Drum Cartridge Developing Bias Adjustment for Print Density
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Solution Overview
Problem
The variability in toner supply from different cartridges to a drum cartridge in image forming apparatuses leads to unstable print density, as the initial and subsequent toner cartridges are used under the same conditions, causing inconsistencies in the amount of toner supplied and affecting image formation quality.
Innovation Solution
The image forming apparatus includes a controller that adjusts the developing bias, transfer current, cleaning bias, and supply bias based on the cumulative number of drum rotations and dot count stored in the drum and toner memories, ensuring that each toner cartridge is initialized with a unique bias setting that compensates for the degradation of both the drum and toner over time, thereby stabilizing the print density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the same initial developing bias is applied to all toner cartridges, then the device operation is simple, but the print density becomes unstable due to variations in toner supply from different cartridges
Solution Approach 1:
The patent applies parameter changes by adjusting the initial developing bias value based on the cumulative number of drum rotations. The controller determines different initial developing bias values for different toner cartridges depending on the drum's usage history, thereby optimizing toner supply and stabilizing print density across multiple cartridges while accounting for drum degradation over time.
Solution Approach 2:
The system implements feedback by using the cumulative drum rotation count stored in the drum memory to determine the appropriate initial developing bias. This feedback mechanism allows the controller to adapt the developing bias based on the actual usage state of the drum, ensuring consistent print quality despite variations in toner cartridges and drum degradation.
2Productivity
If multiple toner cartridges are used with a single drum cartridge, then the productivity is improved, but the manufacturing precision deteriorates due to inconsistent toner supply amounts
Solution Approach 1:
The patent changes the developing bias parameter dynamically based on the cumulative drum rotation count. When a new toner cartridge is installed, the controller retrieves the drum's cumulative rotation data and sets an appropriate initial developing bias value, ensuring consistent toner supply and print quality across multiple cartridges and maintaining manufacturing precision throughout continuous operation.
3Reliability
If the developing bias is adjusted based on cumulative drum rotations, then the print density stability is improved, but the device complexity increases due to additional control mechanisms
Solution Approach 1:
The controller performs multiple functions: it manages image formation control, monitors cumulative drum rotations through the drum memory, determines appropriate initial developing bias values, and applies the bias during image formation. This multi-functionality allows the system to maintain print density stability without adding separate dedicated components, thereby limiting the increase in device complexity.
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 ensures consistent toner adherence and supply to the drum, stabilizing print density by adapting biases according to the cumulative usage, effectively maintaining image quality throughout the lifespan of multiple toner cartridges with a single drum cartridge.
Implementation Method 1
The developing roller is configured to be applied with a developing bias. A first developing bias is the developing bias applied to the developing roller of the first toner cartridge. A second developing bias is the developing bias applied to the second toner cartridge.
Implementation Method 2
The transfer roller is configured to be applied with a transfer current.
Implementation Method 3
The cleaning roller is configured to be applied with a cleaning bias.
Data Source
AI summary
An image forming apparatus includes a controller, a drum cartridge and a toner cartridge. The controller is configured to perform determining a value of a first initial developing bias for a first toner cartridge based on a cumulative number of drum rotations that is stored in a drum memory of the drum cartridge at the time when the cumulative dot count stored in the toner memory of the first toner cartridge is equal to zero. After determining the first initial developing bias, the controller is configured to perform determining a value of a second initial developing bias for a second toner cartridge based on the cumulative number of drum rotations that is stored in the drum memory at the time when the cumulative dot count stored in the toner memory of the second toner cartridge is equal to zero.