Epson TM-T20II-i ePOS-Print XML Users Manual - Page 55

Chapter 3 Programming Guide (XML Print Service) Using the Spooler Function The spooler function is available in TM-DT Software Ver.3.0 or later/TM-i Firmware Ver.4.1 or later. 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-Print Service I/F from the application when the spooler function is disabled. Application ePOS-Print Printer 1 : Request message() 1.3 : Response message() 1.1 : Cmd() 1.2 : Printing results 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-Print Service I/F from the application when the spooler function is enabled. Even if the output printer cannot complete the printing task, ePOS-Print Service I/F does not return an error to the application. If print forwarding is enabled, printing from a substitute printer is available. The application can obtain the print result later by requesting an empty print data with the print job ID 3 specified. Refer to the sequence diagram below. Application ePOS-Print Spooler 1 : Request message (Print data, printjobid="ABC123") 1.1 : send() Printer Forwarding printer 1.3 : Response message (printjobid="ABC123", Execution result) 1.2 : Execution result 2 : Cmd() 2.1 : Print() 4 : Request message (Empty print data, printjobid="ABC123") 4.3 : Response message (printjobid="ABC123", Printing result) Printing results (Failure) 3 : Cmd() 4.1 : send() 4.2 : Printing result Printing results (Success) 3.1 : Print() 55