When instaling new ink carchage it won't print clearly. Is there any printing Mantainace software that can downloaded.

For severe HP OJ 6500/6500A print quality/missing color issues there could be an air bubble/air gaps in the printer ink lines or a portion of the PRINTHEAD is dry, so you should first perform a Clean PrintHead procedure from your printer control panel.
NOTE: If one or more the colors were previously dry fired during printing (i.e. if you continued printing using only a few colors to one, air may have been accidently ingested into the ink lines between the cartridge(s) and PRINTHEAD. To recover from this problem, you may have to run the Clean Printhead procedure 2-3 times.
If a problem persists then it is suggested to review the steps outlined on the following HP 920 support pages, including printhead removal/printer cleaning and service station cleaning. It is suggested you refer to printer manufacturer instructions first as the Inkjet411 procedures are provided for general guidance purposes only. A dirty service station can cause poor image quality and/or ink cross-contamination between different colors:
http://inkjet411.retailinkjet.com/?page_id=1495
If the problem still cannot be corrected, then the PRINTHEAD may be dry and may need to be flushed (i.e. with warm water as it could have dried out, but this is a function of how much you print).
Remove and soak in hot water for 5 minutes...thoroughly dry printhead prior to re-installing. Retest. For more information please visit:
http://inkjet411.retailinkjet.com/?page_id=856
Worst case scenario the PRINTHEAD may simply be electrically damaged or at end-of-life (typically fails between 3,000 and 5,000 printed pages) and may require replacement, usually accompanied by error messages like Incompatible Printhead or Ink Delivery/System Failure. NOTE: The PRINTHEAD will eventually fail in time. For more information on the how the PRINTHEAD works, watch the video here: http://inkjet411.retailinkjet.com/?page_id=1983
To verify Printhead performance, run the Tap 41 diagnostic test, (Pen Status: Pen OK).....for printer model instructions please visit:
http://www.Inkjet411.com

Clean the printhead
If your printed output is streaked or has any incorrect or missing colors, the printhead
might need to be cleaned.
This process uses ink to attempt to unclog and clean the nozzles in the printhead.
This might take a few minutes and will use one or more sheets of paper.
To clean the printhead from the control panel
1. Load letter, A4, or legal unused plain white paper into the main input tray.
2. Press Setup.
3. Press the down arrow button to highlight Tools, and then press OK.
4. Press the down arrow button to highlight Clean Printhead, and then press OK.
The product cleans the printhead.
5. Press any button to return to the Tools menu.
To clean the printhead from the Printer Toolbox
1. Load letter, A4, or legal unused plain white paper into the main input tray.
2. In the HP Solution Center, click Settings.
Work with ink cartridges 1513. In the Print Settings area, click Printer Toolbox.
NOTE: You can also open the Printer Toolbox from the Print Properties dialog
box. In the Print Properties dialog box, click the Features tab, and then click
Printer Services.
The Printer Toolbox appears.
4. Click the Device Services tab.
5. Click Clean Printhead.
6. Follow the prompts until you are satisfied with the quality of the output, and then click
Done.
There are two stages of cleaning. Each stage lasts about two minutes, uses one sheet
of paper, and uses an increasing amount of ink. After each stage, review the quality
of the printed page. You should only initiate the next phase of cleaning if the print
quality is poor.
If print quality still seems poor after you complete both stages of cleaning, try aligning
the printer. If print quality problems persist after cleaning and aligning, contact HP
support.
To clean the printhead from the embedded Web server
1. Load letter, A4, or legal unused plain white paper into the main input tray.
2. Click the Device Settings tab, click Device Services in the left pane, select Clean
Printheads from the drop-down list in the Print Quality section, and then click Run
Diagnostic

Good luck................Pete