Using an HP LJ1320 printer. When I print my page comes out with a faint gray look to it (not white). When I duplex the gray intensifies. I thought my toner cartridge was leaking toner so I replaced the cartridge. The problem is still there. I even put a spent cartridge in and the page still comes out gray. How can I clean my printer and get rid of that grayscale?

Just we need to know about your printer Brand & model.Because some model printer have not support duplex printing.Duplex printing printer is very good canon lbp 3300 and hp Laserjet p2250d.Please check it and reply soon.

According to the specs, this printer does not have a duplex unit and therefore cannot print double sided prints.
DOUBLE SIDED PRINTING USING A SINGLE SIDED PRINTER
If your printer does not have a duplex unit then the printercannot print double sided pages automatically.
You can print double sided pages but you have to do it one page at a time.
First print Page 1 then place the page back into the paper tray, but turn thepage upside down and the print Page 2.
Then print page 3 on one side then page 4 on the other side and repeat for therest of the document.
I suggest you try a test page first, to get the printing the right way up onboth sides of the page so it reads correctly.

This model printer does not have a duplex unit and cannot print double sided documents automatically.
DOUBLE SIDED PRINTING USING A SINGLE SIDED PRINTER
If your printer does not have a duplex unit then the printercannot print double sided pages automatically.
You can print double sided pages but you have to do it one page at a time.
First print Page 1 then place the page back into the paper tray, but turn thepage upside down and the print Page 2.
Then print page 3 on one side then page 4 on the other side and repeat for therest of the document.
I suggest you try a test page first, to get the printing the right way up onboth sides of the page so it reads correctly.

HP P4515n is not a duplex printer by default. It is a network printer. ('n' suggests it is a network printer. Duplex printers have 'd' in the model number).
If you want to print both sides, manually feed sheet by sheet. Or else you can do the following:
If you are using, say MS Word, print only the odd pages (Print the normal way. No need to manually feed paper). Then arrange the printed papers in the proper order and keep the printed side as back side. Insert the set of papers in the printer and print only the even pages.
First print a document of about 6 pages to get the hang of it.

I assume that printer is perfectly installed and
for both side printing,

go to
contro panner ->printer and faxes->right click on printer->select properties->at bottom click on preferences -> choose "duplex printing".

if you cannot duplex printing here need to install duplex printing.

The only way to duplex print on a standard 2420 is to print the first page, then take that page and re-insert it into the paper tray face up. Then print page 2 onto the back of page 1. If you want to automatically duplex print then you need a 2420DN printer which has the duplexing paper path as well as the formatter board with the duplex firmware.
Good Luck and Thank You for using Fixya.

Only if you print the first side then place the paper back into the printer to do the second side. Also referred to as manual duplexing. This printer has no automatic duplexing option.
Also keep in mind that the percentage of duplex prints you do should be very low as this printer has no method of cleaning the fusing unit as most printers do that are made for duplexing. The industry standard is 2% or less should be duplexed.

Hello,

Please try to edit the setting of your printer particularly the printing level of your printer such as the ink it consumes and the color of the ink you are going to used. So if you want to have a good quality result then please select the best quality printing it can give of your printer by editing the printer setting.

Thanks

replace the toner cartridge or get the cartridge refilled as its about to empty .

Follow instructions on page 80 from "User Guide" (http://www.psych.brown.edu/documentation/lj1320.pdf),
pay attention to black soft shaft. Clean it good.
Good luck!