Vertical Fluid Interface With Thermal Level Sensor

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Solution Overview

Problem

Existing fluid-ejection devices, such as inkjet printers, face challenges in accurately determining the remaining fluid level in removable cartridges, particularly when the cartridges are inserted vertically, as existing digital fluid level sensors are not optimized for vertical insertion and may not provide precise measurements due to gravitational effects.

Innovation Solution

The introduction of novel vertical interfaces for fluid supply cartridges, which include digital fluid level sensors that utilize fluidic interconnect septums and electrical interfaces to connect the cartridge to the device, allowing for accurate fluid level detection by measuring heat transfer differences between liquid and air, ensuring precise measurement even when the cartridge is inserted vertically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If existing digital fluid level sensors are used in vertically inserted cartridges, then the device can operate with removable cartridges, but the measurement precision deteriorates due to gravitational effects

Engineering Contradiction:
Improvecartridge insertion orientationVSAvoidfluid level measurement
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent changes the physical principle used for fluid level detection from gravitational-dependent methods to thermal conduction-based methods. The sensor measures the thermal conduction difference between liquid (which conducts heat away from the heated element) and air (which does not), providing accurate measurements regardless of cartridge orientation. This parameter change from gravitational field dependence to thermal property dependence resolves the contradiction between vertical insertion adaptability and measurement precision.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If conventional fluid level detection methods are used, then the system structure remains simple, but the measurement precision deteriorates in vertical cartridge configurations

Engineering Contradiction:
Improvesensor structureVSAvoidfluid level detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical or gravitational fluid level detection mechanisms with a thermal field-based detection system. A heated element conducts heat differently when in contact with liquid versus air, and this thermal conduction difference is measured electrically to determine fluid level. This substitution of the detection principle maintains relatively simple device structure while achieving high measurement precision in vertical cartridge configurations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If existing sensors are adapted for vertical insertion, then compatibility with removable cartridges is improved, but measurement reliability deteriorates due to gravitational interference

Engineering Contradiction:
Improvevertical cartridge compatibilityVSAvoidfluid level measurement reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent fundamentally changes the measurement parameter from gravitational effects to thermal conduction properties. By heating an element and measuring the rate of heat loss (which differs between liquid and air contact), the system achieves reliable fluid level detection that is independent of gravitational orientation, thereby improving both vertical cartridge compatibility and measurement reliability.

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 accurate and cost-effective fluid level detection in vertically inserted cartridges, ensuring optimal fluid delivery and preventing over-exhaustion, thus maintaining device performance and user convenience.

Implementation Method 1

digital fluid level sensors that utilize fluidic interconnect septums and electrical interfaces to connect the cartridge to the device, allowing for accurate fluid level detection by measuring heat transfer differences between liquid and air

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3468804B1Vertical interface for fluid supply cartridge having digital fluid level sensor
Publication Date: 2021.06.30 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3468804B1 patent drawingFigure 1A~1B
  • EP3468804B1 patent drawingFigure 2A~2B
  • EP3468804B1 patent drawingFigure 3A~3B

AI summary

A vertical interface (100) for a fluid supply cartridge (120) is to connect the fluid supply cartridge (120) to a fluid-ejection device (140). The vertical interface (100) includes one or more fluidic interconnect septums (102) to vertically fluidically interconnect a supply of fluid of the fluid supply cartridge to the fluid-ejection device. The vertical interface (100) includes an electrical interface (104) to vertically conductively connect a digital fluid level sensor (124) of the fluid supply cartridge (120) to a corresponding electrical interface (144) of the fluid-ejection device (140).