The typical design is a cylinder covered with a fibrous material that is placed on a frame that has a number of free turning wheels that are positioned on each end of the cylinder. The wheels' axle hooks into a handle which can be of various lengths to accommodate the relevant height of a surface that is to be painted.
The basic device was invented by Canadian Norman Breakey in 1940. Norman James Breakey was born February 25th 1891 in Pierson Manitoba to Elizabeth Jane Fanning and William Henry Breakey. He had one sister, Kathleen who was born June 25th 1897, also in Pierson. When Norman and Kathleen's mother died in August 1899, Norman and Kathleen stayed with their maternal aunt Ruth (Fanning) Dandy and her husband William Dandy. The children later joined their father in Toronto.
Sadly, Norman never was able to produce his invention in large enough numbers to profit from it before others made small changes to the paint roller's design and were able to sell it as their own invention. One of them was Richard Croxton Adams who held the first U.S. patent on the paint roller. He claimed to have developed it in his basement workshop in 1940 while working for the Sherwin-Williams Paint Company.