Photoreceptor Electrical Characteristics for Ghost Suppression
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Solution Overview
Problem
Conventional image formation apparatuses in electrophotographic processing often suffer from image defects known as ghosts due to insufficient charge elimination, especially with the reduction in size and speed improvements leading to reduced space between the transfer and charge units, making it difficult to uniformly set favorable conditions for preventing ghost occurrence.
Innovation Solution
The image formation apparatus includes a photoreceptor with specific electrical characteristics, where the ratio of post-exposure surface potential to charge potential values and the film thickness of the photosensitive layer are optimized within certain ranges to suppress ghost occurrence, specifically through the formulas 0.9≦(|V0(2)−VL|)/(|V0(1)−VL|)≦1.0 and 2.0≦|VL|/L≦3.5, ensuring effective charge elimination even under challenging conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the space between transfer and charge units is reduced to improve device compactness, then device size is reduced, but ghost occurrence increases due to insufficient charge elimination
Solution Approach 1:
The patent applies parameter changes by optimizing the electrical characteristics of the photoreceptor through specific formulas. The first formula 0.9≦(|V0(2)−VL|)/(|V0(1)−VL|)≦1.0 controls the ratio of potential differences to regulate charge distribution, while the second formula 2.0≦|VL|/L≦3.5 controls the absolute potential level relative to film thickness. These parameter adjustments enable effective charge elimination despite the reduced space between units.
Solution Approach 2:
The patent employs composite materials by formulating a photosensitive layer with specific composition and structure that satisfies the given electrical characteristic formulas. The composite nature of the photoreceptor material allows it to exhibit controlled electrical behavior that suppresses ghosts while maintaining compact device geometry.
2Productivity
If printing speed is increased to improve productivity, then output increases, but charge elimination becomes insufficient leading to ghost defects
Solution Approach 1:
The patent uses parameter changes by establishing specific relationships between electrical potentials and film thickness through the provided formulas. The parameter |VL|/L (absolute potential divided by film thickness) being controlled within 2.0-3.5 ensures that the photoreceptor maintains appropriate charge elimination characteristics even at higher printing speeds where residence time is reduced.
3Object-affected harmful factors
If the photoreceptor electrical characteristics are optimized to suppress ghosts, then ghost occurrence decreases, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for electrical characteristics that balance ghost suppression with manufacturability. The ratios and absolute values specified in the formulas provide clear targets for manufacturing while achieving the desired suppression of ghost defects.
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 approach effectively suppresses ghost occurrence across various environmental conditions and maintains favorable printing quality over time, even when charge elimination is insufficient, by ensuring the correct balance of electrical characteristics and charge retention in the photosensitive layer.
Implementation Method 1
evenly charging, by a charge unit, the surface of a photoreceptor as an image carrier
Implementation Method 2
exposing the surface of the photoreceptor charged in the charge step to light by an exposure unit to form an electrostatic latent image
Implementation Method 3
developing, by a development unit, the electrostatic latent image formed in the exposure step to form a developer image
Implementation Method 4
transferring the developer image formed in the development step, to a predetermined printing medium by a transfer unit
Data Source
AI summary
An image formation apparatus includes a photoreceptor, a charge unit, an exposure unit, a development unit, and a transfer unit. The photoreceptor satisfies the following formulas.0.9≦(|V0(2)−VL|)/(|V0(1)−VL|)≦1.02.0≦|VL|/L≦3.5VL denotes a post-exposure surface potential value [V] of a surface portion of the photoreceptor exposed by the exposure unit in a first image formation cycle; V0(2) denotes a charge potential value [V] in a second image formation cycle of a surface portion of the photoreceptor exposed by the exposure unit in the first image formation cycle; V0(1) denotes a charge potential value [V] in a second image formation cycle of a surface portion of the photoreceptor not exposed by the exposure unit in the first image formation cycle; and L denotes a film thickness [μm] of the photosensitive layer.