Scanning with Canon PIXMA MX870 All-in-One Printer using Windows 7 64 bit

Pretty late reply but I think I found a solution as I was having a similar problem.  In doing research online I found that the scanner driver that Canon uses was a 32-bit rather than a 64-bit.  The network scanning worked on my 32-bit XP machine but not my 64-bit Windows 7 computer.

Anyway, I did the following and I can now scan through the network!

1. Launch Control Panel
2. Under "System and Security" click "Review your computer's status"
3. At the bottom of the following window click "Troubleshooting"
4. On th next window click "Run programs made for previous versions of Windows" under the "Programs" header.  This will launch the "Program Compatibility" app.
5. Click "Next" and select the program "Canon IJ Network Scan Utility"
6. Click "Next" and then click "Troubleshoot program"
7. Check the box next to "This program worked in earlier versions of Windows but won't install or run now"
8. Click "Next" and select "Windows XP (Service Pack 2)"
9. Click "Next" and click the "Start the program" (windows will ask you if you want to allow changes, hit yes.
10. On the following screen "Troubleshooting has completed. Is the problem fixed?" click "Yes, save the settings for this program"
11. Click close on the next window.

Now repeat the same steps for the program "MP Navigator EX 3.1".

To add some context, I tried the process on the network scan utility and it did not do anything, it was only when I ran it on the MP Navigator that it started scanning so I am not sure if the process is required for the network scan utility.

I had previously installed the updated drivers from Canon's website so that may be required as well. 

If you give this a try let me know if it works.  I'm very excited now :)

Worked for me. Thank you so much!

Have you tried canon support?

http://www.usa.canon.com/cusa/consumer/products/printers_multifunction/office_all_in_one_inkjet_printers/pixma_mx870#ServiceAndSupport

As of today, 11/27/2015 Canon Support (USA) no longer lists software or drivers for the PIXMA MX870. Printer preferences and other settings can be managed using Devices and Printers. The MX870 performs perfectly on both tested versions of the OS. The printer is connected by secure WiFi to an 802.11ac router, connecting as Wireless b/g/n.

I can also print from an older PC running Vista Pro SP-1 x64.

FYI, The proper drivers are automatically downloaded on Windows 10 Home x64 and Windows 10 Pro x86. Supplementary utility software is apparently no longer available,

Yes, you're right, the MP Navigator EX Ver is for scanning function. If someone need to scan and save it to the computer, they would need to install this software.

You can download it from http://www.usa.canon.com/cusa/support/consumer/printers\_multifunction/pixma\_mx\_series/pixma\_mx870#DriversAndSoftware