Variable Pressing Force Roller Transport for Skew Correction
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Solution Overview
Problem
Transport apparatuses and printing systems face challenges in maintaining the posture of media with oblique or bent leading edges, leading to skew and print quality degradation, as existing methods fail to effectively adjust the medium's posture regardless of its shape.
Innovation Solution
A transport apparatus with a driving roller, a driven roller, and a feeder that adjusts the pressing force using a changer with a spring or cam mechanism, allowing the medium to be pulled back and corrected in posture without bending, ensuring proper alignment and preventing skew during transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the driven roller presses the medium against the driving roller with a large pressing force during transport, then the medium is securely transported without slipping, but the medium cannot be smoothly pulled back and its posture cannot be corrected
Solution Approach 1:
The pressing force of the driven roller is made variable rather than fixed. The changer mechanism adjusts the pressing force dynamically: high pressing force during transport for stability, low pressing force during pull-back for smooth operation. This dynamic adjustment resolves the contradiction between secure transport and ease of pull-back operation.
Solution Approach 2:
The pressing force parameter is changed based on the operational phase. The system transitions from a high pressing force state during transport to a low pressing force state during pull-back. This parameter change allows the system to achieve both reliable transport and smooth pull-back operation without compromise.
2Ease of operation
If the driven roller is positioned far from the driving roller, then the medium can be pulled back more freely, but the medium remains bent and cannot assume an appropriate posture
Solution Approach 1:
The position relationship between the driven roller and driving roller is dynamically adjusted. During pull-back operation, the driven roller is positioned closer to the driving roller to enable effective posture correction through the nipping action, while maintaining sufficient separation during transport for free medium movement. This dynamic positioning resolves the contradiction between pull-back freedom and posture alignment.
3Device complexity
If the feeder pulls back the medium without changing the pressing force, then the pull-back operation is simple, but the medium bends and escapes from the transport path
Solution Approach 1:
The pressing force parameter is changed during the pull-back operation to a lower value, allowing the feeder to pull back the medium smoothly without causing it to bend or escape. This parameter change maintains medium control while simplifying the pull-back operation, resolving the contradiction between operational simplicity and medium control reliability.
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
The solution effectively adjusts the medium's posture, preventing skew and improving print quality by controlling the transport and pull-back distances based on roller rotation and spring tension, ensuring accurate alignment and reducing the risk of bending or escape from the transport rollers.
Implementation Method 1
a changer that changes a pressing force by which the driven roller presses the medium against the driving roller
Implementation Method 2
a changer that changes a pressing force by which the driven roller presses the medium against the driving roller
Implementation Method 3
a driven roller that presses the medium against the driving roller when the medium is transported
Data Source
AI summary
A transport apparatus includes a driving roller that transports a medium in a transport direction, a driven roller that presses the medium against the driving roller when the medium is transported, a changer that changes a pressing force by which the driven roller presses the medium against the driving roller, and a feeder configured to feed the medium toward the driving roller and pull back the medium in a direction opposite to the transport direction. Before the driving roller transports the medium, the feeder pulls back the medium after the changer has changed the pressing force to a value that is smaller than the value of the pressing force set for transport of the medium.