Transfer Unit Guide Stability for High-Stiffness Sheets
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Solution Overview
Problem
In image forming apparatuses, the stiffness of sheets with high rigidity, such as thick paper, causes significant load on guides, leading to potential displacement and instability in conveying posture, which can result in image failures and increased material costs due to the need for larger, more rigid components.
Innovation Solution
A transfer unit design that includes a guide with an engaged part and a lever with an engagement part, where the load from the sheet is directly applied to the levers without passing through a holder, allowing the guide to maintain a constant conveying posture even with high-stiffness sheets, and reducing the impact of holder rigidity and mounting backlash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the guide is made with high rigidity to withstand increased load from stiff sheets, then the guide can maintain stability, but the size and material cost of the guide increase
Solution Approach 1:
The guide structure is divided into multiple segments: a fixed portion attached to the holder and a movable portion that can move independently. This segmentation allows the movable portion to flex under load from stiff sheets without requiring the entire guide to be made of high-rigidity materials, thus maintaining stability while reducing overall size and material cost.
Solution Approach 2:
The guide transitions from a static, rigid structure to a dynamic structure where the movable portion can adjust its position in response to varying sheet stiffness. This dynamic capability allows the guide to accommodate load variations without requiring excessive rigidity throughout the entire structure.
2Manufacturing precision
If the holder is made with high rigidity to prevent displacement under load, then the guide positioning accuracy is maintained, but the holder size and material cost increase
Solution Approach 1:
The holder structure is segmented into a fixed portion that maintains positioning accuracy and a movable portion that absorbs load variations. This segmentation allows the fixed portion to be made with sufficient rigidity for precision while the movable portion can be more flexible, reducing overall material requirements.
Solution Approach 2:
The movable portion of the guide acts as an intermediary between the holder and the sheet, absorbing the impact of sheet stiffness variations before they reach the holder. This protects the holder from excessive loads without requiring the holder itself to be made of high-rigidity materials.
3Reliability
If turning stoppers are positioned near the axial center of the rotating shaft to prevent over-turning, then the holder is protected from excessive rotation, but the turning angle becomes large causing considerable guide displacement
Solution Approach 1:
The guide's movable portion dynamically adjusts its position during the turning operation, compensating for the larger turning angle caused by centrally positioned stoppers. This dynamic adjustment prevents excessive guide displacement while maintaining the protective function of the stoppers.
Solution Approach 2:
The system allows for parameter changes in the guide's position and orientation during operation. By adjusting the movable portion's position, the system can accommodate larger turning angles without resulting in excessive final guide displacement, thus resolving the contradiction between holder protection and guide positioning accuracy.
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 design ensures stable sheet guidance to the transferring nip with constant conveying posture, even with high-stiffness sheets, while minimizing the need for increased rigidity and material costs, thereby preventing image failures and reducing component size and cost.
Implementation Method 1
The spring receiving part 62 is configured to come into contact with one end of a coil spring 72. The other end of the coil spring 72 is supported by a spring receiving part 74 formed on the conveying unit 9.
Data Source
AI summary
A transfer unit includes a transfer roller, a guide, a holder and a lever. The transfer roller is configured to be pressed against an image carrier to form a transferring nip and to transfer a toner image from the image carrier to a sheet at the transferring nip. The guide is configured to guide the sheet to the transferring nip. The holder is configured to support a rotating shaft of the transfer roller in a rotatable manner and to support the guide. The lever is configured to support the holder in a turnable manner around the rotating shaft so as to press the transfer roller against the image carrier. The guide has an engaged part. The lever has an engagement part which is engaged with the engaged part. An engagement of the engagement part with the engaged part prevents a turning of the guide with respect to the lever.