If I turn off my screen, will the tickets be printed?

No, your tickets will not be printed unless you turn your screen back on. Please don't turn off the screen until the print indication disappears. Once the tickets have been issued, then you can switch off your device if necessary.

Thanks to this print icon (located in the left bottom corner for tablets and the right top corner for phones), you can clearly see when the printing is in progress and when it has already finished.