Hello, my name is Michael. I can assist you with your question. Here is HP's response to your problem:
"Unfortunately, you cannot print on an "undefined" paper size with our printers. While the feature is available in word, our printers only recognize the main paper sizes (these change depending on the country sometimes).The reason for this is because non-defined paper sizes open the printer and the print job to a number of risks including paper jams or misaligned printing. This is why the feature is no longer on HP printers.I would recommend finding a traditional paper type that is close to the size you want to print on and selecting that in the page setup of the print job as a work-around for this issue.I hope this helps!"
Well it doesn't. So there is a workaround that should work for you. It's not very elegant, but it should get around the problem. In doing these steps, selecting the Deskjet 9800 should allow you to do it. Let me know how you make out.
To use an alternate print driver for HP printers in Windows 7:1. Click on the Start menu.2. Click on Devices and Printers.3. Right-click on your printer.4. Select Printer Properties.5. Click on the Advanced tab.6. Click on New Driver.7. Click Next.8. Select HP from the first list.9. Select Deskjet 450 from the second list. If the 450 driver isn't there, use the Deskjet 990c driver.10. Click Next.11. Click Finish.12. Click Apply.13. Click OK to close the window.
To assign an alternate print driver in Windows 8: