Hi,
The printer’s paper pickup rollers may be dirty and need to be cleaned.[br]
Here’s a link to a [https://www.youtube.com/watch?v=dGC-wD9tezE|video] which shows how to clean the rollers for a HP Officejet 4620 (I realize that this is not your model but it is in the same series -Officejet 4600 series - so it should be the same procedure).
The section of the video dealing with cleaning the rollers starts at 4:10 minutes into the video and finishes at 10:02 minutes into the video.