Electrophotographic Photoconductor Intermediate Layer with Dual Surface-Treated Titanium Oxide
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Solution Overview
Problem
Electrophotographic photoconductors face challenges in maintaining electrical stability while reducing image defects like black spots and fogging, as conventional techniques either improve electrical stability at the expense of image quality or vice versa, leading to a trade-off between the two.
Innovation Solution
An electrophotographic photoconductor with an intermediate layer comprising first and second titanium oxide particles surface-treated with different reactive organic silicon compounds, such as methyl hydrogen polysiloxane and alkoxy silanes, is used to enhance electron transport and block positive holes, thereby improving electrical stability and reducing image defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electron transport property of the intermediate layer is increased, then electrical stability is improved, but positive-hole blocking property deteriorates
Solution Approach 1:
The intermediate layer is divided into multiple layers with different compositions and functions. The first intermediate layer (closer to the photosensitive layer) uses metal oxide particles with electron affinity to block positive holes, while the second intermediate layer (closer to the support) uses metal oxide particles with high electron mobility to transport electrons. This local differentiation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
The intermediate layer is constructed as a composite structure combining different metal oxide particles (such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, or tin oxide) with distinct electronic properties. This composite approach enables simultaneous achievement of positive-hole blocking and electron transport functions within the same intermediate layer system.
2Stability of the object's composition
If conventional surface treatment methods are used on titanium oxide particles, then dispersibility is improved, but electrical stability and image defect suppression are insufficient
Solution Approach 1:
The patent changes the key parameter of surface treatment by using reactive organic silicon compounds that form covalent bonds with metal oxide particles. This chemical bonding approach fundamentally alters the surface properties compared to conventional physical adsorption methods, resulting in enhanced electrical stability and superior suppression of image defects like black spots and fogging.
Solution Approach 2:
The intermediate layer uses composite metal oxide particles with specific surface treatments. The metal oxide particles are surface-treated with reactive organic silicon compounds to create a composite structure that combines the electrical stability of metal oxides with the dispersibility and surface activity of organically modified surfaces.
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 proposed solution effectively suppresses image defects like black spots and fogging while maintaining long-term electrical stability, enhancing image quality by optimizing the electron transport and positive-hole blocking properties of the intermediate layer.
Implementation Method 1
When the surface is negatively charged and thereafter exposed to light, the charge generation layer generates charges, of which negative charges (electrons) move to the electrically conductive support through the intermediate layer, whereas positive charges (positive holes) move to the surface of the electrophotographic photoconductor through the charge transport layer to cancel negative charges on the surface thereof, thereby forming an electrostatic latent image.
Implementation Method 2
it is desired that the intermediate layer has electron transport property (to allow electrons generated in the charge generation layer to rapidly move to the electrically conductive support) and positive-hole blocking property (to suppress the injection of positive holes from the electrically conductive support to the photosensitive layer)
Implementation Method 3
positive-hole blocking property (to suppress the injection of positive holes from the electrically conductive support to the photosensitive layer)
Data Source
AI summary
The present invention provides an electrophotographic photoconductor including an electrically conductive substrate, an intermediate layer, and a photosensitive layer that are formed on the electrically conductive support, the intermediate layer including first titanium oxide particles surface-treated with a first reactive organic silicon compound, second titanium oxide particles surface-treated with a second reactive organic silicon compound different from the first reactive organic silicon compound, and a binder resin. The first reactive organic silicon compound is methyl hydrogen polysiloxane. The second reactive organic silicon compound is a compound represented by the following general formula (1):R—Si—(X)3 (1)R represents a alkyl group having 1 to 10 carbon atoms substituted by at least one of acryloxy and methacryloxy groups or unsubstituted; and X represents an alkoxy group having 1 to 4 carbon atoms or a halogen atom.