Transfer Device Nip Width Control for Image Quality
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Solution Overview
Problem
Conventional transfer devices exhibit differences in nip width between image bearing members and endless belts during monochromatic and full-color image forming, leading to variations in image quality.
Innovation Solution
A transfer device with a mechanism that adjusts the position of transfer members relative to image bearing members, ensuring a greater pressing force on the endless belt during monochromatic image forming to maintain consistent nip width, thereby equalizing image quality across both modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If transfer members for color are separated from image bearing members for color in monochromatic image forming, then the endless belt can be pressed against the monochrome image bearing member, but the nip width becomes smaller than in full-color image forming
Solution Approach 1:
The transfer member for monochrome is designed to be movable between a first pressing position and a second pressing position. In full-color image forming, it is positioned at the first pressing position to achieve a predetermined nip width. In monochromatic image forming, it is positioned at the second pressing position to increase the nip width while maintaining adequate pressing force. This dynamic positioning resolves the contradiction between pressing force and nip width.
Solution Approach 2:
The pressing position of the transfer member for monochrome is changed as a parameter to control the nip width. By adjusting the position parameter between two discrete settings (first pressing position and second pressing position), the system adapts the nip width to match the image forming mode while maintaining adequate pressing force for image transfer.
2Device complexity
If the transfer member for monochrome is positioned at a fixed pressing position, then the structure is simple, but the image quality differs between monochromatic and full-color image forming
Solution Approach 1:
The transfer member for monochrome is made movable between two pressing positions based on the image forming mode. This dynamic adjustment ensures consistent image quality in both monochromatic and full-color image forming by optimizing the nip width for each mode, while the movement mechanism remains relatively simple.
3Manufacturing precision
If the nip width is increased in monochromatic image forming, then the image quality matches full-color image forming, but the transfer member must be repositioned
Solution Approach 1:
The transfer member for monochrome is designed with a simple two-position movement mechanism that adjusts the nip width according to the image forming mode. This dynamic positioning achieves consistent image quality while keeping the mechanism relatively simple.
Solution Approach 2:
The transfer member for monochrome serves multiple functions: it transfers monochrome images in monochromatic mode and maintains appropriate nip width in full-color mode. The same transfer member is used for both modes with different positioning, achieving multi-functionality without requiring separate transfer members for each mode.
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 ensures equal image quality in both monochromatic and full-color image forming by optimizing the nip width between image bearing members and the endless belt.
Implementation Method 1
The transfer member moving mechanism moves the plurality of transfer members between pressing positions to cause the endless belt to be pressed against the respective plurality of image bearing members and separate positions to cause the endless belt to be separate from the respective plurality of image bearing members
Implementation Method 2
Application of a transfer bias to the transfer members corresponding to the image bearing members that have come into contact with the endless belt causes the developer images to be transferred from the respective image bearing members onto the endless belt
Data Source
AI summary
A Transfer device (10) includes an intermediate transfer belt (41), a plurality of intermediate transfer roller (34A-34D) and a transfer member moving mechanism (20). The transfer member moving mechanism moves the intermediate transfer rollers (34A-34D) between pressing positions causing the intermediate transfer belt (41) to be pressed against respective photoreceptor drums (31A-31D) and separate positions causing the intermediate transfer belt (41) to be separate from the respective photoreceptor drums (31A-31D). The transfer member moving mechanism (20) causes a second pressing position of the intermediate transfer roller for monochrome (34A) in monochromatic image forming to be different from a first pressing position of the intermediate transfer roller for monochrome (34A) in full-color image forming so that an amount of pressing of the intermediate transfer belt (41) by the intermediate transfer roller for monochrome (34A) becomes greater in monochromatic image forming than in full-color image forming.