses clouding and precipitation, ensuring a uniform and high-quality electrophotographic image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of hydrolyzable titanium compound is increased to increase the relative dielectric constant of the surface layer, then the charging performance is improved, but the coating liquid is liable to cloud or cause precipitate
Solution Approach 1:
The patent introduces a chelating agent as an intermediary substance that binds to the hydrolyzable titanium compound, preventing its direct reaction with water while allowing controlled hydrolysis. This mediator enables the use of higher titanium compound amounts (improving dielectric constant and charging performance) without causing uncontrolled clouding or precipitation that would ruin coating uniformity.
Solution Approach 2:
The patent changes the chemical state and reactivity parameters of the titanium compound by forming chelate complexes. This parameter change allows the system to tolerate higher concentrations of titanium compounds while maintaining coating liquid stability, thus resolving the contradiction between achieving high dielectric constant and preventing precipitation.
2Reliability
If the coating liquid is used to form a surface layer with high relative dielectric constant, then the charging performance is improved, but the coating is liable to cause seediness or thickness unevenness
Solution Approach 1:
The chelating agent serves as a mediator that controls the hydrolysis rate of titanium compounds during coating application. By regulating the reaction kinetics, it prevents rapid precipitation that would cause seediness and thickness unevenness, while still allowing sufficient titanium compound content to achieve the desired high dielectric constant for improved charging performance.
Solution Approach 2:
The patent performs preliminary complexation between the chelating agent and titanium compound before coating application. This preliminary action pre-stabilizes the titanium compound, preventing unwanted side reactions during the coating process and ensuring uniform surface layer formation with consistent thickness and properties.
3Reliability
If the coating liquid contains hydrolyzable titanium compound, then the relative dielectric constant is increased, but the coating liquid is liable to react with moisture and cloud
Solution Approach 1:
The chelating agent acts as a protective intermediary that shields the hydrolyzable titanium compound from uncontrolled reaction with moisture in the coating liquid. This intermediary relationship maintains the coating liquid's compositional stability while preserving the titanium compound's ability to provide high dielectric constant when properly activated.
Solution Approach 2:
The chelate complex creates a chemically inert environment around the titanium compound, protecting it from premature hydrolysis and maintaining coating liquid stability during storage and application, while still allowing the desired dielectric properties to be achieved.
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 method produces a coating liquid that prevents clouding and precipitation, resulting in a polysiloxane film with a high dielectric constant, providing excellent charging performance and enabling the production of high-quality electrophotographic images.
Implementation Method 1
a step of hydrolyzing and condensing a hydrolyzable silane compound represented by the following general formula (1) and a chelate titanium compound represented by the following general formula (2)
Implementation Method 2
a second step of crosslinking the hydrolyzed condensate in the coat through cleavage of an epoxy group in the hydrolyzed condensate to form the surface layer
Data Source
Figure 1~2
Figure 3
AI summary
Provided is a method of producing a member for electrophotography capable of providing a high-quality electrophotographic image. The method of producing a member for electrophotography is a method of producing a member for electrophotography having an electro-conductive support, an elastic layer, and a surface layer, the method comprising: a first step of forming, on a surface of the elastic layer, a coat of a surface-layer coating liquid containing a hydrolyzed condensate of a hydrolyzable silane compound and a chelate titanium compound represented by the following general formula (2); and a second step of crosslinking the hydrolyzed condensate in the coat through cleavage of an epoxy group in the hydrolyzed condensate to form the surface layer: