Try this .
1.update Office patches via windows update or office update
2. try different drive, especially between PCL 5 and PCL 6.
3. Check the print processor on the print driver, and try out different data type (i.e. RAW)
4. Print direct and disable the print spool.
5. Last, if all else fails, reinstall Excel and see if the situation will improve.
Hope this helps.