The SCR was originally designed to address the extremely demanding needs of the magnetic recording tape industry in the production of video tape.
When you watch a movie on your VCR, and don't see a lot of the white dots interrupting the picture, you are seeing the benefits of good quality control in tape manufacturing. It's not easy. One of the processes which ensures such quality is the calendering of rolls in series that apply heat and pressure to provide a uniform, smooth tape surface free of debris and surface irregularities.
A natural consequence of this process is that the chrome calendering rolls pick off the debris and need cleaning themselves. In the past, this cleaning has been done off-line, requiring temporary shutdown of the process, if only to install a backup set of calender rolls, still a significant undertaking. This causes process stoppage/interruption and a reduction of process yields.
