The kind of cable you need to connect your MC-780MA to the printer 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 mini-USB <> USB cable to connect your MC-780MA to the PictBridge printer, like this:

2. If your MC-780MA has a normal USB printer output port; it is a newer version and you need a normal USB <> USB cable to connect your MC-780MA to the printer, like this:

See this article to read which printers can be used to print directly with the MC-780MA.