My iMac shows another connect computer what is it?

Solution 1:

It is an Epson device connected to your WiFi network, most likely a printer. However, it could also be a scanner, projector or even a pair of smart glasses.

If it's only new to your network, it could be that someone has plugged a USB stick (or similar) into a printer etc.

I wouldn't be worried unless you don't actually own an Epson product.

Solution 2:

This is an Epson printer, copier or multi-functional device. The reason are may not have seen it before is because it isn't discovered automatically in all cases, as well as not always being discoverable like that in the first place.

The device has a memory card reader (often a SD card and CF card reader on the front, sometimes internally), or has the option to have one. In many cases, the software in the printer, copier or whatever device it happens to be has the ability to share the contents of the card, or, to store scans on the card and expose them over the network. Even when you don't explicitly enable or use this type of functionality, the systems in the device to make it work are quite often online anyway.

There is a second device in your sidebar, which is the same printer/copier/MFD but discovered using a different system. The one with the little computer display icon is a 'Bonjour' discovered device, while the one with the blue screen old-style icon is a NetBIOS, Workgroup or SLP discovered device. Bonjour is the 'newer' style and often used in Macs, the other one is older and used with Windows-based computers. Both of the icons point to the same device and most likely have the same features. Sometimes the Windows icon is used for files, card readers and scans, while the other one has no file functions but is used by macOS to automatically discover the printer when you first set it up.

Long story short: no worries, all is well, even if you didn't plug it in, it's okay to have those icons there, and they don't really do anything.