Moving fluid through a DTG printer may vary slightly from system to system, but the concept is the same; activate a pump to pull ink from the cartridges (or bags/bottles) through the lines into the dampers, then the print head and into the waste ink tank. At FIREBIRD, we like to start this process with the ink cartridges removed and not connected to any source to pull fluid from. We run the pump as long as possible until all visible ink has been removed. This should only take 20-30 seconds for most systems. After this, we will then insert our Cleaning Solution and activate the pump again. Letting the pump run for 10-15 seconds, we then remove the CS while the pump is still running. This will introduce air into the ink lines and act as a plunger to remove additional hidden ink deposits. This procedure may be several times until certain all ink has been removed.
The key to successfully flushing ink from your printer is to be sure to use the proper cleaning solution to do so. Many ink and printer manufacturers offer a cleaning solution that is matched to their inks. There are certain ingredients in these cleaners that are designed to break down the components of water-based pigment ink used in t-shirt production. However, it is actually harmless to switch between brands of direct to garment cleaners. It is only when using an off-the-shelf hardware store product that you are potentially putting the life of your printer at risk.
This is not to say that flushing your system has to be expensive. Cleaning Solution can be purchased in bulk and refilling bags or carts is a simple process. For example, 1500mL of cleaning solution purchased in bulk for a CMYK+WW system will refill all six cartridges with 225mL of fluid and have 5oz left over for the finer detailed swabbed head cleans at a cost of approximately $60 USD. While some printers may still consider this too expensive, it is much less than the cost of a new set of lines and dampers to replace damaged parts.