Sheet Stacking Device Blade Rotation for Curl Prevention
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Solution Overview
Problem
Existing sheet stacking devices face challenges in efficiently guiding and stacking sheets after post-processing, particularly in maintaining alignment and preventing curling, due to inadequate control over the sheet discharge and stacking processes.
Innovation Solution
A sheet stacking device with a pair of sheet discharge rollers, a stacking tray, a blade member, and a controller that executes stop processing and rotation processing to guide the sheet onto the tray, ensuring precise alignment and preventing curling by using a blade member to beat and press the sheet's rear end portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pressing member is configured to be rotatable about a shaft disposed below a rotary shaft of a drive roller, then the pressing member can beat and press the rear end portion of the sheet, but the device complexity increases due to separate drive motors for the pressing member and drive roller
Solution Approach 1:
The patent combines the drive functions by disposing the blade member on the drive roller itself, eliminating the need for a separate drive motor for the pressing member. The drive roller now serves dual purposes: conveying the sheet and driving the blade member through the protrusion that engages with the blade member's groove.
Solution Approach 2:
The drive roller is designed to perform multiple functions: it conveys the sheet through its rotation and simultaneously drives the blade member through the engaged protrusion-groove mechanism. This multi-functionality reduces the overall number of components and simplifies the drive mechanism.
2Device complexity
If the blade member is disposed on the drive roller and driven simultaneously with the drive roller, then the device complexity is reduced, but precise control of the blade member's beating and pressing actions becomes more difficult
Solution Approach 1:
The blade member is designed to rotate about its own axis while being driven by the drive roller's rotation. This dynamic configuration allows the blade member to perform both beating and pressing actions in sequence, with the pressing action occurring when the blade member's groove engages with the protrusion, providing precise control over the timing and force of each action.
Solution Approach 2:
The engagement between the protrusion on the drive roller and the groove on the blade member creates a mechanical feedback mechanism that ensures the blade member is driven at the correct timing and with the correct force. This mechanical coupling provides inherent feedback that maintains precise control over the blade member's actions.
3Manufacturing precision
If the blade member beats the rear end portion of the sheet from above, then the sheet alignment is improved, but the sheet may curl during high speed conveyance
Solution Approach 1:
The blade member performs periodic beating and pressing actions as it rotates, with the pressing action occurring at specific intervals when the groove engages with the protrusion. This periodic pressing action counteracts the curling tendency of the sheet during high speed conveyance, maintaining sheet flatness while preserving alignment precision.
Solution Approach 2:
The blade member applies a preliminary pressing action to the rear end portion of the sheet before the sheet completes its conveyance path. This preliminary anti-action prevents curling from developing during the remaining conveyance distance, especially at high speeds where curling tendencies are more pronounced.
Data Source
AI summary
A sheet stacking device includes: a pair of sheet discharge rollers having a drive roller; a stacking tray for stacking sheets; a blade member; and a controller. The controller executes: stop processing in which the blade member is stopped at a stop position during discharging of the sheet; and rotation processing in which the blade member is rotated by one turn before a rear end of the sheet passes through the pair of sheet discharge rollers and the sheet is placed on the stacking tray. The blade is configured, in the rotation processing, to make the sheet fall on the stacking tray by beating a rear end portion of the sheet from above, and to be brought into contact with the rear end portion of the sheet which falls on the stacking tray from above while pulling the sheet toward an upstream side in the sheet discharge direction.