To reset the HP 51645 (#45) or HP C6115 (#15):

Reset Method 1:

1.  Refill your cartridge using your Mr. Ink Jet refill kit.

2.  Following the diagram at right, place a piece of adhesive tape covering the only the four blue colored contacts (a contact is the individual copper square).  Make sure that only those four are covered and no others. 

3.  Place cartridge in the printer.  The printer may tell you that there is a problem with your cartridge.  Ignore this message.  The printer may print an alignment page.  If so, allow it to do so.

4.  Take the cartridge out of the printer.  Remove the tape from the four blue contacts.  Place the tape over the four red colored contacts.  Make sure that only those four are covered and no others.

5.  Follow step 3 again.

6.  Take the cartridge out of the printer for the final time.  Take the remaining tape off and place back in the printer.  The printer should print out an alignment page and the estimated ink level in the toolbox should read full. 

Reset Method 2:

     If Reset Method 1 did not work on your printer, go through the same procedure again, but this time using the green colored contacts in step 2 and the brown colored contacts in step 4.  This method is more commonly used for the #15 or in the later officejet printers.

Reset Method 3:

    If neither of the reset methods above worked, you can cycle cartridges through to reset the level.  You will need two extra cartridges and the one you refilled.  First, put the refilled cartridge in the printer.  Allow it to recognize the cartridge and print an alignment page.  Take that cartridge out and place in the first extra cartridge.  Allow it to recognize and print an alignment page.  Take the first extra cartridge out and place the second extra cartridge in.  Allow it to recognize and print an alignment page.  Take the second extra cartridge out.  Place the refilled cartridge back in the printer.  It will print an alignment page and then the estimated ink level will be reset to full.