Cascade Developing System for Lithographic Printing Plate Consistency
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Solution Overview
Problem
The developing solution in lithographic printing plate processing becomes less active over time due to the accumulation of removed coating materials, leading to inconsistent lithographic properties as more plates are processed, necessitating a method to maintain a constant activity level.
Innovation Solution
A cascade system is employed where a lithographic printing plate precursor is developed with a first and second solution, with the second solution being regenerated by adding a replenishing solution at a controlled rate, and both solutions are circulated through separate liquid conveying systems, maintaining the volume within specific limits to ensure consistent activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single developing solution is used for processing multiple lithographic printing plates, then the processing capacity is increased, but the activity level of the developing solution decreases over time due to accumulation of removed coating materials
Solution Approach 1:
The single developing solution is divided into two separate solutions in a cascade system. The first solution receives the exposed printing plate precursor and removes coating material, while the second solution further processes the plate. This segmentation prevents excessive accumulation of removed material in one solution, maintaining consistent activity levels across multiple plates while enabling continuous high-volume processing.
2Reliability
If the developing solution is circulated and regenerated by adding replenishing solution, then the activity level is maintained, but the system complexity increases
Solution Approach 1:
The cascade system with two developing solutions automatically maintains activity levels through the natural flow and regeneration process. The first solution is replenished by overflow from the second solution, which itself is regenerated by adding replenishing solution. This self-regulating system maintains consistent activity without requiring complex external control mechanisms, balancing reliability with manageable system complexity.
3Manufacturing precision
If a cascade system with two developing solutions is used, then the lithographic property consistency is improved, but the device complexity increases
Solution Approach 1:
The harmful accumulation of removed coating material is extracted from the system by separating the processing into two distinct solutions. The first solution handles the primary development, while the second solution handles further processing with freshly replenished chemistry. This extraction prevents degradation of lithographic properties that would occur in a single solution, achieving consistent results without requiring overly complex control systems.
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 approach maintains the activity level of the developing solution, ensuring consistent lithographic properties across multiple plates, reduces waste, and optimizes solution usage, thereby improving the efficiency and quality of the printing process.
Implementation Method 1
photopolymer plates which contain a photopolymerizable composition that hardens upon exposure to light
Data Source
AI summary
A method of making a lithographic printing plate comprising the steps of: a) image-wise exposing a lithographic printing plate precursor, comprising a support having a hydrophilic surface or which is provided with a hydrophilic layer and, thereon, a light or heat sensitive coating comprising a photopolymerisable composition, b) processing said precursor with a first solution, consecutively with a second solution, thereby removing the coating from the support in the non-printing areas, wherein said first and second solutions are provided by a cascade system, wherein said second solution overflows into said first solution and said first solution overflows into a container to be further treated as waste, wherein said second solution is regenerated by adding a replenishing solution or a mixture of replenishing solutions at a rate of at least 5 ml/m2 of treated precursor and at most 100 ml/m2 of treated precursor, wherein said first and second solutions are circulated respectively by a first and second liquid conveying system, wherein the first solution present in said first liquid conveying system has a volume of at least Vmin and at most Vmax respectively defined by formula 1 and formula 2, wherein Vmin and Vmax represent respectively the minimum and maximum volume present in said first liquid conveying system, each of them expressed in liter, wherein A and B represents a constant value of respectively 2 and 15, and wherein said processing width represents the width, expressed in m, inside the processing unit, perpendicular to the processing direction, which is available for processing plate precursors in a uniform way across their width.