To switch to the appropriate operation mode, change all items or the items you are using to <Yes>. For more details, see Setting the Machine (PS/PCL/UFR II Printer) via the online manual site.
Are you printing via a print server using the LPR command?
When continuously printing PDF data using the LPR command, execute one job at a time at the interval set in <Timeout>. For more details, see Setting the Machine (PS/PCL/UFR II Printer) via the online manual site.