Primary Transfer Roller Positioning in Compact Image Forming Units
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining compact size, reducing manufacturing costs, and minimizing image density deviations due to complex mechanisms for holding and positioning primary transfer rollers and backup rollers, which often result in increased size and cost.
Innovation Solution
The image forming apparatus incorporates a design where primary transfer rollers and backup rollers are held by rotatable holding members, positioned with precision using pressure members, and integrated into a compact intermediate transferor unit that can be easily inserted and removed, with a belt skew correction mechanism to enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate holding members are disposed for each of the primary transfer roller and backup roller, then the primary transfer rollers and backup rollers can be separated from photoconductors, but the distance between components increases and manufacturing cost increases
Solution Approach 1:
The patent combines the backup roller and primary transfer roller into a single integrated holding member. The backup roller is positioned at the upstream end of the intermediate transfer belt, and the primary transfer roller is positioned at the downstream end, both supported by the same holding member structure. This merging reduces the number of separate holding members from two to one, simplifying the overall device structure while maintaining the ability to separate rollers from photoconductors when needed.
2Adaptability or versatility
If the entire holding member is moved to contact or separate primary transfer rollers when switching modes, then mode switching is achieved, but the size of components increases and manufacturing cost increases
Solution Approach 1:
The holding member is segmented into distinct functional sections: a backup roller support section, a primary transfer roller support section, and positioning sections with contact members. This segmentation allows each section to be optimized independently, preventing the need for a large unified structure. The contact members are positioned at specific locations to provide stable support without requiring the entire holding member to be oversized.
3Volume of moving object
If the holding member is contacted against the transfer frame for positioning, then the size is reduced, but the position of the primary transfer roller with respect to the photoconductor varies due to tolerance accumulation
Solution Approach 1:
The patent introduces contact members as intermediary elements between the holding member and the transfer frame. These contact members are positioned at specific locations on the holding member to provide stable contact points with the transfer frame. By using these intermediary contact members rather than direct contact between the holding member and frame, the positioning accuracy is improved while maintaining a compact structure, as the contact members can be precisely positioned to compensate for tolerance accumulation.
4Device complexity
If no restriction mechanism for belt meandering is installed, then the device is simpler, but an expensive belt needs to be used or the life of the belt is short
Solution Approach 1:
The patent incorporates belt end contact members that preliminarily restrict the movement of the intermediate transfer belt ends before the belt can meander during operation. These contact members are positioned to lightly touch or nearly touch the belt ends, providing a preliminary constraint that prevents excessive belt movement. This preliminary action reduces belt meandering without requiring a complex active restriction mechanism, thereby extending belt life while maintaining simple device structure.
Data Source
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AI summary
An image forming apparatus (100) includes a plurality of image bearers (1a, 1b, 1c, 1d), a plurality of frame members (49a, 49b, 49c, 49d), a plurality of contact members (53a, 53b, 53c, 53d), an intermediate transferor (3), a plurality of primary transfer members (11a, 11b, 11c, 11d), a plurality of holding members (51a, 51b, 51c, 51d), an intermediate transferor frame (37), a plurality of pressure members (50a, 50b, 50c, 50d, 80a, 80b, 80c, 80d, 72), and a plurality of pressing members (57a, 57b, 57c, 57d, 58a, 58b, 58c, 58d). The plurality of image bearers (1a, 1b, 1c, 1d) is positioned by the plurality of pressing members (57a, 57b, 57c, 57d, 58a, 58b, 58c, 58d). The plurality of primary transfer members (11a, 11b, 11c, 11d) are positioned by the plurality of pressure members (50a, 50b, 50c, 50d, 80a, 80b, 80c, 80d, 72).