Create PDF from defined area instead of whole sheet

Question

I created the below script to create a pdf which will be sent to an email and also saved to a Drive Folder. Now I want to change this script that only a certain area (A1:J60) (or a defined named range "Druckbereich" (which is A1:J60)) of my sheet "Fahrtbericht" will be converted to a pdf.

function Fahrtbericht(){
  var today=new Date();
  var ss = SpreadsheetApp.getActiveSpreadsheet(); 
  var ltrsht = ss.getSheetByName("Fahrtbericht");    
  var sheets=SpreadsheetApp.getActiveSpreadsheet().getSheets();
  for(var i =0;i<sheets.length;i++){
    if(sheets[i].getName()!="Fahrtbericht"){ sheets[i].hideSheet() }
    }
    var pdf = DriveApp.getFileById(ss.getId());
    var theBlob = pdf.getBlob().getAs('application/pdf').setName(ltrsht.getRange("B54").getValue()+".pdf");
    var folderID = "XXXX"; // Folder id to save in a folder
    var folder = DriveApp.getFolderById(folderID);
    var newFile = folder.createFile(theBlob);
    var body = 'Hallo ' + ltrsht.getRange("B4").getValue() +',\n\nDieser Mail ist das Dokument ' + ltrsht.getRange("B54").getValue() +' beigelegt.\n\nLG das System';
    GmailApp.sendEmail(ltrsht.getRange("H54").getValue(), ltrsht.getRange("B54").getValue() + " ", body, {attachments: [theBlob]});