HP Laser Jet 2840 Error Message: ‘No paper pickup [Enter] to cont’.

To resolve the issue follow the steps given below

1. Check out that the media is inserted properly in tray 1.
2. For the optional tray 2, verify that the paper-length guide is in the correct position.
3. Reload the media in input tray and press ENTER to continue the job.
4. If problem continues, clean and/or replace the pickup roller.
   
   The procedure for cleaning the pickup roller is given below:
   
   
   • Turn off the device ,unplug the power cord.
     
   • Remove the pickup roller.
     
     
     • Open tray 1.
       
       
     • Locate the multipurpose roller cover beneath the pickup roller in tray 1.
       
       
     • Grasp both sides of the center tab and pull the cover out of the device
       
       
     • Squeeze the tab on the idler roller that is located on both the right and left side of the pickup roller (If the tab is not visible, rotate the idler roller so that the tab is toward the front of the device).
       
       
     • Slide the idler roller to the left/right to separate it from the pickup roller.
       
       
     • Press and hold the button that is on the right side of the pickup roller, and slide the pickup roller slightly to the right, to pull it off of the shaft.
       
       
     • Move the remaining roller cam to the right, so that it is no longer above the separation pad.This will reveal a pin in the roller shaft. But do not remove the pin.
       
       
     • Locate the separation pad beneath the area of the shaft from which the pickup roller was removed.
       
       
     • Insert a flatblade screwdriver into the slot under the separation pad. Pry the pad up from the spring-loaded base by twisting the screwdriver till the tabs are separated from the device.
       
       
     • Push the spring-loaded base down and position the new separation pad in the empty slot.
       
       
     • Hold down the new separation pad, and slide the roller cam back to the left and  snap it  in place with the pin.
       
       
     • Place the new pickup roller so that the button is on the right side, and the open side of the roller faces down.
       
       
     • Check that  small ridge on the open side of the roller aligns with the groove in the shaft.
       
       
     • Slide the left and right idler rollers inward, against the pickup roller, until the idler rollers click into place.
       
       
     • Hold the faceplate cover and align the cover with the rails on the inside of the device.
       
       
     • Grasp both sides of the center tab and insert the cover into the device until the cover clicks into place. Close tray 1.
       
       
     • Reconnect the power cable to the device, and then turn on the device.
       
       
   • Make the tab visible by rotating  the idler roller so that the tab is toward the front of the device.
     
   • Dampen a lint-free cloth with deionized water, and scrub the roller.
     
   • If the problem persists seek technical support.