Inkjet & Ink Processing Conditions & Solutions

Gradient of precision

Initial material and structural screening

Inkjet Manufacturing and Nozzle Condition

Aqueous Dye Ink: Final Clarification

• Condition: Low-viscosity aqueous dye; color components are in solution form.
• Issue: Fibers, salt crystals, gels, and microbial aggregates cause misfire; fine filtration increases adsorption and pressure drop.
• Identification: Check tail particles, turbidity, colonies, viscosity, and batch stability at the end of 0.5–10 µm.
• Solution: 10–20 µm depth filtration before → 1–5 µm pleated clarification; validate 0.2/0.45 µm when microbial control is required.
• Accuracy / Structure: Pre-stage 10–20 µm; final stage 1–5 µm. 0.2 µm is limited to low solids and validated formulas.
• Materials: Hydrophilic PES/PSU or PP; perform dye adsorption and extraction tests on the entire assembly.
• Acceptance: Particles at the end of filtration, color difference, flow-pressure drop, colonies.
• Boundary: 0.2 µm is not the default value for all office or industrial dye inks.

Solvent-Based Piezoelectric Inkjet: Batch Manufacturing

• Operating Conditions: Alcohols, ketones, esters, or hydrocarbon solvents; low to medium viscosity pigment inks.
• Issues: Resin gels, grinding media, fibers, and coarse pigments clog the final filter cartridge.
• Identification: Confirm the complete formulation, temperature viscosity, solvent flash point, particle tail distribution, and compatibility with seals.
• Solution: 10 µm pre-filter → 3–5 µm protection → 1–1.5 µm final; enclosed, grounded, low shear transport.
• Filtration rating / configuration: 5–10 µm prefiltration; 1–1.5 µm final filtration.
• Materials: PP, nylon, or PTFE selected based on solvent; housing and O-rings must be validated in tandem.
• Acceptance: Filtration recovery rate, particle count, clean differential pressure, nozzle continuous operation.
• Boundaries: Public recommendations are a starting point; ketones, aromatics, and halogenated solvents have significant differences in housing/seal compatibility.

UV-Cured Inkjet: Filter under UV protection

• Operating conditions: Acrylate monomers/oligomers, pigments, and photoinitiators; sensitive to light and heat.
• Issue: Soft gels form from localized exposure; temperature rise causes viscosity changes; premature curing in transparent capsule.
• Identification: Check environmental UV, material temperature, residence time, gel formation, and pressure drop in dark.
• Solution: light-protected blending → 5–10 µm prefiltration → 0.5–1.5 µm opaque capsule or pleated final filtration.
• Precision/Structure: Pre-stage 5–10 µm; final stage 0.5–1.5 µm, determined by nozzle and pigment recovery tests.
• Materials: PTFE/PP often used for initial screening; select non-transparent shells, verify compatibility with acrylate and seals.
• Acceptance: Dark storage, curing speed before and after filtration, gel count, and jet stability.
• Boundary: Transparent capsule resistance to UV does not guarantee compatibility of the medium with all monomers.

High White/High Pigment Broad Spectrum Inks

• Operating conditions: TiO2 or high coverage pigments, high solids and viscosity, prone to settling.
• Issue: Sudden increase in fine filter differential pressure; sediment blocks enter the circulation after shutdown; shear is insufficient to form soft flocs.
• Identification: Measure sedimentation rate, low shear viscosity, and particles and circulation dead spots of >3/5/10 µm particles.
• Solution: Slow tank mixing → 20–50 µm coarse filter → 5–10 µm depth filtration → 3–5 µm final filtration.
• Accuracy/Structure: 20–50 µm coarse filter; 5–10 µm protection; 3–5 µm final.
• Material: High capacity PP depth filter or compatible pleated PP; large area with low differential pressure.
• Acceptance: Solids content and brightness recovery, differential pressure curve, nozzle condition after shutdown and restart.
• Boundary: Do not directly use 0.5–1 µm, as it will quickly clog and lose color.

Ceramic and Textile Digital Printing Conditions

Ceramic Tile Digital Inkjet: Organic Carrier Pigments

• Condition: Submicron ceramic pigments, high solids content organic carrier; ground into the inkjet nozzles.
• Issue: d99 tail, hard agglomerates and milling-bead debris clog nozzles; excessively fine filtration changes solids content.
• Identification: D50, D90, D99; 5 µm filtration before and after solids content; stability and sedimentation.
• Solution: milling classification → 20 µm debris capture → 5 µm PTFE filterability confirmation → 3–5 µm final filtration.
• Accuracy / Structure：20 µm protection；5 µm critical filtration；3 µm when necessary final bioburden reduction.
• Material: PTFE or chemically compatible PP; low shear, large surface area; seal confirmed by organic carrier.
• Acceptance: d99<1 µm window, solid content loss, filtration pressure difference, nozzle loss rate.
• Boundary: 5 µm through the test is a dispersion stability indicator, does not guarantee long-term printing.

Textile Reactive Dye Ink

• Operating Conditions: aqueous soluble dye, salt, humectant; cotton/viscose printing.
• Issues: salt crystals, fiber, and microbial contamination; over-filtration may reduce flow rate.
• Identify: Check for low-temperature crystallization, conductivity, colonies, 1–10 µm particles, and color strength.
• Solution: Raw water 0.2–1 µm → Mixing 10 µm → Ink formulation 1–5 µm; perform sterility validation separately for sterile bottling if required. (0.2 µm)
• Accuracy / Structure: Pre-stage for 10 µm; terminal for 1–5 µm; 0.2 µm is an optional step.
• Materials: Hydrophilic PES/PP; evaluate dye adsorption and preservative loss.
• Acceptance: Color difference, crystallization temperature, pressure drop, nozzle continuity.
• Limitations: Dissolved dyes do not require retention by microfiltration membranes to prevent color loss.

Textile Disperse Dyes/Solvent Dyes

• Conditions: Disperse dyes for polyester are fine-grained dispersions, aqueous or transfer systems.
• Issues: Clogging at the nozzle due to grinding tail and dispersion instability; fine filtration causing color concentration loss.
• Identify: Measure D99, >1/3/5 µm particles, solids content, color strength, and post-storage changes.
• Solution: 10 µm depth filtration → 3–5 µm protection → 1–3 µm final small-scale trial.
• Precision / Structure: Pre-stage 5–10 µm; terminal 1–3 µm.
• Materials: PP/PES/Nylon as per formulation selection; avoid high adsorption membranes.
• Acceptance: Solids content and K/S value, post-filter tail particle size, and spray stability.
• Boundary: Match between dye chemistry and substrate does not imply filtration compatibility.

Textile Dyes+Emulsion Binder

• Operating conditions: Coexistence of pigment dispersions and polymer emulsions with high viscosity and soft gel load.
• Issue: Emulsion shear coagulation; rapid formation of a gel cake on the fine membrane surface.
• Identification: Measure emulsion particle size, soft gel, viscosity before and after shearing, and filtration recovery.
• Solution: Filter binders and pigments separately → low shear mixing → 5–10 µm final polishing of the finished product.
• Precision / Structure: Raw material 5–10 µm; finished product 3–10 µm, validated by nozzle window.
• Material: Gradient PP for depth filtration priority; large area PP/PES for final filtration.
• Acceptance: Bond strength, solid content, colorfastness, pressure drop, and spray performance.
• Limitations: Do not directly filter high polymer emulsions over the 0.2–1 µm membrane.

Light-sensitive/Photochromic Ink

• Operating Conditions: Containing light-sensitive dyes, pigments, or microcapsules; requires light avoidance and temperature control.
• Issues: Light, heat, and metal contamination trigger color change or polymerization; microcapsules are retained.
• Identification: Confirm if the active component is in solution, nanocolors, or microcapsules; measure spectrum and particle size.
• Solution: Filter with light-avoiding coarse 20–50 µm → select final 5–20 µm based on effective particle size; try 1 µm for non-particle systems.
• Precision / Structure: Microcapsule system 5–50 µm; dissolution type 1–5 µm.
• Material: Non-transparent PP/PTFE capsule; low metal, low shear.
• Acceptance: Light response, color strength, effective particle recovery, and pressure difference before and after filtration.
• Boundary: First determine the effective component size, do not directly assign to 1 µm based on 'photosensitive' name.

Functional ink, traditional printing, and end-of-line conditions.

Silver nanocarbon conductive ink.

• Condition: Silver nanoparticles with alcohol/ethylene glycol solvents; high-value small batches.
• Issue: Agglomerates clog nozzles; filter adsorption or retention of silver, causing increased resistance.
• Identification: Measure particle size, agglomerate tail, silver content, surface tension, and idle thermal exposure.
• Solution: 5 µm capsule pre-filter → 0.45–1 µm low adsorption terminal; perform quality balance on a small scale first.
• Accuracy / Structure: 5 µm pre-filter; 0.45–1 µm terminal window.
• Material: PTFE or validated nylon/PES; select low retention capsule filter.
• Acceptance: Silver recovery rate, resistance factor, nozzle loss, filter retention.
• Limitations: Drying of nozzles due to high temperature and long-term no flow; filtration cannot resolve the issue.

Graphene/Carbon Nanomaterial Ink

• Operating Conditions: Plate or tubular carbon materials, high aspect ratio.
• Issue: average particle size meets specification, but long fibers bridge nozzles; depth-media adsorption reduces concentration.
• Identification: Measure lateral dimensions, thickness, agglomerates, and carbon content before and after filtration.
• Solution: Ultrasonic/size separation → 10–20 µm coarse filter → 1–5 µm final filter, ensuring particle size is approximately one-tenth of the nozzle diameter.
• Accuracy/Structure: 10–20 µm as protection; 1–5 µm as final filter, based on strip dimensions.
• Material: Low adsorption PP/PTFE; select low retention capsule filter for high-value small batches.
• Acceptance: Carbon content, flake diameter, electrical conductivity, spray continuity.
• Limitations: Spherical particle size distribution cannot fully describe flake-shaped particles.

Offset/gravure ink circulation.

• Operating conditions: medium-to-high flow rates and higher viscosity; pumping circulation may contain doctor-blade and roller wear debris.
• Issues: Membrane, paper fibers, metal shavings scratching the anilox roll and causing print lines.
• Identification: Check the maximum dimension, magnetic properties, viscosity, circulation flow rate, and cleaning method of the contaminant.
• Solution: 100–300 µm basket screen/magnetic separation → 25–50 µm bag or metal-mesh filtration → 5–15 µm pleated polishing filtration.
• Accuracy / Structure: Coarse grade 100–300 µm; medium grade 25–50 µm; fine grade 5–15 µm.
• Materials: Stainless steel mesh, PP depth or solvent-compatible pleated filter cartridges.
• Acceptance: Stripes/Blade Lines, Magnetic Particles, Pressure Differential, and Cleaning Cycles.
• Boundary: The 1 µm inkjet standard is not suitable for high viscosity flexo/gravure main loops.

Screen printing inks with metal or pearlescent pigments

• Condition: High viscosity, coarse pigments or metal flakes; ink layer formation depends on the mesh.
• Issue: Fine mesh clogging with functional films; dry skin and clumps block the mesh.
• Identification: Confirm actual mesh opening, particle D99, temperature, viscosity, and open time.
• Solution: Pre-screen with the 100–500 µm → coarse filter matching the print mesh; no micro filtration.
• Precision/Structure: Typically 100–500 µm; use 50–100 µm for fine line work, retaining functional pigments.
• Material: Stainless steel or polyester mesh; high viscosity low shear transport.
• Acceptance: Film recovery, printability, mesh blockage, and pattern integrity.
• Boundary: Mesh count cannot be directly equated to micrometer openings; also specify wire diameter and open area.

Printing Equipment Wastewater

• Conditions: Contains ink, emulsion fragments, adhesives, and fibers; high variability in solid load.
• Issue: Fine filter cartridge gets clogged instantly; dissolved dyes and surfactants still pass through the water.
• Identification: Measure TSS, COD, oil, particle size, and batch peak values.
• Solution: Sedimentation/Flocculation → 300/100 µm screen → 70 µm → 20 µm bag/filter; further treatment with UF/adsorption required.
• Accuracy / Structure: 300→100→70→20 µm; 5 µm only for low solid polishing.
• Materials: Cleanable screen + PP bag/filter.
• Acceptance: TSS, pressure difference, sludge volume, and discharge indicators.
• Limitations: Pleated filter cartridge does not remove dissolved color or COD.