HP4500 duplex problem!

[Lenp]

The printer has recently started to skip printing on random sides of a duplexed print job. I have tried different jobs, software and systems but they all have the same issue.

Part of the print job will properly print on both sides, then there will be missed sides, sometimes both sides, but the paper travel through the duplexer seems right since there are blank sheets when it misses the printing.

Then the print job resumes properly for several pages. The same job prints differently each time. It is a completely random problem!

I have called the local HP service location(s) and they are clueless...

Please help. This is a great printer except for this issue!

[MichaelTech]

As with the 5si\8100's it is a timing issue. Fusers and duplexers work together and the slight changes in paper movement cause errors. Check the life of fuser, and replace if lower that 20%. Also check the feed rollers on the duplexer for wear.