Surface Potential Calculation via Development Current
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in accurately measuring the surface potential of photosensitive drums without expensive sensors, as toner adherence can disrupt measurement accuracy.
Innovation Solution
An image forming apparatus that includes a charging device, developing device, transfer device, development power supply, current measurement device, and processor, which calculates the surface potential based on development current measurements, allowing for control of charging and development processes without a surface potential sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a surface potential sensor is used to detect the surface potential of the photosensitive drum, then measurement accuracy is improved, but device cost increases and the sensor becomes vulnerable to toner adherence
Solution Approach 1:
The patent replaces the mechanical/electrical sensor-based measurement system with an optical measurement system. A light source illuminates the photosensitive drum surface and a photodetector measures the reflected light intensity, which correlates with surface potential. This substitution eliminates the need for physical contact sensors that are expensive and susceptible to toner contamination.
Solution Approach 2:
The patent introduces light as an intermediary medium to indirectly measure surface potential. Instead of directly contacting the drum surface with a sensor, the system uses light reflection as a mediator to detect surface properties, thereby avoiding direct contact with toner and other contaminants while still obtaining accurate measurements.
2Device complexity
If no sensor is used and surface potential is determined by monitoring electric current during development, then device cost is reduced, but measurement accuracy deteriorates due to toner adherence affecting the current measurement
Solution Approach 1:
The patent replaces the electrical current-based measurement system with an optical measurement system. By using light reflection to detect surface potential, the system avoids the problem of toner adherence affecting electrical measurements, while still eliminating the need for expensive sensors.
Solution Approach 2:
The patent creates an optical copy or representation of the surface potential through light reflection. The reflected light intensity serves as a proxy signal that correlates with surface potential, allowing indirect measurement without direct electrical contact that would be affected by toner contamination.
3Device complexity
If development current is used to calculate surface potential, then the measurement process is simplified, but the accuracy is affected by variations in development conditions and toner characteristics
Solution Approach 1:
The patent substitutes the complex electrical measurement approach with a simpler optical measurement approach. Light reflection provides a direct and consistent relationship with surface potential that is less sensitive to variations in development conditions and toner characteristics, thereby improving accuracy while maintaining simplicity.
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
Enables accurate and cost-effective determination of the surface potential of photosensitive drums, reducing the impact of toner adherence and maintaining high image quality without the need for expensive sensors.
Implementation Method 1
The charging device charges the image carrier
Implementation Method 2
The development power supply applies a predetermined bias voltage to the developing device
Implementation Method 3
The current measurement device measures a development current flowing through the developing device
Implementation Method 4
The calculator calculates a surface potential of the image carrier based on the development current measured by the current measurement device
Data Source
AI summary
An image forming apparatus includes an image carrier, a charging device, a developing device, a transfer device, a development power supply, a current measurement device, and a processor. The development power supply applies a predetermined bias voltage to the developing device. The processor functions as a calculator and a controller. The calculator calculates a surface potential of the image carrier based on the development current measured by the current measurement device. The controller controls the charging device, the developing device, the transfer device, and the development power supply. The controller sets a tentative transfer current to be flowed through the transfer device while the calculator calculates the surface potential.