The kind of printer you need for your MC-780MA depends on if you have an older model MC-780MA or a newer model.
Check the back of your MC-780MA display;
1. If your MC-780MA has a mini USB printer output port; it is the older version and you need a printer with PictBridge technology and a PictBridge USB port to be able to print measurement reports directly from the scale.
Read more information and find a list of compatible printers in this article: About PictBridge printers, to be used with older models MC-780MA.
Mini-USB printer output port on older MC-780MA - compatible with PictBridge printer via PictBridge port:

2. If your MC-780MA has a normal USB printer output port; it is a newer version and you need a printer without PictBridge technology to be able to print measurement reports directly from the scale.
Normal USB Printer output port on newer MC-780MA - compatible with non-Pictbridge, mainly Epsom printers:

Printers compatible with this newer MC-780MA, with normal USB printer output port:
Epson Expression Home XP-4200
Epson Expression Photo XP-8600 Series
Epson Expression Premium XP-7100
Epson Expression Home XP-4100
Epson EcoTank ET-4750
Epson EcoTank ET-15000
Epson Expression Photo XP -15000
Epson SureColor SC-P700
* This is the list of confirmed compatible printers, it is possible that other printers might be compatible too, but we have not confirmed this.
Use a normal USB <> USB cable to connect your newer MC-780MA to your non-PictBridge printer.