Cleaning the HP C309/C310 Inkjet printer

This tip is for those that have already tried HP's well-written illustrated guide to cleaning the print head (link).
I poached some of HP's images to better illustrate this tip (thanks HP)!
You might find that the HP cleaning procedure works, for a while, but that it degrades or stops working again. Or you might want to do a more thorough job because you are a neat freak. In either case, read on...


This tip is divided into 2 stages based on difficulty. The first stage requires no tools other than a pair of tweezers (or similar) and doesn't require opening the printer. The second (neat freak) stage requires a T10 Torx driver to remove the side panel for greater access.

Stage 1a: Get 'Er Done
Power up the printer and open the lid so that the print head moves to the center of the print area. Using HP's instructions (see the link in the first sentence above) remove the ink cartridges and the print head. Clean all the areas described in the instructions, and see if that fixes your problem. If it does go to Stage 1b.
If HP's cleaning method doesn't fix your printing issue, the print head might be clogged. The method I found, in an HP user forum, was to run warm water through the print head to it flush out. Remove the print head again, and look for small circles of silver mesh in the red circled area.

Hold the print head under a weak stream of warm water, getting the water to fall into each silver mesh circle until the runoff is clear. Flip the print head over and clean the underside in a similar fashion until the runoff is clear.
Shake off any excess water and use a hair dryer on the low/air setting to get any water out of the electrical contact area. Let the air hit your fingers, and if its too hot for your hand then hold the dryer farther away. You don't want to risk damaging the print head at this stage. If you don't have a hair dryer use a fan, but do not use anything hotter - like a room heater or heat gun!


Stage 1b: Let's Keep it Clean
The area to the right side of the printer is where the print head is cleaned, capped, and parked when you turn the power off using the power button. Always use the power button and never just unplug the printer (or turn off a power strip) because the print head will not get capped and will quickly clog. In the following picture the parking area is under the plastic cover (P), but you can get a partial look through a small slot.



If you were to take your camera phone and take a picture inside the slot, you would see this.



1. A very open/porous sponge inside a square plastic box
2. Two rubber scrapers
3. A waste ink holding tank


The picture above shows the sponge after I cleaned it. Unfortunately I didn't have the forethought to take a before picture so you could see the solid slab of dried ink on top of the sponge. I used a pair of tweezers to pick up the sponge and clean it out under a stream of warm water. The sponge is very small so use the sink stopper or some other method to restrict the drain opening to prevent it from going down the drain.
For cleaning I cut up a coffee filter and held damp pieces in my tweezers and wiped down the scrapers. Finally, more dry pieces were used to mop out the waste ink tank.
Stage 2: Minor Surgery
In this step I plugged in and operated the printer with the side panel removed, exposing myself to potential injury and property damage. Please follow the remainder of these instructions at your own risk!

If you have completed Stage 1, and your print quality is not back to normal or still degrades rapidly, you may have to do some further cleaning in areas that aren't normally accessible; like the print head cap. Luckily you can get access to this area by removing (2) T10 Torx screws from the top of the printer, (1) from the back, and popping off the side panel. Here are the screw locations.


Once the (3) screws are removed you can start prying the side panel off. Begin at the top-front corner, right at the screw hole. Lift the top cover a little and work the top edge of the side panel free. Next work your way down the front edge of the side panel. The side panel will gradually pivot away from the printer. Finally, you can lift the side panel free from the bottom.



To replace the side panel start from the bottom, engaging the two clips into their matching holes, and then press the tabs on the front edge of the side panel into the holes on the front panel starting from the bottom and working up. I found it useful to press in on the front panel at the same time to help with "buttoning up" the side panel. Finally, lift up on the top panel to allow the side panel to slip underneath. Replace the (3) T10 Torx screws and you are done.
The large red arrow in the picture above shows the path of the cleaning/capping mechanism. from the slot you can only see the sponge and the scrappers because the rest of the mechanism would be inside the printer. The only way I could expose the hidden part of the mechanism was to plug in the printer and wait for the capping mechanism to move into position. At one point the print head moved out of the way and I was able to pull the power cord to "stop the action". Here is what I saw.



1. Two separate plastic caps for the black and color print heads
2. The same scrappers I saw through the slot, plus another pair that was hidden
3. A soft brush.
In my case none of these items was very dirty, but if there was dried ink trapped in the caps that would tend to contaminate the print heads. I used more pieces of damp coffee filter to wipe down all these areas.
My printer worked fine after I put it back together, but you are following these instructions at your own risk.
Good Luck!