Two-Step Cleaning for Ablation Debris Removal

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Solution Overview

Problem

Current laser-based lithographic systems face challenges with the removal of ablation debris from silicone topmost layers, particularly with solventless inks, leading to poor ink-up issues due to residual silicone, which is difficult to clean and affects printing efficiency.

Innovation Solution

A two-step cleaning process is employed, first using an aqueous liquid that is not a solvent for silicone, followed by a second liquid that is a silicone solvent, to effectively remove ablation debris and prepare the printing member for high-solids inks, ensuring efficient ink transfer and printing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single cleaning liquid containing both aqueous and solvent components is used, then cleaning effectiveness is improved, but environmental impact and cost increase due to higher organic solvent content

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidenvironmental impact
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The cleaning process is divided into two sequential steps: first an aqueous-based cleaner removes water-soluble debris, then a solvent-based cleaner removes silicone debris. This segmentation allows each cleaner to be optimized for its specific target, reducing the need for high organic solvent content in a single cleaning solution while maintaining overall cleaning effectiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The aqueous cleaning step acts as an intermediary that removes water-soluble debris before the solvent-based cleaning step addresses silicone debris. This intermediate step prevents the solvent cleaner from needing to handle all types of debris simultaneously, reducing its organic solvent load and environmental impact.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If solventless inks are used, then environmental impact is reduced, but plate cleaning effectiveness deteriorates due to inability to dissolve silicone debris

Engineering Contradiction:
Improveenvironmental impactVSAvoidplate cleaning effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The cleaning process separates debris removal into two distinct phases: aqueous cleaning for water-soluble materials and solvent-based cleaning for silicone. This segmentation compensates for the lack of solvent in the printing ink itself, providing dedicated silicone removal capability without requiring the printing ink to contain solvents.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The aqueous cleaning step is performed as a preliminary action before the solvent-based cleaning step. This preliminary removal of water-soluble debris reduces the overall debris load, allowing the subsequent solvent step to focus specifically on silicone removal with reduced solvent requirements.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If traditional single cleaning liquid is used, then process simplicity is maintained, but cleaning effectiveness with solventless inks deteriorates

Engineering Contradiction:
Improvecleaning process complexityVSAvoidcleaning effectiveness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The cleaning system is segmented into two sequential cleaning stations or steps, each with optimized chemistry for specific debris types. This segmentation provides the cleaning effectiveness needed for solventless inks while keeping each individual cleaning step relatively simple and manageable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cleaning process changes chemical parameters between steps: the first step uses aqueous-based chemistry optimized for water-soluble debris, while the second step uses solvent-based chemistry optimized for silicone. This parameter change allows each step to be tuned for maximum effectiveness against its target debris type.

Inventive Principle:
Principle #35Parameter changes

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 allows for successful ink-up and printing with high-solids inks within fewer cycles, improving printing efficiency and reducing environmental impact by minimizing the use of organic solvents.

Implementation Method 1

subjecting the imaged printing member to a first cleaning liquid that is not a solvent for silicone to remove a portion of the ablation debris

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

subjecting the printing member to a second cleaning liquid that is a solvent for silicone

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 3

Exposure to laser radiation may, for example, cause ablation—i.e., catastrophic overheating—of the ablated layer

Methodology Applied
Scientific EffectAblation: Ablation

Implementation Method 4

ablation debris generated thereunder includes pyrolytic remnants of the imaging layer

Methodology Applied
Scientific EffectPyrolysis: Pyrolysis

Data Source

PatentUS8875629B2Ablation-type lithographic imaging with enhanced debris removal
Publication Date: 2014.11.04 PRESSTEK INC

AI summary

Sequentially subjecting an imaged ablation-type printing member having a silicone topmost layer to, first, a cleaning liquid that is not a solvent for silicone, followed by subjecting to a second cleaning liquid that is a silicone solvent, conditions the printing member for subsequent printing with high-solids inks.