At different stages of the process of invention, design and innovation there's a role that can be played by improvers. The improver is an individual or group whose concern is to do things better by making improvements to existing products or processes.
Such people can help transform an inventor's first prototype and early design into a commercial product. Edison's team at Menlo Park included a number of engineers, chemists and mathematicians who contributed to the improvement of the electric light, as well as other inventions.
Another contribution of improvers is at a slightly later stage in the innovation process when they can make incremental improvements to other people's inventions. For example, in 1877 Edison developed a carbon transmitter that helped improve Bell's recently invented telephone.