Lithographic Printing Plate Edge Stain Prevention
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Solution Overview
Problem
In newspaper printing using planographic printing plates, edge stains occur due to ink adherence at the plate's end portions during continuous printing on roll-like paper, leading to degraded print quality and productivity issues, as existing methods either impair ink impressing properties or result in manual application inefficiencies and plate adhesion problems.
Innovation Solution
A planographic printing plate processing device with a conveyor and coating unit that applies a hydrophilizing agent to the plate's end portions, using a moving coating means perpendicular to the conveyance path, preventing ink adhesion and allowing for automatic, efficient processing without degrading productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the entire surface of the planographic printing plate precursor is coated with processing liquid, then edge stain is prevented, but the impressing property of printing ink in the image portion is deteriorated and print quality degrades
Solution Approach 1:
The patent applies processing liquid only to the end portions (margins) of the printing plate precursor rather than the entire surface. This localized application prevents edge stain in the margin areas while preserving the ink impressing properties of the image portions, thus resolving the contradiction between preventing harmful edge stains and maintaining high print quality.
2Object-affected harmful factors
If manual application of processing liquid to the side surface is performed, then edge stain is prevented, but productivity is degraded
Solution Approach 1:
The patent employs an automatic processing liquid application device that applies the processing liquid to the end portions of the printing plate precursor during automated conveyor operation. This eliminates the need for manual application, thereby preventing edge stain while maintaining high productivity consistent with modern exposure machine capabilities.
3Object-affected harmful factors
If processing liquid is applied to stacked planographic printing plate precursors, then edge stain is prevented, but the precursors adhere to each other and workability deteriorates
Solution Approach 1:
The patent applies processing liquid only to the exposed end portions of individual printing plate precursors during conveyor operation, rather than applying liquid to stacked precursors. This localized application prevents edge stain while avoiding the adhesion problem that occurs when processing liquid is applied to stacked materials, thereby maintaining good workability.
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
Prevents edge stains while maintaining print quality and increasing productivity by ensuring the end portions of the plates are effectively coated with a hydrophilizing agent, preventing plate adhesion and allowing for continuous, high-quality printing.
Implementation Method 1
coating means for coating a region within 1 cm from an end portion of at least one side of the planographic printing plate precursor or the planographic printing plate with a processing liquid that contains a hydrophilizing agent
Implementation Method 2
a conveyor which conveys a planographic printing plate precursor or a planographic printing plate along a conveyance path
Implementation Method 3
the coating unit comprises moving means for moving the coating means from a movement start position provided outside or inside of one side end portion of the planographic printing plate precursor or the planographic printing plate to a stopping position provided outside or inside of the planographic printing plate precursor or the planographic printing plate by passing the coating means (20) over the planographic printing plate precursor or the planographic printing plate in a direction perpendicular to the conveyance path
Data Source
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AI summary
Provided is a planographic printing plate processing device which prevents edge stain without reducing productivity of a planographic printing plate. A planographic printing plate processing device 28 includes a conveyor 18 which conveys a planographic printing plate precursor or a planographic printing plate along a predetermined conveyance path; and a coating unit 22 which is provided in the conveyance path and includes coating means 20 for coating a region within 1 cm from an end portion of at least one side of the planographic printing plate precursor or the planographic printing plate with a processing liquid that contains a hydrophilizing agent. Further, provided is a plate-making system 1 for a planographic printing plate which includes this planographic printing plate processing device 28.