Decorating tumblers with the MUTOH 626UF UV printer

 UV printing is becoming more and more popular in the sign, graphics, and awards industries. The MUTOH 626UF UV printer gives sign and graphics shops endless opportunities to print directly to substrates, including mobile phone covers, notebooks, trophies and promotional items. The white ink supports printing on non-white substrates including transparent and dark items. One of the most compelling business cases for UV printers is the custom drinkware craze.

This enduring market has generated demand for all kinds of decorated mugs, bottles and tumblers. There are lots of ways to approach this market. But a UV-LED printer is one of the best because it’s one of the easiest ways to produces durable, high-quality images on cylindrical objects. We can contact you with a great company that can lease you the printer, and finding a printer leasing company will save you time and money.

It’s a short cut to a very appealing product. Let’s take a look at how to use a MUTOH 626UF to decorate stainless steel tumblers.


Like all MUTOH ValueJet printers, the 626UF UV printer benefits from Mutoh’s patented intelligent interweave, or wave print firmware. Intelligent interweave gives you high resolution at high speed with virtually none of the ‘piezo banding’ that troubles other piezo printers in the market. The MUTOH 626 UF has a 23.3” by 19” bed and can print on items up to 5.9 inches thick. The 626 UF is a six-color printer configured for CMYK plus white and varnish ink. The printer lays the ink down and a UV-LED lamp attached to the head cures and seals the ink instantly. When the print is finished, the decorated item is dry and ready to be handled.

tumbler printed with MUTOH 626UF UV printer

Using the Rotary Attachment

One of the MUTOH 626 UF’s most exciting features is the optional rotary attachment. The rotary attachment enables printing on cylindrical items like tumblers and sports bottles. Like most rotary attachments used in UV direct printing and engraving, it’s designed for items that can roll freely in the attachment. This means traditional ceramic mugs are out of the picture. The handles get in the way. But printing on stainless steel tumblers like Yeti and Arctic products is fully supported.

Rotary UV printing works best on perfectly cylindrical objects. That’s because the piezo print head needs to maintain a precise and consistent distance away from the item being printed. So if your target mug is slightly thicker at the top or bottom, it’s not ideal. But there are some clever ways to get around this problem. We’ll talk more about that in a bit.

For optimal print quality and printer service life, the rotary unit must be installed correctly. There are a few steps involved in converting the 626UF from standard to rotary printing.  Here’s a brief summary of the process.

FIG 1: When prompted, place the unit onto the printer’s flatbed.

FIG 2: Covering the sensor for the Rotary Unit. If this is not covered, the unit will not right.

FIG 3: Using a caliper to find the diameter of the cup.

FIG 4: These images show how using masking tape can help save some time and headaches.

  • Access the printer menu and select Option 5: Rotary Unit. Yes confirms your selection.
  • The menu will guide you with helpful prompts through the process of installing the rotary unit, and setting the height of the table.
  • When printing on flat surface items, the printer uses a laser to optimize head height for items loaded on the table. The rotary unit blocks the laser sensor, so the menu prompts you to enter the diameter of your item instead. This sets the head height for proper print quality and prevents head strikes.
  • Use a metric micrometer to get the diameter of your item. If the item is beveled slightly (think Coke bottle shape), enter the diameter at the widest part of the tumbler.
  • The default image orientation is landscape, which puts the bottom of your image parallel to the top and bottom of the tumbler. Text printed in this orientation wraps around the width of the item. To print reading top to bottom, rotate the image in your Flexi software.
  • Because there are a few variables here, and it’s easy to forget one, it’s always a good idea to do a test print. If you’re printing on an item you have plenty of copies of, that’s easy. But if you only have one, you need to make the test print on the item itself. One easy way to do this is to cover the intended print area with masking tape. Print on the taped tumbler first. If the image and orientation are good, just remove the tape and resend the job on the bare metal.
  • Once you are happy with the placement, prep the item by cleaning it with isopropyl alcohol. This will remove any debris or fingerprints. It would be pretty frustrating to spend all the time to carefully prepare your custom print, then end up with a fingerprint in the middle of your design.
  • Remember that part about coke bottle shapes? The head height must be consistent as the print head passes over the surface of the mug. If not, the image will be out-of-focus on the recessed areas. One simple way to fix this is to elevate the narrower end of the item by wrapping it in masking tape. One ingenious customer of ours uses a little jig made of Legos to support the narrow end of his mugs.
  • Once the tumbler is properly measured, cleaned, and placed in the rotary unit, take note of how far from the top of the mug you want the print to start. Add this as a margin in your Flexi RIP & Print window’s general settings tab. Press send and watch the magic as the rotary attachment gently rolls the tumbler across the table and the printer prints your cool design directly on the tumbler.

UV printing Tips

Static and Overspray: Some items receive UV ink more readily than others. Plastics like coroplast attract a fair amount of static electricity. Static charges on the surface can interfere with the jetting of the ink and cause overspray: blurry images with strands of ink outside the target area. To defeat this, coat these items first with a staticide, or static reducing agent. These are affordable and easy to get. We use Novus which is readily available online. Treat with a fine spray. Then clean with alcohol and make sure the object is dry before printing.

Election Signs: Speaking of substrates, you don’t have to limit yourself to tumblers and sports bottles. The 626UF’s 19 x 23 bed is ideal for direct prints on corrugated plastic sign blanks. During an election year, the demand for these can’t be overstated. Direct printing on cor-plastic saves time and money compared to cutting and weeding vinyl, or even mounting printed vinyl graphics. If you’re in a ‘battleground state’ consider arming yourself with a MUTOH 626UF and adding some campaign cash to your bottom line. Just remember to apply some Novus before printing.

Layering White and Varnish

One of the cool features about the MUTOH 626 UF is the variety of affects you can get from combining CMYK, white, and varnish ink in different layer settings. The bundled FlexiSign & Print 12 software give you lots of options for mixing process color with the white and varnish spot color channels.  The supported options for white and varnish include Under Color, Fill Color, Substrate, Variable under Color, and Fill-Substrate.

The various driver settings determine whether white or varnish is printed under the process color to add opacity on dark objects, whether it’s applied in an even coat, or only where white is needed to support brighter colors. It’s pretty flexible and produces a wide variety of pleasing effects. This is one of the things that makes the 626UF so versatile. See Fig 5 for an idea of some of the different effects possible on dark substrates. Click on the arrows to see the steps.


FIG 5: Shows how to change the driver settings and spot settings for the white and varnish printing.

The color layer settings are accessed in Flexi’s driver options window. There, you can select the under color, spot color and other settings. Click here to download a document that walks you through all of driver options and their intended uses. These options work for both white and varnish. Here’s a brief explanation of what the settings do:

Variable Under Color: This setting adds white beneath CMYK to add opacity. Choose this when printing on dark or clear substrates. The Variable aspect uses the RIP’s data to add more white ink under bright colors and less white under darker tones. This is a cost-saving feature that limits the impact of the higher cost of white ink.

Under Color: Using this setting with White under CMYK gives you a solid layer of white ink under your process color. This produces brighter color, but increases ink cost and reduces print speed.

Fill-Color: This setting floods the image area with white or varnish. It’s a good option for varnish layer if you want to add abrasion resistance.

Fill-Substrate: This setting floods the entire substrate area as determined by the page size setting in Flexi Sign & Print General tab. Use this to apply a solid layer of white or toner to the substrate under or over process color.

Whether you’re decorating election signs, Yeti tumblers, or hockey pucks, the MUTOH 626 UF UV printer is a great choice for applying stunning custom graphics. In today’s hot market for custom drinkware, a 626UF is a license to print cool custom tumblers – and money. It’s a great addition to any serious awards, sign, or graphics, business. If you’re jumping into the tumbler market, be sure to order yours with the optional rotary unit. Stock up on masking tape, isopropyl alcohol, and staticide, experiment with the various driver options and you’ll be selling terrific tumblers in no time.