Sheet Feeder Controller for Noise Reduction
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Solution Overview
Problem
Existing sheet feeders in image forming apparatuses generate impact noise due to reverse rotation of the sheet feed roller caused by restorative force after skew correction, and previous solutions either increase costs or fail to accurately align the sheet leading edge due to slippage and deflection variations.
Innovation Solution
A sheet feeder with a controller that temporarily stops and resumes the sheet feeding unit's drive before the leading edge abuts against the sheet conveying unit, adjusting the stop and resume periods based on a correction coefficient and sheet type to prevent reverse rotation and ensure accurate alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the sheet feed roller is stopped after the sheet has been deflected for skew correction, then the leading edge alignment is achieved, but impact noise is generated due to reverse rotation
Solution Approach 1:
The controller temporarily stops the sheet feed roller before the leading edge abuts against the sheet conveying unit, and maintains this stopped state for a predetermined period. This preliminary action prevents the reverse rotation that causes impact noise while ensuring accurate leading edge alignment through skew correction.
Solution Approach 2:
The patent introduces a predetermined stopped period as a cushioning interval between the deflection phase and the conveyance phase. During this interval, the sheet feed roller remains stopped to allow the restorative force to fully align the leading edge without causing reverse rotation, thereby cushioning against the harmful impact noise.
2Object-generated harmful factors
If the sheet feed roller continuously rotates to prevent reverse rotation and impact noise, then noise is reduced, but accurate alignment of the leading edge becomes difficult due to slippage and deflection variations
Solution Approach 1:
The controller implements periodic action by temporarily stopping the sheet feed roller for a predetermined period during the sheet feeding process. This periodic interruption allows accurate alignment through skew correction while preventing continuous rotation that would cause slippage and deflection variations, thereby maintaining both noise reduction and alignment precision.
3Object-generated harmful factors
If separate drive sources are used for the sheet feed roller and registration rollers to prevent reverse rotation, then impact noise is eliminated, but device complexity and cost increase
Solution Approach 1:
The patent merges the control of the sheet feed roller and registration rollers under a single drive source with a controller that coordinates their operations. By temporarily stopping the sheet feed roller for a predetermined period and then rotating it in synchronization with the registration rollers, the system eliminates impact noise without requiring separate drive sources, thereby reducing device complexity and cost.
4Object-generated harmful factors
If the sheet feed roller is temporarily stopped before leading edge abuts against the conveying unit, then reverse rotation is prevented, but sheet slippage causes positioning inaccuracies
Solution Approach 1:
The controller uses feedback from sheet detection means to monitor the sheet's position and conveyance status. Based on this feedback, the controller dynamically adjusts the timing and duration of the temporary stop period, ensuring that the leading edge is accurately positioned while preventing reverse rotation. This feedback mechanism compensates for sheet slippage and maintains positioning accuracy.
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 solution effectively reduces impact noise and ensures accurate skew correction by dynamically controlling the sheet feeding process, maintaining efficient sheet conveyance without additional drive sources and minimizing alignment errors.
Implementation Method 1
impact noise is generated due to reverse rotation of the sheet feed roller caused by restorative force after skew correction
Implementation Method 2
due to rigidity of the sheet and variation of the coefficient of friction, adhesion of paper dust to the sheet feed roller
Data Source
AI summary
A sheet feeder incorporatable in an image forming apparatus includes a sheet container to accommodate a sheet, a sheet feeding unit, a sheet conveyance member, a sheet conveying unit disposed downstream from the sheet feeding member in a sheet conveyance direction, and a controller to stop the sheet feeding unit before the sheet abuts against the sheet conveying unit and to resume the driving, and to drive the sheet conveying unit to start while rotating the sheet feeding unit. The controller adjusts a temporary stop period for the driving of the sheet feeding unit before the sheet abuts against the sheet conveying unit, according to a period in which the sheet passes first and second points determined optionally between a standby position determined prior to feeding of the sheet and a temporary stop position located before the sheet abuts against the sheet conveying unit.