Ink Short Detection in Print Heads via Current Profiling

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Inkjet printers face issues with ink shorts that can damage the print head or cause overheating, impacting print quality, particularly due to semi-permanent or non-low resistance shorts which are challenging to detect.

Innovation Solution

The solution involves analyzing the image density before printing to predict current consumption profiles and using a current model of the print head to detect low and non-low resistance ink shorts by comparing actual current consumption with programmed thresholds, allowing for early detection and prevention of damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional current monitoring methods are used with fixed high thresholds, then false alarms are reduced, but early detection of ink shorts is delayed

Engineering Contradiction:

Improveprint head protectionVSAvoiddetection delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary analysis of image data to predict current consumption before printing begins. By calculating the expected current profile in advance based on image characteristics, the system establishes a baseline for comparison during printing, enabling earlier and more accurate detection of deviations indicating ink shorts.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the parameter of current threshold from a fixed high value to a dynamic value that varies based on image characteristics. The current threshold is adjusted according to the predicted current consumption profile derived from image density and complexity, allowing sensitive detection without false alarms.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If image density analysis is performed before printing to predict current consumption, then detection accuracy is improved, but processing time increases

Engineering Contradiction:

Improveink short detection accuracyVSAvoidpre-processing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs partial analysis of the image data, focusing only on the necessary characteristics (density, complexity) required for current prediction rather than complete image processing. This selective approach achieves sufficient detection accuracy without the computational overhead of analyzing all image properties.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The invention replaces complex real-time current monitoring and analysis during printing with a simplified predictive model based on image characteristics. By substituting the mechanical/electrical measurement system with a computational prediction system, the overall processing time is reduced while maintaining detection accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS7695089B2Ink short detection

Publication Date: 2010.04.13 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

The present invention provides a method to detect ink short in a print head and an apparatus that performs the method. The method provides the steps of obtaining a density profile and a current consumption profile of an image to be printed and using the profiles to detect a low-resistance ink short or a non-low resistance ink short in a print head.