Sheet Transport Gate Prevents Short Sheet Slippage
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Solution Overview
Problem
Image forming apparatuses face challenges in preventing short sheets from accidentally slipping into the gap below the sheet tray during the image forming process, which can lead to misalignment and damage, especially when handling sheets of varying lengths.
Innovation Solution
A sheet transport device with a gate structure that includes a gate unit positioned on the reversing transport path, which prevents free-falling sheets from entering the gap while allowing sheets with a transport driving force to pass through, using a combination of a gate member and a spring or elastic deformation to control the sheet's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gate mechanism is disposed at an intermediate position of the sheet transport path connected to the gap below the sheet tray, then sheets can be prevented from slipping into the gap, but the device complexity increases and manual intervention or solenoid control is required
Solution Approach 1:
The gate unit is designed to automatically open and close based on the sheet's movement state without requiring external control mechanisms. The spring member automatically returns the gate to its closed position after the sheet passes through, eliminating the need for solenoids or manual intervention.
Solution Approach 2:
The gate unit acts as an intermediary element between the sheet transport path and the gap below the sheet tray. It selectively blocks or allows passage based on the sheet's transport state, preventing accidental entry into the gap while maintaining normal transport operations.
2Reliability
If the gate unit is pressed against the guide wall by a spring member, then free-falling sheets are prevented from passing through, but the manufacturing precision must be high to ensure proper pressing force
Solution Approach 1:
The spring member provides a variable pressing force that automatically adjusts based on the gate's position and the sheet's approach. This eliminates the need for precise manufacturing of fixed pressing forces, as the spring's elastic properties naturally provide the necessary variation in force.
3Productivity
If the gate unit allows passage when the sheet receives transport driving force, then normal sheet transport is maintained, but the gate must be highly responsive to detect transport driving force
Solution Approach 1:
The gate unit automatically responds to the sheet's movement by opening when the sheet approaches and closing when the sheet passes through. This self-actuating mechanism eliminates the need for complex detection systems to sense transport driving force.
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
Effectively prevents short sheets from slipping into the gap, reducing the risk of misalignment and damage, and allows for efficient operation across different sheet lengths without the need for manual intervention or complex mechanisms.
Implementation Method 1
a spring member that presses the gate member against the guide wall when the gate member is not pressed by the sheet
Implementation Method 2
a gate member that blocks the passage of a sheet when the sheet free falls
Implementation Method 3
a sheet transport unit that feeds the sheet from the sheet storage unit and transports the fed sheet along a transport passage
Data Source
AI summary
A sheet transport device includes a sheet storage unit that stores a sheet and that is disposed in a housing having a bottom plate such that a gap is provided between the sheet storage unit and the bottom plate, the gap extending horizontally; a sheet transport unit that feeds the sheet from the sheet storage unit and transports the fed sheet along a transport passage including a reversing transport path along which the sheet is transported downward and then upward to reverse the sheet front to back, the reversing transport path extending vertically and being connected to the gap; and a first gate unit that prevents passage of the sheet that has entered the reversing transport path when the sheet free falls and allows passage of the sheet when the sheet receives a sheet transport driving force from the sheet transport unit.