Canon Pixma MP640 Purge Drive System & Switch System Unit

The purge unit is a possible source of trouble if printheads persistently block. It will cost about £40 +/- to buy in the UK. To be honest we aren't expecting an avalanche of interest. By the time you realize that a problem lies in the purge unit you have probably already lost at least one replacement printhead. In all probablility what goes wrong with a purge unit will be a build up of stale ink; so it could probably be cleaned and set working again.

Web research showed some interest in the purge drive, as might be expected. - one of them a European parts distributor.Purge unit QM3-6891-030 is available to order for a price around a third that of a new printer (list price about 50 Euros) however there appears to be little or no UK stock. It would presumably come from Canon on 7 day lead time.

An aside that has nothing to do with the Canon parts. There is a puzzle here. Most Google listings include mediaform.com.au, mk-electronic, manualslib.com, manualowl.com, internaute.free.fr, mission.com.my, mail.racs.co.bw, wenku.baidu.com and executivecolor.net.All the information seen is clearly derived from some Canon list. There is often the same higgledy-piggledy compatibility list or part of it which we have tried to straighten out above. There is never any difference in the description or a moment's evidence of human thought - why would there be; these parts have never inspired any human interest.

If mediaform.com.au is present they usually top the list. They never have more than part of the compatibility list.

The reliable source of most information with the whole compatibility list seems to be executivecolor.net in the US, and yet they are persistently at the bottom of Google's list. Furthermore the page with product per page is usually lower than the page listing the group - which does of course look as though it has more information.