Hey there,
I don't have personal experience with using ticker tape machines to measure g by free fall, but I have heard of others using them before. It sounds like you're encountering some technical difficulties with getting accurate marks on the tape. Have you tried adjusting the speed of the machine or the tension of the tape? That could potentially help with getting more consistent marks.
Another thing to consider is the condition of the machine and the tape itself. If they are old and haven't been used in a while, they may need some maintenance or replacement parts. It's also possible that the tape itself is too worn or damaged to produce reliable marks.
If you continue to have trouble, perhaps reaching out to others who have used ticker tape machines for this purpose could provide some helpful tips and advice. Good luck with your experiments!