Sheet Feeding Device Speed Control for Jam Prevention
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Solution Overview
Problem
Existing sheet feeding devices often experience sheet feeding failures due to multiple sheets being conveyed together, particularly when the suction conveyer is driven by a stepping motor, leading to inefficiencies in productivity and handling of non-uniform sheet states.
Innovation Solution
A sheet feeding device with a conveyer that has switchable speeds, a corrector for sheet inclination, and detectors to control the conveyance speed based on detected sheet positions, ensuring appropriate slack and preventing excessive conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the suction conveyer conveys sheets by a constant predetermined amount, then the sheet conveyance is simple and stable, but when multiple sheets stick together, the conveyance distance becomes insufficient and causes sheet feeding failure
Solution Approach 1:
The conveyer speed is dynamically adjusted based on real-time detection of sheet separation status. The controller switches between first speed (normal conveyance) and second speed (reduced conveyance when sheets stick together) to adapt to varying sheet states, preventing sheet feeding failure while maintaining simple constant conveyance under normal conditions
Solution Approach 2:
A sheet separation detector provides feedback on whether sheets are properly separated before conveyance. The controller uses this feedback signal to determine the appropriate conveyer speed, creating a closed-loop control system that automatically adjusts conveyance parameters based on actual sheet conditions
2Reliability
If sheets are sufficiently separated before conveyance, then multiple sheets being conveyed together is prevented, but sufficient time for separation must be secured which reduces productivity
Solution Approach 1:
The system dynamically adjusts conveyer speed based on actual sheet separation status rather than using a fixed slow speed for all sheets. When sheets are properly separated, normal high speed conveyance is used. When sheets stick together, the speed is reduced to allow proper separation, thus maintaining productivity for well-separated sheets while ensuring reliability for stuck sheets
Solution Approach 2:
The conveyer speed parameter is changed from a single constant value to a variable parameter with at least two values (first speed and second speed). This parameter change allows the system to optimize between speed and separation quality based on real-time sheet conditions
3Measurement precision
If the conveyer is driven by a stepping motor, then precise position control is achieved, but sheets are conveyed by a certain distance during acceleration and deceleration which causes excessive conveyance when sheets stick together
Solution Approach 1:
The stepping motor's acceleration and deceleration characteristics are dynamically adjusted based on sheet separation status. When sheets are stuck together, the controller reduces conveyer speed which automatically reduces acceleration and deceleration distances, compensating for the inherent motor characteristics and preventing excessive conveyance
Solution Approach 2:
The system performs preliminary detection of sheet separation status before initiating conveyance. Based on this preliminary information, the controller pre-adjusts the conveyer speed and acceleration/deceleration parameters to prevent the problem of excessive conveyance during motor transient states
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
Prevents sheet feeding failures by adjusting conveyance speed based on detected sheet positions, reducing the likelihood of multiple sheets being conveyed together and improving robustness against non-uniform sheet states without compromising productivity.
Implementation Method 1
a suction conveyer (12) that sucks a sheet (S) from the sheet bundle (SS) and conveys the sheet (S) in the sheet conveyance direction
Implementation Method 2
air is blown by the floating air blower toward a sheet end face of a sheet bundle stored in the sheet storage, thereby floating a sheet from the sheet bundle
Implementation Method 3
the sheet is conveyed while having the inclination corrected at the outlet port roller
Data Source
AI summary
A sheet feeding device includes: a sheet storage that stores a plurality of sheets; a conveyer that conveys, in a sheet conveyance direction, sheets stored inside the sheet storage; a driver that drives the conveyer in such a manner that a conveyance speed of the sheet is switchable between two or more speeds; a corrector that corrects inclination of the sheet more on a downstream side in the sheet conveyance direction than the conveyer is; a first sheet detector that detects a sheet positioned at a first predetermined position between the conveyer and the corrector; and a hardware processor that controls the driver to change a conveyance speed of the sheet conveyed by the conveyer in accordance with a detection result of the first sheet detector.