I hear gears turning internally, but can't see them turning as I look at the left side of the roller. The roller is properly in place. So paper won't feed. If I pull paper out manually as I hear the gears working it does print properly.

Problem:
The 'drop down paper grabber' gears are not turning, and the printer gives you an error saying to make sure there is paper in the printer.
All of the fixes on the internet are for working printers, and their approach is to clean the rollers if they are not grabbing the paper. They are assuming they are turning properly and the rubber grabbing wheels are wither dirty of dried out.
In my case, however, the gears were not turning, and so the rubber grabbers wheels were not turning, even though the whole 'paper grabber' unit was dropping down properly
Solution:
Just inside the paper loader tray, along the top, there is a metal rod. It is about 1 inch from the front.
The gears from the drop down paper grabber are supposed to meet a gear that resides on this rod and sort of floats on it. However, the gear on my printer slipped to the left, and was not making contact with the other gears.
You can gently put your finger on the gears as you do a copy command, and confirm this.
To fix the printer, I just slid the floating gear over to the right and into place, and the paper began feeding properly.
Why there is nothing to keep the gear in place is a mystery to me.

This information comes from the User Manual on pages 111-112:
http://h10032.www1.hp.com/ctg/Manual/c01150745.pdf

Internal paper jams on this machine tend to be in the two-sided printing accessory.

To clear a paper jam from the two-sided printing accessory:
1. Turn off the printer
2. Press in the tabs on the left and right side of the two-sided printing accessory, and remove it by pulling out from the center of the printer.
3. Gently pull the paper out of the rollers. If the paper has torn, check the rollers and wheels for small, torn pieces of paper
4. If it's still not clear, open the two-sided printing accessory by pulling up on the tabs, and remove any paper stuck inside it, then close the accessory by pressing down on the tabs until they lock into place
5. Replace the two-sided printing accessory by pushing it forward until it snaps back into place
6. Turn on the printer, and verify that it works by pushing OK to continue the job it jammed on.

Open the print carriage access door. Check for any packing material that may be blocking the internal components. Check for an orange shipping lock that may still be in place on the left side. Pull the shipping lock out, if present, and discard.

Remove and reinstall the cartridges to make sure they are properly installed. Lift the front center of the print carriage access door to open it. Lift the door up until it locks into an open position. Press down on a print cartridge and allow it to spring back up. Lift the cartridge out of the printer. Do the same for the other cartridge. Slide the black cartridge into the slot on the left and the color cartridge into the slot on the right. Press down on each one to lock it into place. Lower the print carriage access door.

Check the print cartridges to make sure the protective tape has been removed from the ink nozzles. Remove the cartridges from the printer. Remove any tape or labels. Replace the cartridges into the printer.

Push in on the tab on the left side of the clean-out door on the back of the printer to open the door. Lift the door out of the printer. Check for any paper jams. Jammed paper can block the printer cartridge carriage from moving. Pull any jammed paper out.

Check the following steps for fixing Hp Carriage Jam Error :

Open the print carriage access door. Check for any packing material that may be blocking the internal components. Check for an orange shipping lock that may still be in place on the left side. Pull the shipping lock out, if present, and discard.

Remove and reinstall the cartridges to make sure they are properly installed. Lift the front center of the print carriage access door to open it. Lift the door up until it locks into an open position. Press down on a print cartridge and allow it to spring back up. Lift the cartridge out of the printer. Do the same for the other cartridge. Slide the black cartridge into the slot on the left and the color cartridge into the slot on the right. Press down on each one to lock it into place. Lower the print carriage access door.

Check the print cartridges to make sure the protective tape has been removed from the ink nozzles. Remove the cartridges from the printer. Remove any tape or labels. Replace the cartridges into the printer.

Push in on the tab on the left side of the clean-out door on the back of the printer to open the door. Lift the door out of the printer. Check for any paper jams. Jammed paper can block the printer cartridge carriage from moving. Pull any jammed paper out.

Theirs a small gear in the gear train on the left hand side that turns the paper roller(Platen).
It has lost a couple of teeth. Has the paper is no longer feeding the print head simply keeps printing on the same place.
You need a service repair.
Cheers
DeJudge

Check the printer properly and see what size paper the printer thinks is in there, or check at the controll panel.
-Carl, please let me know if this helps.

Hi F_bulsara,
First thing to try is to flip the paper over in the input tray. There are 2 sides to paper. One side may curl a bit too much due to heat of the fuser and get caught near the output rollers.

Unless the Output Assembly was assembled wrong, it is impossible for the rollers to turn the wrong way. The gear in the fuser drives the output assembly. The top rollers are rolling out.
If the rollers are not rolling, then one of the gears must be broken or missing. The output rolllers might need cleaning.

Next check the fuser unit. Disconnect power to printer and turn printer round. Remove the back output tray and the two small covers (left and right). Undo the 2 screws that hold the fuser in place. Pull the fuser out. Check the gears on side of the fuser. A broken gear in the fuser could cause this problem.

S88

First – diagnose your problem. In my case the first roller which feeds the paper through the ADF (under small black flip up cover on top) was not turning. Hence no paper advance and error claimed a paper jam (it wasn’t – just a failure to advance paper)
 
The cause turned out to be a stuck gear turning that silver rod at the top. A bit of household oil has worked a charm.
 
To get at the gear, unhinge the ADF cover retaining tie (black flexible plastic stopping it opening all the way). Just lift it up and roll over towards printer.
Then unscrew one screw next to that tie. Gently prise plastic cover off by lifting up from left hand side (near that black tie). It should rotate off. Keep power on and fingers out.
 
Put a few drops of oil on top gear. Place paper in ADF and attempt a batch scan operation. Gears should turn and lubricate parts. Repeat.  Once working, replace cover, screw and tie.
 
Mine had seized months ago and is now working fine. Hope yours does too.
 
P.S. Get a Continuous Ink System (as sold on eBay) - awesome for an ink guzzler...

IF THE ROLLERS DON'T TURN AND MAYBE YOU HEAR A CLICKING NOISE FROM THE LEFT SIDE OF THE PRINTER, THERE IS A SPRING CLUTCH INSIDE THE GEAR AT THE END OF THE SHAFT GOING TO THE SWING ARM. I FOUND THAT SOMETIMES GREASE GETS INSIDE AND CAUSES THE SPRING TO SLIP INSTEAD OF GRIP LIKE IT SHOULD. IF YOU'RE VERY CAREFUL, YOU CAN TAKE OFF THE LEFT SIDE COVER AND LAY THE PRINTER ON ITS RIGHT SIDE (LEFT SIDE FACING UP). THEN REMOVE 3 OR 4 SCREWS AROUND THE GEAR ASSEMBLY AND LIFT THE ASSEMBLY STRAIGHT OFF THE PRINTER. TO GET TO THE SPRING CLUTCH, YOU'LL HAVE TO MOVE A COUPLE GEARS OUT OF THE WAY (REMEMBER HOW THEY GO BACK OR YOU'RE SCREWED - AND WATCH THE TONER ARM SPRING AS WELL). REMOVE THE PLASTIC C-CLIP ON THE END OF THE PICKUP SHAFT AND LIFT OFF THE CLUTCH GEAR. PULL THE GEAR APART AND WIPE OFF ANY GREASE FROM THE INNER SURFACES WHERE THE CLUTCH SPRING SITS. REVERSE YOUR STEPS TO PUT IT BACK TOGETHER.

--SORRY, MY CAPS LOCK DOESN"T WORK AND I DON'T FEEL LIKE HOLDING DOWN THE SHIFT KEY TO TYPE ALL DAY.

your printers gears have got mis-aligned or may be even your paper feeder tray is not availble or not fitted properly, for gears problem u get your printer serviced.wish u success!!