Doctor Blade Primer Coating for Uniform Print Quality
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Solution Overview
Problem
Existing methods for producing decorative foils, particularly those with pre-impregnated papers or plastic film layers, face challenges in achieving consistent print quality due to uneven resin penetration and interaction with printing rollers.
Innovation Solution
A method involving the application of a primer layer with a specific thickness, using a doctor blade to remove excess primer and create a hydrodynamic high-pressure zone, ensuring uniform primer application without direct contact with the roller surface, combined with optimized blade doctor alignment and primer material characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a squeegee is used to scrape off excess primer material during coating, then the primer layer thickness is controlled, but the squeegee directly contacts the roller surface causing uneven resin penetration and poor print quality
Solution Approach 1:
The patent introduces a doctor blade as an intermediary element between the squeegee and the roller surface. The doctor blade is positioned to contact the roller surface and scrape off excess primer material, while the squeegee remains elevated and does not directly contact the roller. This intermediary arrangement prevents direct contact between the squeegee and roller surface, eliminating the harmful effect of uneven resin penetration while maintaining precise control over primer layer thickness through the doctor blade's scraping action.
2Measurement precision
If the squeegee is positioned close to the roller surface to control primer thickness, then coating precision is improved, but the squeegee interacts with the printing roller surface degrading print quality
Solution Approach 1:
The doctor blade serves as a mediator that enables precise primer layer thickness control without compromising print quality. By positioning the doctor blade to contact the roller surface at a controlled distance, the system achieves precise thickness measurement and control through the blade's interaction with the roller, while the squeegee remains elevated and does not interfere with the printing roller surface, thus maintaining print quality consistency.
Solution Approach 2:
The patent segments the coating control function into two separate components: the squeegee for applying and initial shaping of the primer layer, and the doctor blade for precise thickness control and excess material removal. This segmentation allows each component to perform its function optimally - the squeegee can be positioned for effective coating application while the doctor blade is positioned close to the roller surface for precise thickness control, without either component directly interfering with the printing roller surface.
3Manufacturing precision
If excess primer material is scraped off using direct contact method, then layer thickness is determined, but the scraping process creates harmful interaction with the material web
Solution Approach 1:
The doctor blade acts as an intermediary scraping element that determines the liquid material layer thickness by contacting the primer-coated roller surface, not the material web directly. The blade scrapes off excess primer material from the roller surface in a controlled manner, preventing direct harmful interaction between the scraping mechanism and the material web, thus maintaining manufacturing precision while eliminating damage to the material web.
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 results in significantly improved printing results by maintaining an uninterrupted, precisely controlled primer layer thickness, enhancing print quality and resin distribution across the material web.
Implementation Method 1
its tip being arranged at a distance from the material web 1 in a hydrodynamic high-pressure zone which is formed in front of the tip 44 due to the liquid or flowable primer material 6 applied to the material web 1
Data Source
Figure 1
Figure 2
AI summary
The invention relates to an improved method for producing a printable single or multi-layered material web, characterised, inter alia, in that the following features are present: prior to printing, a primer layer (6) is applied to the side of the material web (1a) that is provided for printing, this primer layer (6) is applied in an excess amount to the printing side (1a) of the material web (1), excess primer material is stripped away by means of a doctor blade stripping element (4) that is downstream of the material web (1) in the removal direction or forward feed direction (A), for which purpose the plane of the removal doctor blade (4) is adjustable in its alignment angle (a) with regard to the plane of the material web (1) and in its relative position and/or distance to the plane of the material web (1), and a primer material is used which has a flow time of between 10 and 30 seconds according to DIN norm 53211/4, and/or which has a solids fraction constituting between 30% and 60%.