OUT OF DATE - Work In Progress
NOTE: This part is currently not in use in v2. The friction provided by the PTR roller was not sufficient to hold the film and advance without slipping in tests. As a result, the assembly has been removed and tests are being performed to see if the machine can work without it. If it is determined that a capstan is still desirable, this design is subject to change.
The purpose of the capstan is to "grip" the film and move it forward through the scanner. It is located after the gate but before the take-up reel.
It contains three major elements:
a) PTR roller (shown in green): grips and moves the film
b) rotary encoder (shown in black): tracks angular travel as a backup to the optical perforation sensor
c) drive motor (at top, grey): drives the PTR roller
As a reminder, we have the design principles to guide you when making design decisions.
Other machines have implemented a PTR capstan successfully. How can we make this work more reliably?