Duplex Sheet Conveyance Guide and Roller System
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Solution Overview
Problem
Existing image forming apparatuses face limitations in throughput and operational noise during continuous double-sided image forming operations due to the need for one sheet to occupy a path while ejecting another and the flapper's movement to reverse sheets.
Innovation Solution
An image forming apparatus with a configuration that includes a first path, a second path, a third path, a guide member, a first roller, and a second roller, where the controller positions the guide member to direct sheets into either path for duplex printing, allowing simultaneous conveyance and reversal of sheets without requiring the flapper to move after the first sheet is reversed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If one sheet is reversed using a single path configuration, then the sheet can be conveyed to the second conveyor path, but the path must be occupied for ejecting other sheets which limits throughput
Solution Approach 1:
The patent divides the sheet conveyance system into multiple independent paths (first conveyor path, second conveyor path, third conveyor path) that can operate simultaneously. This segmentation allows different sheets to be processed in parallel without blocking each other, thereby increasing throughput and eliminating path occupation delays.
Solution Approach 2:
The patent introduces a third conveyor path that connects the first and second paths, creating a multi-dimensional conveyance network. This additional dimension enables sheets to be routed through different paths simultaneously, allowing continuous duplex printing on three or more sheets without waiting for path clearance.
2Ease of operation
If the flapper is moved to reverse the second sheet after the first sheet is reversed, then the second sheet can be conveyed, but operational noise is generated
Solution Approach 1:
The patent separates the sheet reversal function from the flapper mechanism by using dedicated first and second rollers for conveying and reversing sheets. This segmentation eliminates the need for flapper movement during sheet reversal, thereby reducing operational noise while maintaining ease of operation.
Solution Approach 2:
The patent extracts the sheet reversal function from the flapper mechanism and assigns it to the roller system. By taking out the reversal function from the noisy flapper, the system achieves quiet operation while preserving the ability to reverse sheets efficiently.
3Device complexity
If a single roller system is used for all sheets, then the structure is simpler, but sheets cannot be conveyed through different paths simultaneously
Solution Approach 1:
The patent divides the roller system into multiple independent roller sets (first roller for first path, second roller for second path) that can operate simultaneously. This segmentation enables parallel sheet conveyance through different paths, increasing productivity while maintaining manageable structural complexity.
Solution Approach 2:
The patent creates a multi-functional roller system where the first roller handles sheets in the first path and the second roller handles sheets in the second path. Both rollers can simultaneously perform conveyance and reversal functions for different sheets, achieving high throughput without excessive complexity.
Data Source
AI summary
In an image forming apparatus capable of turning over a sheet to form images on both sides of the sheet, when duplex printing is executed successively on three or more sheets, a controller causes a first sheet conveyed from an image forming unit and a second sheet conveyed from the image forming unit to be guided into a first path by positioning a guide member in a first position, and then conveyed into a third path by a first roller, and causes a third and subsequent sheets conveyed from the image forming unit to be guided into a second path by positioning the guide member in a second position, and then conveyed into the third path by a second roller.