There are a multitude of variables with any production process that can cause chaos and frustration if they aren’t correctly controlled and understood. This is especially true with the digital direct-to-substrate/garment (D2) printing industry. Though it has been around for several years now, the industry is still very much in its infancy, which means that processes, equipment, and user interaction and methods are still very fluid. Here, we’ll look at many of the significant variables that play a role in getting a good, finished product.
Any building is only as good as the foundation it is built upon, and this especially applies to the digital printing process. The foundation I am talking about here is the shirt. Ring-spun cotton shirts with high thread counts provide the smoothest surface, with fewer instances of fibrillation (where the fibers poke through the print). The smoother the shirt, the more dense the knit (you can’t print on air gaps in the weave of the shirt), and the better the final print.
While cotton is the preferred fabric, it is possible to print on polyester and poly blends. The issue with these athletic garments is that the same great characteristics that help wick moisture away from the skin also have a tendency to make the water-based digital inks “run.” This does not allow for a sharp-looking print. Plus, washability suffers and there’s a significant degradation of the visual brightness of the printed design. However, there are pre-treatments for polyester printing that help increase the brightness and sharpness of the print, and increase the washability. Unfortunately, dark shirt polyester printing is still not a true viable option due to the nature of white ink printing on polyester fabrics. But, as long as the proper procedures are followed, light polyester shirts can be a viable substrate to print on with your DTG printer.
The garment printers themselves are extremely sensitive pieces of equipment. If you read the operating manuals, there is usually an operating temperature and humidity range recommended to help keep your equipment running at peak performance based on the climate in which it is located. This is why it is often recommended the printer be in an air conditioned/climate controlled room.
If you are in the middle of the desert, where the humidity is extremely low and you don’t have your printer in a controlled room (controlled with a humidifier), you will likely experience clogged nozzles. In colder climates in the winter, especially if you are using forced air for heating, you may also need a humidifier to help keep your digital garment printer happy. Some geographical areas that have very high humidity, especially in the summer (i.e. in the south), clogging might not be an issue, but excessive temperatures might factor in and cause other issues.
Find out the optimal conditions for operating your equipment and find a way to maintain those conditions year-round. You will be removing one more element that can cause you headaches in your digital printing process.
Inks for your Printer
Just like milk, your ink has an expiration date. That date is not from when you get it, but is from when the manufacturing facility produces the ink. Generally, for white ink, it seems as though there is about a 180-day window from production to when it is generally not advisable to use. Always check the expiration date prior to inserting the ink into your machine. Expired ink can cause problems with clogging and lead to expensive repair bills.
In addition, make sure that your ink is shaken up prior to use each day. This is a must, especially if your printer doesn’t have an automatic recirculating system for keeping the ink in suspension. If the inks separate out, you may not achieve a bright white ink laydown. Also consider that, if you leave ink in the printer lines for an extended period of time, it could also separate, or precipitate out, causing the same issue until new ink is introduced and fills the ink lines.
Know Your Machine
Knowing how your artwork and printer work is key if you want to print great-looking shirts versus one that looks like every other shirt on the market. Many printers have drivers or RIP software used to interface between the computer and the printer. Using the standard default settings usually achieves satisfactory results. However, taking the time to really understand how the artwork and RIP interact will help you achieve better-than-average results.
Do you need to bump up the contrast for this type of artwork to help make the colors “pop” a little more? Do you need to check to make sure that the correct color in the art program is selected so that it properly prints white ink where you want white ink and not just let the shirt show through? These are just a couple of the many “artwork” questions you will face.
To print white, you need to know how to make the proper adjustments so the RIP/driver knows that it has to print white ink in those locations. This takes time, patience and a lot of practice. But, once you master the artwork/printer interface, the sky is the limit.
Curing the Ink
Most people utilize a standard heat press to cure digital inks. The direct contact of the heating platen with the ink surface, in conjunction with some type of Teflon or paper cover, results in a very smooth ink surface. This surface can be shiny, if Teflon is used, or matte when kraft paper is employed.
Another option that is gaining popularity is conveyor dryers. Using a conveyor dryer generally results in a much nicer-looking print with a little bit of texture on the ink surface. This rivals a fine textured, screen-printed look and less of the flat, smooth look of a transfer. Keep in mind that curing times are often much longer than with a typical heat press, ranging from several minutes or more for a conveyor dryer versus 30 to 90 seconds with a heat press.
No matter the method, it’s imperative to ensure the print is cured properly. Poor curing, either from too short a cure time, or even the possible over heating/curing the ink, can result in poor wash characteristics of the printed image. Cure the garments according to the ink manufacturer’s recommendations. They have generally done the testing, so you don’t have to figure it out yourself.
Maintenance is always an issue. There are always customers that need shirts printed, it is always the end of the day… there’s always some excuse not to do the required cleaning and maintenance. All these little things culminate into the equipment eventually not working correctly, or not at all.
Adhere to the maintenance schedule recommended for the garment printer and pre-treatment machine. It does take time, and it does cost a little money, but the time spent will help reduce downtime due to lack of maintenance. This downtime actually costs more in the long run than the time it takes to keep the machines running properly.
Knowing and understanding the variables in the digital printing process will help you determine where an issue lies when problems appear. Being able to quickly respond to, correct, and get the equipment back up, running, and making money is the key to making digital printing profitable.