Sheet Conveying Roller Alignment With Stepped Pressure Contact
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Solution Overview
Problem
Existing sheet conveying devices in image forming apparatuses suffer from misalignment and sagging of conveying rollers, leading to creases in conveyed sheets.
Innovation Solution
A sheet conveying device with a pair of rollers and a pressing portion that includes a pressing member and urging member, where the first roller has a step portion with a smaller outer diameter than the contact region, ensuring uniform pressure and alignment, thereby suppressing misalignment and sagging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conveying rollers are used without additional pressing mechanisms, then the device complexity is low, but misalignment and sagging of rollers occur leading to sheet creases
Solution Approach 1:
A pressing portion is introduced as an intermediary component between the conveying rollers and the sheet. This pressing portion includes a pressing member that contacts the sheet and applying pressure through a pressing urging member, thereby preventing misalignment and sagging without requiring fundamental changes to the roller structure itself.
Solution Approach 2:
The pressing portion is divided into distinct functional segments: a pressing member that directly contacts the sheet, a pressing urging member that generates the pressing force, and a support structure. This segmentation allows each component to be optimized independently while maintaining overall system simplicity.
2Stability of the object's composition
If uniform pressure is applied across the entire roller surface, then roller alignment is improved, but sheet creases increase due to excessive pressure in non-contact regions
Solution Approach 1:
The pressing portion is positioned to apply pressure only at specific locations where the conveying rollers contact the sheet. The pressing member is arranged to contact the sheet only in the region between the rollers, ensuring that pressure is applied locally where needed for alignment while avoiding creases in other regions of the sheet.
3Force
If the pressing member contacts the first roller directly, then the pressing force is sufficient to prevent misalignment, but the roller timing adjustment capability is reduced
Solution Approach 1:
The pressing portion is designed with movable components that allow adjustment of the pressing member's position and the pressing force. The pressing urging member can be adjusted to vary the pressing force, and the pressing member's position can be modified to accommodate different sheet types and conveying requirements, thereby maintaining both sufficient pressing force and timing adjustment capability.
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 effectively suppresses misalignment and sagging of the rollers and reduces creases in sheets, enhancing the conveying performance and timing adjustment of sheets.
Implementation Method 1
a pressing urging member that urges the pressing member toward the second roller
Data Source
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AI summary
A sheet conveying device (4) includes a first roller (43A), a second roller (43B), and a pressing portion (46). The pressing portion (46) includes a pressing member (461) contacting the first roller (43A) from its side opposite from the second roller (43B) and a pressing urging member (462) urging the pressing member (461) toward the second roller (43B). The first roller (43A) has a step portion (431) formed in an outer circumferential part of it all over its circumference. The step portion (431) has an outer diameter smaller than the outer diameter of a contact region with the second roller (43B) and is contacted by the pressing member (461).