Canon Bubble Jet 10-sx Started printing gobbledygook

I've been using my Canon Bubble Jet 10-sx to print from my Amstrad NotePad for many years. But today when I went to print a document, instead of english being printed it has started printing all sorts of letters and stuff but not the english that is in the document. I can't find an answer in the manual so if anyone has any ideas as to why it's malfunctioning it would be great. Thank you.