Charging Roll with Optimized Dielectric Layer for Low Discharge
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Solution Overview
Problem
Charging rolls in electrophotographic apparatuses face a challenge in achieving sufficient charging without generating harmful substances like ozone and NOx, which can lead to environmental and image deterioration.
Innovation Solution
A charging roll configuration with a specific composition of non-polar and polar rubbers, carbon black, fluororesin, and (meth)acrylic resin, optimized for relative permittivity and resistance values, reduces discharge amount while ensuring effective charge transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the discharge amount is increased to sufficiently charge the photoreceptor, then the charging property is improved, but harmful substances such as ozone and NOx are generated in large amounts leading to environmental deterioration and image deterioration
Solution Approach 1:
The patent changes the physical and chemical parameters of the elastic body layer by controlling the relative permittivity (7 or more and 29 or less) and resistance value (6.0 × 10^4 Ω or more and 6.0 × 10^6 Ω or less). These parameter changes enable the charging roll to achieve sufficient charging property while suppressing harmful substance generation, as the optimized parameters allow for reduced discharge amounts to achieve the same charging effect.
Solution Approach 2:
The patent uses composite materials in the elastic body layer comprising non-polar rubber and polar rubber with specific proportions. This composite structure allows the material to exhibit both high relative permittivity for effective charge transfer and appropriate resistance to control discharge, thereby achieving good charging property with reduced harmful emissions.
2Object-generated harmful factors
If the discharge amount is reduced to suppress harmful substances generation, then environmental and image deterioration are prevented, but the charge amount becomes insufficient leading to image deterioration
Solution Approach 1:
The patent optimizes the resistance value parameter of the elastic body layer to be within 6.0 × 10^4 Ω to 6.0 × 10^6 Ω. This parameter adjustment allows the system to maintain sufficient charge amount even with reduced discharge, as the optimized resistance enables more efficient charge transfer at lower discharge levels, preventing both harmful emissions and insufficient charging.
Solution Approach 2:
The patent adjusts the relative permittivity parameter of the elastic body layer to be between 7 and 29. This parameter change enhances the material's ability to store and transfer electrical charge, allowing the charging roll to achieve sufficient charge amounts with smaller discharge amounts, thus preventing image deterioration while suppressing harmful substance generation.
3Ease of manufacture
If a conventional charging roll configuration is used, then the structure is simple and easy to manufacture, but the charging property is insufficient and harmful substances are generated
Solution Approach 1:
The patent specifies precise parameter ranges for the elastic body layer (relative permittivity: 7-29, resistance value: 6.0 × 10^4 to 6.0 × 10^6 Ω) that can be achieved through material composition adjustments rather than complex structural changes. This approach maintains manufacturing simplicity while dramatically improving charging property, as the parameters can be controlled through rubber compound formulation and processing conditions.
Solution Approach 2:
The patent employs composite materials (non-polar rubber and polar rubber in specific proportions) that can be integrated into conventional charging roll manufacturing processes. This composite approach improves charging property without requiring fundamentally new manufacturing methods, as the composite rubber can be processed using standard vulcanization and molding techniques.
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 optimized composition suppresses harmful substance generation and ensures uniform charge movement, maintaining excellent charging properties with reduced discharge, thus improving environmental and image quality.
Implementation Method 1
a charging system that charges the photoreceptor by discharge from the charging roll to the photoreceptor
Implementation Method 2
the elastic body layer contains a non-polar rubber, a polar rubber, and a carbon black and has a relative permittivity of 7 or more and 29 or less and a resistance value of 6.0 × 10^4 or more and 6.0 × 10^6 or less
Data Source
Figure 1(a)~1(b)
AI summary
Provided is a charging roll for electrophotographic apparatuses, which has excellent electrification properties even with a small electric discharge amount. A charging roll 10 for electrophotographic apparatuses comprises: a shaft body 12; an elastic body layer 14 formed on the outer circumferential surface of the shaft body 12; and a surface layer 16 formed on the outer circumferential surface of the elastic body layer 14. The elastic body layer 14 contains a non-polar rubber, a polar rubber, and carbon black, and has a relative dielectric constant of 7-29 and a resistance value of 6.0×104-5.0×106 Ω. The surface layer 16 contains a fluorine resin and a (meth)acrylic resin, and has a relative dielectric constant of 10-22 and a resistance value of 1.2×104-8.8×105 Ω.