Images_Digital_Edition_November_2019

www.images-magazine.com 28 images NOVEMBER 2019 In the second part of his guide to DTG print heads, Colin Marsh, managing director of Resolute DTG, discusses cleaning and maintenance they will last for the lifetime of the printer, as long as they are properly cleaned and maintained. How does a capping station work? As water-based DTG ink is jetted during printing, some minute particles (satellite droplets) may not reach the substrate and will become airborne for a split second inside the printer. A DTG printer with good extraction and filters should capture most of this, helping to keep the inside of the printer clean, while also pulling the ink mist away from the print head. Inevitably, however, some particles will adhere to the surface of the print head; at this point the ink is still part water and easy to remove. Throughout the working day, natural particle attraction occurs resulting in the minute droplets joining with others and growing in size. These can be seen as very small droplets on and around the print head. During general maintenance an automatic print head clean will remove these droplets whilst performing two different operations. Firstly, a quick sharp belt of suction is used to draw a small amount of ink through the nozzle exit holes quickly, dragging any waste droplets with it. This, in turn, cleans out the exit nozzle hole before the accumulated ink droplets start to set and take on the form of soft rubber. Next, a physical wipe off the surface of the head leaves it clean and ready to print again, or be parked on the capping station. A rubber wiper blade or a fabric roller mechanism are the two most common methods that are used to perform this process. As the capping station cleans the head it becomes dirty, but a capping station can’t clean itself and relies on manual cleaning on a regular basis. Neglecting the capping station can cause your print head serious damage; in some cases it can clog beyond repair and require premature replacement. Cleaning your print heads In general, print heads are more robust than you would imagine, so the cleaning regime for most of them will be the same. Nevertheless, you should only use S imple cleaning procedures play a big part in the longevity and general health of your print heads, but you need to do more than just cleaning the print head itself. The capping station, or maintenance station as it is sometimes referred to, is responsible for general cleaning, as well as providing the correct environment in which to store the print heads when they are not in use. A complex labyrinth of tubes, pumps, rubber seals and a wiping mechanism are usually combined into one unit. Some capping stations are designed to be a consumable part that is discarded and changed once it reaches the end of its lifespan, but other, more industrial maintenance stations, are designed to be serviceable, which means Colin Marsh