Zinc Oxide Undercoat Layer for Residual Image Prevention
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Solution Overview
Problem
Conventional electrophotographic photoconductors suffer from residual image issues, particularly in full-color imaging, due to inadequate electrical stability and charge transport properties, especially when used for extended periods without charge-eliminating devices.
Innovation Solution
An electrophotographic photoconductor with an undercoat layer containing zinc oxide particles and a binder resin, having a volume resistivity of 0.03×10^6 Ω·cm or less, and a photosensitive layer with a specific charge transport material, which prevents residual image formation by canceling trapped positive charges and controlling ionization energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional photoconductors are used for extended periods without charge-eliminating devices, then cost reduction and device simplification are achieved, but residual image and background fouling occur due to deterioration of electrical properties
Solution Approach 1:
The patent modifies the chemical composition and physical parameters of the undercoat layer by incorporating specific metal oxide particles (zinc oxide, titanium oxide, tin oxide) with controlled particle sizes and concentrations. This changes the electrical properties of the undercoat layer to maintain stable charge transport and prevent residual image formation without requiring external charge-eliminating devices
Solution Approach 2:
The patent creates a composite undercoat layer by combining binder resin with metal oxide particles (zinc oxide, titanium oxide, tin oxide) in specific ratios. This composite structure provides both mechanical integrity and enhanced electrical stability, enabling the photoconductor to maintain performance over extended periods without charge-eliminating devices
2Reliability
If the undercoat layer is improved to enhance durability and stability, then electrical stability and charge transport function are improved, but manufacturing complexity and material cost increase
Solution Approach 1:
The patent applies the local quality principle by specifically modifying only the undercoat layer composition with metal oxide particles, while keeping other layers (photosensitive layer, protective layer) relatively simple. This localized improvement achieves enhanced electrical stability without requiring complex changes throughout the entire photoconductor structure
Solution Approach 2:
The patent optimizes parameters such as metal oxide particle size (0.1-10 μm), concentration (1-50 parts by mass relative to binder resin), and types of metal oxides to achieve the desired electrical stability. These parameter optimizations balance performance improvement with manufacturing feasibility
3Reliability
If zinc oxide particles are added to the undercoat layer to control volume resistivity, then charge transport function and prevention of residual image are improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise parameter ranges for zinc oxide particles including particle size (0.1-10 μm), concentration (1-50 parts by mass relative to binder resin), and volume resistivity (10^4-10^8 Ω·cm). These controlled parameters ensure optimal charge transport function while providing clear manufacturing guidelines to maintain precision
Solution Approach 2:
The patent focuses quality control efforts on the undercoat layer's volume resistivity as a key local property. By establishing specific resistivity ranges and using zinc oxide particles with controlled characteristics, the patent enables manufacturers to achieve consistent charge transport performance through targeted quality measures
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 effectively reduces residual image generation and maintains stable electrical properties over time, enhancing image quality and durability in long-term use.
Implementation Method 1
The undercoat layer contains zinc oxide particles and a binder resin and has a volume resistivity of 0.03×10^6 Ω·cm or less
Implementation Method 2
The undercoat layer contains zinc oxide particles and a binder resin and has a volume resistivity of 0.03×10^6 Ω·cm or less in an electrical field of 5 V/μm
Data Source
AI summary
An electrophotographic photoconductor is provided that includes a conductive substrate, an undercoat layer overlying the conductive substrate, and a photosensitive layer overlying the undercoat layer. The undercoat layer contains zinc oxide particles and a binder resin and has a volume resistivity of 0.03×106 Ω·cm or less in an electrical field of 5 V/μm at a temperature of 23 degrees C. and a relative humidity of 55%. The photosensitive layer contains a compound represented by the following general formula (1):where each of R1 to R3 independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms.