HP printer 6510 does not print, message from computer says printer offline?

I can print from my iPhone though.

First, check to see if all connections are secure and in place

Start Devices and printers
Right click your printer icon
Select see what's printing
Click on the word printer
Remove check to use Printer Offline

Reboot the computer

If above does not help, you need to reinstall the software

Wireless
First, check to see if all connections are secure and in place

Reset the IP address

Turn printer off
Reboot the computer
Turn the printer on

If the problem continues
Reinstall the printer software

Windows 8

HOQ DO i GET IT ONLINE?

Try restarting your spooling service

It's offline only for computer.
Go Control Panel / Printers.Right click on your printer icon. On drop-down menu left click Use Printer Online. You are done.

>> Go To Control Panel (Press Windows key + I key)

>> Click on 'Devices and Printers'

>> Now you will get printers list. Now click on which printer you want to set to Online Mode.

>> Right Click on that Printer and then click on "See What's Printing'" option.

>> Now click on 'Printer' Menu.

>> Now select "Use Printer Online"

>> Restart the Computer and check it now…

>> Finished