Intermittently get "communications error has occurred" in printer queue dialog when trying to print via wi-fi to my Canon printer. All drivers and firmware updates ok. Restarting printer usually clears it. Sometimes have to restart Mac.

Can't give you a "solved" yet, because haven't had a chance to check out all the suggestions, but I appreciate the discussion.

To answer the questions you posed:

BOTH MacBook's on the network are running Lion. My wife's is just a few mo old and came with it. Mine is a year old and I upgraded to Lion about 3 mo. ago.......and in fact that MAY be about when this intermittent problem began! I had held off on Lion because of neg. review comments and no clear perceived need to upgrade. But after my wife got herself the new Mac w. Lion, I decided to go ahead and do the upgrade. And, other than possibly this issue, I've had no other negative experience associated w. the upgrade.

But, as I said, interestingly, my wife has NOT had this problem with "communications error" intermittently when trying to send a doc to the printer. I questioned her about it and she said she remembered me telling her how to clear it if it occurred, but it has never occurred. But, as I also said, she doen't print often.

No other routers in the network. Just the Time Capsule, 2 MacBook Pros w. Lion, 2 iPhones (a 3S & a 4) both running iOS5 and 1 iPad running iOS5. My MacBook seems to be the only one having the printer problem (but we rarely print from the phones/iPad and only w. the Canon photo print app.). I DO have a Parallels VM running XP on my MacBook Pro, but I have NOT had the printer comm problem when printing from XP in the VM, though to my uninformed mind it seems like I should, because it's just going through the Mac's wi-fi connection to the printer isn't it? But then again, I do not print very often from my Windows environment.

You suggest "look at the log in the TC." Where does one find that?

My Airport Utility is "Version 6.0" (600.92)...believe it was the result of an update in the not too distant past. Is that what you are referring to as "Lions toy version"??

I will pursue changing network names per your suggestion...I assume you mean for ALL devices, not just the TC?

And I will try shortening the dhcp lease time per your suggestion. Not sure what you mean by "keep the Lion computer more aware of the network by updating more often," unless you mean by more frequent renewal of the dhcp lease??

I did hear back from Canon's tech support and one new suggestion they made was, when the problem occurs, to check in the printer's setup system, on the printer's little led screen, as to whether the printer is showing its WLAN status as "active" or "inactive."

Their suggestion is that, if the printer is showing it's WLAN status as "active," then delete and reinstall the printer on the Mac. But if it is showing as "inactive," then reset the printer and go through the printer based WLAN setup to reconnect it to the network.

Pretty obvious and basic, and clearly it won't help if the problem is coming from a bug in Lion. But I have not as yet had a chance to try it because the problem has not recurred yet.

Thanks for you helpful suggestions and interest.

You could very well be correct that the origin of this was in the Lion upgrade to my MBP. FWIW, the TIme Capsule is of the same era as my MBP. It is the "dual band" 802.11n TC, just about 1 yr. old as is my MBP. I know the TC has evolved in some way since then, because mine is a 1 TB model, which is no longer offered, only 2 & 3 TB.

I'm still a little confused about that Air Port Utility 5.6: I read everything at the link you've given, but all of that says that 5.6 is for "802.11 g" Airports. And, in a place or two, for compatibility with "older Airports" as an alternative to using 6.0 in Lion. Now my "Airport" (Time Capsule in this case) IS of the Snow Leopard era one year ago, and my MBP IS now running Lion, but my wife's newer MBP with native Lion isn't having the problem---at least that we've detected yet (which COULD be the key!).

I do understand that this just might be arising in some obscure and heretofore unrecognized conflict between the various iterations of hardware and software, and thus anything is possible. But from what Apple is saying in that tech info sound more to me like it's for problems with "older" Airports and "newer" computers. I concede anything is possible here!

You've given me a lot of ideas to work on here. GIven intermittent nature of the problem (and the fact that it's a weekend!), the problem has not actually recurred since I first posted. During this coming week, I'll run a bunch of test print jobs to see if, and how often, I can provoke the problem. And whether or not I can observe it on my wife's machine. As I have examples of it "in captivity", so to speak, I will try your suggestion of trying to print from another device without clearing it on my MBP first.

WIth regard to your suggestion of seeing if a cabled connection will bypass the problem, did I make it clear that my Canon MX870 is a WIRELESS printer on the network? It is NOT cabled to the TC. So, your suggestion of going MBP>TC via Ethernet cable would, of course, still be using a wireless leg.

This communication problem only seems to involve the printer, so I would think maybe the first test to try would be to stay wireless between the MBP and the TC, but try cableing the Canon to the TC?? However, I'm not sure whether the TC has a USB port OR the Canon has an Ethernet port. Will of course have to check that (I'm not at home right now).

Thanks for all the thoughtful suggestions. I will work slowly through this and see if I can come up with a fix. It will take a while, but once I see that the problem seems to have stopped, I will repost on this thread. You can be pretty sure that a "clean reinstall of Lion" will be the LAST thing I resort to ;-)) !!. Hope I don't have to get that far on my list!

Ok, I have gone ahead and installed the 5.6 Airport Utility. Hope you didn't think I was ignoring your advice. It's just that when I read the notes for 5.6, they entirely put me off! One never knows in these kind of advice situation whether or not one has provided ALL the pertinent information, or perhaps left out a key detail that leads one's advisor to the wrong conclusion. But it's onboard now (along with the 6.0, since I had not seen any specific instruciton to delete it; if I should, let me know). I'm actually at my daughter's home for the weekend and using her wi-fi (not an Airport), so I can't give you a road test report yet. But In the coming week I will work through all your suggested steps as I have opportunities (ie: when the problem will present itself). Will report back, hopefully positively, by next weekend. Thanks.

I have not had the issue recur since I posted! Surprises me because it was happening frequently at the time. But, after reading about the printer settings on Canon's support site, I decided I should be able to turn on Bonjour and LPR notification without deleting and re-installing the printer. So I tried it, and now the printer utility shows the MX870 as a Bonjour printer and, after turning it on, Bonjour appears in my bookmarks in Safari. Clicking that opens the Bonjour browser access to the printer, and the settings there show that the MX870 has Bonjour and LPR notification enabled.

We'll see if the problem recurs, but as I said, the contrary problem has not appeared since the time of my original post. So, go figure!!?

But thanks for taking the trouble to share your solution. Bonjour seems to be enabled without deleting and reinstalling the printer, fwiw. If the problem recurs, I will try delete/reinstall since, as far as the MX870 is concerned, Bonjour is turned on.