Java Applet Locks IE Window During Printing

I have created a Java Applet that will be used in IE to print images from a remote server. I load the applet in a new popup window from my main web page and it prints fine, but it locks up the new popup browser window while it is printing. When the print job is complete the popup window becomes responsive again. The main browser window remains functional during the printing. Is there something I can do during the printing process to cause it to yield so the popup does not lock up?

package javaprint;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.awt.image.ImageObserver;
import java.awt.print.*;
import java.io.IOException;
import java.io.InputStream;
import java.net.Proxy;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
public class jPrinter implements Printable
{
String ASP_NET_SessionId = null;
ArrayList<URL> pages = new ArrayList<URL>();
BufferedImage lastImage = null;
int lastRequestedIndex = 1;
public EcPrinter(ArrayList<URL> pages, String sessionId)
{
Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
ImageIO.setUseCache(false);
this.pages = pages;
ASP_NET_SessionId = sessionId;
}
public int print(Graphics graphics, PageFormat pageFormat, int pageIndex)
{
if (pageIndex < pages.size())
{
URL url = pages.get(pageIndex);
BufferedImage img = null;
if (pageIndex == lastRequestedIndex)
{
img = lastImage;
}
else
{
URLConnection connection = url.openConnection(Proxy.NO_PROXY);
connection.setRequestProperty("Cookie", "ASP.NET_SessionId=" + ASP_NET_SessionId);
InputStream is = connection.getInputStream();
img = ImageIO.read(is);
lastImage = img;
}
graphics.drawImage(img, 0, 0, null);
return PAGE_EXISTS;
}
return NO_SUCH_PAGE;
}
}