Oblique-feed Unit Skew Correction via Speed and Force Control
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Solution Overview
Problem
Existing sheet conveyance apparatuses face issues with sheet turning during skew-feed correction, leading to reduced accuracy and potential damage when accelerating the oblique-feed roller, which compromises the productivity and reliability of the sheet conveyance process.
Innovation Solution
A sheet conveyance apparatus with an oblique-feed unit that adjusts its driving speed and nipping force after the sheet abuts an abutment surface, transitioning from a first state with a lower speed and stronger nipping force to a second state with a higher speed and weaker nipping force, thereby reducing the moment that causes sheet turning and maintaining the corrected posture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the oblique-feed roller accelerates the driving speed after the sheet butts against the reference side plate, then productivity is improved, but sheet turning occurs and skew-feed correction accuracy is reduced
Solution Approach 1:
The control unit performs preliminary deceleration of the oblique-feed roller before the sheet reaches the reference side plate, ensuring the sheet butts against the plate with reduced impact speed. This preliminary action prevents excessive impact while maintaining subsequent productivity through controlled acceleration phases.
Solution Approach 2:
The system dynamically adjusts the driving speed of the oblique-feed roller through multiple phases: initial deceleration to reduce impact, followed by controlled acceleration to maintain productivity. The control unit monitors sheet position and adjusts motor speed in real-time, transforming a static speed setting into a dynamic, multi-stage speed profile that balances precision and productivity.
2Productivity
If the oblique-feed roller maintains high driving speed to secure productivity, then processing efficiency is improved, but impact damage to the sheet occurs
Solution Approach 1:
The control unit applies preliminary deceleration before the sheet contacts the reference side plate, reducing the impact velocity to prevent damage. This preliminary action is timed based on sheet detection, ensuring high-speed operation for most of the conveyance cycle while protecting against impact damage at the critical moment of contact.
Solution Approach 2:
The oblique-feed roller operates in periodic speed cycles: high-speed phases for productivity, deceleration phases before sheet contact to prevent damage, and recovery phases. This periodic speed modulation allows the system to achieve high average productivity while periodically reducing speed to prevent impact damage.
3Object-affected harmful factors
If the oblique-feed roller decelerates to reduce impact on the sheet, then sheet damage is reduced, but productivity is reduced
Solution Approach 1:
The control unit implements preliminary deceleration only in the specific time window before sheet contact, rather than maintaining low speed throughout the entire operation. This targeted deceleration minimizes impact while preserving high-speed operation during non-critical phases, thereby maintaining overall productivity.
Solution Approach 2:
The system transitions from static low-speed operation to dynamic multi-phase speed control. The oblique-feed roller alternates between high-speed phases (for productivity) and deceleration phases (for impact reduction), with the control unit adjusting motor speed based on real-time sheet position feedback. This dynamic control achieves both impact reduction and productivity maintenance.
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
This approach effectively suppresses sheet turning, enhancing the accuracy of skew-feed correction and reducing the risk of sheet damage, while maintaining productivity by minimizing the impact during the transition.
Implementation Method 1
an oblique-feed unit configured to convey the sheet by imparting to the sheet nipped a force in a direction inclined relative to the sheet conveyance direction
Data Source
AI summary
A sheet conveyance apparatus includes an oblique-feed unit configured to nip and convey a sheet by imparting to the nipped sheet a force in a direction inclined relative to a sheet conveyance direction so that the sheet approaches an abutment surface in the width direction as the sheet proceeds downstream in the sheet conveyance direction; a drive unit configured to drive the oblique-feed unit; a change unit configured to change the force of the oblique-feed unit; and a control unit configured to control the drive unit and the change unit so that, after causing the sheet to abut against the abutment surface in a first state in which the oblique-feed unit is driven at a first speed, the oblique-feed unit is put into a second state in which the oblique-feed unit is driven at a second speed higher than the first speed and the force is weaker than in the first state.