Liquid Ejection Head Electrochemical Cleaning via Temperature Waveform Analysis

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Solution Overview

Problem

Existing liquid ejection apparatuses, such as thermal type inkjet recording devices, struggle to accurately diagnose the cause of ejection failures and select optimal cleaning methods, leading to potential damage to the head and reduced lifespan.

Innovation Solution

A liquid ejection apparatus is designed with a control unit that analyzes the waveform signals from temperature sensors to identify the presence and location of foreign substances, allowing for the selection of appropriate cleaning methods, including electrochemical elution of burnt deposits from the protective film.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cleaning methods are applied to remove foreign substances, then ejection failure can be recovered, but the head may be damaged and lifespan shortened

Engineering Contradiction:

Improveejection recoveryVSAvoidhead lifespan

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent replaces mechanical cleaning methods (such as physical contact cleaning) with an electrochemical method. A voltage is applied to the protective film to electrochemically remove burnt deposits, eliminating the need for mechanical contact that could cause damage to the head structure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the approach from mechanical removal to electrochemical removal by applying voltage to the protective film. This parameter change (adding electrical energy) enables the electrochemical elution of burnt deposits, providing a gentler alternative that recovers ejection function without damaging the head.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If general cleaning is performed without cause analysis, then foreign substances can be removed, but optimal cleaning means cannot be selected and unnecessary cleaning may cause damage

Engineering Contradiction:

Improveforeign substance removalVSAvoidcleaning selection system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses temperature sensor waveforms as feedback to analyze the state of each nozzle and determine the cause of ejection failure. This feedback mechanism enables the system to identify whether burnt deposits are present on the protective film, allowing selective application of electrochemical cleaning only when necessary, rather than performing general cleaning unnecessarily.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent segments the cleaning approach by analyzing each nozzle's temperature waveform individually to determine the specific cause of failure. This segmentation allows the system to target electrochemical cleaning to only those nozzles with burnt deposits, rather than applying cleaning to all nozzles, thereby reducing unnecessary cleaning operations.

Inventive Principle:

Principle #1Segmentation

3Reliability

If physical contact cleaning is used, then foreign substances can be removed, but the head may be damaged

Engineering Contradiction:

Improveforeign substance removalVSAvoidhead damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent substitutes mechanical contact cleaning with an electrochemical process. By applying voltage to the protective film, burnt deposits are removed through electrochemical elution rather than physical contact, eliminating the harmful mechanical forces that could damage the head structure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces voltage as an intermediary means to remove burnt deposits. Instead of directly applying mechanical force to remove foreign substances, the system applies voltage as an intermediary that enables electrochemical removal, thereby avoiding direct mechanical contact that could cause damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach enables targeted and effective cleaning, minimizing downtime and potential damage to the liquid ejection head, thereby extending its lifespan and maintaining high print quality.

Implementation Method 1

driving elements configured to be heated by applying voltage and eject the liquid

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the removal unit is unit for removing the burnt deposit by applying voltage to the protective film and eluting the protective film thereby

Methodology Applied

Scientific EffectElectrochemical elution: Electrolysis

Data Source

PatentUS20250135785A1Liquid ejection apparatus

Publication Date: 2025.05.01 CANON KK

AI summary

Provided is a liquid ejection apparatus, including: a head; a plurality of removal units for removing foreign substances; and a control unit. The head is constituted of a circuit substrate and a passage forming member which are joined, a chamber is disposed in the joined portion, a liquid supply port is disposed on the circuit substrate, nozzles to eject the liquid inside the chamber are disposed in the passage forming member, and a plurality of driving elements and a plurality of temperature sensors are disposed on the circuit substrate. The control unit selects the removal unit by analyzing a waveform of a signal from the temperature sensor, a protective film is disposed between the driving element and the chamber, and the removal unit removes the burnt deposit, which is a foreign substance, by applying voltage to the protective film and eluting the protective film thereby.