Sheet Feeding Apparatus Pickup Rotary Member Control
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Solution Overview
Problem
Existing sheet feeding apparatuses in image forming devices often experience multiple feeding of sheets due to the pickup member inadvertently picking up succeeding sheets during the pickup operation, leading to unstable sheet conveyance and undesirable situations like sheet jamming.
Innovation Solution
A sheet feeding apparatus with a control unit that determines the execution of either a first feed mode or a second feed mode based on the time taken for the first feed process and the length of the sheet, using a detection unit to prevent the pickup of succeeding sheets by adjusting the pickup rotary member's operation state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pickup member performs multiple pickup operations to improve sheet conveyance stability, then the reliability of sheet feeding is improved, but the pickup member may inadvertently pick up succeeding sheets causing multiple feeding
Solution Approach 1:
The pickup member is designed to be movable between a pickup position (contacting the sheet) and a separated position (released from the sheet). This dynamic positioning allows the pickup member to reliably pick up sheets while preventing inadvertent contact with succeeding sheets, thus resolving the contradiction between conveyance stability and multiple feeding prevention
Solution Approach 2:
The pickup member is moved to the separated position after completing the pickup operation, before the sheet is fully conveyed. This preliminary separation action ensures that the pickup member does not contact succeeding sheets, preventing multiple feeding while maintaining reliable sheet conveyance
2Reliability
If the pickup member contacts the sheet for a longer duration to ensure stable pickup, then the reliability of sheet feeding is improved, but the succeeding sheet may be picked up causing multiple feeding
Solution Approach 1:
The pickup member dynamically adjusts its contact duration with the sheet by moving between contact and release states. This allows sufficient contact time for reliable pickup while minimizing the overall time the pickup member remains in contact, preventing inadvertent pickup of succeeding sheets
Solution Approach 2:
The pickup member performs periodic contact and release actions in a controlled cycle. This periodic operation ensures that contact occurs only when needed for pickup, and release occurs promptly to prevent multiple feeding, optimizing both reliability and time efficiency
Data Source
AI summary
A sheet feed portion feeds a sheet by performing a pickup operation in a cycle in which a pickup rotary member is switched from a released state to a contact state and then switched to the released state. A detection unit detects the sheet at a position downstream of the sheet feed portion in the sheet feeding direction. A control unit is capable of executing a first feed mode in which a first feed process of carrying out a pickup operation is executed, or a second feed mode in which the first feed process is executed and then a second feed process of carrying out an additional pickup operation is executed. The mode to be executed is determined based on a time when the sheet is detected by the detection unit and a length of the sheet.