Primer Functionality and Concerns — UV Printer Products (Part 9) ARTJET 2026

1. The Ink Adhesion Problem Even Sellers Didn’t Know About

• Back in 2004, when I was working at a UV printer development company, I thought development was complete as long as the printer could print.
• The concept of “matching base colors through RIP software” didn’t even exist yet.
• At the top of UV printer brochures, it said: “UV Printer — prints on any substrate”
• We marketed it that way, met a few customers, and printed on bathroom tiles, glass, and metal plates — only to discover that the printed ink could be scratched off and was unusable.
• After that, “prints on any substrate” was removed from the brochure and replaced with a list of printable substrates where ink adhesion was confirmed.

2. The First Commercialized Inkjet Primer

• I joined InkTec when they were developing their UV printer.
• In early 2009, when brainstorming how to build the UV printer, the CEO — who held a PhD in chemistry — asked:
• “Instead of doing what everyone else does, what can only we do — as both an ink manufacturer and a machine developer?”
• “There are substrates like glass, tiles, and metal plates where ink doesn’t adhere — if we could just secure adhesion on those materials…”
• The CEO then told the UV ink and machine development teams:
• “The machine team should design the equipment so Primer can be jetted through an inkjet head, and the ink team should develop a Primer that can be fired from the head.”
• When functionality was achieved, the Primer clogged the print head after 3 days of idle time. When clogging was eliminated, the adhesion functionality dropped.
• After a year of discarding countless print heads, the development was finally completed.

3. The Limitations of Inkjet Primer Functionality

• One year after delivering the UV printer, we received a problem report about the Inkjet Primer we had sold.
• “After printing on glass, the ink that adhered well at delivery started peeling off after 6 months.”
• The photo below shows output printed on a metal plate — the symptoms are similar.

• 

• “Primer enhances ink adhesion, but you must conduct alcohol, tape, and humidity tests on your specific substrate to determine suitability yourself.”
• Adhesion testing after printing on a substrate is typically conducted as shown in the YouTube video below.
• Primer Functionality and Limitations
• When delivering Primer-printed products, consider the post-installation environmental conditions (high humidity, high/low temperature, fluctuating conditions) and whether issues may arise after 3 or 6 months.

1. Idle Testing

• During the initial Primer development, countless print heads were discarded.
• The final Primer achieved functionality and could survive a weekend without clogging the nozzles, but:
• “Europe has long vacations — what happens if it sits idle for more than a week?”
• “Let’s set the bar at: after 2 weeks idle, if purge + cleaning can unblock the clogged nozzles — even with difficulty — we’ll consider it acceptable.”
• We achieved this level and sold the Inkjet Primer, but the complaints we kept hearing were:
• “The Primer print head is gradually clogging — after hours of purge + cleaning, the blocked nozzles simply won’t open.”

3. Is the Primer Made in China or Korea?

• I used to think this way too, but a common question from customers is:
• “Is this Korean ink? Or Chinese ink?”
• This question usually carries the implicit assumption that “Chinese = bad, Korean = better.”
• How many inkjet ink manufacturers in Korea actually have systematic quality control?
• Outside of major companies, there are fewer than you’d think.
• For companies with systematic production, one of the most critical factors is: “whether there are problems after delivery.”
• Inkjet Primer should have become mainstream by now, but it hasn’t.
• The reason is that in one form or another, “post-delivery problems” keep occurring.
• Some smaller Korean companies advertise Inkjet Primer online, but what’s concerning is that their Primer bottles list multiple print head models together.
• A single Primer claiming compatibility with multiple heads means it’s not optimized for any of them.
• Using such a product is likely to cause various issues.

4. The State of International Inkjet Primer

• Four years ago, we tested a European-made Inkjet Primer designed for the Xaar1201 print head.
• Adhesion was improved with the Primer, but over time the head clogged.
• We stopped using it because of this.
• As an additional test, we tried applying the Xaar1201 Primer to an XP600 print head.
• Voltage had to be raised excessively just to achieve marginal jetting, and too much ink scattered sideways — so we abandoned the attempt.
• This illustrates that Primer must be developed specifically for one print head to even achieve acceptable jetting — and even then, head clogging remains a concern.
• The likely reason China — despite being quick to adopt new technologies — hasn’t mass-produced Primer is the risk of post-delivery problems.

• 

1. Japanese UV Primer

• It’s not that the Primer itself is fully stabilized — rather, thanks to the automatic cleaning system, Primer is viable on Japanese compact UV printers.
• However, whether adhesion actually works properly on metal plates or glass must be confirmed directly.
• Currently, some Chinese or Korean equipment makers claim Primer is “usable,” but stability remains to be seen.

2. Manual Primer

• Some UV printer operators use manually applied Primer liquid instead of Inkjet Primer.
• Apply Primer to the substrate with a cotton pad, UV print on top, then wipe off unprinted areas with alcohol to finish.
• However, even if you accept this inconvenience, there are additional considerations:
• A single Primer doesn’t work on all substrates — there are separate types for glass, acrylic, and metal. Primer types vary by substrate.
• One customer sourced a metal Primer from another company, applied it, and delivered to a government facility — but the ink peeled off due to summer humidity. “Just because adhesion works at the time of printing doesn’t guarantee there won’t be problems later.”
• Manually applying Primer, then wiping off unprinted areas afterward — all this labor time is a cost. Small batches can be managed, but for large volumes, factor the application time into your pricing.
• Another consideration: employees often dislike manual Primer application due to the odor and environmental concerns.