Printer Medium Transport Friction Gradient for Skew Control
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Solution Overview
Problem
Existing medium transport apparatuses face challenges in suppressing skewing or meandering of recording media between the transport unit and the winding unit due to biased winding positions, as increased friction coefficients can lead to jamming and reduced transport accuracy.
Innovation Solution
A medium transport apparatus with a medium support portion having a higher friction coefficient at the downstream end and a lower friction coefficient at the upstream end, utilizing an elastic member formed from an elastomer to provide necessary sliding resistance while preventing jamming, and featuring a first support surface for unwound media and a second convex support surface for wound media to manage sliding resistance effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the friction coefficient of the roller is significantly increased to suppress medium deviation, then the medium deviation is reduced, but the recording medium will jam during transport due to extremely large frictional resistance force
Solution Approach 1:
The invention applies different friction coefficients to different parts of the medium support surface. The downstream end portion has a higher friction coefficient (0.4-0.6) to suppress medium deviation, while the upstream end portion has a lower friction coefficient (0.1-0.3) to prevent jamming. This local differentiation resolves the contradiction by optimizing each region's friction characteristics according to its specific functional requirements.
Solution Approach 2:
The medium support surface is segmented into multiple regions with different friction characteristics. The surface is divided into a first end portion (downstream) with high friction coefficient and a second end portion (upstream) with low friction coefficient. This segmentation allows each segment to perform its specific function optimally without interfering with the other.
2Manufacturing precision
If the friction coefficient is increased to prevent medium skewing, then medium skewing is suppressed, but the transport position accuracy drops due to jamming
Solution Approach 1:
The invention implements local quality differentiation by providing a higher friction coefficient at the downstream end portion where medium skewing occurs, while maintaining a lower friction coefficient at the upstream end portion where transport position accuracy is critical. This localized optimization prevents skewing without compromising transport accuracy.
Solution Approach 2:
The invention changes the friction coefficient parameter spatially along the medium support surface. By varying the friction coefficient from the upstream end to the downstream end, the system optimizes both skewing suppression and transport position accuracy according to the different functional requirements at different locations.
3Manufacturing precision
If a very large frictional resistance force is applied to suppress deviation at the transport unit, then medium deviation is reduced, but the medium becomes inclined and transport position accuracy drops
Solution Approach 1:
The invention applies local quality by concentrating the high friction coefficient at the downstream end portion where deviation occurs, while keeping the upstream end portion with low friction coefficient. This localized approach suppresses deviation without creating excessive overall frictional resistance that would cause medium inclination.
Solution Approach 2:
The invention converts the potentially harmful effect of friction into a beneficial one by strategically positioning high friction only where needed (downstream end) to suppress deviation, while allowing low friction elsewhere to maintain smooth transport and prevent inclination.
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 configuration effectively suppresses media deviation and jamming, ensuring high-quality printing by controlling sliding resistance and maintaining transport accuracy even during biased winding, with a static-kinetic friction coefficient difference of 0.1 or less.
Implementation Method 1
a friction coefficient between the medium support surface at an end portion of the downstream side in the transport direction and the recording medium is higher than a friction coefficient between the medium support surface at an upstream side in the transport direction from the end portion of the downstream side and the recording medium
Data Source
AI summary
A recording medium after printing which is discharged from a main body of a printer is guided from the main body to a support surface of a discharge support portion extending to a lower anterior side, and is wound as a roll body by a winding unit in a path that passes a tension roller. A tape-shaped elastic member is fixed on an end portion of a downstream side in a transport direction of the discharge support portion so as to extend in a width direction. An elastic friction surface is formed on the end portion of the downstream side in the transport direction of the support surface. A friction coefficient between the elastic friction surface and the recording medium is higher than the friction coefficient between a portion at an upstream side in the transport direction from the elastic friction surface in the support surface and the recording medium.