If a film does not appear in the delivery port of an automatic processing machine, what is the likely cause?

In an automatic processing machine designed for developing x-ray films, if a film does not appear at the delivery port, one likely cause is dirty rollers. The rollers in these machines are crucial for moving the film through the various processing stages, including developing, fixing, and washing. If the rollers are contaminated with chemicals or debris from previous films, this can obstruct the film’s passage. As a result, the film may become stuck or unable to advance through the machine properly, leading to its absence at the delivery port.

Other potential causes, while they can impact processing, are less directly related to the immediate issue of the film not arriving at the designated location. For example, an electrical fault could halt the machine's operation entirely, while inadequate solution levels or low solution temperature would affect the quality of the development rather than the physical movement of the film through the machine.