Printer engine structure

The invention provides a printer engine structure. The printer engine structure comprises a lower engine shell; a shifting sheet separating mechanism used for separating labels and a thermal transfer ribbon is arranged at the part, close to the paper outlet side, in the lower engine shell, is connected to the lower engine shell in a rotating mode and is provided with a label channel; and a label unwinding sensor is arranged in the lower engine shell and is located between a printer paper cutting port and a printing head. Because label paper penetrates through the shifting sheet separating mechanism and can be overturned when jamming occurs, the structure has the advantage that clearing is more convenient compared with fixed structures of traditional printers. The labels can be effectively prevented from exiting through unwinding detection.