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3.1.2.1 Light Source
The light source provides enough light along the vision strip so that after being modified
by the original image
The light source (lamp) stabilizes after the scanner has been on for approximately one
hour. Therefore, if the color reproduction is critical and you don't want to see
differences from one end of the copy to the other, it is advisable to start scanning one
hour after powering on the scanner.
3.1.2.2 Paper Movement and glass plate
Since only one strip of the original image at a time is "seen" by the color sensors, either
the sensors are moved to scan the original (as in most home/office scanners) or, as in
the case of a large format scanner, the original is moved through a looking glass by a
roller mechanism.
As the paper is moved over, small fragments of the original media or dust stuck onto the
glass plate may cause image quality problems, like undesired vertical bars appearing
on the copy. To minimize this problem make sure that your original is completely dry
before loading it into the scanner and, as previously mentioned, handle it with care,
choosing the proper document height in the loading mechanism. If the original is thicker
than 2mm., please refer to section 3.6 for guidelines on how to handle it.
Before starting a new color reproduction job it is recommended to clean the glass plate,
following the guidelines provided in the maintenance manual, as well as to clean the
white background element (white plate) that is in the removable top assembly. This
element is used from time to time by the scanner to self-adjust the sensors and if it is not
clean, some colors may be scanned incorrectly, particularly the grays.
3.1.2.3 Cameras
There are two cameras to digitize the full width of the original image. Each of them
consists of an optics part
same active elements found in digital cameras. The CCD is able to digitize the color of
the pixels in three components: Red, Green and Blue. When scanning in Black and
White mode a combined signal is produced from the Red, Green and Blue signals.
Red patches absorb more light in the blue, green and yellow parts of the visible spectrum than in the red
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part.
The optics part of a camera is a series of mirrors and lenses that enable the small CCD to see 22" of the
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original.
Color Reproduction for the HP Large Format Color Copiers family: cc800ps, 815mfp, 5500mfp and 4200 scanner
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, there is sufficient reflected light to reach the image sensors.
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and a tri-linear CCD (Charge-Coupled Device), which are the
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