REPOST - HP3505n Paper Curl problem

I was advised to put this in a different forum.  Any light anyone can shed on this topic will greatly help me.  Thank you!

Printer Model:

HP 3505n

Paper Type/Brand:

24lb White Navigator

Issue:

Paper curls away from print side on the left and right sides of the paper

Location:

St. Paul, MN

Avg. Daily Humidity:

55

I've tried different types of paper and different weights of paper.  I've been printing at different times of year, so I don't think humidity plays a factor.  We are also in a climate controlled office.  I've also tried adjusting the paper curl option:

i.e. optimize>paper curl on/off - neither have changed the curl amount.

I'm trying to get an attractive, flat finish to my pages.

Thanks for anyone's help in advance!