I would say that needle setup and speed are most likely the biggest issues. Many are not having the ink creep problem when using the Dragonflys....and some are. I would suggest taking a look at your needle bar bend, maybe bend less, maybe bend more. You need to closely look at how the needles are setting up at the tip. Are they curving up due to too much bend or elastic, are they not fully riding in the tip. Also I would suggest slowing down the run speed. After working with rotary machines for more than 6 years I can tell you that most artists will start out by running their machines too fast, and I have found that by slowing the rotary machine down, the artist will find that "sweet" spot that works the best for them.....and the ink will fly in.

On the engineering side of things...with some of the new rotary machines with adjustable give....not dampening, that there could be inherent vibrations produced inside the system. The spring rate may be vibrating at a resonant frequency with respect to the running speed. I would think that progressive wound springs or double springs with different spring rates would fix any vibration effect. So I would suggest that the machine builders take a look into this.... in order to make their machines that much better. I'm a "mad scientist" type and I designed a vibration analysis test fixture that we use here....I can mount tattoo machines and measure and record the vibrations going on....along with other data....and one would be suprized at what liitle changes made in any machine can do for those strange vibrations and harmonics. With the wrong vibrations, the needle bar can act like a feed mechanism and move the pigments right up the bar.
- Ray