Apple users complain en masse on the HP forums about an issue with AirPrint and specific HP Officejet printers. The printers make miniature, stamp sized prints on paper. The issue seems to mainly affect users on iOS 11.
With AirPrint, users can print from their mobile devices from the share menu, as long as their AirPrint compatible printer is on the same Wifi network. Apple introduced AirPrint with iOS 4.2 but since iOS 11 especially OfficeJet Pro 8600 owners complain about miniature prints. Some OfficeJet Pro 8500 and HP Officejet 4620 owners report they experience the same.
When HP OfficeJet Pro 8600 owners with iOS 11 devices try to use AirPrint from e.g. Safari or Mail, the printer, "produces small thumbnail sized prints on top left of a page", an user explains the issue. Other users describe the problem as, "printed documents are about 1 fifth off the original size" and, " print comes out the size of my iPhone screen".
The issue seems to mainly exist when users print from Apple's own apps like Safari and Mail, it seems third-party applications are not affected by the issue.
Interestingly, HP lists the OfficeJet Pro 8600 as AirPrint compatible, while Apple doesn't list the printer on its page with AirPrint compatible printers. The company does list HP Officejet Pro 8600 variants like the 8610, 8620, 8630, 8640, 8650 and 8660, as compatible.
