Capacitive Fountain Solution Thickness Control on Imaging Surfaces

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Solution Overview

Problem

Conventional lithographic printing systems are unable to accommodate high-speed variable data printing processes and are sensitive to the amount of fountain solution applied, lacking real-time measurement capabilities, which leads to inconsistent print quality due to manual adjustments and reliance on open-loop systems.

Innovation Solution

A method and system for controlling fountain solution thickness on an imaging member surface using a capacitive proximity sensor to measure capacitance differences, allowing for real-time adjustments of the fountain solution dispense rate to maintain optimal thickness, thereby ensuring consistent print quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If manual adjustment of fountain solution amount is used, then system simplicity is maintained, but print quality consistency deteriorates

Engineering Contradiction:

Improvesystem simplicityVSAvoidprint quality consistency

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback control system where a capacitive sensor measures the actual fountain solution thickness on the imaging member surface, and this measurement is fed back to automatically adjust the fountain solution application rate. This closed-loop feedback mechanism resolves the contradiction by eliminating manual adjustment while ensuring consistent print quality through real-time automated control.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs self-adjustment of fountain solution thickness without external manual intervention. The capacitive sensor continuously monitors the fountain solution layer and the control system automatically modifies the application parameters to maintain optimal thickness, enabling the system to service itself and maintain print quality consistency.

Inventive Principle:

Principle #25Self-service

2Device complexity

If open-loop fountain solution system is used, then system complexity is reduced, but measurement capability is lost

Engineering Contradiction:

Improvesystem complexityVSAvoidfountain solution thickness measurement

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces complex mechanical measurement systems with a capacitive sensing system. The capacitive sensor measures fountain solution thickness by detecting changes in capacitance caused by the dielectric properties of the fountain solution layer, providing precise measurement capability while maintaining relatively simple system architecture.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If automated real-time control is implemented, then print quality consistency is improved, but device complexity increases

Engineering Contradiction:

Improvefountain solution thickness controlVSAvoidcontrol system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs a feedback control architecture where capacitive measurements of fountain solution thickness are continuously fed back to the control system, which automatically adjusts the fountain solution application rate. This feedback mechanism achieves precise thickness control while keeping the control logic relatively simple through direct measurement and adjustment.

Inventive Principle:

Principle #23Feedback

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 enables precise control of fountain solution thickness, reducing manual intervention and print quality issues by allowing for automated, real-time adjustments, enhancing the reliability and efficiency of digital printing processes.

Implementation Method 1

measuring a capacitance between a capacitive proximity sensor and the imaging member surface with the fountain solution layer therebetween

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

An imaging system then evaporates regions of the fountain solution layer in an image area by exposure to a focused radiation source (e.g., a laser light source, high power laser) to form pockets

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS11552636B2Method and device for controlling fountain solution thickness on an imaging surface using a capacitive proximity sensor

Publication Date: 2023.01.10 GENESEE VALLEY INNOVATIONS LLC

AI summary

An ultra-high resolution capacitive sensor affixed above an imaging member surface measures the thickness of fountain solution on the imaging member surface in real-time during a printing operation. The sensor is considered ultra-high resolution with a resolution high enough to detect nanometer scale thicknesses. The capacitive sensor would initially be zeroed to the imaging member surface. As fluid is added, the capacitive sensor detects the increase and can measure and communicate with the image forming device to adjust fountain solution flow rate to the imaging member surface and correct for any anomalies in thickness. This fountain solution monitoring system may be fully automated. The capacitive sensor may have a resolution (e.g., as low as about 1 nm resolution) of about 0.001% of the distance/gap that the capacitive sensor is mounted away from the imaging member surface.