Liquid Detector Bottom Bypass Ink Detection

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Solution Overview

Problem

Existing liquid detection methods in ink jet recording apparatuses are prone to erroneous detection due to air bubbles and capillary phenomena, leading to ink remaining in the upstream buffer chamber and potentially causing idle printing and reduced lifespan of the recording head.

Innovation Solution

A liquid detector with a sensor base and sensor chip arrangement where the first and second holes are parallel at the same height, and a bottom bypass is formed at the lowermost position to communicate the upstream and downstream buffer chambers, preventing air bubbles from entering the sensor cavity and ensuring accurate ink detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensor cavity is positioned in the flow channel to detect ink level, then ink consumption can be monitored, but air bubbles may enter the sensor cavity causing erroneous detection

Engineering Contradiction:

Improveink level detection accuracyVSAvoiddetection reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The harmful air bubbles are extracted from the detection path by providing a separate vent hole that allows air bubbles to escape from the sensor cavity to the atmosphere, preventing them from interfering with the ink level detection in the sensor cavity

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

A vent hole is introduced as an intermediary pathway between the sensor cavity and the atmosphere, allowing air bubbles to be transferred out of the detection system without affecting the ink level measurement function

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If ink flows through the sensor cavity for detection, then ink level can be monitored, but ink remaining in the upstream buffer chamber causes idle printing and reduced recording head lifespan

Engineering Contradiction:

Improveink level monitoring accuracyVSAvoidrecording head lifespan

Core Design Contradiction:

Measurement precisionVSDuration of action of moving object

Solution Approach 1:

Remaining ink in the upstream buffer chamber is extracted through the bottom bypass passage that provides an alternative flow path, allowing ink to be discharged from the upstream buffer chamber without passing through the sensor cavity, thus preventing idle printing

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The flow channel is segmented into multiple pathways: the sensor cavity for detection and the bottom bypass passage for draining remaining ink, allowing these two functions to occur independently without interfering with each other

Inventive Principle:

Principle #1Segmentation

3Productivity

If the first and second holes are arranged vertically at different heights, then ink flow through sensor cavity is maintained, but air bubbles rise and enter sensor cavity causing detection errors

Engineering Contradiction:

Improveink flow continuityVSAvoiddetection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The first and second holes are positioned at the same height to create equipotential conditions, preventing air bubbles from rising into the sensor cavity due to gravitational potential differences, while maintaining ink flow through the sensor cavity

Inventive Principle:

Principle #12Equipotentiality

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 configuration reduces erroneous detection and allows for efficient discharge of remaining ink from the upstream buffer chamber to the downstream chamber, enhancing the reliability of ink detection and extending the lifespan of the recording head.

Implementation Method 1

a piezoelectric element and of absence of ink in the sensor cavity

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a bottom bypass is formed at a lowermost position in the vertical direction of each of the upstream and downstream buffer chambers to communicate the upstream and downstream buffer chambers with each other

Methodology Applied

Scientific EffectGravitation: Gravitation

Data Source

PatentUS7802861B2Liquid detector and liquid container having the same

Publication Date: 2010.09.28 SEIKO EPSON CORP

AI summary

A liquid detector includes: a case; a sensor base; a sensor chip; and a partition wall, dividing a part of a flow channel in the case into an upstream and downstream buffer chambers. The sensor chip includes a sensor cavity adapted to receive a liquid to be detected. The sensor base has: a first hole through which the liquid is introduced from the upstream buffer chamber to the sensor cavity; and a second hole through which the liquid is introduced from the sensor cavity to the downstream buffer chamber. The first and second holes are arranged in parallel at the same height, the partition wall is arranged between the first and second holes so as to extend along the sensor base, and a bottom bypass is formed at a lowermost position of the upstream and downstream buffer chambers to communicate the upstream and downstream buffer chambers with each other.