Canon Pixma ip5000 Printer?

I do a lot of photo printing,and recently I have noticed that while the Image itself is perfectly good,the top and sometimes the bottom of the photo have what looks like a streak of surplus ink across them. On investigating I found a loose piece of sponge which I believe sits between the wipers that cleans the ink off the printhead,but when I tried to retrieve it the carriage moved, and by the time I had moved it back,the piece of sponge had disappeared.Now I have perfectly good Printer,which I am unable to use,all because of a piece sponge no more than a centimeter or so long by about 5mm thick.Any suggestions Please!!!