Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
Gem Update: Printopia 2.1.5 Offers Major Improvements To a Gems Favorite
The application of AirPrint of iOS 4.2 has promised to let its users print wirelessly from the iOS device to any of the printers that are installed with the Mac operating systems. But, unfortunately, AirPrint provided the result of being compatible with specific AirPrint enabled printers. In recent time, one of the most popular Mac Gems named as Printopia and has been designed as a utility tool which delivers all unfulfilled promises of Apple and a lot more than that.
Analyzing the feature, it can be said that Printopia has the ability to start where the AirPrint feature ends, thereby, providing the Mac system to share all or any of the configured printers, no matter how they have been attached to the Mac system or the iOS devices on the local wireless network. Any of the application of iOS which also supports printing, all you have to do is to tap the print button, select the printer and simply print. The Printopia works in complete harmony with Mac OS X 10.7 Lion, Mac OIS X 10.6 Snow Leopard, Mac OS X 10.5 Leopard and several other power Macs which makes the feature of AirPrint usable by every user of Mac models. In case of iOS devices, it should be iOS 4.2 or a later version.
Printopia also has several other tricks which make it a utility tool useful for situations in which the user never actually intended to print. A special feature of Send to Mac allows the user to save a copy of the document with PDF, PNG or JPEG format of an image to a folder of Printopia located in the Documents folder of the Mac. On the other hand, a Send To Dropbox On Mac printer allows the user to save a document to the Dropbox folder of the Mac, from where the files are automatically synced to all the Dropbox enabled devices. These features are very beneficial for saving receipts from online purchases, which are made from the iPhone or iPad and for the transferring screenshots f OS onto your Mac operating system.
Another new feature which has been introduced is that the user can setup Mac apps in the form of virtual printers and then ‘print’ on them. By doing this, a copy is sent to the Mac system from where it instantly opens the document in the selected application.
the next new feature is that there is a password security for each printer, whether real or virtual, which provides the benefit of the fact that if someone does gain access t your Wi-Fi network, they will be unable to print to your printer(s), or save files to the Mac system without inserting in the appropriate password.
the feature holds several side benefits as well. the first is that as long as the other Mac systems are running on Lion, the user can disable Printer Sharing feature by using the Printopia which means that using both Printopia and Printer Sharing so as to share the printers with both Mac and iOS devices. Secondly, if you operate a system which does not have Lion drivers, the printer can be connected to a Mac operating on Printopia and will then print from a printer from any Mac operating on 10.7.