Printing Guide Variable Thickness for Medium Kicking
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Solution Overview
Problem
In printing devices, the phenomenon of 'kicking' occurs when the medium leaves a guide with a high conveyance surface, leading to conveyance errors and reduced printing quality due to a pushing force between the guide and the medium.
Innovation Solution
A printing device design where the guide's top surface is positioned higher than the tangent line at the conveyance roller's contact point, with a thinner downstream end and optionally beveled corners, to reduce the likelihood of kicking by minimizing the pushing force on the medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the guide's top surface is positioned at a high position to support the medium, then the medium can be properly supported upstream from the conveyance roller, but kicking occurs when the medium leaves the guide causing conveyance errors
Solution Approach 1:
The guide structure transitions from a uniform thickness design to a variable thickness design where the downstream end has reduced thickness. This local modification creates a gradual thickness reduction toward the downstream end, allowing the guide to provide support where needed while minimizing the pushing force that causes kicking at the exit point.
Solution Approach 2:
The guide's downstream end features rounded corners with a specified radius of curvature. This curvature prevents abrupt edges that would create sudden pushing forces on the medium, thereby reducing kicking while maintaining proper medium support throughout the conveyance path.
2Stability of the object's composition
If the guide has a high conveyance surface to prevent medium sagging, then medium support is improved, but a pushing force acts on the medium causing it to be pushed out in the conveyance direction
Solution Approach 1:
The guide employs variable thickness with the downstream end having smaller thickness than the upstream end. This creates a gradient in structural support that reduces the pushing force at the critical exit region while maintaining adequate support upstream, thereby preventing medium ejection without compromising stability.
Solution Approach 2:
Rounded corners at the downstream end with specified radius of curvature eliminate sharp edges that concentrate pushing forces. The curved transition gradually reduces the force applied to the medium as it leaves the guide, preventing the medium from being pushed out while maintaining proper support during conveyance.
Data Source
AI summary
To prevent conveyance defects due to kicking, a printing device includes a conveyance roller for conveying a medium in a conveyance direction; a guide for supporting the medium on a top surface of the guide on an upstream side in the conveyance direction from the conveyance roller; and a head for ejecting ink and printing on the medium on a downstream side in the conveyance direction from the conveyance roller; wherein the top surface of the guide is positioned higher than a line tangent to the conveyance roller at a position of contact between the conveyance roller and the medium; and an end part of the guide on the downstream side in the conveyance direction has a smaller thickness in the direction in which the medium is supported than on the upstream side of the end part in the conveyance direction.