I have implemented Laser printers using USB printer servers connected to a SCO server. Sometimes print jobs get stuck on the queue and I havent found a way of getting the printer back to work without canceling the jobs and rebooting the system.
Why jobs get stuck?
How do I get this solved without canceling and rebooting?
Try /usr/lib/lpshut to stop the print service , and then /usr/lib/lpsched to restart it, rather than rebooting the system, after canceling the job that still shows as on the printer in lpstat -t.
Are you using PCL print commands?
Do all the print files have CRLF line termination?
Do you have <esc>&k2G in the escape sequence (turns LF into CRLF)?
Yes, I we are using PCL print commands, however, i am not sure about CRLF. Today the jobs got stuck again, i stopped and started print services before and after deleting the jobs but it did not do anything, I had to cancel all the jobs and restart the server.
I'm not sure about these two:
Do all the print files have CRLF line termination?
Do you have <esc>&k2G in the escape sequence (turns LF into CRLF)?
How do I get that information?
Are you using the HPLaserJet printer model?
Are you sending raw and text files to the printer?
To find the contents of the print files add a 'cp' statement to the driver file in /usr/spool/lp/admins/lp/interfaces to save a copy somewhere, then examine the file using 'vi' or whatever.
Also see what escape sequences the printer model might add to the print stream though echo statements.
Yes, I'm using HPLaserJet and printing text files only.
Its not likely that the problem is caused by the content. Can you try the following. Connect the printer to a networked workstation running MS Windows and then set up the printer on SCO as a network printer, using either VisionFS or Samba. Then even if the problem still occurs you will not have to reboot the server, and if it doesn't recur you can probably assume the problem is somewhere in the usb driver or the firmware.
Another piece of equipment had the same IP address that is why this whole conflict was taking place 
Thank you guys for your help!
Another problems that I am having is related to a corrupted driver on this same machine.
The HPLaserJet driver stopped working, I had to use DECLaser3250? Everything works fine with DECLaser driver. It is weird because nothing stays on the queue if I use HPLaserJet it looks like everything is printing but is not. If you use a different driver than HPLaserJet it works fine. Is there a way of reinstalling this driver?
I couldn't understand what IP addresses had to do with your problem, until I reread your original post and saw the word 'server' between usb and attached to SCO.
My original concept was that the printer was directly connected to the USB port on the SCO box, but now I think that you are using a box similar to a HP JetDirect with usb ports instead of parallel. If so have you set up the printer using the HP Network Printer Manager (option 2), or the Printer Manager (option4) in Printers in scoadmin.
Jack
HP Network Printer Manager (option 2)
The print driver that is used is located in /usr/spool/lp/admins/lp/interfaces/model.orig/DEST, where DEST is the destination name of the printer.
This file is a copy of the file in /usr/spool/lp/model renamed to the destination name.
You will see that the files in the model directory are all 0444 so they can not be changed inadvertently.
You can copy one of these into the model.orig directory to change the print characteristics, or you can edit the one in the model.orig directly (maybe to remove banner pages.)