Acrylic Latex Polymer Ink for Continuous Inkjet Recirculation
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Solution Overview
Problem
Continuous inkjet printing systems face issues with low optical density and filter plugging due to pigment-based inks, leading to fluid demobilization and system shutdown, especially when recirculating pigment inks with large particle sizes and gear pumps cause agglomeration and clogging.
Innovation Solution
The use of an acrylic latex polymer with specific polyethylene oxide groups in the inkjet printing fluid compositions provides improved optical density and stability, preventing fluid demobilization and filter clogging by maintaining ink recirculation for extended periods without significant pressure build-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pigment-based inks are used in continuous inkjet printing systems, then optical density and durability of printed images are improved, but filter plugging and fluid demobilization occur due to large particle sizes and agglomeration during recirculation
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by incorporating specific polymers (acrylic polymer, polyvinyl alcohol, carboxymethyl cellulose) at controlled concentrations (0.1-10% w/v). These parameter changes modify the physical-chemical properties of the pigment suspension, reducing particle agglomeration and improving flow characteristics during recirculation, thereby preventing filter plugging while maintaining high optical density
Solution Approach 2:
The patent creates a composite ink formulation by combining pigment particles with multiple polymer components (acrylic polymer, polyvinyl alcohol, carboxymethyl cellulose) and surfactants. This composite structure provides both the optical density of pigments and the stability/dispersibility of polymers, preventing particle aggregation and filter clogging during continuous recirculation in CIJ systems
2Productivity
If recirculating pigment inks are used in continuous inkjet systems, then printing productivity is improved, but fluid demobilization and system shutdown occur due to particle agglomeration
Solution Approach 1:
The patent enables continuous recirculation of pigment-based ink by formulating it with polymers that prevent particle aggregation and maintain fluid stability. This allows the recirculation system to operate continuously without shutdowns caused by filter plugging or fluid demobilization, extending the duration of useful printing action and improving overall productivity
Solution Approach 2:
The polymer-formulated ink formulation provides self-protection against agglomeration and filter plugging during recirculation. The ink maintains its own flow properties and particle stability without requiring external intervention, allowing extended continuous operation before maintenance is needed
3Stress or pressure
If gear pumps are used to maintain fluid pressure in recirculating systems, then fluid pressure stability is improved, but particle demobilization and agglomeration occur leading to filter clogging
Solution Approach 1:
The patent modifies the rheological parameters of the ink by adding polymers that change the fluid's flow behavior and particle interaction characteristics. These parameter changes reduce the harmful effects of gear pump operation on pigment particles, preventing demobilization and agglomeration while maintaining the pressure stability needed for CIJ operation
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 acrylic latex polymer enhances optical density and durability of printed images while preventing filter plugging and fluid demobilization, allowing for continuous operation of CIJ systems with reduced maintenance needs.
Implementation Method 1
an acrylic latex polymer that includes repeating units of alkylene oxide groups
Implementation Method 2
Great lengths are undertaken to reduce a pigment particle to a sufficiently small particle size and to provide sufficient colloidal stability to the particles
Implementation Method 3
The non-printing droplets are recirculated by being returned to the supply reservoir via a droplet catcher and a return line
Implementation Method 4
a positive displacement pump, such as gear pump, is preferred for use as the ink supply pump
Implementation Method 5
Ink is delivered through a supply line from a supply reservoir to a manifold that distributes the ink to a plurality of orifices, typically arranged in linear array(s), under sufficient pressure
Implementation Method 6
filters are employed at appropriate locations in fluid system to remove oversized particles prior to ink entering into print head orifices and avoid print head clogging
Implementation Method 7
Ink streams issue from the orifices of the print head
Implementation Method 8
a continuous stream of droplets is generated and expelled in an image-wise manner onto the surface of the image-recording element
Data Source
AI summary
An inkjet printing fluid for printing systems employing recirculating printing fluids is described. The printing fluid including water, colorants, and an acrylic latex polymer that includes repeating units of alkylene oxide groups.