Conductive Roller Phase Difference Control for Image Defects
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Solution Overview
Problem
Conductive rollers used in image-forming apparatuses face issues with defective images due to current leakage caused by carbon black particle aggregation, leading to inconsistent image quality despite stable electrical resistance.
Innovation Solution
A conductive roller with a metallic core and a rubber elastic layer containing carbon black micropowder, where the phase difference ratio within a specific frequency range is maintained within a predetermined limit to ensure uniform dispersion and prevent conductive path formation, along with an inspection method to evaluate the roller's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon black is added to impart electrical conductivity, then electrical resistance variation is minimized, but carbon black particles aggregate causing current leakage and defective images
Solution Approach 1:
The patent changes the particle size parameter of carbon black from conventional larger sizes to micropowder size (1-10 μm), which fundamentally alters the dispersion characteristics and prevents aggregation while maintaining electrical conductivity. This parameter change resolves the contradiction by enabling consistent resistance without current leakage pathways.
Solution Approach 2:
The patent creates a composite material system combining carbon black micropowder with specific rubber matrices (epichlorohydrin rubber, nitrile rubber, or neoprene rubber). This composite approach optimizes both the conductive network formation and particle dispersion, preventing aggregation while achieving reliable electrical resistance characteristics.
2Measurement precision
If electrical resistance is used as the inspection criterion, then conductivity is verified, but image quality cannot be predicted
Solution Approach 1:
The patent introduces a feedback mechanism where image quality results are fed back into the inspection process. By correlating image quality outcomes with electrical resistance measurements under various conditions, the system refines the inspection criteria to predict image quality more accurately, transforming a simple resistance check into a predictive quality assurance system.
Solution Approach 2:
The patent transitions from a static resistance measurement to a dynamic inspection approach that evaluates resistance under multiple operating conditions (different temperatures, humidities, and voltages). This dynamic assessment captures the real-world performance variations and enables reliable image quality prediction.
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 ensures reliable and consistent performance of the conductive roller by preventing current leakage and maintaining image quality, reducing the occurrence of defects like black lines, and allowing for effective evaluation of carbon micropowder dispersion without relying on electrical resistance measurements.
Implementation Method 1
the rubber elastic layer being formed from a conductive rubber which has ion conductivity and which contains carbon black micropowder
Implementation Method 2
θmax represents the maximum value of phase difference θ as measured upon application of an AC voltage of 1.0 V within a frequency range of 100 mHz to 10 kHz
Data Source
AI summary
To provide a conductive roller which does not cause defective images with, for example, black lines, which would otherwise be caused by current leakage due to aggregation of carbon black particles or a similar phenomenon, and a method for inspecting the roller.The conductive roller having a metallic core and at least one rubber elastic layer provided on the outer peripheral surface of the core, the rubber elastic layer being formed from a conductive rubber which has ion conductivity and which contains carbon black micropowder, characterized in that said rubber elastic layer satisfies the relationship represented by the following formula:|θmax/θmin|≦5, [F1]wherein θmax represents the maximum value of phase difference θ as measured upon application of an AC voltage of 1.0 V within a frequency range of 100 mHz to 10 kHz, and θmin represents the minimum value of phase difference θ as measured under the same conditions.