Conductive Charging Roller Roughness for Photoreceptor Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing electrophotographic image forming apparatuses with positively-charged single layer type photoreceptors face issues of uneven charging, carrier trapping, and film peeling due to local discharge from the charging roller, which reduces the charging ability and lifespan of the photoreceptor.
Innovation Solution
An image forming apparatus with a contact charging member made of electrically conductive rubber having an Asker-C rubber hardness of 62 to 81° and specific surface roughness, which prevents uneven charging and carrier trapping by enlarging proximity discharge regions, thereby stabilizing the photoreceptor's surface potential and preventing film peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the discharge voltage is increased to prevent local discharge and uneven charging, then the charging ability is improved, but the film of the photoreceptor peels off, reducing its life-span
Solution Approach 1:
The invention changes the surface roughness parameter of the charging roller to a specific range (Ra: 5-20 μm, Rz: 10-30 μm) to optimize the discharge characteristics. This parameter modification allows electricity to be discharged uniformly from the charging roller surface without requiring increased discharge voltage, thereby preventing both uneven charging and film peeling while maintaining reliable charging ability.
2Manufacturing precision
If the discharge voltage is increased to prevent uneven charging, then the charging uniformity is improved, but the amount of electric discharge increases, causing film peeling
Solution Approach 1:
The invention modifies the surface roughness parameters of the charging roller (Ra: 5-20 μm, Rz: 10-30 μm) to control the discharge distribution. This parameter change enables uniform charging across the photoreceptor surface by optimizing the contact interface, eliminating the need to increase discharge voltage and thereby preventing film material loss.
3Ease of manufacture
If a single layer type photoreceptor is used to simplify the structure and reduce cost, then the ease of manufacture is improved, but carrier trapping occurs, reducing charging ability
Solution Approach 1:
The invention changes the surface roughness parameter of the charging roller to a specific range (Ra: 5-20 μm, Rz: 10-30 μm) to optimize the discharge characteristics. This parameter modification allows electricity to be discharged uniformly from the charging roller surface without requiring increased discharge voltage, thereby preventing both uneven charging and film peeling while maintaining reliable charging ability.
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 prevents uneven charging and film peeling, enhancing the charging performance and lifespan of the photoreceptor, while reducing ozone generation, making it environmentally responsive and industrially applicable.
Implementation Method 1
a contact charging member for charging a surface of the photoreceptor... which is made of electrically conductive rubber... enlarging proximity discharge regions
Data Source
AI summary
An image forming apparatus includes a positively-charged single layer type electrophotographic photoreceptor, a charging device with a contact charging roller for charging a surface of the photoreceptor and an exposure device for exposing the charged surface of the photoreceptor to light to form an electrostatic latent image thereon. A developing device develops the electrostatic latent image into a toner image and a transfer device transfers the toner image to a transferred body. The charging roller is made of electrically conductive rubber having an Asker-C rubber hardness of 62 to 81°. A roller surface roughness of the charging roller has an average distance (Sm) between asperity peaks on a cross-sectional curve of 55 to 130 μm and that a ten-point average roughness (Rz) is 9 to 19 μm. The image forming apparatus is capable of preventing carrier trapping, film peeling and uneven charging in the photoreceptor.