Can I use photocopier toner to refill laser printer toner?

I have a large bottle of toner from my old photocopier. I was wondering if I can use it to refil the toner of my Epson C1100 Acculaser

How old a bottle? Like the kind where it looks like a big jug of black liquid? I don’t think so…those old photocopiers used a methanol-based toner, IIRC. I don’t think any modern laserjets use similar toner, they all use dry ink toner.

I wouldn’t.
Although it might work, there are many, many different types of toners, and unless these two are very similar, you are likely to get poor results.

Old copier toner was sometimes made with magnetic particles. Tiny magnetic particles released throughout the system of a machine not built to contain them = bad, very bad indeed.

Not that I’ve ever made such a mistake. . . ::ducks and runs::