Canon ImageClass 8180c giving error messages on almost all carts at once?

[myfathersson]

My heavily underused 8180c has started giving error messages on most
carts at once: Replace K cart (which Canon tells me means that a
sensor has detected that the toner level is too low and shut the whole
printer down), on an almost new cartridge (it has only done 100-200
pages) Prepare new C cartridge and check Y cartridge all at once and
as far as I can tell, without warning.

Does anyone think these coincidental messages mean what they say, or
does this mean that some sensor has become dirty, or the whole printer
is dying?

 

[myfathersson]

I get error messages from my underused HP C7280 but in my case the
cartridges are past their expiry date, and it wants me to replace with
new cartridges.

Hey thanks for that: Now that I come to think of it, I don't remember
changing the colour ones since I got the printer a few years ago.

The black one is an aftermarket one and I asked the re-filler about
any possibility that the cart (which they sent me only a few months
ago) is actually preventing the printer from working and they said
they are sending me a new one. I am preparing some colour ones but now
I suspect that as these are also HP carts, it might be something in
the cart which is giving out these messages

There should be some way of weighing them to see how much toner there
is in them, - wouldn't that be the easy way of knowing roughly what is
going on!