<s>
In	O
multifunction	O
or	O
all-in-one	O
printers	O
,	O
fax	O
machines	O
,	O
photocopiers	O
and	O
scanners	O
,	O
an	O
automatic	B-Device
document	I-Device
feeder	I-Device
or	O
ADF	O
is	O
a	O
feature	O
which	O
takes	O
several	O
pages	O
and	O
feeds	O
the	O
paper	O
one	O
page	O
at	O
a	O
time	O
into	O
a	O
scanner	B-Application
or	O
copier	O
,	O
allowing	O
the	O
user	O
to	O
scan	B-Application
,	O
and	O
thereby	O
copy	O
,	O
print	O
,	O
or	O
fax	O
,	O
multiple-page	O
documents	O
without	O
having	O
to	O
manually	O
replace	O
each	O
page	O
.	O
</s>
<s>
ADF	O
is	O
so	O
ubiquitous	O
in	O
fax	O
machines	O
that	O
some	O
fax	O
machine	O
owners	O
use	O
the	O
machine	O
as	O
a	O
scanner	B-Application
,	O
faxing	O
multi-page	O
documents	O
to	O
themselves	O
.	O
</s>
<s>
There	O
are	O
two	O
kinds	O
of	O
document	O
feeders	O
capable	O
of	O
two-sided	O
(	O
duplex	O
)	O
scanning	O
:	O
a	O
reversing	O
automatic	B-Device
document	I-Device
feeder	I-Device
or	O
RADF	B-Device
scans	O
one	O
side	O
of	O
a	O
page	O
,	O
then	O
flips	O
it	O
and	O
scans	O
the	O
other	O
side	O
.	O
</s>
<s>
A	O
duplexing	O
automatic	B-Device
document	I-Device
feeder	I-Device
or	O
DADF	O
scans	O
both	O
sides	O
in	O
one	O
pass	O
.	O
</s>
<s>
RADFs	B-Device
and	O
DADFs	O
are	O
rated	O
in	O
images	O
per	O
minute	O
(	O
IPM	O
)	O
,	O
the	O
number	O
of	O
sides	O
they	O
can	O
scan	B-Application
each	O
minute	O
;	O
this	O
may	O
depend	O
upon	O
the	O
resolution	O
being	O
used	O
(	O
rather	O
than	O
the	O
maximum	O
resolution	O
supported	O
)	O
.	O
</s>
