Sheet Conveyance Speed Control via Dual Sensor Detection
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Solution Overview
Problem
Image forming apparatuses face challenges in conveying small-sized documents without jamming, as existing solutions require complex and costly sensor configurations to detect document sizes accurately, complicating the routing of wires within the document tray.
Innovation Solution
A sheet conveyance apparatus with a pivotable sheet supporting unit, featuring first and second detection sensors positioned within specific ranges to determine document size, controlling conveyance speed accordingly, thereby eliminating the need for sensors within the document tray and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are provided within the document tray to detect document size, then document size detection precision is improved, but device complexity and manufacturing cost increase due to complex wire routing
Solution Approach 1:
The detection sensors are extracted from the document tray and relocated to the apparatus body. This extraction eliminates the need for complex wire routing within the pivotable document tray while maintaining document size detection capability through alternative sensor positioning in the apparatus body.
Solution Approach 2:
The side regulating plates serve as intermediaries between the document and the detection sensors. When the document is placed on the document tray, the side regulating plates regulate the document's widthwise position, and this regulated position is then detected by the sensors in the apparatus body, enabling indirect but accurate size detection.
2Productivity
If conveyance speed is increased for large documents, then productivity is improved, but reliability deteriorates due to jamming and multi-feed issues with small documents
Solution Approach 1:
The conveyance speed is made dynamic rather than fixed. The control unit adjusts the conveyance speed based on the detected document size: faster speed for large documents to maintain productivity, and slower speed for small documents to prevent jamming and multi-feed, thus maintaining reliability across different document types.
Solution Approach 2:
The conveyance speed parameter is changed according to document size. By detecting whether the document extends beyond the first widthwise range to the second widthwise range, the system changes the conveyance speed parameter appropriately - higher speed for documents in the second range and lower speed for documents confined to the first range.
Data Source
AI summary
A sheet conveyance apparatus includes a sheet supporting tray to support a sheet, a sheet conveyance unit to convey the sheet supported on the sheet supporting tray, a first detection sensor to detect the supported sheet at a first detection position, and a second detection sensor to detect the supported sheet at a second detection position farther from a center of the sheet supporting tray in a sheet width direction than the first detection position. In addition, a control unit controls the sheet conveyance unit in a first mode in a case where the first and second detection sensors detect the sheet, and controls the sheet conveyance unit in a second mode in which a sheet conveyance speed is slower than that of the first mode in a case where the first detection sensor detects the sheet and the second detection sensor detects no sheet.