Is the print head in the carttridge on the HP 45

Make sure if it is new cartridge that you took protective film off of copper contact side.. If you did clean the contacts with a pencil eraser.

To clean the print head from the control panel
1. Load letter, A4, or legal unused plain white paper into the input tray.
2. Touch Setup on the display.
3. Touch Tools.
4. Touch Clean Print Head.
The HP Photosmart cleans the print head and prints a page that you can recycle or
discard.

To clean the print head from the HP Photosmart Software
1. Load letter, A4, or legal unused plain white paper into the input tray.
2. In the HP Solution Center, click Settings, point to Print Settings, and then 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 Services tab, and then click
Service this device.
The Printer Toolbox appears.
3. Click the Device Services tab.
4. Click Clean the Print Head.
5. Follow the prompts until you are satisfied with the quality of the output, and then click
Done.
If print quality still seems poor after you clean the print head, try aligning the printer.
If print quality problems persist after cleaning and aligning, contact HP support.

It sounds like the same problem I've had and unfortunately it is the printer head.

the cartridge is either clogged or the contacts are dirty on the rear of the cartridge. try running the cartridge clean utility first. then remove cartridge if this does not work. cleant the contacts with a q-tip swab dipped in water, dry it with the clean dry end of the q-tip. if this does not work you may clean the print head part of the cartridge the same way, then immediatly insert carttridge and print. this should unclog the jets.

Hi, this usally is becuase the carttridges are not calibrated/aligned.
To align the cartridges:
(extrated from HP.com)

1. Open the HP Deskjet Toolbox .
2. Click Align the Print Cartridges .
3. Click Align , and the first test page will print.
4. Examine the test page and follow the onscreen instructions to complete the Align Print Cartridges dialog box.
5. After completing the Align Print Cartridges dialog box, click Continue . The second test page prints.
6. Compare the second test page to the onscreen example and follow the onscreen instructions to complete the alignment process.

Cheers,
Ed

clean the feeder roller for possible debri and clean the encoder strip located at alongside with the carrier carttridge. It is usualy the done that guides your cartridge for alignment. Also try to inspeact and clean the encoder wheel located at the leftmost side of your printer. This is the timing wheel for paper feeder. 

Clean the inside of the printer with a soft rag, be gentle and get as much toner up as you can, also your toner carttridge may be empty or the crum may be bad, start with a fresh toner carttridge and clean the printer out where the cartridge sits.

I suspect the problem for both of you is either the blockage of the position sensing path (a slot in the carriage) or the plastic band that is imprinted with many vertical stripes and lets the printer know where it is and needs to go is not where it belongs.
Open the printer as you would to change cartridges and look carefully with a flashlight inside for a thin ~ 6mm (~1/4") plastic strip and insure that it is clean and stretched between both ends. One end is normally anchored to the chassis, the other attached to a spring suspension.   

You Need to change the Ink Carttridge. it has either Dried from lack of use or you have run ou tof ink.

you may need to clean the Jets as well a simple Q-tip with some rubing alchol would work.

You could also try the Printers Cleaning Utility, but either way you'll need to replace the cartridges

Andres

cartridge must be damaged and need to replace