Planographic Printing Plate Edge Stain Prevention
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Solution Overview
Problem
Current methods for producing planographic printing plates suffer from edge stains during newspaper printing, particularly due to ink adherence at the ends of the printing plate, and existing solutions either fail to provide adequate image formation or degrade under white light exposure.
Innovation Solution
A planographic printing plate precursor with an anodized film and an image recording layer containing an infrared absorbing agent, where the end portions are cut to a sagging shape and treated with an ink repellent agent, ensuring a sufficient image forming region and improved storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the end portions of the printing plate are treated with liquid containing organic solvent and water-soluble resin, then edge stain is prevented, but the treatment width and treatment shape are poor and desired picture cannot be drawn on the end portions
Solution Approach 1:
The invention applies different treatments to different regions of the printing plate. The end portions are treated with ink repellent agent to prevent edge stain, while the image formation region maintains its original properties for proper picture formation. This local differentiation resolves the contradiction by allowing edge stain prevention without compromising image quality.
Solution Approach 2:
The printing plate is divided into distinct functional regions: the end portions treated with ink repellent agent and the image formation region with proper image properties. This segmentation allows each region to be optimized independently, preventing edge stain while ensuring proper picture formation in the image region.
2Object-affected harmful factors
If the end portions are treated with coating solution containing hydrophilizing agent, then edge stain is prevented, but the treatment width and treatment shape are poor and desired picture cannot be drawn on the end portions
Solution Approach 1:
The invention applies different treatments to different regions of the printing plate. The end portions are treated with ink repellent agent to prevent edge stain, while the image formation region maintains its original properties for proper picture formation. This local differentiation resolves the contradiction by allowing edge stain prevention without compromising image quality.
3Reliability
If photosensitive layer contains sensitizer, then photo sensitivity is improved, but stability under white light is degraded
Solution Approach 1:
The invention uses an infrared absorbing agent as an intermediary substance that absorbs harmful infrared radiation and converts it to heat, protecting the sensitizer from degradation. This intermediary allows the sensitizer to maintain high photo sensitivity while being protected from white light-induced degradation by the infrared absorbing agent.
Solution Approach 2:
The photosensitive layer is formulated as a composite material containing both the sensitizer and infrared absorbing agent. This composite structure allows the sensitizer to provide high photo sensitivity while the infrared absorbing agent provides stability under white light by absorbing detrimental infrared radiation, thus resolving the contradiction between sensitivity and stability.
4Manufacturing precision
If development treatment using alkaline developer is performed, then image formation is achieved, but film traces remain and edge stains occur
Solution Approach 1:
The invention applies ink repellent agent to the end portions of the printing plate, creating a local property difference between the treated end portions and the image formation region. This local treatment prevents edge stains and film traces at the ends while maintaining proper image formation capabilities in the image region through subsequent development treatment.
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 solution effectively prevents edge stains by reducing ink adherence and enhancing the storage stability of the printing plate under white light, ensuring clear and consistent printing.
Implementation Method 1
the image recording layer contains an infrared absorbing agent
Implementation Method 2
an aluminum support which has an anodized film
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Provided are a planographic printing plate precursor and a method of producing a planographic printing plate precursor, in which an image forming region during printing on newspaper page is ensured and edge stains are eliminated. Provided are a planographic printing plate precursor (10b) including an aluminum support (12) which has an anodized film (14), and an image recording layer (16) on the aluminum support (12), in which an end portion of the planographic printing plate precursor (10b) has a sagging shape having a sagging amount (X) of 25 µm to 150 µm and a sagging width (Y) of 70 µm to 300 µm, the image recording layer (16) contains an infrared absorbing agent, and a part or an entire side surface of two sides of the aluminum support (12), the two sides having the sagging shape and opposing each other contains an ink repellent agent (44); and a method of producing the planographic printing plate precursor (10b).