Printhead Ink Collection Overflow Detection

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Solution Overview

Problem

Existing printing systems face issues with contaminants like dried ink accumulating at printhead nozzles, leading to clogging and performance degradation, and existing methods for detecting when the ink collection container is full are inaccurate or complex, causing potential overflows and printer downtime.

Innovation Solution

A system with a container having a main cavity and an overflow pocket for collecting excess ink, where a sensor outside the container detects the presence of liquid in the overflow pocket, sending a user message to replace the container, using inductive or capacitive sensors that do not require calibration upon new container installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor is placed inside the ink collection container to detect ink level, then measurement precision is improved, but device complexity and calibration requirements increase

Engineering Contradiction:

Improveink level detection accuracyVSAvoidsensor alignment and calibration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary magnetic field as a mediator between the external sensor and the ink liquid. The magnetic field penetrates through the non-magnetic container wall to detect ink level, eliminating the need for direct contact sensors inside the container and avoiding calibration issues related to sensor positioning.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical contact-based ink level sensing with a magnetic field-based detection system. The external sensor detects changes in magnetic field properties caused by the ink's magnetic characteristics, eliminating mechanical complexity and calibration requirements associated with internal sensors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If drop counter data is used to estimate ink volume in the collection container, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:

Improveink level sensing system simplicityVSAvoidink volume measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces indirect estimation methods (drop counting) with direct magnetic field-based detection. This substitution provides accurate real-time ink level measurement while maintaining relatively simple device architecture, as the external sensor requires no mechanical connection or complex calibration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The ink liquid itself serves as the sensing element through its magnetic properties. The ink's inherent magnetic characteristics interact with the external magnetic field, enabling self-detection without requiring additional internal sensing components or complex calibration procedures.

Inventive Principle:

Principle #25Self-service

3Ease of operation

If the ink collection container is made as a consumable disposable item, then ease of operation is improved, but manufacturing cost increases

Engineering Contradiction:

Improvecontainer replacement simplicityVSAvoidproduction cost of disposable container

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The patent applies the disposable principle to the ink collection container, designing it as a low-cost, single-use component. The container is intentionally made inexpensive enough to be discarded when full, eliminating complex sensor systems and calibration mechanisms, thereby improving ease of operation despite increased per-unit manufacturing cost.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 reduces ink collection container overflows, minimizes printer downtime, simplifies user replacement, and decreases costs by eliminating the need for precise sensor alignment and complex ink level sensing, resulting in more accurate and efficient printhead servicing.

Implementation Method 1

using inductive or capacitive sensors that do not require calibration upon new container installation

Methodology Applied

Scientific EffectInductive sensing: Electromagnetic Induction

Implementation Method 2

using inductive or capacitive sensors that do not require calibration upon new container installation

Methodology Applied

Scientific EffectCapacitive sensing: Capacitance

Data Source

PatentUS11214070B2Collection of liquid ejected from a printhead

Publication Date: 2022.01.04 HP SCITEX LTD

AI summary

In an example of the disclosure, a printhead is caused to spit a liquid into a main cavity of a container. The container includes an overflow pocket for collecting liquid that has overflown from the main cavity. A sensor is caused to detect whether liquid is present in the overflow pocket. Responsive to sensor detection that liquid is present in the overflow pocket, a warning or instruction message is caused to be sent for user consumption.