1 copy to front and back from computer

Select the simplex/duplex mode.
1 sided - 1 sided
1 sided - 2 sided
2 sided - 2 sided
When using 1 sided to 2 sided the originals must be even

In the 4 cylinder the firing order is 1,3,4,2 and the cylinders are numbered 1,2,3,4 from the Passenger side to the drivers side.

In a V6 the firing order is 1,6,5,4,3,2 and the cylinders are numbered 1,3,5 in the front from the passenger side to the drivers side and 2,4,6 in the back from the passengers side to the drivers side.

goto the additional function then to printer settings reset the printer settings

Have you heard of duplex printing it should be under your properties in your printers pop up screen
this will give you a two sided copy ( Not sure if you have a document feeder) or a scan bed try an be more specific

IF you have the optional duplex unit installed on your printer then when you go to print something, your printer setup screen should have a duplex/2 sided printing box you can check. This will be under printing preferences or properties. If you do NOT have the optional duplex option then you have to manually duplex. That means on say a 2 page document that you want 10 copies of you have to print 10 copies of page 1. Then take those 10 copies and place them back into the paper tray and print 10 copies of page 2 onto the backs of page 1.
Those are you 2 choices for duplex printing.
Good Luck and Thank You for using Fixya.

If the your copier machine don`t have the duplex unit for make 2 sided copy to use for 1 sided the paper tray and to 2 side the by pass(manual)paper tray.

http://www.brother-usa.com/ModelDocuments/Consumer/Software%20Users%20Manual/SUM_DCP_7030_7040_MFC_7340_7345N_7440N_7840W_EN_1650.PDF

here is the manual p4 and p16 discuss the topic:
Duplex printing 1
The supplied printer driver supports duplex printing.
Guidelines for printing on both sides of the paper 1
�� If the paper is thin, it may wrinkle.
�� If paper is curled, turn over the stack, straighten it and then put it back in the paper tray or the Manual Feed
Slot.
�� If the paper is not feeding properly, it may be curled. Remove the paper, straighten it and turn over the
stack.
�� When you use the manual duplex function, it is possible that there may be paper jams or poor print quality.
If there is a paper jam, see Paper jams in the User’s Guide. If you have a print quality problem, see
Improving the print quality in the User’s Guide.
Manual duplex printing 1
The machine prints all the even-numbered pages on one side of the paper first. Then, the Windows® driver
instructs you (with a pop-up message) to reinsert the paper. Before reinserting the paper, straighten it well,
or you may get a paper jam. Very thin or thick paper is not recommended.
Simultaneous scanning, printing and faxing 1
Your machine can print from your computer while sending or receiving a fax in memory, or while scanning a
document into the computer. Fax sending will not be stopped during PC printing. However, when the machine
is copying or receiving a fax on paper, it pauses the PC printing operation, and then continues printing when
copying or fax receiving has finished.


�� Manual Duplex
Check Manual Duplex. In this mode, the machine prints all the even numbered pages first. Then the
printer driver stops and shows the instructions required to re-install the paper. When you click OK the odd
numbered pages are printed. There are six types of manual duplex binding directions available for each
orientation.
�� Booklet Printing
When you want to print a booklet, use this function. To make the booklet, fold the printed pages down the
middle.
�� Binding Offset
If you check the Binding Offset option, you can also specify the offset for binding in inches or millimeters

By using the Duplex button on your machine, you can set the machine to
print copies on both sides of paper.
1 Press Duplex.
2 Load originals face up in the ADF.
3 Press the Scroll buttons until the binding option you want appears.
• Off: Prints in Normal mode.
• 1->2Side Short: Prints pages to be read by flipping like a note
pad.
• 1->2Side Long: Prints pages to be read like a book.
• 2->1Side: Scans both sides of the original and prints each of them
on separate two papers. (SCX-6322DN only)
• 2->2Side: Scans both sides of the original and prints them on both
sides of a paper, this function produce exactly the same print out
from the original. (SCX-6322DN only)
• 2->1Side Rotate2: Scans both sides of the original and prints one
of them on separate two papers, but the information on back side
of the original is printed 180° rotated. (SCX-6322DN only)
4 Press OK to save your selection.
If the mode is enabled, the Duplex button is backlit.

Collation

You can set the machine to sort the copy job. For
example, if you make 2 copies of a 3 page original,
one complete 3 page document will print followed by a
second complete document.
1 Press Copy.
2 Load originals face up into the ADF.
For details about loading an original, see
page 5.1.
3 Enter the number of copies using the number
keypad.
4 Press Menu until Copy Feature appears on the
bottom line of the display and press OK.
5 Press OK when Copy Collation appears.
6 Press the Scroll buttons to select Yes.
7 Press OK or Start to begin copying.
One complete document will print

http://www.websitetoolbox.com/mb/copierquestions

1.install the latest print driver; see if the rip/spool time is long or the printing time is long. The rip time depends by your computer (!) and the print driver (disable the collate option when printing multiple copies of 1 page = on the printer you should see 1/5 spit a page then 2/5 and spit another page for 5 copies of same page. If you see processing the spit the page then processing and spit the page means your computer is sending 5 times the same page instead of sending once and ask for 5 copies !!! )
2.use network connection instead the USB.
3.expand the printer memory
4.switch the printer from PCL to KPDL or Auto when printing pdf files.

Is this happening when you print or when you scan? If when scaning you could have something on the scanner bed... If this is happening when you print, it could be the cartride is defective.