The techniques used to embed the tattoo in the skin are sometimes linked to a particular region or culture. For example some tattoos are obtained during cultural ceremonies, as rites of passage. However all tattoos result in creating permanent marks and designs on the body.
In more industrialized western countries like the United States tattoos are applied using a tattoo machine. Tattoo machines are professional equipment that that greatly aid tattoo artists in applying ink pigment into the skin. They have electromagnetic coils that repeatedly insert a needle into the skin in order to embed ink or pigment. The tattoo machine contains a hand-held device that allows that artist to draw very fine lines to broad shapes. It's interesting to note that tattoo artists usually refer to their equipment as a tattoo machines or a tattoo irons whereas novices often use the term tattoo gun.
Most people would be surprised to discover that Thomas Edison, who is usually associated with the advent of the light bulb, is partially responsible for inventing the first tattoo machine prototype. Mr. Edison patented a battery powered device in 1876 and called the "Stencil-Pens." This device would punch holes in paper indifferent designs and patterns. The punched paper would be placed over a solid surface object and colored powder would be dusted over the paper. This served to transfer the pattern onto the object. It's not too difficult to imagine how this technique could be used to place patterns and designs on the skin.
Sure enough fifteen years later the Stencil-Pens was modified by Samuel O'Reilly to include an improved tube assembly, an ink chamber, a needle to insert ink into the skin, an on and off switch, and stroke adjustment capabilities. O'Reilly registered his design and received the first tattoo machine patent.
However, the design patented by Percy Waters in 1929 is the one that most closely resembles the modern day tattoo machine. Waters' design included two electromagnetic coils set parallel with the frame. It also included a spark shield and an easier to use on and off switch. Waters continually improved upon the configuration of the device but the basic design stayed the same for many years.
A patent for the next tattoo machine wasn't registered until fifty years later in 1979. It was issued to Carol "Smokey" Nightingale, a former Merchant Marine who was dubbed "The Man with the Golden Needle." Carol claims to have learned about tattooing techniques from his mother, a circus worker. His design included springs of different lengths for different types of detail work and a lever for total adjustability of the coils.
Modern tattoo machines can control needle speed, depth, and pressure, which have allowed tattooing to become a very precise art form. The machines are so precise and sensitive that a particular type of facial tattooing called dermapigmentation or permanent makeup has evolved.
As you can see the tattoo machine has gone through numerous modifications since the first device was designed by Edison over 100 years ago. This practice continues to this day. Almost all tattoo artists purchase standard machines and then modify them to accommodate their tattoo styles and application techniques. As such, no two tattoo machines are the same. Although most tattoo artists don't take the time to patent and register their modifications they are nonetheless improving upon the original design, regardless of how slight the changes may be.
Tattoo machines will continue to evolve in design and application as tattoo artists continue their search for the "perfect" tattoo machine.