Printer HP, CM1312MFP will not print from Scanner

[GKSmith]

I have been using the CM1312MFP Laser printer since new without issue. Halfway through printing a document (30 pages double sided) it stopped working. It was scanning sheets in the feed scanner tray and printing the second side of sheets already printed on one side  and being feed from paper tray at base of printer. 

I have tried everything I can think of. 

Have turned the printer power off and on numerous times.

Put more and less paper in the bottom feed tray. 

Changed printer paper options

Opened the back of the printer and removed and replaced print cartridges, removed and reinstalled paper tray.

Have tried printing just one page at a time from feed scanner. (Success occasionally, sometimes it prints a partial page, often wont feed paper from bottom - just clicks as though it is trying to feed paper from bottom tray.)

It has no problem feeding sheets through scanner and all lights work.

After turning printer off and on again, and trying to do a feed run through scanner with say 10 pages, it will feed all sheets through scanner and may feed each page through from bottom tray to print on. Sometimes it will print the second side of first sheet and all the rest are blank on second side. Yes I am definitely putting the scanner feed document the right way up and also the sheets to be printed on second side in bottom tray - absolutely sure they are correct.

I am using good quality paper and sheets printed on one side remain flat when put back in tray to print second side.

Have tried printing the single side on new paper and only works half the time on first sheet after printer is turned back on. Other times it wont print anything on single side of new sheet which has fed from bottom tray and other times the feeder wont take paper from bottom tray.

Is there a factory reset for printer or is the issue deeper than resetting printer?

How can the issue be fixed?

Regards,

Garry

Sometimes