Direct Dampening Fluid Application in Variable Data Lithography
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Solution Overview
Problem
Existing lithographic techniques, such as offset printing, face challenges in achieving uniform dampening fluid thickness and are prone to contamination and cavitation issues due to the use of intermediate rollers, which hinder high-speed variable data printing and increase costs for shorter print runs.
Innovation Solution
A system that applies dampening fluid directly to a reimageable surface in a variable data lithographic system, utilizing subsystems like ultrasonic sprayers, nebulizers, and impeller-based systems to convert the fluid into a dispersed state for precise deposition, eliminating the need for intermediate rollers and enabling on-the-fly thickness control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If intermediate rollers (form roller) are used to apply dampening fluid, then the system is mechanically simple and easy to manufacture, but the dampening fluid thickness becomes non-uniform due to mechanical alignment errors, positional tolerances, and component wear
Solution Approach 1:
The patent replaces the mechanical roller-based dampening fluid application system with a direct deposition system that uses controlled dispensing mechanisms. This substitution eliminates the form roller and its associated mechanical alignment issues, positional tolerances, and wear problems, thereby achieving uniform dampening fluid thickness without relying on mechanical precision. The system directly deposits dampening fluid onto the reimageable surface in controlled amounts, bypassing the intermediate roller entirely.
2Reliability
If intermediate rollers are used to transfer dampening fluid, then the device structure is simple, but contamination and cavitation issues occur due to roller contact with the reimageable surface
Solution Approach 1:
The patent extracts and removes the intermediate roller (form roller) from the dampening fluid application process. By eliminating this intermediate component that comes into contact with the reimageable surface, the system prevents contamination and cavitation issues that arise from roller contact. The dampening fluid is applied directly to the reimageable surface without passing through an intermediate roller, thereby ensuring print quality consistency and eliminating roller-related defects.
3Productivity
If traditional offset printing with permanently patterned plates is used, then long print runs are cost-effective, but variable data printing requires plate replacement which reduces productivity
Solution Approach 1:
The patent employs a reimageable surface that can be dynamically reconfigured without physical replacement. The surface can be re-imaged with new patterns by applying fresh dampening fluid and ink, allowing variable data printing to proceed at high speed without the downtime associated with plate removal and installation. This dynamic capability enables true high-speed variable data printing where the image can change from impression to impression.
4Manufacturing precision
If form roller is used to apply dampening fluid, then the system is easier to operate, but ribbing instability occurs leading to non-uniform dampening fluid layer
Solution Approach 1:
The patent replaces the mechanical roller-based application system with a direct deposition system that controls dampening fluid application through dispensing mechanisms rather than roller contact. This substitution eliminates ribbing instability and the associated non-uniformities in the dampening fluid layer that occur with roller-based systems. The system achieves uniform application while maintaining operational simplicity through automated controlled dispensing.
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 ensures a uniform and controlled dampening fluid layer, reducing artifacts and costs by eliminating roller-related issues, allowing for high-speed variable data printing with improved print quality and reduced operational delays.
Implementation Method 1
A system for direct application of dampening fluid for a variable data lithographic apparatus... utilizing subsystems like ultrasonic sprayers, nebulizers, and impeller-based systems to convert the fluid into a dispersed state
Implementation Method 2
utilizing subsystems like ultrasonic sprayers, nebulizers, and impeller-based systems to convert the fluid into a dispersed state
Data Source
AI summary
A system and corresponding methods are disclosed for applying a dampening fluid to a reimageable surface of an imaging member in a variable data lithography system, without a form roller. In one embodiment, the system includes subsystems for converting a dampening fluid from a liquid phase to a dispersed fluid phase, and for directing flow of a dispersed fluid comprising the dampening fluid in dispersed fluid phase to the reimageable surface. The dampening fluid reverts to the liquid phase directly on the reimageable surface. In another embodiment a continuous ribbon of dampening fluid may be applied directly to the reimageable surface. This embodiment includes a body structure having a port for delivering dampening fluid in a continuous fluid ribbon directly to the reimageable surface, and a mechanism, associated with the body structure, for stripping an entrained air layer over the reimageable surface when the reimageable surface is in motion.