I read with interest the letter from Bert Poole regarding the problem he had with his Canon Pixma iP4500 (Shopper 355).
I have a Canon Pixma iP4000 which, about a year ago, developed the same problem as Bert’s; namely I received an error code indicating that the ink absorber was full. So, being unwilling to contact Canon (ie, spend money), I searched the web for a solution and found a PDF copy of a genuine Canon service manual for my printer. In there was a section about how to reset the counter.
So, I duly reset the counter, and a year later it’s still working. Now, I’m not saying that this will work for Bert’s problem, but anything is better than throwing the printer into the skip.