Undercoat Layer Impedance Control for Photoreceptor Discharge
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Solution Overview
Problem
Electrophotographic photoreceptors using organic photoconductive materials suffer from streak-like image quality defects due to abnormal discharge caused by charge movement between the contact type charging device and the photoreceptor, leading to uneven charging and decreased image quality density.
Innovation Solution
Incorporating a conductive substrate with an undercoat layer containing metal oxide particles, where the angular frequency ωmax of the complex impedance component falls within 2 (rad)≦ωmax≦10 (rad), as determined by Cole-Cole plot analysis, to control charge movement and prevent abnormal discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a contact type charging device is used to charge the photoreceptor, then charging efficiency is improved, but abnormal discharge occurs causing streak-like image quality defects
Solution Approach 1:
The patent introduces an undercoat layer as an intermediary between the conductive substrate and the photosensitive layer. This undercoat layer acts as a mediator that prevents direct charge movement between the charging device and the photosensitive layer, thereby eliminating abnormal discharge while maintaining efficient charging. The undercoat layer has specific electrical properties (controlled by metal oxide particle content and Cole-Cole plot parameters) that enable it to fulfill this mediating function.
Solution Approach 2:
The patent applies parameter changes by controlling the electrical characteristics of the undercoat layer through precise adjustment of metal oxide particle content and formulation. By optimizing parameters such as the angular frequency ωmax (within 2≤ωmax≤10 rad) obtained from Cole-Cole plot analysis, the undercoat layer achieves optimal charge blocking performance that prevents abnormal discharge while maintaining charging efficiency.
2Speed
If charge movement is allowed between the charging device and photoreceptor, then charging speed is improved, but uneven charging occurs leading to streak-like defects
Solution Approach 1:
The undercoat layer serves as a mediator that regulates charge movement. It allows sufficient charge transfer for fast charging while preventing the abnormal, uneven charge movement that causes streaks. The layer's specific electrical properties (controlled by metal oxide particle formulation and Cole-Cole plot parameters) enable it to maintain charging speed while ensuring uniform charge distribution across the photoreceptor surface.
3Reliability
If metal oxide particles are added to the undercoat layer, then abnormal discharge is prevented, but device complexity increases
Solution Approach 1:
The patent manages formulation complexity by establishing specific parameter ranges for the undercoat layer. By controlling the metal oxide particle content and adjusting formulation parameters to achieve the Cole-Cole plot characteristic (ωmax within 2≤ωmax≤10 rad), the patent simplifies the development process. These parameter specifications provide clear guidelines for manufacturing while ensuring abnormal discharge prevention.
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
This configuration effectively prevents streak-like image quality defects and maintains image quality density, ensuring consistent performance even during prolonged use of the image forming apparatus.
Implementation Method 1
at the time of performing Cole-Cole plot analysis with respect to the undercoat layer, an angular frequency ωmax, at which a maximum complex impedance component is obtained, falls within a range of 2 (rad)≦ωmax≦10 (rad)
Data Source
AI summary
An electrophotographic photoreceptor includes a conductive substrate, an undercoat layer provided on the conductive substrate and including metal oxide particles, and a photosensitive layer provided on the undercoat layer,wherein, at the time of performing Cole-Cole plot analysis with respect to the undercoat layer, an angular frequency ωmax, at which a maximum complex impedance component is obtained, falls within a range of 2 (rad)≦ωmax≦10 (rad).