Sheet Feed Device Torque Limiter Fulcrum Angle Control
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Solution Overview
Problem
Existing sheet feed devices fail to effectively convey two sheets simultaneously downstream without one sheet being separated, due to inadequate torque management and dynamic pressing forces.
Innovation Solution
A sheet feed device incorporating a torque limiter and a holder supported by a driving unit, which adjusts the fulcrum angle to manage dynamic pressing forces, ensuring that only one sheet is conveyed downstream by generating appropriate anti-torque and static pressing forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two sheets are simultaneously conveyed between the pair of rollers, then the conveying capacity is improved, but one of the sheets is conveyed downstream while the other is not, causing conveyance inconsistency
Solution Approach 1:
The torque limiter applies preliminary anti-torque to the second roller in opposition to the sheet conveyance direction. This pre-established counteracting force creates a threshold that prevents the second sheet from being conveyed when two sheets are simultaneously fed, while still allowing the first sheet to pass through by overcoming this preliminary anti-action through sufficient friction force.
2Reliability
If the torque limiter imparts anti-torque to the second roller, then single-sheet conveyance is ensured, but the dynamic pressing force becomes insufficient to convey two sheets simultaneously
Solution Approach 1:
The holder supporting the second roller is made rotatable about a fulcrum, transforming the static pressing force into a dynamic system. When the driving unit rotates the holder toward the first roller, the fulcrum angle changes, dynamically adjusting the pressing force. This dynamic mechanism allows the system to adapt the pressing force magnitude based on operational requirements, overcoming the insufficiency of fixed anti-torque while maintaining single-sheet conveyance control.
Solution Approach 2:
The driving unit changes the fulcrum angle parameter of the holder, which directly alters the dynamic pressing force applied by the second roller. By adjusting this geometric parameter, the system can modulate the pressing force to achieve both single-sheet reliability and sufficient force for two-sheet conveyance when needed, resolving the force insufficiency contradiction.
3Force
If the holder is biased toward the first roller by the driving unit, then the dynamic pressing force is increased, but the fulcrum angle changes cause instability in the pressing force
Solution Approach 1:
The system incorporates feedback through the fulcrum mechanism where changes in holder position automatically adjust the fulcrum angle. The driving unit rotates the holder, and the resulting change in fulcrum angle provides inherent feedback that stabilizes the pressing force. This feedback loop allows the system to maintain stable pressing force despite the dynamic nature of the rotatable holder, resolving the stability contradiction.
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 ensures reliable single-sheet conveyance while preventing simultaneous conveyance of two sheets, maintaining consistent static pressing force and adjusting dynamic pressing forces based on fulcrum angle changes.
Implementation Method 1
The torque limiter imparts an anti-torque to the second roller in order to generate a force on the second surface in a direction opposite to the first direction
Implementation Method 2
The driving unit moves the holder and biases the holder toward the first roller
Implementation Method 3
The holder rotatably supports the second roller. The driving unit moves the holder and biases the holder toward the first roller
Implementation Method 4
The first roller conveys a sheet in a first direction while being in contact with a first surface of the sheet. The second roller faces the first roller and is in contact with a second surface which is the back side of the first surface of the sheet
Data Source
AI summary
According to one embodiment, a sheet feed device includes a first roller, a second roller, a torque limiter, a holder, and a driving unit. The first roller conveys a sheet in a first direction while being in contact with a first surface of the sheet. The second roller faces the first roller and is in contact with a second surface which is a back side of the first surface of the sheet in a state of sandwiching the sheet between the second roller and the first roller. The torque limiter imparts an anti-torque to the second roller in order to generate a force on the second surface in a direction opposite to the first direction. The holder rotatably supports the second roller. The driving unit moves the holder and biases the holder toward the first roller.