Table height (platen height) is adjustable and should be set for each type of garment that you are going to print on. The purpose of adjusting the height of the table (platen) is to ensure that the garment you are going to print on is the optimal distance from the print head, ensuring the best possible quality of print. As described in the getting started guide, the printhead uses piezoelectric technology (vibrating crystals) to move ink from the printhead to the surface of the garment and the distance that the printhead is from the garment has a significant impact on print quality. Since the printhead cannot be moved up and down, you will move the garment closer or farther to the printhead by adjusting table height.
The standard table that is shipped with the MelcoJet G2 is slightly thicker than the optional tables. Because of this, it has a slightly smaller maximum material thickness. With the standard table, the maximum thickness for a material to be printed is 0.5" or 12.7mm.
The optional tables are thinner and provide a bit more room for printing. With these optional tables, the maximum material thickness for printing is 1.06" or 26.8mm.
Adjusting the Table
Table height can be adjusted at any time and while the table is in any position, however you should only adjust the table height while it is in the "load" position. This is because it is entirely possible, depending on the "thickness" of the garment you are printing on, to contact the printhead (with the garment). This must be avoided at all costs as this scenario is called a "printhead strike" and can damage the printhead beyond use.
In order to help you avoid a printhead strike, the printer is equipped with two laser sensors that will alert you if you move a garment too high. To set table/platen height:
- Move the table to the load position by pressing the Auto Out button.
- Load your garment on the platen and carefully close the platen frame over the garment.
- "Step" the table in using the Manual In button until the garment is just inside the height sensors (see image below).
- Raise the table up until the table height limit light is illuminated by pressing the UP button on the table control panel. The table will stop and there will be an audible beep indicating the table is too high. This signal will only indicate when the table is too high, there is no indicator that the table is too low.
- To achieve the exact table height for this garment, press the DOWN button on the table control panel until the table height LIMIT light indicator goes out. When the light is out the height has been adjusted for the garment.
- You will now need to move the table in to the print position by pressing the dashed up arrow button on the table control panel marked with a red #4. This will automatically move the table all the way out (load position) and then back in to the print position.
The optimal distance for all printing is .08 inches (2mm) of space between the lowest point of the print head nozzle plate and the highest point of the garment.
If the garment it is too far from the nozzle plate, the print quality will suffer and ink over spray will be visible. If the garment is too close to the nozzle plate, there is risk of the printhead touching the garment and scratching the nozzle plate coatings, which makes the printhead unusable.