Canon mx712 is saying wrong printer head - Canon PIXMA MP780 All-In-One InkJet Printer

Kohdi, Could not find your exact model to show disassembly or unjaming paper, your manual and service manual are at links below.
Check the attached links,instruction and guides, Good luck
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https://www.usa.canon.com/internet/portal/us/home/support/details/printers/support-inkjet-printer/mx-series/pixma-mx712
Canon MX700 Service Manual
PIXMA MG2420 MG2520 Removing jammed paper inside the printer
PIXMA MG3520 Removing jammed paper inside the printer

Power Supply Unit needs replaced.

Try the following:

1. Open the cover of the printer.
2. Remove all ink tanks from the printer.
3. Lift up the gray locking lever on the side of the ink tank holder.
4. Gently remove the print head from the carriage unit.
5. Place the print head back in and lock the lever down.
6. Place all of the ink tanks back in the printer.
7. Close the cover and turn the printer off.
8. Unplug the power from the printer. Leave the power unplugged for about 5-10 minutes.

install the software before connecting the printer usb cable. the nonly connect it when the software asks you to.

Is this a brand-new printer? If so, make sure you haven't left any of the packaging materials inside the printer (any of the colored tape, foam, paper, shipping plastic pieces, etc.).

Make sure you don't have any empty cartridges, and that there's nothing jammed in the printer.

connect with wi fi maybe

cns assoc's answer was spot-on. I found the burnt-out nozzle under an empty cartridge, which I tried to take a picture of...

computer connected to my router, now need to connect my wireless printer, but installation insists on using a usb cable to install my printer how does one set up printer wireless

You may download software and drivers from here.