Polyester Film Coating Composition for Digital Printing
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Solution Overview
Problem
Existing coated polyester films with high static charge are not suitable for all types of digital printing processes, particularly those using both liquid and dry toners, due to poor runability and electrostatic properties, limiting their compatibility with various digital printing machines.
Innovation Solution
A coating composition combining polyethylene carboxylic acid dispersion with homopolymer or copolymer of polyacrylate and/or polyvinyl acetate dispersion is applied to oriented polyester film, allowing for reduced static charge and enabling printing on all types of electrostatic printers with both liquid and dry toners, using either inline or offline coating methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If EAA coating is applied to polyester film to enable digital printing, then printability is improved, but static charge increases causing poor runability
Solution Approach 1:
The patent applies a composite coating system consisting of multiple layers: a bottom layer of polyethylene carboxylic acid copolymer (EAA) for printability, and a top layer of acrylic or vinyl acetate copolymer to reduce static charge. This composite structure combines the advantages of both materials - the EAA layer provides electrostatic printing capability while the outer layer controls static charge to improve runability through printing presses
Solution Approach 2:
The coating is applied with different properties at different depths - the lower layer (EAA) has high polarity and electrostatic properties for toner adhesion, while the upper layer has lower polarity and reduced static charge for improved handling. This local differentiation of coating properties resolves the contradiction between printability and runability
2Adaptability or versatility
If coating is applied to enable printing on all types of printers (liquid and dry toners), then adaptability is improved, but coating composition complexity increases
Solution Approach 1:
The patent develops a universal coating composition that works with both liquid toners (HP Indigo) and dry toners (Xerox, Konica Minolta, Ricoh, Canon). The multi-layer structure with specific polymer combinations provides a single solution that replaces multiple specialized coatings, achieving universality across different digital printing technologies while managing composition complexity through systematic material selection
3Strength
If polyethylene carboxylic acid dispersion is used to improve adhesion, then adhesion is improved, but static charge increases affecting runability
Solution Approach 1:
The coating is segmented into functional layers: the EAA dispersion layer provides adhesion and printability at the substrate interface, while a separate outer layer of acrylic or vinyl acetate copolymer provides static charge control. This segmentation allows each layer to optimize its specific function without compromising the other
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 coated polyester film exhibits improved runability and electrostatic printing properties, allowing for seamless printing on diverse digital printing systems, including HP Indigo, Xerox, Ricoh, and Canon machines, with reduced static charge and enhanced adhesion of both liquid and dry toners.
Implementation Method 1
The present invention is to provide a coated polyester film where the coating is done either inline i.e. during process of film formation or offline i.e. after film formation... The present invention is to provide a coated polyester film for reducing static charge on the said film, so as to pick an individual film one by one by the printer while printing
Implementation Method 2
Image is formed on the imaging surface by use of a uniform electrostatic charge distribution throughout the surface. The electrostatic charge can be created by the corona and the print image is developed by applying toner which adhere to the surface and develop the image
Data Source
AI summary
The present invention relates to a coating composition for polyester film capable of printing on all types of printers with liquid and dry toners. The coating composition comprising of a combination of polyethylene carboxylic acid dispersion and homopolymer or copolymer of polyacrylate dispersion and/or homopolymer or copolymer of polyvinyl acetate dispersion, wherein acrylate and/or acetate content be is in the range of 1 to 50% of carboxylic acid content in the dispersion.