Garment was improperly fixed. Inks need to be brought up to approx. 150-180 degrees C. for 180 – 240 seconds for white and for darker garments. Too much or too little pressure applied when heat pressing. When pressing the garment in the heat press the top of the heat press should gently rest over the silicone paper. This allows the moisture of the inks to escape and properly fix. Temperature of heat press is not correct (Either to hot or too cold). Make sure the heat press is heating up evenly or correctly. (Should be 150-180 degrees C) You can test this with a touch less infrared thermometer or heat testing strips. Pre-treatment improperly applied. Pre-treatment may still be wet. Simply fix longer.
Poorly pre-treated? Apply more pre-treatment on successive shirts and fix again. Too much pre-treatment. Use less pre-treatment in future. See pre-treatment on dark and coloured textiles. Type of fabric being printed For best results print onto 100% cotton! With 100% colours will look their best. For 50/50 blends of cotton and polyester ink needs needed to be fixed quickly to reduce possible bleeding. How the garment is being washed. Wash at maximum 40ºC inside out preferable with liquid detergents and delicate dryer settings. Make sure heat press is heating up evenly and correctly. Heat press should lightly press garment. Pre-treat evenly and away from printer. Fix Pre-treat properly.