Often publications resulting from funded research are published after the grant ends. It seems nowadays more and more publishers are requiring fees (submission fees, page charges, and open access fees). How does one pay for these fees after a grant ends?
The way it works here in Japan, is that each professor has an amount of money called "discretionary spending", from there, they get money for these kinds of things. And is usual that if a professor has his name in the paper , he should use part of this money to pay for the submission.
That money does not comes form a grant, but the University's endowment, so I guess it depends on that.
I refuse to publish in a journal that charges me for publishing my years of sweat and labour for their financial gain and asks me for money as well. Its against my principles.
Once I was asked to pay 500 dollars for color pictures. I asked them to revert them back to black and white and just have them in colour online.
Open access is a different story and I see it as being legitimate on their part to ask for money for it. It you don't have the grant money => no open access. Put a preprint somewhere and publish somewhere that allows preprints or at least turns a blind eye.