Inkjet Head Electrode Smoothing for Laser Nozzle Durability

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Solution Overview

Problem

Inkjet heads with organic protection films on electrodes face damage from laser beam exposure during nozzle formation, potentially leading to print quality and durability issues when using conductive inks, due to the formation of pin holes caused by surface roughness.

Innovation Solution

A manufacturing method for inkjet heads involves forming a smoothed electrode with an inorganic material having an average surface roughness of 0.6 μm or less and an electrode protection film with a thickness of 1.0 μm or more, which prevents pin hole formation and ensures electrical insulation between the electrode and conductive ink.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an organic protection film (poly-chloro-para-xylylene film and poly-para-xylylene film) is formed on the electrode surface to provide smooth ground for pin hole prevention, then the film formation is improved, but the film is damaged by laser beam exposure during nozzle formation, leading to print quality and durability issues

Engineering Contradiction:

Improveprotection film integrityVSAvoidlaser beam damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the organic protection film from the electrode surface before laser beam processing. By extracting this vulnerable component, the laser beam can form nozzles without damaging the protection film, thereby preventing pin hole formation and maintaining both print quality and durability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary actions by forming the electrode with controlled surface roughness (Ra ≤ 0.6 μm) and bonding the nozzle plate before laser beam processing. This sequence ensures that the protection film is not exposed to laser damage, as the nozzle plate is already in place to shield or protect critical areas during nozzle formation.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the electrode surface roughness is not controlled, then the manufacturing process is simpler, but pin holes form in the protection film, reducing reliability

Engineering Contradiction:

Improvepin hole preventionVSAvoidsurface roughness control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by controlling the electrode surface roughness to Ra ≤ 0.6 μm. This specific parameter control prevents pin hole formation in the protection film while maintaining manufacturing feasibility through standardized polishing or electrochemical treatment processes.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If laser beam is used to form nozzles in the nozzle plate, then nozzle formation efficiency is improved, but the protection film on the electrode is exposed and damaged, affecting durability

Engineering Contradiction:

Improvenozzle formation efficiencyVSAvoidinkjet head durability

Core Design Contradiction:

ProductivityVSDuration of action of stationary object

Solution Approach 1:

The patent performs preliminary bonding of the nozzle plate to the base substrate before laser beam processing. This preliminary action positions the nozzle plate to either shield the electrode protection film or direct the laser beam away from sensitive areas, enabling efficient nozzle formation without compromising durability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts or removes the vulnerable protection film from the laser beam path by repositioning or reconfiguring the electrode structure. This allows laser beam processing to proceed efficiently without exposing the protection film to damaging radiation, thereby maintaining both productivity and durability.

Inventive Principle:

Principle #2Taking out (Extraction)

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 solution effectively prevents pin hole formation and maintains electrical insulation, ensuring the durability and print quality of inkjet heads even when using conductive inks, by using an inorganic material for the electrode protection film and smoothing the electrode surface.

Implementation Method 1

a smoothed film made of an inorganic material and having an average surface roughness of 0.6 μm or less is formed on a surface of the electrode

Methodology Applied

Scientific EffectSurface smoothing:

Implementation Method 2

the protection film on the inner wall surface of the ink chamber may be exposed to the laser beam, and the protection film may be damaged

Methodology Applied

Scientific EffectLaser beam resistance:

Implementation Method 3

there is a fear that the print quality of the inkjet head and the durability can not be maintained

Methodology Applied

Scientific EffectElectrical insulation:

Data Source

PatentUS9333751B2Manufacturing method of inkjet head

Publication Date: 2016.05.10 RISO TECH CORP

AI summary

A process of manufacturing an inkjet head includes forming an electrode part, in which after an electrode is formed on an inner surface of a groove part formed in a substrate of the inkjet head, a smoothed film made of an inorganic material and having an average surface roughness of 0.6 μm or less is formed on a surface of the electrode, and then, an electrode protection film having a thickness of 1.0 μm or more is formed on a surface of the smoothed film; bonding a nozzle plate to an opening end face of a pressure chamber in the groove part by an adhesive after the electrode part is formed; and forming, in the nozzle plate, a nozzle communicating with the pressure chamber by laser machining after the nozzle plate is bonded.