Creating a print job via plsql

I have the following code to produce the print record in the 'ACTIVE_SEP_WO_PRINT_REP' table.  

DECLARE
  printer_id_ varchar2(250);
  print_job_attr_ varchar2(200);
  report_attr_ varchar2(2000);
  parameter_attr_ varchar2(2000);
  print_job_id_ number;
  printer_id_list_ varchar2(32000);
  wo_no_ NUMBER := 303826;
  result_key_ NUMBER ;
      
begin
  printer_id_ := ifsapp.printer_connection_api.get_default_printer(ifsapp.fnd_session_api.get_fnd_user, 'ACTIVE_SEP_WO_PRINT_REP');
  ifsapp.client_sys.clear_attr(print_job_attr_);
  ifsapp.client_sys.add_to_attr('PRINTER_ID', printer_id_, print_job_attr_);
  ifsapp.print_job_api.new(print_job_id_, print_job_attr_);
   
  ifsapp.client_sys.clear_attr(report_attr_);
  ifsapp.client_sys.add_to_attr('REPORT_ID', 'ACTIVE_SEP_WO_PRINT_REP', report_attr_);
  ifsapp.client_sys.add_to_attr('LAYOUT_NAME', 'Delivery Collection WorkOrder.rpt', report_attr_);
 
  ifsapp.client_sys.clear_attr(parameter_attr_);
  ifsapp.client_sys.add_to_attr('WO_NO', wo_no_, parameter_attr_);
  ifsapp.client_sys.add_to_attr('NUMBER_OF_COPIES', 1, parameter_attr_);
  ifsapp.archive_api.new_instance(result_key_, report_attr_, parameter_attr_);

  ifsapp.client_sys.clear_attr(print_job_attr_);
  ifsapp.client_sys.add_to_attr('PRINT_JOB_ID', print_job_id_, print_job_attr_);
  ifsapp.client_sys.add_to_attr('RESULT_KEY', result_key_, print_job_attr_);
  ifsapp.print_job_contents_api.new_instance(print_job_attr_);

  ifsapp.logical_printer_api.enumerate_printer_id(printer_id_list_);
  if (printer_id_list_ is not null) then
    if (print_job_id_ is not null) then
       ifsapp.print_job_api.print(print_job_id_);
    end if;
  end if;
  if print_job_id_ is null then
    ifsapp.error_sys.record_general('ACTIVE_SEP_WO_PRINT_REP',' Unable to generate Print Job.');
  end if;
  
  COMMIT;
end print_report;

The REP table record is being written but the pdf blob is blank, what am I missing ?

Thanks