HP Deskjet 940C Problems

[Nick]

Probably a blocked jet. You are, of course, using *real* HP cartridges

On windows, assuming you're using the correct driver,

1. Click Start , Programs , HP Deskjet 900c series , and HP Deskjet 900c series Toolbox .
   
   
2. On the Printer Services tab, click Clean the Print Cartridges . The Clean Print Cartridges dialog box appears.
   
   
3. Click Clean .
   
   
4. A page prints that shows the results of the first cleaning. If the print quality is good, click Done. Click Intermediate Clean to do a more thorough cleaning and continue to the next step.
   
   
5. Another page prints that shows the results of the intermediate cleaning. If the print quality is good, click Done . Click Prime , to prime the print cartridges and continue to the next step.
   
   
6. A third page prints that will show the results of the priming. If the print quality is good, clickDone . Click Clean Again to clean the print cartridges again. If the print cartridges are not clean after this last test, they may be faulty and need to be replaced.
   

See: http://support.hp.com/us-en/document/bpd06920