Ink Level Detection in Image-Recording Apparatus Sub Tank

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Solution Overview

Problem

The existing liquid-ejecting devices face challenges in accurately determining whether a cartridge is empty and in accurately measuring the residual ink amount in the sub tank, often leading to incomplete ink consumption and potential air introduction into the ink flow path.

Innovation Solution

An image-recording apparatus with a cartridge and tank configuration that includes a first storage chamber for ink and a second storage chamber, featuring air communication passages to ensure complete ink consumption and accurate detection of residual ink levels through a detected portion and detector system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the liquid level in the sub tank equals the liquid level in the cartridge storage chamber, then the detected portion changes state for detection, but air may be introduced into the ink flow path connecting the sub tank to the liquid-ejecting head

Engineering Contradiction:

Improvedetection accuracy of residual ink amountVSAvoidair introduction into ink flow path

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating a sealed environment specifically in the ink flow path between the sub tank and liquid-ejecting head, while allowing the storage chambers to be open to atmosphere for level equalization. The seal member locally prevents air contamination without restricting the overall liquid level equalization process.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a seal member as an intermediary element in the ink flow path that mediates between the need for liquid level equalization (requiring open chambers) and the need to prevent air introduction. The seal member allows liquid passage while blocking air contamination.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the detected portion is disposed in the cartridge to detect empty status, then the cartridge can be monitored, but the method cannot accurately detect whether the attached cartridge is empty or the residual amount in the sub tank

Engineering Contradiction:

Improvecartridge monitoring capabilityVSAvoidaccuracy of empty detection and residual amount measurement

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent implements feedback by using the detected portion to monitor liquid level and providing detection signals to the control unit. The control unit uses this feedback information to determine when the liquid level has equalized between chambers, enabling accurate determination of cartridge emptiness and sub tank residual amount through the established relationship between liquid levels.

Inventive Principle:

Principle #23Feedback

3Productivity

If both storage chambers are opened to atmosphere for liquid level equalization, then liquid can flow freely between chambers, but accurate detection of residual ink amount becomes difficult

Engineering Contradiction:

Improveink consumption efficiencyVSAvoidresidual ink amount detection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the system into two functional zones: open-to-atmosphere storage chambers for liquid level equalization and ink supply, and a sealed ink flow path for contamination-free transport to the ejection head. This segmentation allows simultaneous achievement of free liquid flow and accurate detection capabilities.

Inventive Principle:

Principle #1Segmentation

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

The apparatus ensures complete consumption of ink from the first storage chamber and accurate detection of residual ink in the second storage chamber, preventing air introduction and enhancing the reliability of ink level monitoring.

Implementation Method 1

Since the sub tank and liquid storage chamber are both opened to an atmosphere, a liquid level of the ink in the sub tank becomes ultimately at the same height as a liquid level of ink in the liquid storage chamber of the cartridge

Methodology Applied

Scientific EffectGravitational force: Gravitation

Data Source

PatentUS10549531B2Image-recording apparatus including detected portion movably disposed in storage chamber of tank connectable to liquid cartridge

Publication Date: 2020.02.04 BROTHER KOGYO KK

AI summary

An image-recording apparatus includes a cartridge including a first storage chamber, a tank including a second storage chamber, a recording portion for ejecting liquid stored in the second storage chamber, a detected portion, and a detector. The first and second storage chambers can communicate with an atmosphere. The tank includes a liquid inlet port and a liquid outlet port positioned lower than the liquid inlet port. Liquid in the first storage chamber is supplied to the second storage chamber through the liquid inlet port, and from the second storage chamber to the recording portion through the liquid outlet port. The detected portion can change in state when a level of the liquid stored in the second storage chamber becomes equal to a vertical position of the liquid inlet port. The detector is configured to detect the change in state of the detected portion.