I can confirm that I have the same bug on Windows 7 using Chrome Version 35 but I share my partial solution who is open a new tab on Chrome and showing a dialog.
For other browser when the user click on cancel automatically close the new print window.
//Chrome's versions > 34 is some bug who stop all javascript when is show a prints preview
//http://stackoverflow.com/questions/23071291/javascript-window-print-in-chrome-closing-new-window-or-tab-instead-of-cancel
if(navigator.userAgent.toLowerCase().indexOf('chrome') > -1) {
var popupWin = window.open();
popupWin.window.focus();
popupWin.document.write('<!DOCTYPE html><html><head>' +
'<link rel="stylesheet" type="text/css" href="style.css" />' +
'</head><body onload="window.print()"><div class="reward-body">' + printContents + '</div></html>');
popupWin.onbeforeunload = function (event) {
return 'Please use the cancel button on the left side of the print preview to close this window.\n';
};
}else {
var popupWin = window.open('', '_blank', 'width=600,height=600,scrollbars=no,menubar=no,toolbar=no,location=no,status=no,titlebar=no');
popupWin.document.write('<!DOCTYPE html><html><head>' +
'<link rel="stylesheet" type="text/css" href="style.css" />' +
'</head><body onload="window.print()"><div class="reward-body">' + printContents + '</div>' +
'<script>setTimeout(function(){ window.parent.focus(); window.close() }, 100)</script></html>');
}
popupWin.document.close();