My fax keeps jamming up when I try to print. It will start to print then it gets jammed up.

Most printers/faxes need more than one or two sheets of paper in the hopper in order for printing to commence. If it's not that, take out all paper. Turn off the printer/fax. Wait five minutes and turn printer/fax back on. With some printers/faxes, that almost acts like a re-boot. Good luck!

any sensor actuator broken?

If the jam is consistent with exiting the drum, there's a chance the drum isn't secure and is the paper is getting caught on the exposed area of the drum. If this isn't the case, there may be paper caught in the feeder wheels.

Your document feed is separate from your received and report prints so that's why your reports are printing ok and the document feeder jams. When you open up the doc feeder and look inside the machine you will see a roller and above it on the cover that opens you will see a rubber pad. Clean both the roller and pad (in fact anything in there that is rubber) with a rubber cleaner, alcohol, or even soap and water on a cloth without it been dripping wet. You will probablt find that they are very dirty. The roller feeds the document in so that needs to be clean and the pad helps to keep all the other docs from feeding in at the same time and that should be very clean so it produces good friction.

when fax gives msg ,fax in memory,just remove jammed paper .put fresh papers in tray.if the msg is coming on screen that fax in memory just press START key.there is a green button labeled as fax start .u will receive all faxes in memory.MIAN AKHLAQ .do not forget to rate the solution.

You can set the fax portion of the machine to manual receive like this:
"User tools"
"fax features" ok
"reception settings" ok
"switch reception mode" ok
"Manual reception" ok
"user tools" to exit
Thia will prevent the machine from picking uo any incoming faxes

....However, if the machine is jamming trying to print a 'fax' report, it will jam regardless of the feature you are using -they are unrelated. Depending on the cause of the jam, it could be a specific tray that is causing the problem, so you may want to remove the paper from that tray, and see how it works. The other reason, that is common for jams from one particular tray is that the size is set incorrectly. Check that the paper size dial on the tray is set for the appropriate size in the tray (including orientation).

If none of this helps, please describe the location of the jams, and I may be able to give further advice.

Does it say clear jam immediatly or does it start to run then declare a jam?
If it starts then tells you to clear a jam and no paper is in the machine, your feed rollers are shot. Smooth like trying to drive a car on ice.
If it says that all the time, no attempt to feed then you have a sensor either dirty, knocked out of place or something stuck on a sensor.
Either in the paper path or in the scanner.

look at the paper tray,some of your sensor are jammed,try tyo find out where is the sensor on paper try

open the machine and clear the paper jam and then closed.The machine will start printing again.

Please check rear door area for paper, can you use manual feed slot? Power off machine with all jams removed and paper loaded, then power on, can you tell us exact error message/lights that are shown in this state?