How to open up a Canon i450?

[Peabody]

I can't find any screws except a small plate where the power cord
plugs in.

Are there hidden latches?

Do I need a Magic Decoder Ring?

(If it matters, I want to inspect the waste ink tank.)

 

[John]

LOL an axe
;-)

 

[Bill]

I can't find any screws except a small plate where the power cord
plugs in.

Are there hidden latches?

I believe the i450 is similar to the rest of the i-series line in that
the plastic covers are snapped into place.

If you look closely, you should find a few slots in the outer casing. A
small flat screwdriver is needed to gently push in the snaps and allow
the casing to be removed.

Do I need a Magic Decoder Ring?
Nope.

(If it matters, I want to inspect the waste ink tank.)

The waste ink tank is not really a tank. It's merely a reservoir on the
bottom of the printer with a pad to absorb some of the ink.