Inkjet Coating for Opaque Articles
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Solution Overview
Problem
Existing coating methods for achieving an even and high gloss surface finish on articles are capital intensive, wasteful, and prone to uneven thickness, 'orange peel' effects, and require complex masking processes, while also lacking effective abrasion resistance.
Innovation Solution
A method using inkjet heads to apply a coating composition with at least 30 wt% solvent, allowing for drying before curing to achieve a consistent, high gloss, and abrasion-resistant finish, utilizing inkjet technology with UV curing and controlled viscosity to minimize waste and ensure even application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coating methods (dip coating, flow coating, spray coating) are used to apply coating onto articles, then coating can be achieved, but the process is capital intensive requiring substantial facilities and services as well as highly qualified technical support
Solution Approach 1:
The patent replaces conventional mechanical coating systems (dip coating, flow coating, spray coating equipment) with an inkjet printing system that uses digitally controlled inkjet heads to deposit coating material. This substitution eliminates the need for substantial facilities and highly qualified technical support while maintaining reliable coating application capability.
Solution Approach 2:
The patent changes the delivery mechanism parameter from continuous mechanical application to digitally controlled droplet deposition. By using inkjet technology with precise digital control, the system achieves reliable coating without requiring complex mechanical facilities or specialized operational expertise.
2Reliability
If flow coating is used to apply coating onto articles, then coating can be achieved, but waste of coating material and uneven coating thickness are achieved across the article
Solution Approach 1:
The patent applies local quality by using digitally controlled inkjet heads that can precisely control coating material deposition at each specific location on the article. This allows for uniform coating thickness across the entire surface while eliminating waste, as material is deposited only where needed with exact precision.
Solution Approach 2:
The patent replaces the mechanical flow coating system with a digitally controlled inkjet system that offers precise control over material placement. This substitution enables uniform coating thickness and eliminates the material waste associated with conventional flow coating methods.
3Reliability
If spray coating is used to apply coating onto articles, then coating can be achieved, but excessive waste and possible occurrence of an orange peel effect due to variable flow, uneven coating due to uneven drying and lateral application of the composition and inclusion of air bubbles due to high pressure used in the process
Solution Approach 1:
The patent replaces the high-pressure spray coating mechanical system with a digitally controlled inkjet deposition system. This substitution eliminates excessive waste, orange peel effects, uneven coating, and air bubble inclusion by precisely controlling material delivery through non-contact droplet deposition at low pressure.
Solution Approach 2:
The patent introduces digital control as an intermediary between the coating material and the article surface. The digital control system precisely manages droplet deposition timing, location, and quantity, eliminating the harmful effects (orange peel, uneven coating, air bubbles) that result from uncontrolled high-pressure spray application.
4Reliability
If existing coating methods are used to apply coating to selected areas of articles, then coating can be achieved, but masking of parts of the article is required which makes the process more complex and labour-intensive
Solution Approach 1:
The patent replaces the mechanical masking process with a digitally controlled inkjet system that can selectively deposit coating material only on desired areas of the article. This substitution eliminates masking complexity and labor while maintaining precise selective coating capability through digital pattern control.
Solution Approach 2:
The patent changes the selectivity control parameter from physical masking to digital pattern control. By using digitally programmable inkjet heads, the system achieves selective area coating without masking, reducing process complexity and labor requirements while maintaining precise selective application capability.
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 method produces coatings with consistent thickness, reduced 'orange peel' effects, enhanced abrasion resistance, and a high gloss finish, improving both the visual and physical performance of the coated articles.
Implementation Method 1
The coating composition has a viscosity of from 5 to 50 cp at 25°C
Implementation Method 2
applying from one or more inkjet heads a coating composition
Implementation Method 3
drying the coating composition for at least 30 seconds
Implementation Method 4
curing the coating composition to form a cured coating
Data Source
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AI summary
A method of producing a coated opaque article comprising a) applying from one or more inkjet heads (302) a coating composition comprising at least 30 wt% of solvent to a surface (101) of a transparent or opaque article to be coated (100); b) drying the coating composition for at least 30 seconds; and c) curing the coating composition to form a cured coating. The coating composition has a viscosity of from 5 to 50 cp at 25°C and when the article to be coated (100) is a transparent article, an opaque coating is applied to another surface (102) of the article after step c), thereby rendering the coated article opaque.