Canon MP510 printer does not work under 12.04

I upgraded to 12.04 when Update under the previous version announced its availability. The download and installation was entirely under the control of Ubuntu.

My Canon MP510 has been runing fine under successive versions of Ubuntu but does not now respond at all to a print command though it does scan and the result can be saved but not then printed..

Drivers cnijfilter-mp510 (version 2.70-2) and scangearmp-mp510 (version 1.00-1) are listed by Synaptic Package Manager as installed manually and either local or obsolete. I do in fact remember using terminal to install them years ago but they were still working fine a week ago.

The printer is the only one connected and is shown as the default Two disconnected printers are still listed so this looks like a legacy from the previous settings. No test page can be printed.

I've experienced problems with Scribus and Lazarus too but I've not yet analysed exactly what is happening.

Advice on the printing problem will be welcome.