Liquid Electrostatic Printing Adhesion Promoter Layer
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Solution Overview
Problem
In liquid electrostatic printing, particularly in one-shot mode, images experience adhesion issues when transferred to print substrates, leading to poor bonding and potential peeling, which is more pronounced compared to multi-shot mode.
Innovation Solution
A method involving a liquid electrostatic ink composition with a carrier liquid and chargeable resin particles, combined with an adhesion promoting composition containing a tackifier with a polar functional group and a number average molecular weight less than 5000, is applied to form an adhesion promoting layer on an intermediate transfer member, which is then transferred to the print substrate alongside the developed ink image, enhancing adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If liquid electrostatic ink composition is transferred directly to print substrate, then printing process is simple, but adhesion of printed image to substrate is poor
Solution Approach 1:
An adhesion promoting composition is introduced as an intermediary substance between the liquid electrostatic ink composition and the print substrate. This composition contains adhesion promoters that chemically or physically bond to both the ink particles and the substrate surface, creating a strong interface that prevents peeling and improves adhesion reliability without complicating the overall printing process flow
2Reliability
If adhesion promoter is applied to improve bonding, then adhesion of printed image improves, but process complexity increases
Solution Approach 1:
The adhesion promoting composition is merged with the existing liquid electrostatic ink composition application step. The adhesion promoter is applied to the intermediate transfer member in conjunction with the ink transfer process, allowing both functions (ink transfer and adhesion promotion) to be achieved in an integrated manner rather than as separate sequential steps, thereby minimizing process complexity increase
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 significantly improves the adhesion of printed images on the substrate, especially in one-shot mode, and also benefits multi-shot mode and duplex printing, providing superior peeling resistance compared to methods without an adhesion promoter.
Implementation Method 1
an adhesion promoting composition comprising an adhesion promoter... transferring the adhesion promoting layer to a print substrate... such that the adhesion promoting layer is disposed on the print substrate
Implementation Method 2
the adhesion promoter comprises a tackifier having a polar functional group and a number average molecular weight Mn of less than about 5000
Implementation Method 3
The charged toner particles adhere to the image areas of the latent image while the background areas remain clean
Data Source
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AI summary
Herein is described a liquid electrostatic printing method comprising providing a liquid electrostatic ink composition comprising a carrier liquid and chargeable particles comprising a resin; and providing an adhesion promoting composition comprising an adhesion promoter. The liquid electrostatic ink composition is contacted with a latent electrostatic image disposed on a surface to create a developed ink image. The developed ink image is transferred to an intermediate transfer member. The adhesion promoting composition is deposited on the intermediate transfer member to form an adhesion promoting layer. The adhesion promoting layer and the developed ink image are transferred to a print substrate, such that the adhesion promoting layer is disposed on the print substrate and the developed ink image is disposed on the adhesion promoting layer.