Ink-jet Head Corrosion Protection via Polymer Buffering

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Solution Overview

Problem

Nickel-containing metal ink-jet heads in ink-jet recording apparatuses face corrosion issues due to pH changes in the ink, leading to premature corrosion and reduced performance.

Innovation Solution

Incorporating an ink composition that includes water, a coloring agent, and a polymer comprising alkali metal or ammonium salts of polyacrylic acid, along with a benzotriazole derivative, which helps maintain a stable pH and reduces corrosion on nickel-containing metal components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pH adjuster is added to make the ink weak alkaline or neutral, then the initial corrosion resistance is improved, but the ink becomes acidic over time and corrosion occurs

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidpH stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

A polymer containing carboxyl groups (polyacrylic acid or its crosslinked product) is introduced as an intermediary substance between the pH adjuster and the nickel-containing metal. This polymer acts as a buffer that stabilizes pH and prevents direct corrosive interaction, thereby resolving the contradiction between initial corrosion resistance and long-term pH stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the chemical composition parameters by introducing specific polymers with carboxyl groups that have buffering capacity. This parameter change enables the ink to maintain stable pH over time, preventing the transition from weak alkaline/neutral to acidic state, thus resolving the stability issue while maintaining corrosion resistance.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the ink pH is adjusted to weak alkaline or neutral, then initial corrosion protection is achieved, but corrosion occurs after pH changes over time

Engineering Contradiction:
Improvecorrosion protectionVSAvoidservice life of ink-jet head
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The polymer with carboxyl groups is added preliminarily to the ink formulation to establish long-term pH stability before corrosion can occur. This preliminary action ensures that the buffering capacity is already in place to prevent pH shifts that would lead to corrosion, thereby extending the service life of the ink-jet head while maintaining corrosion protection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The polymer serves as a mediating substance that maintains the chemical environment stable over time. By introducing this intermediary buffer system, the ink maintains its protective pH range throughout the operational life of the ink-jet head, preventing the time-dependent corrosion that occurs in conventional formulations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If conventional ink formulations are used, then printing performance is maintained, but nickel-containing metal components corrode

Engineering Contradiction:
Improveprinting performanceVSAvoidcorrosion of metal components
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention creates a composite ink formulation by combining conventional ink components with polymers containing carboxyl groups (polyacrylic acid or its crosslinked products). This composite formulation maintains the printing performance of conventional inks while adding corrosion protection through the buffering and protective actions of the polymer components.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The polymer with carboxyl groups acts as an intermediary protective layer in the ink formulation that prevents direct contact between corrosive ink components and the nickel-containing metal. This intermediary substance allows conventional ink formulations to maintain their printing performance while being protected from corrosion by the polymer's buffering and protective effects.

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

The solution effectively delays the occurrence and reduces the amount of corrosion on nickel-containing metal components, enhancing the durability and performance of ink-jet heads by maintaining ink stability and preventing material deposition.

Implementation Method 1

a polymer which comprises at least one of an alkali metal salt of a polyacrylic acid and an ammonium salt of a polyacrylic acid

Methodology Applied
Scientific EffectpH buffering:

Implementation Method 2

a benzotriazole derivative, which helps maintain a stable pH and reduces corrosion on nickel-containing metal components

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP1818375B1Ink for ink-jet recording, ink-jet recording apparatus, method of treating nickel-containing metal, treatment agent of nickel-containing metal, and use of a polymer for the manufacture of a treatment agent of nickel-containing metal
Publication Date: 2012.03.28 BROTHER KOGYO KK
  • EP1818375B1 patent drawingFigure 1
  • EP1818375B1 patent drawingFigure 2
  • EP1818375B1 patent drawingFigure 3

AI summary

An ink for ink-jet recording that is used in an ink-jet recording apparatus. The ink-jet recording apparatus includes an ink-jet head provided with an ink flow passage formed of nickel-containing metal. The ink contains water, a coloring agent, and a polymer. The polymer contains at least one of -COOM and -SO3M, where M denotes at least one of an alkali metal ion and an ammonium ion.