Wiping Roller Surface Tension Control for Print Media
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Solution Overview
Problem
Printing media containing substances like plasticizers and adhesives can cause these substances to migrate to the printing surface, leading to uneven surface tension and defects in printed images, such as graininess and pinholes, due to non-uniform deposition of printing fluids.
Innovation Solution
A wiping element, such as a wiping roller with an elastic layer and a textile sheath, is positioned upstream of the print zone to contact the printing surface at a relative speed, spreading substances evenly and reducing surface tension differences, thereby improving image quality by distributing micro-droplets and contaminants across a larger area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If printing media are stored or transported in rolled form at high temperatures, then flexibility is maintained, but substances migrate to the printing surface causing defects
Solution Approach 1:
The wiping element performs a preliminary cleaning action on the printing surface before printing occurs. This prevents substances that have migrated to the surface from causing defects, by removing or redistributing them in advance of the printing process
Solution Approach 2:
The wiping element acts as an intermediary between the problematic printing media and the printing process. It mediates the interaction by modifying the printing surface condition, allowing printing to proceed without defects despite substance migration in the media
2Productivity
If printing fluids are deposited on surfaces with migrated substances, then printing can proceed, but non-uniform deposition occurs causing image defects
Solution Approach 1:
The wiping element performs preliminary treatment of the printing surface before printing fluid deposition. This prepares the surface to receive printing fluid uniformly, preventing defects while maintaining printing throughput
Solution Approach 2:
The wiping element converts the harmful effect of migrated substances into a beneficial pre-treatment condition. By spreading or removing these substances before printing, the surface is actually prepared for more uniform fluid deposition than an completely clean surface might provide
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 reduces defects in printed images by ensuring uniform deposition of printing fluids, enhancing image quality and maintaining contact with the printing surface despite misalignments, while being adaptable and easy to maintain.
Implementation Method 1
The friction caused by wiping may have the effect that substances such as plasticizers that may be present on the printing surface in a non-continuous or uneven distribution
Data Source
AI summary
An example printing apparatus is described comprising a wiping element before the print zone, for slipping in contact with a print medium and wiping a printing surface of the print medium. An implementation of a wiping roller for wiping the printing surface of a print medium may comprise a rigid core, a layer of elastic material and a driving pinion. An example method for printing is also described, comprising spreading over a larger print medium area, by wiping, amounts of a substance that may migrate through a print medium and that is present on the printing surface of a print medium, before printing on the print medium.