Help with Canon MX870 - scanner stopped working

Question

Hi,
I bought a Canon Pixma MX870 printer/scanner a month or so ago and it was working fine up till this week. I had installed the Canon software and ran the OS X Software updpate when setting it up.
All of a sudden last week I couldn't print. It kept saying the printer couldn't be found. So I downloaded the Apple Canon printer software and reinstalled it thinking it couldn't do any harm. The printer is working again. The scanner not so much. If I do manage to get it to work (either by using the scanner from System preference > Print/Fax > and choosing open scanner or by using the MP Navigator it typically now will only work 1 time. After that it says "scanner not found" and sometimes if I close and reopen the scanner from Print/Fax it says "trying to open scanner session".
I know the MX870 is connected to the network. The blue wifi light is lit, it shows in the router's list of connected devicies, it also shows in Safari's list of Bonjour Devices.
I need this machine to scan and play nice with OS X - I need to scan more than print.
I ran Disk Warrior, ran chrons to do maintenance and fix permissions etc. I tried deleting and re- adding the scanner. That didn't work and I had to restore it from backup.
Anyone have any ideas on what to do next?
Thank you.

Answer 1

Marlinespike wrote:
However, I went to take a screenshot and something very weird happened. It popped up a dialog box where the scanner was checked as shown in your screenshot with an 80.????? IP address (the ? are because I don't recall)
The 80 number would have been the MX870 wifi network address - not the IP address. The scanner selector tool does not show the device IP address, only the network address.
...asking if "Canon IJ Network Scanner Selector 2" could accept incoming connections from the network and there was a 3rd choice listing the scanner as "Canon MX870 series_3DXXXXX (where I am putting in Xs because I suspect it is a serial number).
Based on this I would guess that the firewall is enabled on your Mac and the prompt is to add an exception to for the networked MX870 (and the X's are the last digits of the wifi network address shown in the selector tool) so that communication can flow between both devices.