Electrophotographic Photoreceptor Protective Layer with Ultrafine Titanium Dioxide
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrophotographic photoreceptors face issues with uneven coated layers, reduced mechanical strength, and productivity due to insufficient dispersibility of metal oxides, leading to electrical resistivity and light scattering problems.
Innovation Solution
Incorporating a protective layer with a combination of rutile and anatase type titanium dioxide, along with a curing compound and polymerization initiator, to improve dispersibility and electrical resistivity control, while maintaining mechanical strength and preventing sedimentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of metal oxide is added to the coating solution to control electrical resistivity, then electrical resistivity is improved, but unevenness of the coated layer is generated
Solution Approach 1:
The patent changes the physical and chemical parameters of the metal oxide particles, specifically using ultrafine particles with a number average primary particle diameter of 1-100 nm. This parameter change allows achieving the desired electrical resistivity (1×10^9-1×10^15 Ω·cm) while maintaining coated layer uniformity, as the ultrafine particles disperse more evenly in the coating solution compared to conventional larger particles.
Solution Approach 2:
The patent creates a composite material system combining ultrafine metal oxide particles with a specific binder resin and solvent formulation. This composite approach enables simultaneous control of electrical resistivity and coated layer uniformity by optimizing the interaction between the ultrafine particles and the binding matrix, preventing particle aggregation that would cause unevenness.
2Manufacturing precision
If the addition amount of metal oxide is reduced to improve dispersibility, then coated layer uniformity is improved, but mechanical strength of the protective layer is lowered
Solution Approach 1:
The patent changes the particle size parameter to ultrafine (1-100 nm) which fundamentally alters how the metal oxide contributes to mechanical strength. At this scale, particles can reinforce the matrix more effectively without requiring high concentrations, thus maintaining both uniformity and strength simultaneously.
Solution Approach 2:
The patent replaces the conventional mechanism where metal oxide particles provide strength through their bulk mechanical properties with a different mechanism where ultrafine particles provide strength through their high surface area to volume ratio and effective bonding to the resin matrix. This substitution allows lower overall metal oxide content while maintaining or improving mechanical strength.
3Reliability
If metal oxide is added to control electrical resistivity, then electrical resistivity is improved, but productivity is reduced due to sedimentation of metal oxide
Solution Approach 1:
The patent changes the particle size parameter to ultrafine (1-100 nm) which fundamentally improves suspension stability. Ultrafine particles have higher Brownian motion and lower settling velocity according to Stokes' law, preventing sedimentation even at the concentrations needed for electrical resistivity control. This ensures long-term stability of the coating solution and high productivity.
4Reliability
If metal oxide is added to control electrical resistivity, then electrical resistivity is improved, but light scattering is caused by dispersed particles
Solution Approach 1:
The patent changes the particle size parameter to ultrafine (1-100 nm) which is smaller than the wavelength of visible light. According to Rayleigh scattering theory, scattering intensity is proportional to the sixth power of particle size, so ultrafine particles cause negligible light scattering compared to conventional particles. This allows electrical resistivity control without compromising optical performance.
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 solution results in a photoreceptor with high wear resistance, efficient toner transfer, and improved productivity by ensuring even electrical resistivity and mechanical strength, eliminating defects and light scattering.
Implementation Method 1
a protective layer which is formed by a crosslinking reaction, and has high wear resistance
Implementation Method 2
The electrical resistivity of this protective layer in which metal oxide is dispersed is tried to be controlled
Implementation Method 3
a coating solution into which a large amount of metal oxide is added was coated
Data Source
AI summary
An objective is to provide an electrophotographic photoreceptor having a protective layer in which no unevenness is generated in a coated layer even though a coating solution containing a large addition amount of metal oxide is coated, mechanical strength of a protective layer is high; productivity is high with long life of the coating solution because of no sedimentation of metal oxide, electrical resistivity and mechanical strength are satisfactory, and metal oxide generating no coated layer defect together with no light scattering caused by dispersion failure is dispersed, and also to provide an image forming method and an image forming apparatus employing the electrophotographic photoreceptor. Also disclosed is an electrophotographic photoreceptor possessing a conductive support, at least a photosensitive layer and a protective layer, wherein the protective layer comprises rutile type titanium dioxide and anatase type titanium dioxide.