Lithographic Printing Plate Processing with Low Alkali Solution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for preparing lithographic printing plates face challenges such as high environmental impact, high running costs, and poor printing durability due to the use of alkaline developers and gum solutions, which result in waste disposal issues and surface staining problems.
Innovation Solution
A method involving a lithographic printing plate precursor exposed to a low alkali aqueous solution with a pH of 8.5 to 10.8, containing a low molecular weight hydroxycarboxylate ion, pH buffer, and surfactant, processed with circulation to maintain solution level, and using a rubbing member for non-image area removal, reducing waste and improving safety and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional alkaline developers (pH 11 or more) and gum solutions are used for processing lithographic printing plate precursors, then development capability is achieved, but environmental pollution and disposal costs increase due to large amounts of waste liquid
Solution Approach 1:
The invention changes the pH parameter from conventional high alkalinity (pH 11 or more) to low alkalinity (pH 9.0 to 10.5), and modifies the chemical composition by using specific alkali metal hydroxycarboxylates with controlled molecular weights (500-2000) instead of conventional alkali hydroxides. This parameter change enables development capability while reducing environmental pollution and disposal costs.
2Manufacturing precision
If multiple processing steps (developing, washing, gumming) are used to ensure proper plate processing, then processing quality is maintained, but device complexity and space requirements increase
Solution Approach 1:
The invention merges multiple processing functions (development and gumming) into a single processing bath. The low alkali aqueous solution contains both developing agents (alkali metal hydroxycarboxylates) and gumming agents (water-soluble polymers with specific functional groups), allowing both functions to be performed in one step, thereby reducing device complexity and space requirements while maintaining processing quality.
Solution Approach 2:
The processing solution is designed to perform multiple functions simultaneously: it acts as both a developer (removing non-image area) and a gumming agent (protecting the image area and preparing for printing). This multi-functionality is achieved by incorporating specific polymers with carboxyl, hydroxyl, or amino groups that can both dissolve exposed resin and provide protective gumming.
3Productivity
If conventional high alkali developers are used for processing, then development speed is sufficient, but printing durability deteriorates due to surface staining and image area dissolution
Solution Approach 1:
The invention changes the alkali concentration parameter to a lower range (pH 9.0 to 10.5) and uses specific alkali metal hydroxycarboxylates with controlled molecular weights. This parameter change reduces the aggressiveness of the developer, preventing image area dissolution and surface staining that occur with conventional high alkali developers, thereby improving printing durability while maintaining adequate development speed through the addition of specific polymers.
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 enables safe, efficient, and cost-effective one-solution processing that simplifies steps, reduces waste, and enhances printing plate durability and surface protection, preventing surface staining and maintaining printing quality.
Implementation Method 1
processing the imagewise exposed lithographic printing plate precursor in a state where the imagewise exposed lithographic printing plate precursor is immersed in a developing tank holding an aqueous solution having pH of 8.5 to 10.8 and containing a low molecular weight hydroxycarboxylate ion
Implementation Method 2
containing a low molecular weight hydroxycarboxylate ion having a molecular weight of 500 or less, a pH buffer agent and a surfactant
Implementation Method 3
containing a low molecular weight hydroxycarboxylate ion having a molecular weight of 500 or less, a pH buffer agent and a surfactant
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A method for preparing a lithographic printing plate, includes: exposing imagewise a lithographic printing plate precursor including a hydrophilic support and an image-recording layer containing a sensitizing dye, a polymerization initiator, an addition polymerizable compound having an ethylenically unsaturated double bond and a binder polymer; and processing the imagewise exposed lithogaphic printing plate precursor in a state where the imagewise exposed lithographic printing plate precursor is immersed in a developing tank holding an aqueous solution having pH of 8.5 to 10.8 and containing a low molecular weight hydroxycarboxylate ion, a pH buffer agent and a surfactant with circulation of the aqueous solution between the developing tank and an external tank provided outside a processing path line including the developing tank so as to keep constant a liquid level of the aqueous solution in the developing tank.