Recovering a UV White Print Head After 1 Month Idle (Real Field Case, XP600) _Head related problem 5

Who Should Read This

UV printer operators experiencing white ink output failure after extended downtime
Field technicians troubleshooting white channel recovery or replacement decisions
Production operators needing realistic recovery expectations before replacing a print head

⚠ Warning

This procedure may damage the print head if performed incorrectly.
Perform recovery attempts at your own risk.

Result Summary

6 white channels → 5 channels recovered
1 channel permanently blocked
White printing usable for production (with channel masking applied)

Recovering a UV White Print Head After 1 Month Idle (Real Field Case, XP600) _Head related problem 5 _ARTJET 2026

So far, I have summarized the information related to UV Printers below. If you click on the article, you will be taken to the link for related information.

If cleaning, pumping, or printing is not working properly, there are two approaches you can take:

1. Ink supply

Printing errors caused by ink supply (including cleaning and pumping issues) have been recently updated.
For printers using dampers, troubleshooting can be done through the link below.
This is a table of contents, with 23 articles, complete with photos and explanations. Click on the link to view the relevant articles.
Printer Cleaning Problems Part 23 Table of Contents ARTJET 2026

2. DATA-related issues (electronic board, head, DATA cable, etc.). Currently updating.

In the first session, the symptoms and solutions that occur when a DATA cable becomes contaminated with ink.
In the second session, the 17 used heads I had in storage, how many were usable after cleaning them with alcohol, and what errors occurred.
In the third hour, I discussed the issue of certain colors being printed strangely during printing.
In the fourth hour, we explained how to deal with light-reflective materials when printing and what is more dangerous than light reflection and what can block the head nozzle.

Today, I’ll explain the “Reviving a Clogged Whitehead” section of the ink supply problem series. I actually revived a whitehead that hadn’t been used for a month.

[Click here to see the article about reviving a clogged whitehead]

I. Failure Symptoms — Recovering a UV White Print Head After 1 Month Idle

Due to health-related reasons, the customer did not operate the printer for approximately one month.

After restarting the machine, color and varnish channels recovered after several pumping and cleaning cycles.

However, the white channel did not recover, even after repeated pumping and cleaning procedures.

During pumping, ink was discharged into the waste ink tank normally.
However, nozzle tests showed poor or missing output, and test image printing showed no meaningful improvement.

Ink Drying and Hardening on the Print Head Surface

In damper-based ink systems, the print head is parked against a captop, which seals the nozzle area using a rubber sealing surface to reduce air exposure.

However, during extended idle periods, the sealing performance of the rubber captop can degrade over time.

When sealing weakens:

The captop surface may begin to dry
The print head surface may also begin to dry

As the head surface dries, residual white ink inside the nozzle openings can dry and harden, preventing proper ink jetting.

Compared to white ink, color and varnish inks typically contain:

Smaller pigment particles
Lower concentrations of photo initiators related to curing

As a result, they are generally less prone to clogging.

White ink typically contains:

Larger pigment particles
Higher photo initiator content

This increases the likelihood of curing and hardening, particularly during extended idle conditions.

II. White Nozzle Recovery Procedure — Recovering a UV White Print Head After 1 Month Idle

1. Recovery Procedure for Ink-Clogged Print Head

Full recovery is not always possible. However, recovery can be attempted by filling the captop with IPA 99% and performing controlled pumping.

Procedure:

Move the head carriage to the left position.

Fill the square captop on the right side with IPA 99% alcohol. Avoid overfilling (minor overflow is generally acceptable). When filling alcohol, take care not to contaminate the X-axis linear scale.

After filling the captop, press the Reset button in the ARTJET software to move the print head into the capping position.

When capped, the white print head surface will contact the IPA 99% alcohol inside the captop.

To sufficiently soak dried white ink residue at the nozzle tips:

Standard condition: ~5 minutes
This case (1 month idle): 10 minutes

⚠ Important Warning

UV ink begins dissolving when exposed to IPA 99%.

However, exposure longer than 10 minutes may cause chemical interaction between ink and alcohol, potentially hardening ink residue and fully blocking the nozzle.

Do not exceed 10 minutes.

After soaking, perform ink load (pumping) to remove white ink from the damper.

Residual alcohol inside the captop will also be removed during pumping.

Once white ink flow begins:

Pump for approximately 30–50 seconds
Do not exceed 1 minute

Excessive pumping can force ink through extremely fine nozzles and may damage the print head.

After pumping:

Perform head cleaning
Perform nozzle pattern testing

Results — First Recovery Attempt

At this stage, recovery success was uncertain, and print head replacement was already under consideration.
Therefore, recovery was performed aggressively.

Procedure used:

10-minute IPA captop soak
1-minute pumping
Cleaning

Since nozzle pattern improvement was unlikely, a full white test image was printed first.

Results:

White output was restored (previously nearly zero)
Significant banding remained

Nozzle pattern results (6 white channels):

3 channels: near normal
2 channels: partial output
1 channel: no output

Results — Second Recovery Attempt

The same recovery method was repeated.

Since head replacement was already being considered, pumping duration was extended from 1 minute to 2 minutes.

⚠ Pumping beyond 1 minute may damage the print head.

Results:

5 of 6 channels: near complete recovery
1 channel: partial output but determined unrecoverable

2. Operating With Five White Channels (Channel Masking)

The final unrecoverable channel was disabled using the ARTJET software channel lock function.

If channel lock is not applied, unstable nozzle output can cause white banding during printing.

When a channel is locked:
The software generates a new print mask using the remaining functional channels, reducing banding.

Typical Japanese UV printer configurations limit white density to approximately 200% relative to color.

In this XP600-based configuration:
One full head is dedicated to white (6 white channels total).

This allows white output up to approximately 600% relative to color.

Even with one channel disabled:
White output remains approximately 500%, which is typically sufficient for production.

The remaining 5 channels showed stable nozzle condition and minimal white banding during test image printing.

한달 사용하지 않은 White 헤드 살리기 실제 사례

White Channel Lock Setting

Channel locking can be configured in the software control panel.

Select the red box on the left to open the channel control screen.

Channels 7–12 correspond to white channels.

Identify the faulty channel using nozzle pattern results.

Example:

White under Black = Channel 7
White under Light Magenta = Channel 12

Select the affected channel → press down arrow → select [Close]

This disables ink jetting for that channel during printing.

Nozzle pattern testing will still show the channel pattern.

After applying the setting, confirm the status on the main screen.

한달 사용하지 않은 White 헤드 살리기 실제 사례

3. Long-Term Stability Considerations

If nozzle condition recovers, stable operation is typically possible after 1–2 weeks of normal usage.

However, if after one month of idle time, recovery remains around ~5% nozzle recovery despite repeated cleaning and pumping, the head may remain unstable.

Common risk:
Diagonal jetting instead of straight jetting, leading to persistent white banding.

In similar recovery cases:
If nozzle condition remains unstable, banding-free white printing is unlikely.

Preventive maintenance recommendation:

At minimum: once per week
Maximum interval: once every two weeks

Perform:

Pumping
Cleaning
Test image printing

To maintain white nozzle condition.

III. ARTJET UV Printer

Based on over five years of sales and maintenance experience with ARTJET UV printers, one key lesson stands out:

After product stability, the next most critical factor is troubleshooting data.

Every product can encounter issues — whether caused by equipment conditions or user operation.
In real production environments, product reliability depends on how quickly and efficiently those issues can be identified and resolved.

ARTJET continuously collects and organizes real field troubleshooting data to support faster and more accurate problem resolution.

You can view print quality samples here:

[Print quality sample by video]

You can view ARTJET pricing and sales conditions here:

[Pricing & Sales Condition].

(Note: Exterior design has been updated)

You can also review a complete list of products that can be produced using UV printers here:
[UV Printable Product Guide]

쉬운 목차

INKJET UV Printer & Laser Cutting Machine