Ink Conductivity Measurement via Electrode Currents

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Newer inks lack measurable low field conductivity, making it impossible to infer their high field conductivity, which is essential for maintaining high print quality in printing systems.

Innovation Solution

A method and device to measure high field conductivity of ink by calculating it using the measured currents from the main and squeegee electrodes, optical density of the printed ink, and solid density, with the equation σ=C⁢δres⁡(I1+I2)2⁡ODPaper2, where σ is the high field conductivity, C is a calibration factor, δres is the solid density, I1 and I2 are the electrode currents, and OD is the optical density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If low field conductivity measurement method is used, then measurement simplicity is maintained, but measurement capability is lost for newer inks

Engineering Contradiction:

Improvemeasurement simplicityVSAvoidmeasurement capability

Core Design Contradiction:

Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent changes the measurement parameter from low field conductivity to high field conductivity. By applying a high voltage (e.g., 1000V) across the ink sample, the system measures conductivity under high electric field conditions, which produces a measurable signal for newer inks that lack low field conductivity while still maintaining a straightforward measurement process.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If high field conductivity is inferred from low field conductivity, then measurement process is simple, but measurement accuracy deteriorates for newer inks

Engineering Contradiction:

Improvemeasurement process complexityVSAvoidconductivity measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent directly measures high field conductivity by applying a high voltage electric field to the ink sample, eliminating the need to infer conductivity from low field measurements. This direct measurement approach provides accurate conductivity data for newer inks while keeping the measurement process relatively simple through automated voltage application and measurement.

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

Enables the printing system to adjust and enhance print quality by determining and modifying the conductivity of the ink, ensuring optimal printing processes.

Implementation Method 1

a main electrode that serves to charge the ink (112)

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

a squeegee electrode that serves to further charge the ink (112)

Methodology Applied

Scientific EffectElectrostatic separation: Electrostatics

Implementation Method 3

The ink is then transferred to an intermediate soft rubber material, which is sometimes referred to as a blanket, via different electrostatic forces

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatics

Data Source

PatentUS8774682B2Method for measuring conductivity of ink

Publication Date: 2014.07.08 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

Methods and devices for measuring conductivity of ink in a printing system are disclosed. An embodiment of the method is used with a printing system having a developer roller, wherein the ink is formed on the developer roller using electrostatic forces and is used to print on a substrate. A first current charges the developer roller during the printing. The first current is measured and the conductivity of the ink is determined, wherein the conductivity is proportional to the square of the first current.