Paper jam with no paper jammed on our pixma 450 hp officejet j3640, how can the roller be worn out? printer has never been used, (bought on 12/29/08. "paper jam" keeps coming up.HELP PLEASE! with or whit out paper in the tray. cant getpass this problem.

i think you are not using proper paper, try some other type of paper like diffrent grams, havy paper is better

Several things can cause a jam. I can suggest checking the paper path very well, especially if you have had a jam in the past, a little piece of paper there could be triggering a sensor and causing the message. Another thing might be rollers worn out or dirty. If the rollers rotate 3 times and no pick up happen it will show paper jam, try a humid tissue to clean it.

An error code showing that there is paper jam alert, but no paper is in anywhere in the machine except in the tray.....I have checked all areas, taken the back carriage of the unit, opened the top and opened the machine. removed the paper tray, everything, but there is no paper stuck in the unit

Possible problems:
- Tiny paper or something is stuck in your printer.
- Your printer roller may have dirt on it.

Solutions:
-There may be a very tiny bit of paper stuck somewhere - look very carefully. Also, open all areas and then close them - sometimes a printer has to have that before it resets from a jam. Check your paper to see if it is being grabbed by the rollers. if they are dirty or worn, the paper will not catch and the printer thinks it is jammed. wipe the rollers with a bit of alcohol on a paper towel (barely damp) if that is the case.

Look for little pieces of paper that get stuck in the rollers, also verify that the gears and roller didn't get misaligned when you cleared the jam.
Good Luck, 

Printers that jam usually have worn feed rollers, some where in the machine, or a bad sensor. If worn feed rollers are the problem the paper usually jams in different locations in the machine. If a sensor is bad the paper usually jams in the same spot each time paper is fed into the machine. A new machine does not have worn rollers, but could have a broken sensor. It sounds like the a roller might be worn. There is a company called Tech Support that use to sell a cleaning fluid for paper feed rollers. You can use alcohol but alcohol dries out rubber, but you can use it to diagnose the problem. Clean all visible rollers. Especially the rollers that the paper jams between.

there are 2 possibilities, it is either the printer has small bits of paper on the rollers in the printer, or the printer drivers needs an update to make it run again.

you may open the printer up, inspect the rollers (paper path, where the paper goes in and out) then check if the rollers rubber coatings are worn out or damage, or has pieces or papers on them.

in installing the drivers, just access the HP's download site and download the latest drivers for your printer.

hi!!!

try to install them first
if your have the driver of thoes printer
if you don't have the driver of those printer
here is the link download below

hp photosmart 7760

http://h10025.www1.hp.com/ewfrf/wc/softwareDownloadIndex?softwareitem=ps-18223-2&lc=en&dlc=en&cc=us&lang=en&os=228&product=305375

hp officejet j3640

http://h10025.www1.hp.com/ewfrf/wc/softwareDownloadIndex?softwareitem=mp-53329-1&lc=en&dlc=en&cc=us&product=3540751&os=228&lang=en

or try to email me ronaldsuboc@gmail.com

this is problem with your printerpintch roller witch is used for pickup paper , please get it on Hp service Center near by you to replaced Roller ...

If this Information is useful for you please rate me........

Most likely worn pads & rollers, I'm afraid. Kits are available though. Not too dear.