I see. So it's not a current model ;-)
In this USA manual on page 47 it says: AD-30 as the type designation for an AC adapter. But this is probably for 110V and not for 230V. Pictures clearly show a USA plug on the power supply.
https://www.brother-usa.com/-...
On page 45 it says: AC adaptor (7V, 1.2A).
In Europe, there is a MODEL-G, which is apparently no longer available "new".
Consequently: Buy second-hand or try the risk with: a universal adapter (voltage and polarity +/- must be set accordingly!). Example: goobay universal power supply

PT-310? Does it really exist?