Movable Driven Roller for Stable Sheet Feeding
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Solution Overview
Problem
Existing document reading apparatuses experience image quality deterioration due to rapid document shifting when the rear edge separates from the rollers, leading to issues like curved lines being mistaken for straight lines and color deviations, especially with thicker documents.
Innovation Solution
A sheet feeding apparatus with a driven roller that is reciprocally movable within a predetermined range, allowing it to counteract the reactive force when the rear edge of the document separates, maintaining a constant feeding speed and reducing image blur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressing means is applied to the roller to ensure contact with the document, then the document can be conveyed reliably, but the roller cannot respond to the gap when the rear edge separates, causing rapid document shifting
Solution Approach 1:
The roller is designed to be movable in the feeding direction rather than fixed. When the rear edge of the document separates from the rollers, the roller can move forward to close the gap, and when the document is fed, the roller moves backward to maintain contact. This dynamic movement allows the roller to adapt to changing conditions and prevent rapid document shifting while maintaining reliable conveyance.
2Stability of the object's composition
If the roller instantly moves to close the gap when the rear edge separates, then the gap is eliminated, but the document is kicked out and rapidly shifts position
Solution Approach 1:
The roller's movable design allows it to respond smoothly to the gap without causing sudden document displacement. The roller moves forward to close the gap gradually rather than instantly, and its position is controlled by the balance between the pressing means force and the document feeding force, maintaining consistent feeding speed.
Solution Approach 2:
The roller's position parameter is made variable rather than fixed. The roller can move within a predetermined range in the feeding direction, changing its position parameter to adapt to the gap condition. This parameter change allows the system to maintain both gap elimination and feeding speed consistency.
3Device complexity
If a fixed roller structure is used, then the apparatus structure is simple, but image quality deteriorates due to rapid document shifting during reading
Solution Approach 1:
The roller is designed with movable capability in the feeding direction while maintaining a relatively simple structure. The movability is achieved through a predetermined range of movement mechanism rather than a complex active control system. This dynamic design prevents rapid document shifting during reading, improving image reading precision without significantly increasing apparatus structure complexity.
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 minimizes changes in feeding speed and image quality deterioration, even with thick documents, while maintaining a simple and cost-effective structure, preventing rapid document displacement and ensuring stable feeding.
Implementation Method 1
a compression spring that presses the driven roller toward the driving roller
Implementation Method 2
a driven roller that is placed opposite the driving roller, has contact with a roller surface thereof, and rotates in response to movement of the driving roller
Data Source
AI summary
The sheet feeding apparatus of the invention includes a driving roller that is rotated by a predetermined driving source, a driven roller that rotates in response to movement of said driving roller, said driven roller being placed opposite said driving roller and having contact with a roller surface of said driving roller, a pressing member that presses a roller surface of said driven roller toward said roller surface of driving roller at a predetermined pressure, and driven roller holding member that includes an opening being elongated in a tangential direction at a contact point between said driven roller and said driving roller or between said driven roller and a sheet, on a circle forming said roller surface of said driven roller.