How to reset hp 5650 printer

Try unplugging the power source for one minute. That usually resets the printer.

Hope this helps.

Reset Your Printer

1. Turn off your printer by pressing and holding down the "Power" button.

2. unplug the power cord from the electrical outlet.
3. Press the "Power" button on the HP 5650 again. If it won't turn on, try plugging it to another electrical outlet, not a surge protector. A circuit may have blown, preventing the printer from working properly

HP printers have several methods of resetting. like the hp officejet series:
 
There are "maintenance resets" and other resets, such as "memory reset", "cold reset" etc.
 
I need to know what you are trying to reset and what HP model you have.

1. 
   Press the Power button ( ) to turn on the product.
2. 
   With the product turned on , unplug the power cord from the back of the product.
3. 
   Disconnect the power cord from the wall outlet.
4. 
   Wait at least 15 seconds.
5. 
   Connect the power cord to the wall outlet.
6. 
   Connect the power cord to the back of the product.
7. 
   If the product does not turn on by itself, press the Power button ( ) to turn it on. reference: hp 11x17 printer

unplug for a few mins to clear the printer cache memory 

unplug it for a while to reset printers cache