Got a Canon i850s used with no instructions. How do I load paper?

That is an adjustment on the paper tray.

Same problem here. Any ideas yet?

The Canon i850 uses cartridges of type BCI-3. according to Canon, the color cartridges are compatible to:
BJC-3000 Series, BJC 6000, i450, i550, i850 Series, MultiPASS F30, F50, F60, F80, MP 700 and MP 730, S400, S450, S500, S520, S530D, S600, S630, S630 Network and S750.
The black one will work in a few more models.

I changed the USB port that the printer was connected to and... VOILA...works like a charm with the new cartridges installed. Not sure what the problem was as windows recognized the printer and the drivers were correctly installed before the new cartridges even came into the picture.

Please try to uninstall and reinstall your printer.

Clean your printer heads.

Perform a hard reset to your printer.

Print a test page.

Try using a different bond paper.

Make sure you are using original canon cartridge

If still you get an error. Replace your printer heads.

1. Turn the printer off and open the access cover.
2. Look for any obstructions in the paper path and remove them if necessary. (It is possible to move the carrier assembly with the power off.)
3. Turn the printer on, load some paper, and press the Form Feed button.
4. Watch the paper as it feeds through and try to determine where the jam is occurring.
5. Check to see if all the rollers are turning.

If all the rollers are turning, there may be something in the feed path that you can't see. Go to step 6.
If not, there is probably a feed motor or a gear problem and the printer may require service.
6. If the paper is jamming under the carrier assembly, you may be able to fix it using the manual feed slot.
7. Turn the printer off.
8. Take a #10 envelope and feed it through the left side of the manual feed slot until it comes right through the printer to the back of the exit rollers.
9. Move it up and down first, and then slowly move it over to the right side. If something is stuck under the black guide plate, this may work it loose.

Check your default paper size on both the document program you are using and the printer. You could have it set for 5X7 and that's what it will figure for, even with 8 1/2X11 paper.

NEED TO FAN THE PAPER AND ROLL THE PAPER THAN SURF IT LIKE IT IS ON WAVES OF WATER,

STRAIGHTING OUT PAPER

MAY NEED TO TRY DIFFERENT TYPE OR BRAND OF PAPER.

THERE IS A PROGRAM THAT MAY HELP YOU WITH THIS PROBLEM IT IS CALL

GREENPRINT WORLD DOWNLOAD

ENTER

ROD

CHANGE TO DIFFERENT PAPER PRODUCT

CLEAN THE ROLLERS

GO ON LINE TO

CANON 850i WILL NOT PICK UP PAPER

AND FIND OTHERS WITH THE SAME PROBLEMS

ROD

try running your maintenance program.
go to your printer settings
right click on canon i850
left click on properties
run cleaning or deep cleaning,
then print head alignment and/or nozzle check