Ink Splitting Multi-Roll Cleaner for Variable Data Lithography
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Solution Overview
Problem
Conventional cleaning subsystems in digital offset printing systems are ineffective in completely removing residual ink from imaging members, leading to ghosting and inefficiencies in high-speed variable data printing processes.
Innovation Solution
A cleaning roller train with a cleaning member having a thin, uniform layer of ink that adheres to and removes residual ink from the imaging member through cohesion, utilizing ink-splitting mechanics to transport and collect the ink waste, eliminating the need for shear forces and chemical methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cleaning subsystems (wiping with cleaning web or pad, blade scraping) are used to remove residual ink from imaging member, then some residual ink is removed, but complete removal is not achieved leading to ghosting and poor cleaning effectiveness
Solution Approach 1:
The patent replaces conventional mechanical cleaning methods (wiping, scraping) with an ink-splitting mechanism based on fluid dynamics and surface tension. The cleaning roller uses a thin layer of ink that automatically splits and removes residual ink through capillary action and adhesion forces, eliminating the need for physical contact cleaners that cause ghosting.
Solution Approach 2:
The invention changes the state of the cleaning surface by maintaining it as a thin, uniform ink layer rather than a solid or liquid cleaner. This parameter change allows the cleaning surface to dynamically adapt to residual ink through ink-splitting mechanics, achieving complete removal without ghosting.
2Reliability
If chemical methods are used to remove residual ink, then residual ink can be removed, but the system becomes complicated with chemical waste and feasibility issues
Solution Approach 1:
The cleaning subsystem uses the ink itself as the cleaning agent through the ink-splitting mechanism. The thin layer of ink on the cleaning roller automatically removes residual ink from the imaging member without requiring external chemicals, simplifying the system and eliminating chemical waste while maintaining effective residual ink removal.
3Productivity
If high-speed variable data printing is implemented, then productivity increases, but complete ink transfer cannot be guaranteed leaving residual ink on imaging member
Solution Approach 1:
The cleaning roller is positioned to immediately address residual ink after the transfer nip, performing preliminary cleaning before the imaging member returns to the inking station. This preliminary action ensures that even at high speeds, residual ink is removed before the next printing cycle, preventing ghosting and maintaining image quality.
Solution Approach 2:
The cleaning subsystem operates continuously as the imaging member passes through the transfer nip and returns, maintaining constant removal of residual ink. This continuous action ensures that at high printing speeds, no residual ink accumulates on the imaging member surface, enabling sustained high-speed operation without quality degradation.
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
The solution effectively removes residual ink, preventing ghosting and ensuring a clean imaging surface for subsequent prints, improving print quality and efficiency in high-speed variable data lithographic printing.
Implementation Method 1
residual ink remaining on the imaging member adheres to the cleaning member through cohesion
Implementation Method 2
residual ink remaining on the imaging member adheres to the cleaning member through cohesion
Data Source
AI summary
A cleaning subsystem for a variable data lithography system includes a cleaning roller train having a cleaning member in physical contact with an imaging member such that residual ink remaining on the imaging member, such as following transfer of an inked latent image from the imaging member to a substrate, adheres to the cleaning member through cohesion and is thereby removed from the imaging member. The cleaning roller train uses the ink-splitting mechanics to remove, transport and collect the ink waste. The key cleaning roller train is a thin but uniform layer of ink on the cleaning member that contacts the imaging member causing removal on the residual ink through cohesion.