Rotatable Blade Chamfer for Sheet Discharge in Printers
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Solution Overview
Problem
Conventional sheet material cutting devices in printers cause the leading edge of cut sheets to be bent downward by the rotatable blade's forward shaft surface, leading to deformation and blockage, making smooth discharge difficult and potentially damaging the sheet material.
Innovation Solution
A chamfered or stepped portion is formed on the outer surface of the rotatable blade's rotary shaft to prevent the cut sheet's rear edge from being pressed downward, allowing it to be discharged smoothly without deformation, and a sheet-suspension prevention unit is integrated to ensure the sheet is not suspended within the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the forward shaft surface of the rotatable blade presses downward on the rear edge of the cut sheet material, then the sheet material is guided and fed toward the fixed blade, but the leading edge of the cut sheet material is bent downward and deformed, preventing smooth discharge
Solution Approach 1:
The rotatable blade is designed with different surface characteristics at different locations: the backward shaft surface maintains a circular arc shape for guiding the leading edge, while the forward shaft surface is made flat to avoid pressing and deforming the rear edge of the cut sheet material. This local differentiation resolves the contradiction by providing guidance where needed while preventing deformation where harmful.
2Productivity
If the conveying mechanism is arranged in the downstream side of the sheet material cutting device, then the cut sheet material can be conveyed and discharged, but the printer configuration becomes complicated and the outer shape increases
Solution Approach 1:
The conveying mechanism is merged with the rotatable blade structure itself. The rotatable blade serves dual functions: cutting the sheet material and simultaneously conveying it outward for discharge. This integration eliminates the need for a separate downstream conveying mechanism, simplifying the printer configuration and reducing the outer shape while maintaining the discharge function.
3Speed
If the leading edge of the cut sheet material is pressed downward by the forward shaft surface, then the sheet material is fed forward, but the sheet material becomes suspended within the device, causing blockage and paper jam
Solution Approach 1:
The rotatable blade features a flat forward shaft surface that eliminates the pressing action causing suspension and blockage, while the backward shaft surface maintains its circular arc shape to ensure continuous guidance and feeding of the leading edge. This local differentiation maintains feed speed while eliminating the reliability issue of suspension and blockage.
Data Source
AI summary
According to one embodiment, a sheet material cutting device includes a rotatable blade including a blade unit, which extends from one end of the rotary shaft to the other end thereof and defines a predetermined angle relative to an axial direction of the rotary shaft, provided on the outer circumference of a rotary shaft rotatably supported by a support frame. The sheet material cutting device further includes a fixed blade mounted on the support frame so as to be opposed to the rotatable blade and configured to cut a sheet material in a transverse direction perpendicular to the feed direction of the sheet material that is perpendicular to the axial direction of the rotary shaft. The sheet material cutting device further includes a sheet-suspension prevention unit configured to prevent a rear edge of the sheet material in its feed direction from being suspended within the support frame.