Scanner is a widely used computer input devices. As an optoelectronic, mechanical integration of high-tech products, it is our commonly used office equipment, but once it fails to make us at our wits' end, some of the faults need to be repaired by professionals, there are many faults can be eliminated on their own. The following to introduce some common troubleshooting methods:
A scanner disassembly
In the maintenance and overhaul often need to dismantle the scanner, so the first for you to introduce the scanner disassembly of the basic methods:
1. First remove the glass platform, with a cross screws into the round holes unscrewed screws, you can up to take down the top cover and the glass platform. After opening the scanner, you can see the stepper motor, drive belt, scanning head and circuit board and other parts. Some of the scanner's upper and lower parts are not screws but with a plastic buckle articulation, disassembly with a small flat screw into the gap to pry open the plastic buckle, can be separated from the upper and lower parts, pry the plastic buckle action should be light, do not damage the plastic parts.
2. Unplug the data cable. Scanners generally have two internal circuit boards, one fixed in the scanner head on the back side, the other - installed in the rear side of the scanner, the two circuit boards are connected through the data soft line. The two boards are connected by a data cable. The data cable needs to be removed before removing the scanning head. The data cable is stuck in the slot on the circuit board, and when removing the cable, the pins on both sides of the slot should be pivoted outward, and then the cable can be easily withdrawn.
3. Remove the scanning head. Most of the scanning head worn in the round metal rod (rail), driven by the drive belt along the scanner longitudinal movement, just remove the round metal rod from the base of the plastic card base, so that the scanning head from the drive belt, you can remove the scanning head and round metal rod upward, and then the round metal rod from the scanning head out of the draw.
4. Remove the lamp. The lamp is located on the top of the scanning head, placed horizontally along the scanning head, stuck in the scanning head on both sides of the plastic card holder, and its power supply plug in the back of the scanning head on the circuit board. The lamp can be removed from the scanning head by simply removing the power supply plug for the lamp on the circuit board. The thinnest lamps are only about the thickness of a matchstick and require special care when removing and placing them.
5. Remove the circuit board. Unscrew the two screws can be removed from the scanning head of the circuit board, in the circuit board on the front of the double in-line package can be seen CCD device. As the CCD device needs to scan the optical lens in the optical path, the installation of improper restoration will affect the quality of scanning, it is recommended that you do not just remove the scanning head of the circuit board.
Second, common causes of failure and troubleshooting
1. The whole image is only a small part of the acquisition
Causes of failure and troubleshooting: focusing rectangular box is still stuck in the preview image; only the area within the rectangular box is acquired. After focusing, click to remove the focus rectangle and repeat the test to acquire the image.
2. Excessive Patterns in the Image (Noise Interference)
Cause and Troubleshooting: The scanner is operating in an environment where the humidity is outside of its allowable range (perhaps the scanner has been stored or transported outside of the allowable range). Let the scanner work within the allowable range. Turn off the computer, then turn off the scanner, then turn on the scanner first, then turn on the computer to recalibrate the scanner.
3. The difference between the color of the original and the screen color is too large
Causes and troubleshooting: (1) Check that the screen's settings for chroma, brightness, and contrast are in accordance with normal requirements.
(2) Check whether the screen setting options of ColorLinks are correct.
(3)If FotoLook is executed under Photoshop, please check whether File-PreferencesMonitorSetup, PrintinglnksSetup and SeperationSetup are correct.
(4) Assuming that all of the above settings are correct, you can do the color correction between the scanner and the display.
4. Scanning the entire image distortion or blurred
Reasons and troubleshooting: (1) Scanner glass plate is dirty or reflective mirror strip is dirty; use a soft cloth to wipe the glass plate and clean the reflective mirror strip.
(2) Scanning originals documents are not always flat on the document table; make sure the scanning originals are always flat on the platform.
(3) Ensure that documents are not moved during scanning.
(4) Scanner vibrates during scanning due to uneven placement; take care to place the scanner on a smooth surface.
(5) Adjust the software's `exposure setting or `gamma' setting.
(6)If the above situation occurs with a parallel port scanner, there may be a problem with the transmission cable, and it is recommended to use a high performance cable of IEEE-1284 or higher.
5. The scanned image always appears to be missing dotted lines when displayed on the screen or printed out
Reasons for the failure and troubleshooting: (1) Check whether the scanner's sensor is malfunctioning or the paper guiding mechanism of the automatic document feeder is malfunctioning, and look for a professional to carry out inspection and maintenance.
(3) the optical lens of the scanner to do dust treatment, with a special small vacuum cleaner works best.
(4) Check whether the white correction strip on the outer cover of the scanner is dirty and needs to be cleaned in time.
(5) Check to see if the table glass is dirty or scratched, which can be avoided by thoroughly cleaning the scanner or replacing the table glass on a regular basis. The latter should be done by contacting your local Authorized Technical Service Center.
6. Scanning prints, tortoise (cross-image) appears in a specific area of the image
Reasons for failure and troubleshooting: First, let's understand the simple principle of color print imaging. Try to take a magnifying glass to observe the general color prints, in fact, any graphic is composed of four colors, is often referred to as cyan, magenta, yellow and black. These colors are very small ink dots (good color printing should have a resolution of 1200 dpi), the use of ink dots arranged in such a way as to give the eye an illusion, such as a certain area of red ink dots are more, the human brain's visual system will think that this area is red. Such small dots, in the scanning time will be sensitive photographic components detected, so the scanning results will make the whole picture has a variety of lines appear, seriously affecting the quality of the scanned image. The following programs can be used to avoid the generation of tortoise lines.
(1) Select the Color Photo (De-Retina) setting in the Image Type or the De-Retina setting in the Image Type dialog box.
(2) Place a transparency sheet between the document and the drafting table to defocus the image.
(3) Position the image correctly.
(4) You can slightly reduce the image size.
(5) Check the Clear Edge Sharpening check box in the scanner's TWAIN.
Scanner maintenance tips
Scanner as an image input device, has been popularized to thousands of households, then in the use of how to correctly go to the maintenance of the problem is also worth noting. Today, I would like to introduce you to the daily maintenance of the scanner to pay attention to the place.
1, do not arbitrarily hot swap data transmission line. General home scanners are EPP interface, in the scanner after power, if you feel free to hot-plug interface data transmission line, will damage the scanner or computer interface, replacement is more trouble, although you try not to have a problem, please do not do so.
2. Don't plug and unplug the power cord from the scanner's connector too often. This often plug and unplug the power cord and the scanner's connector, will cause poor contact at the connection, resulting in circuit failure, maintenance is also very troublesome. The correct power cut-off should be to unplug the inline power converter from the power outlet.
3, do not cut off the power in the middle. As the mirror group in the work of slower movement, when scanning an image, it takes part of the time from the bottom of the return, so we do not cut off the power supply in the case of normal power supply, wait until the scanner's mirror group is completely back in place, and then cut off the power supply. Now there are some scanners in order to prevent vibration during transportation, but also to the mirror group part of the added lock, visible mirror group return to the mirror group of how important the protection.
4, place the items to be positioned accurately at a time. Some models of scanners can scan small three-dimensional items, in the use of such scanners should pay attention to: placing the items to be positioned accurately at a time, do not casually move to avoid scratching the glass, and do not move the items in the scanning process.
5, do not place items on top of the scanner. Because of office or home space constraints, and the scanner is more space, so some users often put some items on top of the scanner, over time, the scanner's plastic cover because of the hollow pressure will lead to deformation, affecting the use.
6. Cut the power when not in use for a long time. Some scanners are not designed to cut off the power switch completely when not in use, when not in use for a long time, the scanner lamp is still on, because the scanner lamp is also a consumable, so we recommend that users cut off the power supply when not in use for a long time.
7. It is recommended that you do not use the scanner in a window location. As the scanner will produce static electricity in the work, over time will be adsorbed dust into the body of the internal impact of the work of the mirror group, so try not to lean against the window or easy to adsorption of dust position to use the scanner, in addition to keep the scanner to use the environment of the humidity, to reduce the impact of floating dust on the scanner.
8, the mechanical part of the maintenance. Scanner after a long time, to remove the cover, with a cotton cloth soaked in sewing machine oil to wipe the mirror group of two tracks on the grease, wipe clean, and then the appropriate amount of sewing machine oil drops in the transmission gear set and the belt at both ends of the bearings on top, and then finally loaded to test, you will find that the noise is a lot smaller.
Scanner is now more advanced instruments, in many places are widely used, but the use of a long time, the scanner will appear this and that kind of problem, so do you know the repair of the scanner method is what? Here is what I have organized for you to repair the scanner is what the relevant content, I hope you useful!
What is the way to repair the scanner
One, the noise emitted when scanning is very loud.
The scanner works with a large vibration, accompanied by a large noise, which is generated by the movement of the mechanical parts of the scanner work, there are two reasons, one of which is closely related to the scanning speed. According to the specific software of each brand machine, set the scanning speed to medium or low speed can solve the problem. The second, related to the working environment, especially in winter. Scanner internal slide bar will become dry, when the work noise will increase. The way to deal with it is very simple, one is to improve the room temperature, the second is to open the scanner, to the slide bar on a few drops of lubricant can be.
Two, scanning intermittently.
Scanner scanning slowed down when scanning, scanning intermittent, seem very strenuous. This may occur because the memory is too small, the scanner first scan a part of the scanner, and then scan the other part. Then go back and connect the two smoothly. The solution has the following two methods: one method is to expand the memory; another method is to adjust or disable the virtual memory in the "Control Panel / System / Performance / Virtual Memory".
Three, the output image is not colorful enough.
If the scanned image is not colorful enough, you can first adjust the monitor's brightness, contrast and gamma value. gamma value is the human eye from the dark tone to the bright tone of a feeling curve.
The higher the gamma value. The higher the gamma value, the richer the perceived level of color. In the scanning application software that comes with the scanner, the gamma value can be adjusted. Of course, for better results, you can also adjust the gamma value in Photoshop and other software, but this is an after-the-fact adjustment. You can adjust the gamma value according to the specific situation of the scanned photo. In the software that comes with the scanner. If it is for general use, the gamma value is usually set to 1.4, if it is used for printing, it is set to 1.8; photos on the web page is set to 2.2. There is also that the scanner should be color-corrected before use, otherwise it is very likely to make the scanned image distortion; in addition, you can also be specific adjustments to the brightness/contrast options in the scanner driver dialog box.
Four, the scanner sweeps out the picture color fuzzy, some color is not correct.
One of the reasons may be that the scanner's flatbed glass is dirty. Please wipe this glass with a clean cloth or paper. Be careful not to wipe it with a liquid such as alcohol, as that will make the scanned image appear rainbow colored.
The second reason is that the resolution is not set properly. First check the scanner to use the resolution is how much. If 300dp) scanner scanning 1200dpi above the image will be more fuzzy. Because 300dpi scanner scanning 4200dpi is equivalent to a little put to the net times larger.
The third reason is that the monitor settings are not correct. Check and set the monitor setting to 16bit color or above.
Scanner selection techniques
One, brand
Two, performance parameters
Describing the scanner's performance parameters are many, the following general user needs to consider when buying technical indicators.
1. Scanning format: scanning format usually A4, A4 extended, A3, A1, A0 and other specifications. Large format scanner price is very high, the general family and office users are recommended to choose A4 format scanner. According to the need for office users can also consider buying A3 format or even larger format scanner.
2. Resolution: resolution reflects the clarity of the scanned image. The higher the resolution of the scanner, the clearer the scanned image. The resolution of the scanner with the number of dots per inch of length DPI (DotPerInch) said. General office users are recommended to purchase a 'scanner with a resolution of 600 x 1200 (horizontal resolution x vertical resolution). Horizontal resolution by the scanner optical system to determine the true resolution, vertical resolution by the scanner drive mechanism of the precision of the decision to purchase the main examination of the horizontal resolution.
3. Color bits: color bits reflect the ability to distinguish the color of the scanned image. The higher the color bits of the scanner, the more colorful the scanned image. Color bits are expressed in binary digits. For example, a 1-bit image can carry 1 bit of binary information per pixel and can only produce two colors, black or white. an 8-bit image can give 8 bits of binary information per pixel and can produce 256 colors. Common scanner color bits are 24-bit, 30-bit, 36-bit and 42-bit and other common standards. It is recommended to purchase a scanner with 30-bit color or 36-bit color. 30-bit scanners have become obsolete and are not recommended.
4. Light-sensitive components: light-sensitive components are the eyes of the scanner, scanning quality and scanner using light-sensitive components related to the common scanner useful light-sensitive components CCD (ChargeCoupledDevice) and CIS (ContactImageSensor). CCD light-sensitive components of the scanner technology is mature. It with the light source, a few mirrors and optical lenses composed of imaging system, imaging on the sensor surface, there is a certain depth of field, can scan the uneven physical objects. CIS is widely used in fax machine sensor, its limit resolution of 600DPI or so, compared with the CCD technology there is a certain gap, only used in low-grade flatbed scanner.
Three, supporting software
Scanner functions are to be realized through the appropriate software, in addition to the driver and scanning interface, almost every scanner will be randomly presented with some image editing software, OCR text recognition software. Different scanning software performance, operation method is different. For users who are not familiar with graphics processing, it is recommended to choose a scanner that offers simple operation and ease of use.
Four, interface
Interface refers to the scanner and computer connection, common SCSI interface, EPP interface and USB interface.
SCSI interface scanner through the SCSI interface card connected to the computer, data transfer speed. The disadvantage is that it is more complicated to install and requires an expansion slot and limited computer resources (interrupt numbers and addresses). If you often scan a large number of graphic files, you should choose the SISC interface scanner, which can save a lot of time.
EPP interface (printer parallel port) can be connected to the scanner, printer and computer with a cable, easy to install. Can be connected to a laptop. But its data transfer speed is slightly slower than the SCSI interface scanner, the scanning speed requirements are not high, the amount of scanning is not large, infrequent use of the scanner users, it is recommended to buy EPP interface scanner.
USB interface scanner speed, support for plug and play, and computer connection is very convenient, but requires your computer support USB interface, the conditions of the user, it is recommended to buy USB.
Scanner maintenance methods
1. To protect the optical components
Scanner in the process of scanning images, through a called photoelectric converter Parts of the analog signal into a digital signal, and then sent to the computer. This photoelectric conversion setup is very delicate, and the position of the optical lens or reflector head has a great impact on the quality of the scan. Therefore, do not alter the position of these optics in the course of your work, and try to avoid vibrating or tilting the scanner. Encountered scanning
The scanner malfunction, do not unauthorized dismantling and repair, must be sent to the manufacturer or the designated repair station to go; In addition in the delivery of the scanner, be sure to the back of the scanner security lock lock, in order to avoid changing the position of the optical accessories.
2. Do a good job of regular cleaning
Scanner can be said to be a more delicate equipment, usually must be careful to do a good job of cleaning. Scanner in the glass plate, as well as reflective lenses, lenses, if the dust or some other impurities, will make the scanner's reflective light weakened, thus affecting the picture scanning quality. For this reason, be sure to use the scanner in a dust-free or dusty environment as little as possible, and after use, be sure to cover the scanner with a dust cover to prevent more dust from intruding. When not in use for a long time, it should also be cleaned regularly. To clean, wipe the dust off the case with a soft, fine cloth, then clean it carefully with detergent and water. Then clean the glass plate, because the cleanliness of the panel is directly related to the scanning quality of the image, so when cleaning the panel, first wipe it with glass cleaner, and then use a soft dry cloth to wipe it dry and clean.
How to maintain the scanner
How to maintain the scanner
The scanner in the scanner belongs to the computer-aided design (CAD) in the input system, through the computer software and computers, the output device (laser printer, laser plotter) interface, composed of a network of pre-printing computer processing system, and applicable to office automation (OA), widely used in the signage panel, Printed panels, printing industry, etc. Below, I share with you the method of maintaining the scanner and the use of scanner skills, I hope to help you!
Maintaining the scanner method
Do a good job of regular cleaning
The scanner can be said to be a more delicate equipment, usually must be careful to do a good job of cleaning. The glass plate in the scanner, as well as the reflector lens, lens, if dust or some other impurities, will make the scanner's reflected light weaker, thus affecting the quality of the picture scanning.
For this reason, be sure to use the scanner in a dust-free or dust-minimized environment, and when you're done, be sure to cover the scanner with a dust cover to prevent more dust from coming in.
When not in use for an extended period of time, it should also be cleaned regularly. To do this, wipe the dust off the casing with a soft, fine cloth, then clean it carefully with detergent and water.
Then the glass plate is cleaned, because the cleanliness of the panel is directly related to the scanning quality of the image, so when cleaning the panel, first wipe it with a glass cleaner, and then wipe it dry with a soft dry cloth.
To protect the optical components
The scanner in the process of scanning images, through a part called photoelectric converter analog signals into digital signals, and then sent to the computer. This optoelectronic conversion setup is very delicate, and the position of the optical lens or reflector head has a big impact on the quality of the scan.
So don't alter the position of these optics during operation, and try to avoid vibrating or tilting the scanner. Encountered scanning
The scanner malfunction, do not unauthorized dismantling and repair, must be sent to the manufacturer or the designated repair station to go; In addition in the delivery of the scanner, be sure to the back of the scanner security lock lock, in order to avoid changing the position of the optical accessories.
Tips for using a scanner
(1) Determine the appropriate scanning method
Using a scanner can scan images, text, and photos, etc., and different scanning objects have their own different scanning methods. Open the scanner's driver interface, we found that the program provides three scanning options, including "black and white" mode for black and white originals, the scanner will be in accordance with the 1 bit to represent the black and white pixels, which will save disk space.
"Grayscale" is for mixed-text manuscripts with both pictures and text, scanning both text and pictures with multiple grayscale levels. "Photo" applies to scanning color photographs, which are sampled and stored at multiple levels for the red, green and blue channels.
Before scanning, be sure to choose an appropriate scanning method based on the object being scanned before you can get high scanning results.
(2) Optimize scanner resolution
The higher the scanning resolution the clearer the image obtained, but taking into account that if you exceed the resolution of the output device, the clearer the image is not possible to print out, simply occupy more disk space, no real value.
So it is necessary to choose the appropriate scanning resolution. For example, be prepared to use a 600 dpi resolution printer output results scanned at 600 dpi. If possible, scale down large images after scanning. For example, to 600dpi scanning a 4 * 4 inches of the image, in the group version of the program will reduce it to 2 * 2 inches, then its resolution is 1200dpi.
(3) set up the scanning parameters
Scanner in the pre-scanning image, are in accordance with the system's default scanning parameter values for different scanning objects as well as different scanning methods. The effect may be different. Therefore, in order to get a high quality of image scanning, the parameters can be adjusted manually, for example, when the brightness of grayscale and color images is too bright or too dark, the brightness can be changed by dragging the slider on the Brightness slider.
If the brightness is too high, the image will look white; if it is too low, it will be too dark. You should drag the brightness slider so that the image is moderately bright. Similarly for other parameters, you can follow the same adjustment method to make local modifications until you are satisfied with your vision.
In short, a good scanned image does not have to use the image processing software to make more adjustments to meet the print output, and the closest to print quality.
(4) set the size of the file
Whether the object being scanned is text, images or photographs, through the scanner output is the image, and the size of the image size is directly related to the size of the file capacity, and therefore in the scanning should be set to the size of the file size.
Often, scanners are able to automatically calculate the file size when previewing the original manuscript sample, but understanding how the file size is calculated is more helpful when managing your scanned documents and determining the appropriate scanning resolution.
The formula for a binary image file is: Horizontal Size x Vertical Size x (Scanning Resolution) 2/8. The formula for a color image file is: Horizontal Size x Vertical Size x (Scanning Resolution) 2 x 3.
(5) Storing the curves and loading into the scanning software
Sometimes, in order to get the best color and scanning contrast, it is better to do the low resolution first. scan, open it in Photoshop, and use Photoshop's curves feature to make color and contrast improvements.
Store the curve and load it back into the scanning software and the scanner will use this color correction curve to create a better high resolution file. The same curve can be used if several images are scanned with a similar color gamut range, and it is also possible to store curves frequently and load them back as needed.
(6) according to the desired effect of placing a good scanning object
In the actual use of the image in the process, sometimes hope to be able to pour to obtain the oblique effect of the image, there are a lot of designers tend to be through the scanner to the image input to the computer, and then use the professional image software to rotate, in order to make images to achieve the effect of the rotation, do not know that this process is a great waste of time, depending on the the size of the angle of rotation, the quality of the image will be degraded.
If you know in advance how the image is placed on the page, then using a protractor and the bottom edge of the original to place the original at a precise angle on the roller and the platen will result in the highest quality image without having to rotate it in the image processing software.
(7) Finding the best scanning area on the glass flatbed
To get the best . image scanning quality, you can find the scanner's most serving scanning area, and then place the object to be scanned here to get the best, most fidelity image results.
Specific steps to find the following: First of all, the scanner will be set to automatic or silent state of all controls, select all areas, and then scanned a blank, white or opaque block of the sample at a low resolution; and then the professional image processing software Photoshop to open the sample, the use of the software in the equalization of commands (Equalize menu item) for the sample Processing, processing can be seen on the scanner where there are cracks, stripes, black spots.
You can print the file and cut out the best areas (i.e., the most stable areas) to help place the image.
(8) Use a transparency accessory to get the best scan
Many flatbed scanners come with a transparency accessory that sits on top of the scanning bed. To get the best scans of transparencies or slides, remove the picture from the rack and slide mount and mount it on the glass scanning bed, reverse side down (the reverse side is usually the gross side).
Cut out a mask from black paper to cover the entire scanning bed except where the manuscript is set. This will minimize flashing and excessive exposure to light during scanning. Similarly, when scanning 3D objects, cover the scanner's lid with an object whose color contrasts strongly with the object you are scanning. This will help you select it more easily with the PhotoshopColorRange tool.
(9) Maximizing the color gamut of scanned images
To take full advantage of the increased color range of a 30- or 36-bit scanner, try to adjust the colors as much as you can using scanner software (like Agfa's FotoTune) or other companies' software. Because Photoshop software is limited to 24-bit images, images may be inserted in the widest color gamut possible.
(10) Scanning Prints Using Screen-Free Techniques
When scanning prints, a screen flower will appear on successive tones of the image. If the scanner does not have a de-screening feature, try to find the resolution that minimizes the screen bloom. Often, a resolution that is the same as or double the screen line of the print may work.
Once you get a reasonably good scan, use Photoshop's GaussianBlur filter (with a setting of less than 1 pixel) to soften the stenciling a bit until it's not visible. Then apply UnsharpMask to sharpen the image back up. Scanning can also be improved by rotating the image slightly, due to changing the mesh angle of the continuous tone. For black-and-white images a 45-degree rotation is just right; for CMYK images, experimentation will be needed.
Scanner troubleshooting and repair method is how
Scanner several common troubleshooting and repair methods, mainly including the following aspects: a. Scanning emits a lot of noise. Scanner work produces greater vibration, accompanied by greater noise, which is generated by the movement of the mechanical parts of the scanner work, there are two reasons, one of which is closely related to the scanning speed. According to the specific software of each brand machine, set the scanning speed to medium or low speed can solve the problem. The second, related to the working environment, especially in winter. Scanner internal slide bar will become dry, when the work noise will increase. Treatment is very simple, one is to improve the room temperature, the second is to open the scanner, to the slide bar on a few drops of lubricant can be. Second, intermittent scanning. Scanner scanning speed slows down, scanning intermittently, seem to be very strenuous. This situation may be because the memory is too small, the scanner first scan a part of the scanner, and then scan the other part. Then it goes back and smoothly connects the two. The solution has the following two methods: one method is to expand the memory; another method is in the "Control Panel/System/Performance/Virtual Memory" to adjust or prohibit virtual memory. Third, the output image color is not bright enough. If the scanned image is not colorful enough, you can first adjust the monitor's brightness, contrast and gamma value. gamma value is the human eye from dark tones to bright shades of a feeling curve. gamma value is higher. The higher the gamma value, the richer the perceived level of color. In the scanner's own scanning application software, you can adjust the gamma value. Of course, in order to seek better results, you can also be in Photoshop and other software to adjust the gamma value, but this belongs to the aftermath of the adjustment. You can adjust the gamma value according to the specific situation of the scanned photo. In the software that comes with the scanner. If it is for general use, gamma value is usually set to 1.4, if it is used for printing, it is set to 1.8; photos on the web page is set to 2.2. There is also a scanner should be used before the color correction, otherwise it is very likely to make the scanned image distortion; In addition, you can also be specific adjustments to the brightness/contrast options in the scanner driver dialog box. Fourth, the scanner swept out of the screen color blur, some colors are not correct. One of the reasons may be the scanner's flatbed glass is dirty. Please wipe this glass with a clean cloth or paper. Be careful not to use alcohol and other liquids to rub, that will make the scanned images show rainbow colors. The second reason is that the resolution setting is not reasonable. First check the scanner to use the resolution is how much. Such as 300dp) scanner scanning 1200dpi above the image will be more blurred. Because 300dpi scanner scanning 4200dpi is equivalent to a little put to the net times larger. The third reason is that the monitor settings are not correct. Check and set the monitor settings to 16bit color or above.