Hi ,
Thank you for posting on HP Support Forums. It is a great place to find the help you need, from other users, HP experts, and other support personnel. I came across your post and wanted to assist you. I see from the post that you are having an issue with your HP Photosmart printer printing excess of paper after a print job or when it's idle. Don't worry as I have a few steps to help you get through this concern,
Let's start off by performing a Hard reset on the printer and make sure that the printer is connected directly to the wall outlet and not to the surge protector.
With the printer turned on, disconnect the power cord from the rear of the printer and also unplug the power cord from the wall outlet.
Remove USB cable, if present.
Wait for 2-3 minutes, press and hold the power button on your printer for about 30 seconds to remove any additional charge.
Now plug back the power cable straight to a wall outlet without any surge protector or an extension cord and then plug back the power cord to the printer.
Turn on the printer and wait till warm-up period finishes and the printer is idle.
Next thing, I would suggest here is to open the tray and check for any obstructions inside the printer. If nothing appears, close the tray and make sure it's properly inserted.
If your printer connected wirelessly, make sure to temporary connect the device with USB and then follow the link to check for the latest firmware update if available for your printer, click here: http://ftp.hp.com/pub/softlib/software13/printers/ps6520/PS6520_R1606A.exe
Once the Firmware programming Update has completed, please test printing again to verify if the paper feed issue has been resolved.
I would start by checking the installed printer software by downloading and running the HP Print and Scan Doctor. This tool can diagnose and fix many printing and printer software related issues. Please use this link to help you with that information: http://hp.care/2biN2XE
Keep me posted on how it goes for further assistance.
Feel free to post your query for any other assistance as well,
It's been a pleasure interacting with you and I hope you have a good day ahead.
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Good Luck.