Sheet Conveying Device Overlapping Rollers for Duplex Printing
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Solution Overview
Problem
Conventional image-forming apparatuses with duplex printing capabilities face challenges due to complex conveyance paths and large sizes, particularly when reverse rollers are used for inverting sheets, which complicates the arrangement and increases the overall size of the apparatus.
Innovation Solution
The design incorporates a sheet-conveying device with pairs of first and second rollers that partially overlap in the width direction, allowing for efficient discharge and re-conveyance of sheets, reducing the apparatus's size by optimizing the arrangement of discharge and reverse rollers, and utilizing a double-side flapper to switch between discharge and duplex conveyance paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If reverse rollers are disposed close to discharge rollers for duplex printing, then the conveyance path is simplified, but the apparatus size becomes large
Solution Approach 1:
The patent applies dimensional reconfiguration by arranging the first and second rollers in an overlapping configuration when viewed in the width direction of the sheet. This spatial arrangement in the width dimension allows the rollers to be positioned close to each other without increasing the apparatus length, thereby simplifying the conveyance path while maintaining a compact apparatus size.
2Area of stationary object
If reverse rollers are disposed close to discharge rollers, then the apparatus size is reduced, but the conveyance path becomes complicated
Solution Approach 1:
The patent resolves the complexity issue by using the width direction as an additional spatial dimension. The first and second rollers are arranged to overlap when viewed in the width direction, creating a streamlined conveyance path that moves sheets through the apparatus in a more direct manner, thereby reducing path complexity while maintaining compact dimensions.
3Productivity
If discharge portion and inverting portion are separated components, then productivity is improved, but the apparatus size increases
Solution Approach 1:
The patent combines the discharge portion and inverting portion into an integrated roller assembly where the first rollers (discharge) and second rollers (inverting) are disposed in close proximity with overlapping arrangements. This merging of functions into a single compact unit maintains high productivity by enabling continuous operation while reducing the overall apparatus size compared to completely separate components.
Solution Approach 2:
The roller assembly serves multiple functions simultaneously - the first rollers discharge sheets while the second rollers invert them for duplex printing. This multi-functionality allows the same structural region to handle both discharge and inverting operations, improving productivity without proportionally increasing apparatus size.
Data Source
AI summary
An image-forming apparatus for forming an image on a sheet includes an image-forming unit that forms the image on the sheet, and a conveying unit that conveys the sheet on which the image is formed by the image-forming unit. The conveying unit includes a pair of first rollers that discharges the sheet to the outside of the image-forming apparatus and a pair of second rollers that conveys the sheet in a direction in which the sheet is discharged to the outside of the image-forming apparatus and that subsequently switches a conveyance direction of the sheet to an opposite direction to convey the sheet again to the image-forming unit. The pair of the first rollers and the pair of the second rollers partially overlap when viewed in a width direction of the sheet that is perpendicular to the conveyance direction of the sheet.