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Document Scanner Solutions
When deciding on which document scanner to
purchase, first and
foremost you need to consider the amount of documents you will need to scan over
a given time period. There are many excellent makes & models of document scanners on the market
(and also many not so good document scanners).
At the low end of the spectrum you can get a 15 page per minute document scanner for under $500,
which is very acceptable for general office document scanning, while a refurbished drum scanner can start around $5,000, and a new drum scanner
can be upwards of $45,000.
Even though your volume requirements should dictate the document scanner of choice you need to consider
the following attributes of a document scanner: the
document scanner’s media type; its light sources and filters; sensors and related
systems; the scanner’s mechanics (drum, flatbed, sheet fed); how well it performs
(speed); image processing features; connectivity; and obviously the cost. Of these eight
attributes it is the scanner’s sensor system that is the most critical to attain
the best quality.
The purpose of a scanner’s sensor
system is to convert light from the original image into electronic data – the
original gets digitized into pixels. There are two types of
sensor-based systems: Photo Multiplier Tubes (PMTs) and
Charged Coupled Devices (CCDs) used in flatbed scanners.
The heart of the PMT verses CCD debate is based
on how shadow details are captured by scanners. PMT is known to have better shadow details,
while some CCD-based
scanners struggle with detecting shadow details. The resulting scan can lack
shadow details and become grainy.
Document Scanner Types
As a starting point you should understand the
various document
scanner types, approximate pages per minutes you can expect them to process, the
price range that they fall into, and especially the application where they are
best applied. This will help you narrow down your search considerably for
the right type of document scanner. You definitely do not want to be purchasing a flatbed document scanner, without a document feeder knowing full
well that you are going to scan at least 5,000 documents per month. Imagine
feeding 5,000 documents, sheet by sheet, into a flatbed scanner - a time
consuming process. On the other hand why purchase a $50,000 drum scanner
when all you need to digitize general office documents only - no need to
care for shadow details on the document's numerical data.
 Handheld or portable document scanners. A
handheld or portable optical document scanner is an optical
document scanner which is
designed to be moved by hand across the object or document being
scanned. These types of document scanners generally cannot handle
larger than A6 documents in a single pass - the imaging array is
very narrow. Handheld document scanners are typically connected
directly to a PC or like device to aid in document digitization. The
handheld document scanner has the slowest processing capabilities over the
other document scanners but is the least expensive of all document scanners. This type of document scanner can usually scan a single page in
under 4 seconds. Theoretically, there speed is around 15 ppm, but
due to latency time between pages and the inherent narrow imaging
array,
7 PPM would
be a more realistic & practical number to work with. You can probably pick up one of these
document scanners for under $500. Most hand held document scanners are used for
acquiring information from printed media, and the device is directed to general
purpose uses. This type of document scanner is not suited for high end
commercial document scanning. |
 Flatbed Document Scanners. Flatbed
document scanners are the most commonly used document scanners. A document is
scanned by placing the document face down on a platen window, while
a scan head moves over the document - very similar to how a
photocopier works. Once the document is scanned, the document is converted into a
digitized image.
There is a huge range of fltbed scanners on the market - from $50 to
$25,000 and more. Its hard to believe that a $50 flatbed document scanner
can come fully loaded with OCR software, and can produce an optical resolution of
a 1200 dots per inch scan. On the flip side, the $25,000 i600 Kodak series flatbed
document scanners offers performance, accuracy, and functionality,
like auto page rotation, image cleansing, color document scanning, scans up
to 480 pages per minute, has an auto feed tray, and is suited for
120,000 page document per day.
A good flatbed document scanner has an optical resolution of
1600–3200 ppi, while high-end flatbed document scanners can scan up
to 5400 ppi.
The low end models typically
process 15-20 pages per minute; The better models process 20-30 pages per
minute; The high end 30+ pages per minute; And the elite models which
have the ability to process 400+ pages per minute.
If you are using the flatbed scanner in a commercial environment,
scanning documents daily, its best to consider scanners
that have a starting price of approximately $300. This price range
typically implies 20+ pages per minute and an acceptable quality
document management scanner. The low to medium
end models (15-30 PPM) are good for general business document
scanning use. The 30-50 PPM are well suited for higher volumes. If
you are going to scan significant volumes of documents, consider purchasing a
document feeder. The high end models
(100+ PPM) are best suited for high
volume applications such as mail room, service provider, larger
organizations with large 5k+ volume of documents to scan.
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 Sheet Fed Document Scanners.
Personal
sheet fed document scanners have grown in popularity, mainly
due to their
affordability and size. These document scanners are more like a fax machines
than a copiers, because the page being scanned moves past the
scanning head, rather than the scanning head moving past the paper
as in the flatbed document scanner. Sheet fed document scanners only
process a single
sheet of paper at a time. Sheet fed document scanners tend to be less exact
than their flatbed document scanner counterparts, because of the movement of paper
through the scanning mechanism. Sheet fed document scanners are generally
smaller than flatbed document scanners, thus giving more desktop space, but
sacrificing resolution in the process. Once again the
comparison should be done just like in the flatbed document scanners -
ability for document scanner to handle necessary daily volumes, image
cleansing, auto page rotation, etc.
The features of the high end
models are equivalent to those of the high end models in the flatbed
document scanning category. The most major difference being the technology
used for document scanning - sheet fed.
Just like
flatbed document scanners, there is a huge range for the amount of pages the
flatbed document scanner can process. The low end models typically
process 15-20 PPM; The medium end 20-30 PPM; The high end 30+ PPM. Their are
high end models which
have the ability to process 400+ PPM.
Pricing, is similar to flatbed
document scanners. However the starting point for a reasonable
quality sheet
fed document scanner is around $300 up to and in excess of $10,000. The low to medium end models (with a
15-30 PPM) are good for general
business document scanning use. The 30-50 PPM are well suited for higher
volumes. The sheet
fed document scanners typically come with a page hopper - holding
30-50+ pages. The high end models
(100+ PPM) are best suited for high
volume applications such as mail room, service provider, larger
organizations with large 5k+ volume of documents to scan.
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 Drum
Document Scanners. Drum
Document Scanners are used for high end applications. Their advantage lies in
the fact that they typically use photomultiplier tubes (PMTs), which
are more sophisticated sensors than the charge-coupled devices (CCDs)
and contact image sensors (CISs) used in other document scanners types. The
original documents are rotated past the PMTs repeatedly at high
speed. Drum document scanners are generally higher
quality but are also very expensive. Resolution of drum scanners
range from 2000 dpi to 12,000 dpi. The drum document scanners have a larger scan area than other types of document
scanners - typically are 20" x 24" or larger. A
good drum document scanner has an optical resolution of 8000–14,000
ppi. Drum scanner speeds are measured in Megabits per second. You'll
typically find speeds for the high end drum scanners around 300mb
per second. Drum scanners can cost from $25,000 to several hundred thousand dollars.
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