Epson TM-T70-i ePOS-Device XML Users Manual For TM-i firmware v4.1 - Page 38

Using the Spooler Function A printing job will be executed immediately and a response will be returned to the application after printing is complete when sending a printing request to ePOS-Device Service I/F from the application when the spooler function is disabled. Application ePOS-Device Printer 1 : device_data message() 1.3 : device_data message() 1.1 : Cmd() 1.2 : Printing result 1.1.1 : Print() The print data job will be added to the queue and a response will be returned to the application without waiting for printing to complete when sending a printing request to ePOS-Device Service I/F from the application when the spooler function is enabled. Even if the output printer cannot complete the printing task, ePOS-Device Service I/F does not return an error to the application. Printing on a substitute printer can be done by enabling print forwarding. The application can obtain printing results at a later time by specifying the print job ID and requesting empty print data. Refer to the sequence diagram below. Application ePOS-Device Spooler 1 : device_data message (Print data, printjobid="ABC123") 1.3 : device_data message (printjobid="ABC123", success="true", code ="" status="2", battery="0") 1.1 : send() 1.2 : Execution result Printer Forwarding printer 2 : Cmd() 2.1 : Print() 4 : device_data message (Empty print data, printjobid="ABC123") 4.3 : device_data message (printjobid="ABC123", Printing result) Printing results (Failure) 3 : Cmd() 4.1 : send() 4.2 : Printing results Printing results (Success) 3.1 : Print() 38