Oily Inkjet Ink Nozzle Clogging Prevention
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Solution Overview
Problem
Oily inkjet inks, particularly cyan inks, suffer from nozzle clogging due to the accumulation of water-soluble solid materials like copper phthalocyanine pigment, leading to jetting-out failures, as these materials dissolve and deposit in the inkjet head nozzles due to water evaporation and moisture absorption by hydrophilic solvents.
Innovation Solution
Formulating an oily inkjet ink with a pigment containing no more than 0.15% by mass of water-soluble ingredients, using ester and/or alcohol solvents, and employing a dispersant to minimize the accumulation of water-soluble materials at the nozzle, thereby reducing the risk of clogging and ensuring stable jetting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oily inkjet ink containing ester solvent and/or alcohol solvent is used, then excellent on-printer stability and non-adhering printed surface are achieved, but water-soluble solid material accumulates in the vicinity of nozzles causing clogging
Solution Approach 1:
The patent changes the chemical composition parameters of the pigment by controlling the water-soluble ingredient content to 0.15% or less, while maintaining the use of ester and/or alcohol solvents. This parameter change allows the ink to retain excellent on-printer stability and non-adhering properties while preventing water-soluble solid material accumulation in the nozzle vicinity.
2Object-generated harmful factors
If water-soluble ingredient content in pigment is reduced to at most 0.15% by mass, then solid material accumulation is suppressed, but pigment dispersibility may be affected
Solution Approach 1:
The patent creates a composite ink formulation combining pigment with controlled water-soluble content (≤0.15%), ester and/or alcohol solvents, and appropriate dispersants. This composite approach maintains pigment dispersibility while suppressing solid material accumulation, as the dispersant compensates for the reduced water-soluble content in the pigment.
3Manufacturing precision
If cyan ink is used for long period, then high resolution and good image quality printing is achieved, but jetting-out defects occur due to nozzle clogging
Solution Approach 1:
The patent takes preliminary action by pre-controlling the water-soluble ingredient content in the pigment to 0.15% or less before the ink is used in the printer. This preliminary composition control prevents solid material accumulation and nozzle clogging from occurring during extended printing operations, thereby maintaining both high image quality and reliable jetting-out performance throughout the ink's service life.
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 approach significantly reduces nozzle clogging and enhances storage stability and long-term jetting performance by minimizing the accumulation of water-soluble solids, maintaining low viscosity and image density while preventing undesirable jetting defects.
Implementation Method 1
Since water is apt to evaporate in the vicinity of the nozzle, the water-soluble solid material deposits due to the evaporation of water and accumulates in the vicinity of the nozzle.
Implementation Method 2
In the cases of an oily inkjet ink containing organic solvents having hydrophilic groups, such as an ester solvent and an alcohol solvent, there is a tendency for the water quantity in the ink to increase due to moisture absorption
Data Source
AI summary
An oily inkjet ink comprises a pigment, a dispersant, and an organic solvent. The organic solvent contains an ester solvent and/or an alcohol solvent. A containing quantity of a water-soluble ingredient in the pigment is equal to at most 0.15% by mass.