Sloping Guide Member for Curved Sheet Conveyance
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Solution Overview
Problem
Conventional sheet feeding devices experience difficulties in smoothly conveying thick sheets due to curvature caused by moisture evaporation, leading to conveyance failures known as no-feed, especially when sheets are left in low humidity environments.
Innovation Solution
The sheet feeding device incorporates guide members with sloping guide surfaces that are wider on the upstream side and narrower on the downstream side, positioning the uppermost stream point upstream of the separation point and the lowermost stream point downstream, preventing the leading edge of curved sheets from being caught and ensuring smooth conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If guide members with parallel guide surfaces are used in conventional sheet feeding devices, then thin sheets can be conveyed, but thick sheets with curvature cannot be conveyed smoothly due to the leading edge being blocked by the guide member
Solution Approach 1:
The guide member is designed with a sloping guide surface that transitions from a wider upstream end to a narrower downstream end, creating a dynamic conveyance gap that adapts to sheets of different thicknesses and curvatures. This dynamic geometry allows the guide surface to accommodate curved thick sheets while maintaining proper guidance for thin sheets.
Solution Approach 2:
The conveyance gap width is changed along the conveyance direction by positioning the upstream end of the guide member farther from the pickup roller than the downstream end. This parameter change creates a sloping guide surface that reduces the blocking effect on curved thick sheets while maintaining effective guidance.
2Manufacturing precision
If the guide member is positioned closer to the pickup roller to improve sheet guidance, then sheet alignment improves, but curved thick sheets are more likely to be blocked by the guide member
Solution Approach 1:
The guide member is positioned at an angle relative to the pickup roller axis, creating a sloping guide surface in the conveyance direction. This dimensional arrangement allows the guide surface to interact with the curved leading edge of thick sheets in a way that prevents blocking while maintaining alignment.
Solution Approach 2:
The sloping guide surface prepares the curved sheet by gradually guiding it into the separation device before the sheet reaches the critical separation point. This preliminary action reduces the curvature of thick sheets in advance, preventing blocking during the separation process.
3Reliability
If a narrow conveyance gap is used to improve sheet separation, then single sheet feeding improves, but curved thick sheets cannot pass through due to blocking
Solution Approach 1:
The conveyance gap is designed with dynamic width variation, being wider at the upstream end and narrower at the downstream end. This dynamic geometry allows the gap to accommodate curved thick sheets during their passage while maintaining the narrow spacing needed for effective single sheet separation at the separation point.
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 allows for stable and smooth feeding of both thick and thin sheets, preventing conveyance troubles like no-feed, even when sheets are curved, by guiding the leading edge effectively to the separation point, thus enhancing the reliability of sheet feeding.
Implementation Method 1
a sheet feeding device which includes a pickup device which feeds a sheet by rotating while the pickup device comes in contact with a sheet located at an outermost position of a loaded stack of sheets
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
As a guide member (110) provided on a conveyance path through which a sheet is conveyed toward a separation device (103,104), a guide member (110) having a sloping guide surface (110C) is used, and the aforesaid guide member is arranged so that an uppermost stream point (P2) of the sloping guide surface (110C) may be positioned at the upstream side of a separation point (P1) of the aforesaid separation device (103,104) and a lowermost stream point (P3) of the aforesaid guide surface (110C) may be positioned at the downstream side of the aforesaid separation point (P1).