Shafi,
OK. here is some code to get the map image and add it to the DOM. How you get this to the server or do this differently using your server generated pdf workflow is all on you. This is just a concept example.
'esri/tasks/PrintTemplate',
'esri/tasks/PrintParameters',
'esri/tasks/PrintTask',
'dojo/dom-construct',
//Hide the maps info window
this.map.infoWindow.hide();
var oWid = this.map.width;
var oHgt = this.map.height;
var printTask = new PrintTask('http://your server/arcgis/rest/services/ExportWebMap/GPServer/your servers Export Web Map task');
var template = new PrintTemplate();
//my calculation to maintain the maps aspect ratio and still have good resolution in output
this.imgHeight = (740/oWid) * oHgt;
template.exportOptions = {
width: 1542,
height: (1542/oWid) * oHgt,
dpi: 200
};
template.format = "jpg";
template.layout = "MAP_ONLY";
template.preserveScale = false;
template.showAttribution = false;
var params = new PrintParameters();
params.map = this.map;
params.template = template;
printTask.execute(params, lang.hitch(this, this.printResult));
//I place a div that will be a place holder for the map image and have a image inside it that indicates work is in progress
var map = domConstruct.toDom('<div id="mapImgDiv" style="height:400px;width:740px;border:solid 1px black;background-color:lightgray;"><div style="width:100%;height:100%;position:relative;"><div class="loading-container"><img src="images/downloading.gif"/><p>Retrieving Print Quality Map Image...</p></div></div></div>');
domConstruct.place(map, dom.byId('main'), 'last');
//in the printResult function I replace the temp map div in the dom with the returned map image
printResult: function(rsltURL){
var mapImg = domConstruct.toDom('<img src="'+rsltURL.url+'" border="0" style="width:740px;height:'+this.imgHeight+'px;"/>');
domConstruct.place(mapImg, dom.byId('mapImgDiv'), 'replace');
},
