Printing Negative with transparencies.

[MoonMoon]

I want to print negative hard-copy (background  black and text clear ) text labels with plastic transparent sheets, I  use this negative sheet for ultraviolet  exposure purpose.  Printer is HP LaseJet M402, My problem is,  even for density 5 negative image quality bad,  what is notived is first 3cm of the page printing quality is good, rest of the page with bad quality and not good for exposure purpose. If you guys have any idea , please advice to me  how to take a good quality negative hard-copy using HP printer .

(This is a new printer with original toner, Special laser quality transparencies sheet tested ) 

Thanks

[Valsimot]

What printer did you use previously for printing negatives?

If you can get an old HP Laserjet 6L and print one sheet and you will see what can a good old printer do.

[MoonMoon]

Thank you very much for your suggestion,

Not used any printer before, Got a new HP M402 printer for this purpose. Except market available  how to find old printer, I guess , HP 6L toner not available now. As i remember HP 6L used  around year 2000 - 2006 ?