Keep getting error messages

SOURCE: Open Door. Clear carriage jam, and then press Enter

Sounds like you have a jam. Open the back of the printer and checl for any paper large or small. If there is no paper, just opening the door and closing it may get rid of the message. All it takes is a piece of paper the diameter of a pea to send a signal that there is a paper jam. After yuou have finished close the door and push enter to let the printer know you are finished. See if this helps. I don't think it has anything to do with the ink cartridges. It sounds more like something stuck causing the jam. Be sure not to have anything like a staple attached to the paper you are printing on to. A speck of dirt could casue a jam message too.

SOURCE: printer will not start

This is likely a hardware problem. However you can try a sem-full reset to factory default conditions by 1. unplugging the power cord while the printer is powered on and 2. press and hold the OK and Cancel buttons while plugging in the power cord. If this this does not clear the error you probably have a hardware issue. On my printer, after going through a diagnostic procedure with the HP Chat Tech and concluding a hardware issue I did a bit more research and then took the printer apart. It turns out that a fairly common problem is for the large white gear on the left side of the printer that drives the ink pump comes off the shaft. I reassembled it to the shaft and put the printer back together. When I plugged in the power cord the printer started and did about a 5 minute maintenance procedure and now works fine.

SOURCE: my HP Officejet 7210 all in one is showing the

Carriage jam means the carriage, where you put the inks, can't move right to left properly. Sometimes ink on the clear strip behind it is the cause. You can carefully clean with damp Q-tip, and check also that the cleaning assembly on the right where the printhead parks, is not stuck.

SOURCE: HP j4680 all in one printer constant Paper jam message

Based on encouragement from olsnake above, I fixed it easily. It definitely WAS the encoder wheel (a thin clear plastic disk printed
with timing marks) on the left side of the paper-feed roller, as you look at it from the front. This wheel provides motion feedback to the paper feed control software. If the disk is detached/loose, the device thinks the paper feed roller is stuck or impeded, and thus gives the annoying error.

What I did:
1) Remove the scanner assembly (it comes off with a few screws, and is a totally separate unit; The printer works with it completely disconnected (after it complains that the scanner is malfunctioning). Beware that you don't break off the little control panel. Or you can be safe and remove the one screw holding it on, by prying off the 'HP OfficeJet...One" plastic cover.

2) Once you have removed the scanner assembly:
at the left side you will see three white plastic gears meshed together; the farthest one is covered in a circular black
plastic cover. With some care you CAN remove this cover without any additional screwdriver work.

3) in my case (and most others I bet) the thin disk was detached from the gear to which it should be attached. I just shoved it back on, so it was tightly mated to its white gear. You should also ensure that the clear disk goes through the optical sensor at the bottom (mine was).

4) I did not bother to replace that cover, if you can do it, good for you.

5) Test, and reassemble.

This is about the WORST product engineering imaginable. But I have a working printer again!

SOURCE: Cartridge Error message - I've cleaned the

I have same exact issue. Please contact me if you get answer.