Xerow pro 423 copy, fax,scan it says paper jam

Probably it's the jammed paper that might caused the error. I suggest have it serviced by the technician. Be aware of the paper handling capacity of your machine to minimize jamming:

3300MFPV_X
Phaser 3300MFPV/X, Copy/Print/Colour Scan/Fax, B&W, 28 ppm, A4, 1200 dpi, 50-sheet ADF, 250-sheet Paper Tray, 50-sheet Multipurpose tray, 150-sheet Output Tray, 96 MB, Automatic 2-sided printing, USB/Ethernet, PCL/PS3, Scanning software, 220 V

My HP 6210 has a paper jam and I don't know how to fix it

Does it also jam when you're just copying or scanning? Try to check if the scanner is closed all the way down. The cover needs to be closed all the way down for the paper to flow properly from the ADF to the exit tray.

Leading cause of paper jams is debris / foreign objects that accidentally fell into the paper feed area. Please try this approach to fix the problem:

1. Remove the sheets of paper from the feeder.
2. Grab a flashlight and look inside the feeder for any debris or foreign objects.
3. If you're willing and physically able, you may also carefully turn the printer over. Any debris should just freely roll out from the feeder.
4. If feeder is clear, place the printer on the table. Open the printer cover and remove the cartridges.
5. Check the cartridge area for any obstructions in the paper path.
6. Close the printer cover.
7. Re-brick your printer by pulling out the power supply - the black box where the power cord is plugged into. Re-plug after 30 seconds.
8. When the printer turns on, reinsert the cartridges and load some paper. Try to print again to verify that the problem is fixed.

dear sir,kindly follow the below instructions
Instructions

1. Ensure that all cables are securely connected. First, make sure that the printer cable connecting your computer to your printer is connected securely. Then, make sure that the power cord is inserted into a wall outlet. Try your print job again after you have ensured that all cables are properly connected.
   

2. Clear a paper jam if your printer is not responding or you are receiving a "Paper Jam" error message on your printer. To clear a jam, first open the rear output door by pushing down on the two levers on each side of the door. Opening the rear door simply makes it easier to clear a jam. Open the top cover on the front of the printer by pressing the release button on the right side of the printer. Locate the paper jam and use two hands to gently remove the paper jam. Try your print, scan, fax or copy job again.
   

3. Clear stored or saved faxes if you are having trouble sending or receiving faxes. Old faxes may be stuck in the fax queue, which may be causing the printer to not respond. To remove stored faxes, press the "Menu" button on the printer and select "Fax Functions." Then select "Clear Saved Faxes." Wait for the queue to clear and try your fax job again.
   

4. Remove paper from the automatic document feeder (ADF) input tray if your scan job is coming out crooked. The ADF input tray can only hold up to 50 sheets at a time. If there are more than 50 sheets in the input tray, the output may appear skewed. Try your scan job again after removing the paper.
   

5. Adjust your computer monitor's display settings if your scanned image is not an accurate representation of the original image. This can be done in the "Control Panel" in Windows. Set the settings to the highest possible resolution and try your scan job again.
   

6. Perform a power cycle on your printer if the previous steps were unsuccessful. To do this, turn off your printer, then unplug it from the wall. Wait a few minutes and plug the printer back in. Try your print, scan, fax or copy job again.
   

take care..thank you

If a document jam occurs during a transmission, the message "DOCUMENT JAM" is displayed. If this occurs, follow the procedure below. It is recommended that a duplicate from a copier, of the jammed document be used to reduce the chance of a jam when resending the document.
See Chapter 3, "Loading Documents" for document specifications and recommendations which may help avoid paper jams.
Note: The power can be left ON when clearing a paper jam.
Typical Causes of Document Jams
Recommended Procedure
The document is fed at an angle.
Adjust the Document Guides to the edges of the
document.
The document paper is too thin or too thick.
Make a duplicate using a copier and use the copy
as the sending document.
Document has tape or pieces of paper taped to it.
Remove the tape or make a duplicate using a copier and use the copy as the sending document.
The Control Panel Cover is not fully closed.
Close the Control Panel Cover fully.
The document is stapled. Remove the staple(s), or make a duplicate using a copier and use the copy as the sending document.
Basic Troubleshooting
1. Remove all documents from the Document Support.
2. Open the Control Panel Cover.
3. Remove the document jam. Remove any pieces of paper, paper clips, or staples that may have caused the jam.
4. Close the Control Panel Cover.
5. Verify the display has returned to the Standby Mode.

Re check all the connections. When taking off the paper feed assay, other parts and plug and jack connections were needed to be taken off first.
Make sure the drum seats in its correct position, silver grounds are not bent.
The copy cartridge and Dev housing are not connecting very good somewhere.
Make sure the machine is unplugged.
Try running copies.

Check if the ADF backing is tucked under the the ADF frame. You can view here http://h10032.www1.hp.com/ctg/Manual/c00863866.pdf steps 7 & 8 on page 155.

CHECK THE ADF
IT IS JAMMED OR NEEDS TO BE REPLACED!
CHEK AGAIN ..EVEN THE TINNEST PIECE OF PAPER CAN JAM IT.

Go to the menu and make sure it is set to Letter and not Legal size.