Disturber Roller Vacuum Cleaning for Digital Lithography Ghosting

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Solution Overview

Problem

Existing systems for variable data digital lithographic image forming struggle with ghosting issues due to incomplete removal of dampening solution from the inking member, leading to ink rejection and reduced image quality, as conventional methods like doctor blades and air knives are inefficient in removing residual ink and dampening solution without wasting ink or increasing humidity.

Innovation Solution

A disturber roller with a pliable silicone surface and porous base is introduced to agitate and remove stale ink from anilox cells, combined with a vacuum system to extract residual dampening solution, ensuring fresh ink flow and efficient recycling of dampening solution vapors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If doctor blades and air knives are used to remove dampening solution from the inking member, then the inking member surface is cleaned, but residual ink and dampening solution remain causing ghosting issues

Engineering Contradiction:

Improveimage qualityVSAvoidresidual ink and dampening solution

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent employs an anilox roller with a porous surface structure containing cells that hold ink. The porous material allows for controlled ink retention and release while enabling vacuum extraction of dampening solution through the porous base, effectively resolving the ghosting problem by allowing selective removal of contaminants while maintaining ink availability.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent introduces a vacuum system that uses pneumatic pressure differential to extract dampening solution and residual ink from the anilox roller surface. The vacuum source creates negative pressure that draws contaminants through the porous anilox cells, eliminating ghosting without requiring aggressive mechanical scraping that would waste ink.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Loss of substance

If conventional cleaning methods are used, then some dampening solution is removed, but ink is wasted and humidity increases

Engineering Contradiction:

Improvedampening solution removal efficiencyVSAvoidink waste and humidity control

Core Design Contradiction:

Loss of substanceVSLoss of energy

Solution Approach 1:

The patent implements a system that recovers dampening solution vapors extracted by the vacuum system. The vapors are condensed and returned to the dampening solution reservoir, preventing ink waste and humidity buildup while maintaining continuous operation. This closed-loop approach eliminates the need to discard valuable dampening solution.

Inventive Principle:

Principle #34Discarding and recovering

3Device complexity

If a single anilox chamber blade system is used, then the system structure is simplified, but ghosting elimination is insufficient

Engineering Contradiction:

Improveinker unit structureVSAvoidghosting elimination

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent divides the anilox roller surface into multiple cells with different functions: ink storage cells, transfer cells, and cleaning zones. This segmentation allows different regions of the roller to perform specialized functions, enabling effective ghosting elimination while maintaining a relatively simple single-roller architecture.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a disturber roller as an intermediary element that contacts the anilox roller surface to agitate and remove stale ink from cells. This intermediary mechanism provides effective cleaning without requiring complex multi-roller systems or aggressive blade scraping, resolving the contradiction between simplicity and effectiveness.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution effectively eliminates ghosting by ensuring complete removal of residual dampening solution and stale ink, improving image quality and reducing operational costs through efficient ink and solution recycling.

Implementation Method 1

a vacuum system to extract residual dampening solution

Methodology Applied

Scientific EffectVacuum: Vacuum

Implementation Method 2

A disturber roller with a pliable silicone surface and porous base is introduced to agitate and remove stale ink from anilox cells

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS9272506B2Systems and methods for implementing an advanced inker unit surface conditioning system in a variable data digital lithographic printing device

Publication Date: 2016.03.01 XEROX CORP

AI summary

A system and method are provided for providing an improved inker unit surface cleaning and conditioning system, including in a single anilox chamber blade system, for improving image quality, including eliminating ghosting, in a proposed variable data digital lithographic image forming architecture. Techniques are provided to remove acquired oil from an inking member. A particularly-configured containment encloses a cleaner (disturber) roller to emulsify the acquired oil on the inking roller. The cleaner roller is preferably configured with a pliable surface including a silicon roller surface over a porous base. The silicon roller (1) absorbs dampening solution oil; and (2) agitates ink that may be still held in certain cells/cavities of the inking member or roller. In embodiments, a vacuum pressure is applied to the inside of the hollow cleaner roller to better remove the residual ink and dampening solution from the inking roller.