Hints & Tips For Optimum Contex Scanning

The best scanning results are achieved when the light source has stabilized. This stabilization occurs approx. 20 min. after an initial cold-start power ON. When powering off the scanner on a daily basis we recommend using the power button located on the operators panel to place the scanner into Standby Mode. This feature reduces the amount of time to stabilize to just a few minutes. If you are going to turn off the scanner for long periods of time then you may use the main power switch located at the back of the scanner.

Once the light stabilization has occurred, it is best to clean the scan glass area and run the Scanner Maintenance Calibration. The Scanner Maintenance calibration should be run at the initial scanner setup and then only as needed, typically once a month.

Scanner Maintenance, when properly run, will refine the scanner’s White and Black Point calibration automatically. It will provide a balanced Grayscale and RGB calibration using an industry standard IT8 color target. It aligns both vertical and horizontal Camera stitch by automatically adjusting the position of the cameras in reference to the scan-line. It is recommended to allow the scanner to warm-up at least 1 hour before performing a Scanner Maintenance Calibration.

Additionally, CONTEX scanners automatically perform a BASIC calibration periodically throughout the day when they are IDLE, compensating for dirt and foreign matter that may have been introduced onto the glass or white background plate. However, it is still recommended that users occasionally clean the scan glass and the white background plate between scans.

All sheet-fed scanning devices push the scan originals thru the document transport as the scan is captured. If there are any significant particles or imperfections introduced by the original or detected in the scanner optics – this may result in streaking in scanned images. Scanner Maintenance and BASIC calibration work together to overcome slight imperfections detected in the optics.

Below is a discussion of the possible situations that may be encountered and recommendations on how to overcome them.

Scanner Hygiene
If significant dust / dirt / fibers / or scratches are present on the scan glass or on the white background plate or somewhere else in the scanner’s optical area, either during the last calibration or during the last scan – consequent scans are likely to result in vertical streaking in the scan images. If streaks are encountered, simply clean off the scan glass and try to scan again. Most times this will resolve the issue. If not, see information below for further information.

Streak Classification
“Random Streaks”
Random Streaks are streaks which appear in a certain area of a scanned image – but if the image is rescanned, these streaks may move to a different area. These are most likely caused by dust / fibers moving around in the optical area.

“Hard Streaks”
Hard Streaks are streaks that appear in a certain area of a scanned image and if the image is re-scanned, the streak will appear in the same location These are most likely caused by scratches or “fixed” imperfections on the surface of the scan glass or the surface of the white background plate or in other areas of the optics. Hard streaks that are light or neutral in color may also represent dirt that was present during the last Scanner Maintenance. If the dirt has now been removed from the surface of the glass the calibration will over compensate for the removed dirt, resulting in a light streak.
NOTE: The Optical Area is the area from the CCD Arrays > through the Camera Lens > through the Mirror Chassis > through the Scan Glass to the surface of the White Background plate

Focused vs Unfocused Streaks & Short Streaks
There is a further classification of the two basic types of streaks noted earlier. Streaks whether Random or Hard can be additionally categorized as sharply defined thin lines that appear “ in Focus” or somewhat blurry “Un-focused” lines. Lastly, are the “Short Streaks”, also known as ‘Comets’, that appear to ‘come and go’ but do NOT continue throughout the complete image

“Sharp / Focused Streaks”
These type of lines are typically caused by imperfections detected in the Upper Area of the scanner optics – at the glass or white calibration strip.
Below is an example of this type of streak:

“Blurry /Un-focused Streaks”
These types of streaks typically occur when imperfections are detected in the Lower Area of the scanner optics – at the CCD array, Camera Lens or in the Mirror Chassis area.
Below is an example of this type of streak:

“Short Streaks” (Comets)
These types of streaks typically occur when imperfections are ‘momentarily’ detected in the Upper scanner optics – at the Scan Glass. This obstruction is stationary at some point in the scan capture but then moves off the scan –line for the remainder of the scan capture. So the streak is typically well defined, sharply focused but will only streak partially thru a uniform background color – then appear to disappear – like a ‘Comet’. Typically the source of the streak is from small dirt particles or grit rubbing off the document itself, onto the stationary glass and then getting removed shortly thereafter by the moving document.
Below is an example of this type of streak:
Cleaning the Upper Optics
Most streaking can be addressed by following the steps below:

  1. Open the Lid to access the scan glass and white background plate
  2. Carefully inspect both the scan glass (top and bottom surfaces), the surface of the white background plate and the area around the fluorescent bulb and reflector strip. Consult the user documentation for information on how to access the scan glass.
  3. Look for ANY dirt / dust / marks / scratches or other contaminants.
  4. Clean ANY dirt / dust / marks as best as possible (do not use any chemicals or liquids when cleaning the reflector strip).
  5. If significant scratches are detected on the scan glass or white background plate – the part will need to be replaced.
    NOTE: – Significant streaking MAY have a negative affect on the scanner’ ability to successfully perform its Stitch Alignment
  6. When the individual parts and fluorescent bulb area is cleaned, set all parts back in the default Power-ON position, turn the scanner Power OFF/ON
  7. Wait for the scanner to complete the Warm-Up then run Scanner Maintenance
  8. Scan again and evaluate.
  9. If necessary, clean a specific area again then run Scanner Maintenance again
  10. Scan again and evaluate.

Enhanced Scanner Treatments
There are other treatments that can be applied to specific scanner chassis areas to help minimize the chance of encountering streaks in scanned images. The movement of some originals in the normal action of scanning, especially if it has staples or paper clips that have not been removed, will eventually scratch the scan glass and white background plate which will result in streaking on scans. Depending on the scanner’s environment, electro-static build-up, typically in the scan glass / bulb area, will also promote the possibility of dust build up in these areas which may increase the chance of streaking.

Conditioning the Scan Glass
The scan glass can be conditioned with a silicon-based glass treatment, like RAIN-X, which when applied will provide a thin protective silicon coating to the surface of the glass. This protective coating will shield the glass surface from direct contact with an original during the scanning process. Simply apply the treatment to the glass surface, rub-in, let dry then lightly buff until the surface is smooth. There is an added benefit to this treatment in that dust / fibers will no longer adhere to the glass surface but will slide off the glass because of the smooth slick surface.
NOTE: After applying this treatment, it is best to run Scanner Maintenance

Anti-Static Treatment
One other treatment that can be applied to the scanner chassis is some type of anti-static treatment. This treatment can be in the form of a spray or liquid application. An example would be Static-Cling Spray, available in most Department or General stores. This anti-static treatment when applied to the metal surface areas in and around the document transport and front feed-tray document insertion area (any metal place an original may come into contact with during a scan) will help to neutralize static build-up and repel any dust / fibers from sticking to these surface areas minimizing the chance of these obstructions getting in the cameras optical area.
NOTE: After applying this treatment, it is best to run Scanner Maintenance

Conclusion
For optimum scanning results, it is necessary that the user understand the necessary periodic maintenance requirements to keep the scanner optics and document transport areas as clean as possible.

  1. ALWAYS clean the scan glass and white background plate BEFORE turning the scanner Power ON
  2. Make it a point to clean these areas occasionally BETWEEN scans for the very best color scan quality
  3. If Streaking does occur, inspect and clean all suspected areas -> Always run Scanner Maintenance after you have cleaned
  4. If you suspect the streaks are caused by optical obstructions in the Lower Optical Area – call for On -Site assistance from a Certified Service Technician
  5. Try the additional Glass and Anti-Static treatments described earlier
  6. Since the main source of contaminants introduced into the scanner are from the documents themselves, it may become necessary to wipe down the document prior to scanning to remove as much dirt, grit or lint as possible before scanning.
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Hackworth

In 1991, Hackworth opened its doors as a blue printer. More than 20 years later under the direction of Dorothy and Charlie Hackworth and their son Charles, the business is a full fledged technology and document solutions company.

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