If your network printer is printing gibberish and random characters that is a common driver-related issue.
I had this problem on Ubuntu and Linux Mint with my Samsung M2070 printer connected over Wi-Fi network.
When I tried to print some single-page document, the printer went crazy and printed out a series of strange random symbols on multiple sheets.
Network Printer Prints Gibberish
My issue with the network printer printing random characters like below has been fixed by manually re-adding it with the “LPD network printer via DNS-SD” protocol:
Start the “Printers” from an application menu or from the terminal:
$ system-config-printer
Click on “Add”, go to “Network Printer” -> “Find Network Printer”, wait for a couple seconds until your printer is found, click on it, select the “LPD network printer via DNS-SD” connection type and click on “Forward”.
On the next windows, select the printer’s vendor, model, give it a name and click on “Apply”.
Print a test page to see if it worked.
I just ran into this on Mint with a Brother network printer. I noticed that two printer entries were showing up in the print menu of xed. One would print tons of pages of gibberish, while the other would print properly. To get rid of the entry that produced gibberish, I had to go into the Network->Protocol settings of the printer configuration web page, and disable IPP.