You can use the following code:
var viewer = new Stimulsoft.Viewer.StiViewer(options, "StiWebViewer1", false);
viewer.renderHtml("viewerCont");
viewer.jsObject.controls.menus.printMenu.items["PrintPdf"].style.display = "none";
We apologize for the delay, but we need some extra time to investigate the issue thoroughly. We will keep you informed about the result as soon as possible.