Transfer Roller Resistance Stabilization for Image Forming Apparatus
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Solution Overview
Problem
Existing image transfer devices in electrophotographic systems face inefficiencies due to variations in resistance caused by environmental factors like temperature and humidity, leading to unstable transfer efficiency and potential reverse transfer issues during full-color image formation.
Innovation Solution
Incorporating a resistance element connected in series between the power supply device and the transfer roller to stabilize the transfer bias voltage, ensuring consistent transfer efficiency across varying environmental conditions and reducing reverse transfer by adjusting the resistance element's value to maintain optimal voltage settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If environmental factors (temperature, humidity) vary, then the resistance of the transfer roller and transfer medium changes, but the transfer efficiency deteriorates because a sufficient transfer electric field cannot be generated
Solution Approach 1:
The patent applies a transfer bias voltage to the transfer roller and adjusts this voltage based on the measured resistance values of the transfer roller and transfer medium. By dynamically changing the voltage parameter in response to environmental conditions, the system maintains sufficient transfer electric field strength despite resistance variations caused by temperature and humidity changes.
Solution Approach 2:
The patent employs a control system that measures the resistance values of the transfer roller and transfer medium, then uses these measured values to determine and adjust the transfer bias voltage. This feedback mechanism ensures that the transfer electric field remains adequate under varying environmental conditions, preventing transfer efficiency deterioration.
2Reliability
If a control system with sensors and storage devices is used to measure resistance and achieve optimal voltage setting, then transfer efficiency can be optimized, but the apparatus becomes complicated and cost increases
Solution Approach 1:
The patent determines optimal transfer bias voltage by measuring resistance and applying calculated voltage settings. This parameter adjustment approach achieves optimized transfer efficiency without requiring complex control systems with multiple sensors and storage devices, thereby avoiding apparatus complication and cost increase.
3Reliability
If the resistance of the conductive roller drops remarkably in certain environments, then the percentage occupied by toner resistance increases, but the transfer efficiency varies depending on toner layer thickness and attached amount
Solution Approach 1:
The patent measures the resistance of the transfer roller and transfer medium, then determines and applies an optimal transfer bias voltage based on these measured values. This dynamic voltage adjustment compensates for resistance drops in the conductive roller, ensuring stable transfer efficiency regardless of toner layer thickness or attached amount variations.
Solution Approach 2:
The control system measures resistance values and uses this feedback to adjust the transfer bias voltage accordingly. This feedback mechanism stabilizes transfer efficiency by compensating for environmental resistance changes, preventing variations caused by toner layer thickness and attached amount.
4Productivity
If a transfer bias of plus potential is applied to the transfer roller during full-color image formation, then toner can be transferred, but reverse transfer occurs due to white background inrush current when no toner is present
Solution Approach 1:
The patent measures the resistance of the transfer roller and transfer medium before applying transfer bias, then determines an optimal voltage setting based on these values. This pre-measurement and adaptive voltage setting prevents excessive inrush current during white background areas, thereby preventing reverse transfer while maintaining full-color image formation capability.
Solution Approach 2:
The patent performs resistance measurement of the transfer roller and transfer medium before applying the transfer bias voltage. This preliminary action allows the control system to determine an appropriate voltage setting that prevents reverse transfer during subsequent full-color image formation, avoiding the harmful inrush current effect before it occurs.
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 achieves stable and high transfer efficiency regardless of environmental variations, while minimizing reverse transfer and maintaining effective toner transfer across different toner layers, thus enhancing image quality and color balance.
Implementation Method 1
electrostatically transfers the toner image to the surface of the transfer medium by providing an electric charge having an opposite polarity from the polarity of an electric charge of the toner to the back surface of the transfer medium
Implementation Method 2
a value of resistance of the transfer roller increases under a low-temperature and low-moisture environment, and the value of resistance of the transfer roller is lowered under a high-temperature and high-moisture environment
Data Source
AI summary
An image transfer device according to the present invention applies a transfer bias voltage to a toner image developed on a surface of an image carrying member, the transfer bias voltage having an opposite polarity from the polarity of an electric charge of the toner image, by a transfer roller from a power supply device, and electrostatically transfers the toner image to a transfer medium. A resistance element is connected between the power supply device and the transfer roller in series. The resistance element has a value of resistance which varies little with environmental variation, and a ratio between the value of resistance and a synthetic value of resistance of a transfer device including the conductive roller is set to a value which restrains variations in transfer efficiency of the electrostatic transfer with respect to variations in the synthetic value of resistance with the environmental variations.