Document Management and Document Imaging systems require document scanners to scan paper documents and save
them as images. Scanner manufacturers include Fujitsu,
Xerox. Here are a few points to
Flatbed or ADF (Sheetfeed) scanner?
A Flatbed Scanner allows you to position a document on the glass and scan it.
This provides the flexibility to scan damaged or fragile documents, books or
stapled documents but is a relatively slow method of scanning.
A Sheet-feeder (or Automatic Document Feed) allows a pile of documents to be
scanned, though all must be in good condition and unstapled.
Some scanners offer both Flatbed and Sheetfeed (or Automatic Document Feeds). Sheetfeed-only scanners are
typically faster and less expensive than dual purpose scanners.
A typical scanner with both Flatbed and
Colour or Monochrome scanner?
Black and White scanning is suitable for most Document Imaging. There is
usually little point in scanning, say, Invoices or Letters in colour.
In many cases Drawings and Photographs are better scanned in Greyscale (that
is in various shades of grey) rather than Black and White.
More and more there is a requirement to scan in colour. Colour leaflets and
photographs can be accurately reproduced with a colour scanner. You should identify your requirements and select a suitable scanner.
Most scanners will scan in colour, greyscale or monochrome (black and
white) but some (particularly high speed scanners) may not be capable of
Duplex (double-sided) scanning?
Duplex scanning is the ability to scan both sides of a sheet of paper at the
same time. The requirement for this feature is entirely dependent upon the type
of documents you wish to scan.
Simplex scanners scan only one side of a sheet.
A4 or A3 or larger ?
Most document scanners scan A4 (or Letter) sized documents. Optionally A3
scanners may be preferred (these will also scan A4 of course). Larger formats
such as A0 size are also available.
Scan Speed ?
Document Imaging scanners are available in a range of scan speeds. 10-15
pages per minute is usually the minimum acceptable speed. Desktop or workgroup scanners
typically scan at 20-45 pages per minute, mid-range or departmental scanners at
over 50 pages per minute whilst production or high-volume scanners scan at over
70 pages per minute. Scan speeds are available at up to 120 pages per minute.
Duplex Scanners (see above) can scan both sides of a page at the same
time resulting in higher scan speeds (when measured in images per minute rather
than pages per minute).
Note that most manufacturers quote scan speeds when scanning at
200dpi (and in A4 even if the scanner can scan A3 sizes),
higher resolutions will result in lower speeds.
Not to be confused with scan speed, throughput measures
how many pages a scanner can scan in a day. A heavy-duty scanner will
have a higher throughput than a light-duty scanner even if their scan
speeds are identical.
For example, Kodak's i1320 and i1420 scanners both scan at 60
pages per minute but the i1320 is rated at 1,500 pages per day whilst
the i1420 can scan 7,500 pages per day.
Scanners allow a choice of resolution. Typically the higher the resolution
the better the quality of the scan but the storage requirement will also be
Resolution is measured in dots-per-inch (dpi).
We normally recommend scanning monochrome documents at 200dpi or preferably 300 dpi. If you
also wish to OCR (see below) a document 300dpi is usually required.
There is normally no advantage in scanning in a document at a higher resolution
than it was originally printed. If a letter was printed on a laser printer at
300dpi scanning at more than 300dpi will not improve it.
Note that scanners achieve a given resolution in two possible ways - either
by scanning optically at that resolution or by scanning at a lower optical
resolution and then digitally enhancing the scan. A scanner with a high optical
resolution will give better results than a scanner that relies on digital
enhancement (but such scanners are usually more expensive).
Personal, Workgroup or Production Scanners ?
The strategy for scanning will depend upon your particular requirements. You
may provide individual users with their own (usually small and low-speed)
scanners, you may provide a workgroup or department with a shared (usually
mid-range) scanner or you may have a dedicated scanning facility (using high
speed production scanners).
A typical Desktop scanner, sheet-feed only,
60 pages per minute, Colour and Monochrome.
Optical Character Recognition (OCR)
A scanned image is rather like a photograph or photocopy. You cannot
electronically 'read' or edit the text on it. Optical Character Recognition
gives you this facility. OCR will convert any text it finds on an image into
electronically readable text. This text may then be edited (by Word Processing
software, for example) or may be stored with the scanned image to enable
searching for a given word or phrase.
A scanned image when saved to disk (either directly or
via software such as document management or imaging) will be saved in a
particular format. It is important to ensure that the format chosen is
suitable for your requirements, and that the scanner can save into that
The two most common formats for document imaging are TIFF and PDF
(Acrobat). TIFF is the most widely used for most Imaging applications
but PDF can often be better if images need to be viewed by external
users (via the internet or e-mail, for example). Not all scanners can
save in PDF format however. PDF/A is a version
of PDF used for archiving.
Other formats include JPEG (often used for colour photographs) and
TWAIN is an industry-standard method of allowing software to communicate
with a scanner. A software package (such as Alliance Imager)
can drive a scanner using TWAIN. The physical connection of a scanner to a PC will typically be via a
USB or SCSI connection, though connection to a network (10/100 Ethernet)
is also possible with some models.
Imaging for Windows uses TWAIN scanning
An alternative method for a software package (such as Alliance
BatchScan scanning) to drive a scanner is to use a Kofax Adrenaline interface card.
This provides a physical connection of scanner to PC and also the driver
software. Kofax is especially suitable for high speed scanners.
An enhancement to Kofax is Virtual
ReScan scanning enhancement.
Virtual ReScan (VRS) enables you to get perfect scans every time. As
quickly as images pass through the scanner, VRS performs a multi-point
inspection of each document. It instantly checks and corrects for
alignment (skew), brightness, contrast, and image clarity, so that only
the best images are moved into your application.
Note that not all scanners can support Kofax.
Scanned documents need to be "indexed" - that is given some data
to make them unique and identifiable to the system they are to be used in.
This may be simply giving a name to the created file, or may involve adding more
metadata (such as name, date, account number, etc) depending upon the
requirements of the system.
Scanners need application software to drive them. A document management application, such as
document imaging or Alliance
PaperChase records management can scan and index the scanned
documents. This is typically
suited to relatively low volumes of scanning.
For large volumes of scanning
recommended. Alliance BatchScan scanning software
stores at high speed for subsequent indexing.
Indexing is the entry of data against each scan so that the document may be
found when required. The amount of data entered for each document will be
dependent upon the requirements of your application.
Indexing may be manual (by typing in the required data) or automatic (from a
barcode printed on the document, or from OCR, or by sequential numbering).
Most scanners are suitable for use with Microsoft/Kodak/Wang Imaging for
We supply scanners from a range of manufacturers including:
We also supply barcode