Cleaning Roller Compression Ratio for Charging Device Streaks
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Solution Overview
Problem
Charging devices with foamed elastic layers in image forming apparatuses often cause streak-like image defects due to contamination and compression set, leading to reduced cleaning performance and shorter device life.
Innovation Solution
A charging device configuration with a cleaning roller having 25-50 ends/mm2 of cell skeleton protrusions and a compression ratio of 30% or less, ensuring effective cleaning while minimizing lateral streaks by controlling the foamed elastic layer's compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compression ratio of the foamed elastic layer is increased to improve cleaning contact, then cleaning performance is improved, but lateral streak-like image defects increase due to compression set
Solution Approach 1:
The patent optimizes the compression ratio parameter to be 30% or less, balancing cleaning effectiveness with prevention of compression set. This parameter optimization resolves the contradiction by finding the optimal operating point that achieves sufficient cleaning contact while avoiding excessive compression that causes lateral streaks.
2Reliability
If the number of ends of cell skeleton protruding from the surface is increased to improve cleaning effectiveness, then cleaning performance is improved, but the foamed elastic layer becomes more prone to compression set
Solution Approach 1:
The patent specifies that the number of ends of cell skeleton protruding from the surface should be 25 ends/mm² or more and 50 ends/mm² or less. This parameter range optimization balances cleaning effectiveness with structural stability, preventing excessive compression set while maintaining adequate cleaning performance.
3Object-generated harmful factors
If the compression ratio is kept low to prevent lateral streaks, then lateral streak-like image defects are reduced, but cleaning contact effectiveness decreases
Solution Approach 1:
The patent establishes the compression ratio at 30% or less as the optimal parameter setting. This value represents the boundary condition that prevents lateral streak formation while maintaining sufficient cleaning contact effectiveness, resolving the contradiction between defect prevention and cleaning performance.
4Reliability
If the foamed elastic layer is highly compressed to ensure cleaning contact, then cleaning performance is improved, but the device life is reduced due to compression set
Solution Approach 1:
The patent optimizes the compression ratio parameter to 30% or less, which prevents excessive compression set that would degrade the foamed elastic layer over time. This parameter control ensures both adequate cleaning performance and extended device life by avoiding conditions that accelerate material degradation.
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 configuration improves cleaning performance, reduces longitudinal and lateral streak-like image defects, and extends the life of the charging device by maintaining the foamed elastic layer's integrity.
Implementation Method 1
a cleaning roller that includes a core and a foamed elastic layer disposed on an outer circumferential surface of the core and that rotates in contact with a surface of the charging roller
Data Source
AI summary
A charging device includes a charging roller and a cleaning roller that includes a core and a foamed elastic layer disposed on an outer circumferential surface of the core and that rotates in contact with a surface of the charging roller. The number of ends of a cell skeleton that protrude from a surface of the foamed elastic layer is 25 ends/mm2 or more and 50 ends/mm2 or less. The cleaning roller is disposed in contact with the charging roller such that the compression ratio of the foamed elastic layer is 30% or less. The compression ratio is represented by Equation (1):compression ratio (%)=(r1/2+r2/2−d)/t1×100 Equation (1):where r1 is the outer diameter (mm) of the cleaning roller, r2 is the outer diameter (mm) of the charging roller, d is the interaxial distance (mm) between the charging roller and the cleaning roller, and t1 is the thickness (mm) of the foamed elastic layer of the cleaning roller.