ImagesMagUK_March_2022

www.images-magazine.com MARCH 2022 images 29 TIPS & TECHNIQUES easiest solution is to switch to a barrier- coated transfer paper that doesn’t allow the gas to transfer through the back of the paper. Rivering Rivering is an unwanted transfer print effect that looks a bit like a river, tree or arc. This happens when gases that build up during sublimation seep out to the edges of the textile because the transfer paper and the textile are both non- porous. The bigger the print, the lower the porosity, the worse the effect. It can be resolved by switching to a transfer paper that is, to at least some degree, porous. Alternatively, you could use a different, more porous textile. Print cost A high print cost could be due to a number of reasons. It may relate to the paper used: it could be too expensive, too high gsm, an unsuitably high grade, or the coating may not be high enough release, resulting in excess ink usage. It could also be due to the ink profile being too heavy. The best solution is to trial new, economical transfer papers from a reputable supplier, or, if you are already using an economical paper, look at adjusting the printer profile. It’s best, however, to leave the profile unaffected and save money by changing the paper instead. www.i-sub.co.uk felts; it is relatively simple to replace felts on flatbed presses. Other issues include the fabric being unsuitable (wrong yarn content, laminated with unsuitable material, etc), printing on the wrong side of the transfer paper, having the wrong print profile set, or using unsuitable or low-quality papers; if it’s the latter, a high-release barrier or coated paper may be the solution. Horizontal and vertical lines There are a number of factors that can cause horizontal lines in print, including blocked nozzles, incorrect paper feeding speed, and a low pass rate. To check to see if your nozzles are blocked, run a test print. If there is a small amount of missed nozzles, it is best to run a light clean. Alternatively, you can run a full calibration: bi-directional alignment, media feed compensation, and print head alignment. The printer may be struggling to achieve the quality desired at the existing pass rate so another solution is to increase the pass rate. Most RIP softwares will allow an increased pass rate without a significant change in colour or quality. Vertical lines are often caused by consistent heads strikes, in which case look at switching to a higher gsm paper that is able to hold a higher amount ink, and/or use a faster drying paper; use a dryer to reduce the drying time; and reduce the amount of ink used by adjusting the profile. And, as usual, ensuring the environment conditions of the room are in line with the printer requirements is always helpful. A less common reason for vertical lines may be due to the pinch rollers; if they get dirty or there is excess toner stuck to the roller, it can leave a smudge down the paper as it’s moved through the printer. The simple solution would be to clean the rollers or, in some cases, replace the rollers. Slow drying speed A main cause of prints not drying quickly enough is the ink printing profile being too ‘heavy’. Another common cause is using a slow-drying sublimation transfer paper: if the print doesn’t have sufficient time in which to dry, this can cause ‘stamping’, ie the wet ink rubs off as the roll is winding up at the front. Common solutions include using a fast-drying sublimation paper, using a dryer (integrated or standalone), or reducing the amount of ink used. Again, it’s also important to ensure the print room environment is suitable for the printer’s requirements. Gassing through the reverse of the paper This is when the dye sub gas transfers through the paper in the reverse direction during heating. This can cause staining of ancillary equipment, for example silicon mug wraps, and the primary cause is the structure of the transfer paper. The Head strikes such as this can damage the nozzles of the print head Rivering, as highlighted here, is caused by gases building up and seeping out during sublimation