Sheet Conveyance Deviation Correction via Feedback Control
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Solution Overview
Problem
In image forming apparatuses, sheets can experience deviation in the width direction along the conveyance path from the sheet correction mechanism to the discharge tray, especially when the conveyance path is long, leading to misalignment upon discharge.
Innovation Solution
A sheet conveying device equipped with a sheet conveying portion, a sheet discharge portion, a sheet shift portion, a conveying position detecting portion, a discharge position detecting portion, and a control portion. The control portion calculates the deviation between the discharge position and a reference position, and adjusts the sheet shift portion to correct the sheet's position along the conveyance path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the conveyance path length is increased to allow proper sheet correction, then sheet correction capability is improved, but sheet position stability deteriorates due to accumulated deviation over the long conveyance path
Solution Approach 1:
The patent implements a feedback control system where sensors detect the actual sheet position at multiple points along the conveyance path, and the control unit adjusts the sheet shift mechanism to compensate for detected deviations. This closed-loop feedback ensures that sheet position stability is maintained over the long conveyance path while preserving correction capability.
Solution Approach 2:
The patent replaces purely mechanical sheet positioning with a control system that uses detection results to dynamically adjust sheet position. The control unit processes detection data and commands the sheet shift mechanism, substituting passive mechanical alignment with active controlled positioning to maintain stability over long conveyance paths.
2Manufacturing precision
If a sheet correction mechanism is added to correct sheet position, then sheet position accuracy is improved, but device complexity increases
Solution Approach 1:
The patent designs the sheet shift mechanism to serve multiple functions: it acts as both the primary sheet correction device and the adjustment mechanism for compensating conveyance path deviations. This multi-functionality reduces overall device complexity while maintaining sheet position accuracy throughout the conveyance path.
Solution Approach 2:
The control unit automatically processes detection results and generates appropriate correction commands without requiring external intervention. The system self-regulates sheet position by using its own detection capabilities to drive its correction mechanism, reducing the need for additional control systems or manual adjustment mechanisms.
3Productivity
If the conveyance path is made long to accommodate image formation processes, then image formation capability is improved, but sheet position stability deteriorates due to position shifts during conveyance
Solution Approach 1:
The patent performs preliminary position detection and correction before sheets enter the long conveyance path for image formation. By pre-correcting sheet positions and establishing stable alignment at the start of the conveyance path, the system ensures position stability is maintained throughout the extended path required for complete image formation processes.
Solution Approach 2:
The patent uses continuous or periodic detection of sheet position during the conveyance process, with the control unit adjusting the sheet shift mechanism based on detected deviations. This feedback control maintains sheet position stability throughout the long conveyance path, enabling extended image formation processes without position drift.
Data Source
AI summary
An object of the present invention is to correct the deviation of a sheet in the width direction occurring on a conveyance path from a sheet correction mechanism (4) to a discharge tray. A sheet shift portion (41, 43, 44) moves a sheet in the width direction. A conveying position detecting portion (45, 46, 47) detects the position of the sheet in the width direction. A discharge position detecting portion (54, 8a) detects a discharge position of the sheet, in the width direction, discharged onto a discharge tray (33) in a sheet discharge portion (31). A control portion (8b) derives an amount of deviation between the discharge position and a discharge reference position based on a detection result of the discharge position detecting portion (54, 8a). Furthermore, the control portion (8b) corrects a conveying position of the sheet in a sheet conveying portion according to the amount of deviation.