Sheet Discharge Roller Control for Accurate Stapling Retraction
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Solution Overview
Problem
Conventional post-processing apparatuses face issues with sheet displacement during retraction onto the processing tray due to the driving roller bouncing back, leading to degraded output quality, especially when stapling is performed.
Innovation Solution
The control portion adjusts the downward movement speed of the driving roller based on whether stapling is required and the number of sheets stacked, setting it to a lower speed during stapling to prevent bouncing and displacement, and adjusts contact pressure accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the driving roller moves downward at normal speed to discharge sheets, then productivity is maintained, but sheet displacement occurs during retraction causing degraded output quality
Solution Approach 1:
The driving roller's downward movement speed is dynamically adjusted based on the operation mode: normal speed for discharge operations to maintain productivity, and reduced speed for retraction operations to prevent sheet displacement and bouncing, thereby resolving the contradiction between productivity and positioning accuracy
Solution Approach 2:
The control portion changes the movement speed parameter of the driving roller according to the operational context (discharge vs. retraction), optimizing both productivity and sheet positioning accuracy by using appropriate speed levels for each operation type
2Reliability
If the driving roller contacts the sheet with high force to prevent slipping, then conveyance reliability improves, but sheet displacement occurs due to bouncing back
Solution Approach 1:
The driving roller applies higher contact force during discharge operations to ensure reliable sheet conveyance, while reducing contact force during retraction operations to prevent bouncing and sheet displacement, thus resolving the contradiction between conveyance reliability and positioning accuracy through dynamic force adjustment
Solution Approach 2:
The control portion adjusts the contact force parameter of the driving roller based on operation type, increasing force for reliable discharge conveyance and decreasing force for precise retraction positioning, thereby optimizing both reliability and precision
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
Prevents sheet displacement on the processing tray, maintaining output quality and productivity by effectively retracting and discharging sheets without glitches, particularly in inkjet recording apparatuses.
Implementation Method 1
the driven roller is disposed below the driving roller across the sheet conveyance passage and nips the sheet with the driving roller
Implementation Method 2
rotates the driving roller backward so as to retract the sheet from its trailing edge onto the processing tray
Data Source
AI summary
A post-processing apparatus includes a conveyance portion, a processing tray, a post-processing portion, a discharge tray, a discharge portion, and a control portion. The discharge portion includes an arm, a driving roller, and a driven roller. When stacking a sheet on the processing tray, the control portion brings the driving roller into contact with the sheet. Except when the sheet as the target of post-processing is retracted onto the processing tray, the control portion sets the downward movement speed of the driving roller to a normal speed. When the sheet as the target of post-processing is retracted onto the processing tray, the control portion sets the downward movement speed of the driving roller to a speed lower than the normal speed.