Flexographic Printing Plate Oxygen Barrier for Laser Imaging
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Solution Overview
Problem
Flexographic printing plates face challenges in maintaining small dot sizes and achieving thorough curing due to atmospheric oxygen inhibition, leading to poor surface roughness and dot definition, especially in direct write technology.
Innovation Solution
A method involving a flexographic printing blank with a backing layer, photoresin, and a removable coversheet, where the photoresin is cured before imaging using a UV laser within the 250-420 nm range, and the coversheet remains on during imaging to limit oxygen diffusion and enhance surface cure, resulting in well-defined dot shapes and reduced surface roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct write laser imaging is used on flexographic printing plates, then imaging speed and productivity are improved, but atmospheric oxygen inhibition causes poor surface cure and dot definition
Solution Approach 1:
The patent applies a preliminary oxygen barrier layer to the photosensitive printing element before laser imaging. This pre-prepared barrier prevents oxygen diffusion during the imaging process, eliminating oxygen inhibition effects and enabling proper surface cure and dot definition to be achieved during the high-speed direct write imaging process.
Solution Approach 2:
The patent introduces an intermediary oxygen barrier layer between the atmosphere and the photosensitive material. This intermediary layer blocks oxygen from reaching the photoresin during laser imaging, thereby preventing oxygen inhibition while allowing the laser energy to effectively cure the photoresin and create well-defined dots.
2Measurement precision
If small dot sizes are used in flexographic printing plates, then printing resolution is improved, but oxygen inhibition prevents thorough curing and causes poor surface roughness
Solution Approach 1:
The oxygen barrier layer serves as an intermediary that protects small dots from oxygen inhibition during laser imaging. This barrier enables thorough curing of even the smallest dots by preventing oxygen from quenching the photopolymerization reaction, thereby achieving both high printing resolution and smooth surface finish.
Solution Approach 2:
The patent creates a localized inert environment by applying an oxygen barrier layer directly to the photosensitive material. This effectively excludes atmospheric oxygen from the imaging zone, allowing small dots to be thoroughly cured with smooth surfaces even during high-speed direct write imaging.
3Device complexity
If conventional imaging methods are used without oxygen barrier, then process simplicity is maintained, but additional treatments are required to correct surface cure deficiencies
Solution Approach 1:
The oxygen barrier layer is applied as a preliminary step before imaging, preventing surface cure deficiencies before they occur. This pre-prepared barrier eliminates the need for subsequent corrective treatments such as re-imaging or chemical surface treatments, thereby maintaining process simplicity while improving manufacturing ease.
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 method improves dot size accuracy, surface roughness, and curing quality, reducing the need for additional treatments and minimizing material costs, while ensuring high-quality plate imaging and printing performance.
Implementation Method 1
the photoresin comprises a crosslinkable elastomeric compound, a plasticizing compound, monomeric binder compounds and one or more photoinitiator compounds
Implementation Method 2
the coversheet remains on during imaging to limit oxygen diffusion and enhance surface cure
Data Source
Figure 1A~2B
Figure 3C~4D
Figure 5E~6F
AI summary
A method of making a relief image printing element from a photosensitive printing blank is provided. The method comprising the steps of: 1) providing a photosensitive printing blank comprising a backing layer, at least one layer of photoresin on top of the backing layer and a removable coversheet on top of the at least one layer of photoresin; 2) imaging the photosensitive printing blank through the removable coversheet using a laser to create a relief image therein; and 3) removing the removable coversheet.