Transfer Member Resistance Measurement Using Photoconductor Capacitance
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Solution Overview
Problem
The electrical resistance value of transfer members in electrophotographic image forming apparatuses increases with the number of pages printed, reducing their capability to transfer toner images and affecting image quality, as existing methods inaccurately calculate resistance values without considering the capacitance of the photoconductor drum.
Innovation Solution
The apparatus includes acquisition processing portions to determine the electrical resistance value of transfer members based on the state of the surface layer, charging current, and applied voltage, using equations derived from equivalent circuits to accurately calculate resistance values without requiring special power sources or surface potential sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electrical resistance value is calculated based on voltage and current only, then the calculation is simple, but the measurement precision is insufficient due to not considering capacitance effects
Solution Approach 1:
The patent replaces complex hardware measurement systems with a computational approach. Instead of using additional sensors or complex measurement circuits to account for capacitance, the invention uses mathematical modeling and calculation based on equivalent circuits to determine resistance values accurately, thereby avoiding increased device complexity while improving measurement precision
Solution Approach 2:
The patent changes the parameters used in resistance calculation from simple voltage-current relationships to a more comprehensive model that includes capacitance effects. By incorporating the state of charge and capacitance parameters into the calculation, the system achieves higher measurement precision without requiring additional physical measurement devices
2Measurement precision
If special power sources or surface potential sensors are used to measure resistance accurately, then the measurement precision improves, but the device complexity and cost increase
Solution Approach 1:
The patent substitutes specialized measurement hardware (surface potential sensors, special power sources) with a computational method based on equivalent circuit analysis. This approach maintains high measurement precision while significantly simplifying the manufacturing process, as it requires only standard voltage and current measurement capabilities already present in typical image forming apparatus
Solution Approach 2:
The system uses its own existing operational parameters (voltage and current during normal operation) to calculate resistance values. Instead of requiring external specialized measurement equipment, the apparatus leverages its own operational data and built-in measurement capabilities to perform accurate resistance assessment, making the system self-sufficient and easier to manufacture
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 method allows for accurate determination of electrical resistance values, enabling timely replacement of transfer members and maintaining image quality by accounting for the capacitance of the photoconductor drum, thus improving the reliability of image transfer.
Implementation Method 1
a charging member configured to charge the image-carrying member
Implementation Method 2
a transfer member configured to transfer a toner image formed on the image-carrying member
Data Source
AI summary
An image forming apparatus includes first, second, and third acquisition processing portions. The first acquisition processing portion acquires the potential value of a charged area, charged by the charging member, on the image-carrying member. The second acquisition processing portion acquires a state value regarding the state of a surface layer of the image-carrying member based on the potential value of the charged area acquired by the first acquisition processing portion and the current value of a charging current flowing through the charging member during formation of the charged area. The third acquisition processing portion acquires the electrical resistance value of the transfer member based on the state value acquired by the second acquisition processing portion, the voltage value of a transfer voltage applied to the transfer member, and the current value of a transfer current flowing through the charged area in response to application of the transfer voltage.