Wikoff Blog

Water-Based Flexo Troubleshooting Guide

by Ink Specialist|04.13.22

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More than just an ink supplier, we’re here to help your pressroom run as efficiently as possible. With years of experience under their belt, the Wikoff Technical Solutions team has seen it all, and helped solve the problems that keep water-based flexo printers up at night.

The next time you encounter one of these 15 most common water-based flexo issues on press, consult this simple guide for our expert recommended solutions.

1. Ink is drying too fast

The ink is drying on your plates, your ink rollers and maybe your anilox. It may even be failing to transfer to the substrate.

POSSIBLE CAUSE

POSSIBLE SOLUTION

Too much heat from dryers or air blowing on print station
Reduce dryer heat
Eliminate air flow on print station
Slow press speeds

Clean the plates and increase press speed
Improper ink pH
If pH is below 8.8, increase it with the recommended additive*

*Wikoff Color Technical Data Sheets list the recommended additives for pH adjustments

2. Ink is drying too slow

The ink is picking off, offsetting on the press idler and might be causing blocking issues.

POSSIBLE CAUSE

POSSIBLE SOLUTION

Ink viscosity is too high
Reduce ink viscosity*
Drying systems are insufficient
Increase warm air flow
Improper ink metering
Replace doctor blade and/or make sure chamber is parallel

*Wikoff Color Technical Data Sheets list the recommended solvents for viscosity adjustments

3. Pinholes

You’re seeing tiny holes in your print area, sometimes called fisheyes.

POSSIBLE CAUSE

POSSIBLE SOLUTION

Substrate dyne level is low, possibly related to improper treatment
If ink adhesion is OK, add 0.5% pinhole additive under agitation
Too much defoamer has been added to the ink
Add fresh ink to reservoir
Ink viscosity is too low
Anilox roller is worn
Clean or change anilox roller
Ink is drying too fast
Slow the ink dry rate*
Plate mounting tape is too soft
Use a harder mounting tape

*Wikoff Color Technical Data Sheets list the recommended additives for drying adjustments 

4. Print is too strong

Print density is too high.

POSSIBLE CAUSE

POSSIBLE SOLUTION

Ink viscosity is too high
Reduce ink viscosity*
Improper metering roller or doctor blade settings
Increase metering roller pressure
Anilox cell volume is too high
Use lower volume anilox
Ink is too strong
Reduce ink with extender

*Wikoff Color Technical Data Sheets list the recommended additives for viscosity adjustments

5. Print is too weak

Print density is too low.

Possible Cause

Solution

Ink viscosity is too low
Increase metering roller pressure- Less than 1,000 hours/bulb
Anilox roller is plugged
Replace doctor blade
Anilox cell volume is too low
Use higher volume anilox
Anilox is worn
Change anilox roller
Improper metering roller or doctor blade settings

6. Haloing

That pesky shadow or line is showing up on the outer edge of your image areas.

POSSIBLE CAUSE

POSSIBLE SOLUTION

Plate cylinder is over impressed onto substrate
Reduce impression
Plate mounting tape is too hard for the images
Remount plate with softer tape

7. Picking

You’re seeing spots or ink being lifted off your print area.

POSSIBLE CAUSE

POSSIBLE SOLUTION

Ink is drying too slowly
Contact your local Wikoff team for a faster drying formulation
Drying systems are insufficient
Increase heat and air flow
Ink viscosity is too high
Increase heat and air flow
Reduce ink viscosity*

*Wikoff Color Technical Data Sheets list the recommended solvents for viscosity adjustments 

8. Mottled print

Your solid print areas are spotted and/or speckled.

POSSIBLE CAUSE

POSSIBLE SOLUTION

Ink viscosity is too low
Add fresh ink to the reservoir
Printing plate surface is uneven
Mount a new plate
Substrate surface is rough or uneven
Contact your local Wikoff team for a primer
Anilox is worn
Change anilox roller

9. Adhesion problems

The ink is having a hard time adhering to the substrate.

POSSIBLE CAUSE

POSSIBLE SOLUTION

Ink system may not be optimized for your application
Contact your local Wikoff team to verify you have the right ink system
Inadequate substrate treatment
Check substrate dyne level
Ink viscosity is too low
Add fresh ink to the reservoir

10. Dirty print

The edges of your print area are fuzzy and/or irregular.

POSSIBLE CAUSE

POSSIBLE SOLUTION

Ink is drying too fast
Slow the ink dry rate*
Too much heat from dryers or air blowing on print station
Reduce dryer heat
Eliminate air flow on print station
Too much anilox-to-plate or plate-to-substrate pressure
Reduce ink viscosity*
Reset anilox and plate pressure

*Wikoff Color Technical Data Sheets list the recommended additives for dry rate and viscosity adjustments

11. Foaming

Ink is foaming in reservoir.

POSSIBLE CAUSE

POSSIBLE SOLUTION

Ink pump is too vigorous
Remake Reduce power/air to ink pump
Ink viscosity is too high
Reduce ink viscosity*
Not enough defoamer in ink
Add defoamer to ink, small amounts at a time

*Wikoff Color Technical Data Sheets list the recommended additives for viscosity adjustments 

12. Poor trapping

Second-down ink doesn’t lay well over the first-down ink.

POSSIBLE CAUSE

POSSIBLE SOLUTION

First-down ink is drying too slowly
Use lower volume anilox for first-down ink
Increase heat and air flow on first-down unit
Reduce viscosity of first-down ink*
Second-down ink is drying too fast
Skip a unit between first-down and second-down ink
Slow down the second-down ink dry rate

*Wikoff Color Technical Data Sheets list the recommended additives for viscosity and dry rate adjustments 

13. Streaking

A continuous line is showing up in your print area.

POSSIBLE CAUSE

POSSIBLE SOLUTION

Particles are lodged under the doctor blade
Filter ink and clean behind the doctor blade
Anilox roller is scratched
Replace anilox roller
Doctor blade is nicked
Replace doctor blade

14. Blocking

The ink is offsetting onto the backside of the stock in rewind.

POSSIBLE CAUSE

POSSIBLE SOLUTION

Ink is drying too slowly
Ink is drying too slowly

Rewind is wound too tightly
Reduce rewind pressure
Rewind temperature is too warm
Reduce web temperature before rewind with a chill roller

15. Bridging/filling in

The print is connecting in small type and screens.

POSSIBLE CAUSE

POSSIBLE SOLUTION

Anilox cell volume is too high
Change to higher screen count, lower volume anilox
Ink is drying too fast
Slow the ink dry rate*
Ink viscosity is too high
Reduce ink viscosity*
Rubber roller is too soft
Change to a harder durometer rubber roller
Improper anilox roller settings
Adjust anilox roller to “kiss” impressions

*Wikoff Color Technical Data Sheets list the recommended additives for viscosity and dry rate adjustments

Get Technical Support

If you’re still not seeing the results you need on press, we’ll be glad to help you troubleshoot your water-based flexo issues. Give us a call or send us a message and the Wikoff Technical Solutions team will work with you to get your press back up and running smoothly. We are your experts, and happy customers are our number one priority