Dynamic Transfer Voltage Adjustment for Image Defects
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in accurately adjusting the transfer voltage for various recording materials, leading to potential image defects such as 'roughening' and 'white void' due to fixed increment widths during chart formation, which do not account for the varying electrical resistance of materials in different environments.
Innovation Solution
An image forming apparatus with a controller that adjusts the change width of the test voltage per level during chart formation based on real-time detection results, allowing for dynamic adjustment of the transfer voltage to suit specific recording materials and environments, ensuring optimal transfer conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed increment width is used during chart formation, then the adjustment process is simple and fast, but the transfer voltage cannot be accurately adjusted for recording materials with varying electrical resistance, leading to image defects
Solution Approach 1:
The patent applies dynamics by making the increment width of test voltage adjustable rather than fixed. The controller dynamically changes the increment width based on detection results from the reading device, allowing the system to adapt between fast fixed-increment mode and precise variable-increment mode depending on the recording material's electrical resistance characteristics
Solution Approach 2:
The patent implements feedback by using the reading device to detect the electrical resistance of the recording material and feed this information back to the controller. The controller then uses this feedback to automatically adjust the increment width of test voltage during chart formation, creating a closed-loop control system that balances speed and precision
2Adaptability or versatility
If a large increment width is used, then the adjustment range is wide and covers various materials, but the precision is insufficient for low-resistance materials causing white void defects
Solution Approach 1:
The patent applies local quality by using different increment widths for different ranges of test voltage. For low-resistance recording materials, a smaller increment width is used in the relevant voltage range to achieve precise adjustment and avoid white void defects, while larger increment widths can be used for other ranges to maintain broad adaptability
Solution Approach 2:
The patent changes the parameter of increment width based on the detected electrical resistance of the recording material. When low-resistance material is detected, the system switches to a smaller increment width parameter to ensure precise voltage adjustment, thereby maintaining both versatility and precision across different material types
3Measurement precision
If a small increment width is used, then the precision is high for specific materials, but the adjustment time increases and the process becomes complex
Solution Approach 1:
The system dynamically selects the increment width based on real-time detection of recording material properties. Instead of always using a small increment width, the system uses a larger width when appropriate (for high-resistance materials or initial adjustments) and switches to a smaller width only when precision is needed, thereby reducing overall adjustment time while maintaining high precision when required
Solution Approach 2:
The system performs preliminary detection of the recording material's electrical resistance before beginning voltage adjustment. This preliminary action allows the system to pre-determine the appropriate increment width, avoiding unnecessary time-consuming fine adjustments when a larger increment would suffice, thus optimizing the balance between precision and time
4Reliability
If the transfer voltage is increased to ensure sufficient transfer current, then the transfer reliability improves, but electric discharge occurs causing white void defects
Solution Approach 1:
The patent changes the parameter of voltage increment width to achieve more granular control over transfer voltage. By using a smaller increment width for low-resistance recording materials, the system can precisely adjust the voltage to the minimum level needed for reliable transfer, avoiding excessive voltage that would cause electric discharge and white void defects
Solution Approach 2:
The system uses feedback from the reading device to detect recording material properties and automatically adjusts the transfer voltage parameters accordingly. This feedback mechanism ensures that the transfer voltage is optimized for each specific material, achieving reliable transfer without exceeding the threshold that would cause harmful electric discharge
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 approach enables precise adjustment of the transfer voltage, reducing the risk of image defects by accommodating the electrical resistance variations of different recording materials, thereby improving image quality and usability across diverse media types.
Implementation Method 1
The transfer of the toner image from an image bearing member such as the photosensitive member or the intermediary transfer member to a transfer-receiving member is often performed electrostatically by applying a transfer voltage to a transfer member which contacts the image bearing member to form a transfer portion
Implementation Method 2
a detecting portion configured to detect a voltage value or a current value when the applying portion applies the voltage to the transfer member
Data Source
AI summary
An image forming apparatus includes an image forming portion, an image bearing member, a transfer member, a voltage applying portion, a detecting portion, and a controller capable of executing an operation in an adjustment mode in which a chart on which a plurality of test images are transferred by stepwise changing a test voltage applied to the transfer member by the applying portion is formed on a recording material and then a transfer voltage applied to the transfer member by the voltage applying portion during transfer of the toner image is adjusted. The controller is capable of changing a change width per level of the test voltage applied during formation of the chart[[,]] on the basis of a detection result of the detecting portion when the voltage is applied to the transfer member when the recording material on which the chart is formed is in the transfer portion.