Many of today's scanners are easier to install and operate than their predecessors. Still, as with any machine, there are times when the device doesn't work properly. A scanner that's on the fritz may result in dirty images or no image at all. Before you ditch your scanner and invest in another one, we have some simple troubleshooting steps to help resolve the problems.

Often, when something isn't working, we miss the common causes. An unplugged cable, an inadvertently turned off switch, or a loose connection are some of the first problems you should rule out before delving into the more complicated solutions.

Anna Lee, a marketer for Acer Peripherals, says some scanners have a lock to protect the charge-coupled device (CCD; a light-sensitive unit that lets the scanner store and produce shades) from getting damaged during shipping. Some customers forget to unlock the unit.

Trying the simple but often overlooked solutions should be your first step. Afterward, you can begin to examine some other possibilities.



Installation

With Plug-and-Play technology and easy-loading software, installing a scanner should be easy for Windows 95/98 (Win9x) and Windows NT users.

Even so, Steve Walker, manager of technical services for scanner manufacturer Umax, says many users still experience problems getting the scanner to work after they've installed it.

"At some point," Walker says, "software doesn't get installed properly, or users don't get all the software installed." Some scanners come with the software on two CDs, and the customer doesn't notice the extra disc, he says. Or, the user installs the hardware before loading the software. The proper order of installing software and hardware is important, Walker says, so Windows knows what type of scanner you have and installs the drivers correctly. If you load the wrong drivers or install the drivers incorrectly, Windows won't have the data it needs and will list the scanner as an unknown device that you can't use.

Fixing this installation problem is easy, Walker says. Just reinstall the scanner and software in the recommended order. Before reinstalling the scanner, however, be sure to go into the Win9x Device Manager and delete the scanner you had previously installed. Click the Start button on your Windows Desktop, select Settings, and click Control Panel. Scroll down and double-click the System icon. Then, select the Device Manager tab and make sure you've selected the View Devices By Type radio button so you can see a list of the devices installed on your computer. Click the plus sign next to Imaging Device, select the name of the scanner you wish to delete, click Remove and then OK. Now, click Close to exit, and you're ready to reinstall your software and scanner.

Although configuration problems are rare, Walker says a computer's hardware may interfere with or may not work correctly with the scanner.

A configuration problem involving monitor settings could affect the quality of your displayed scanned images. According to a technical representative from Hewlett-Packard (HP), a monitor set to 256 colors replicates as best it can any shades outside of its color range. Because most scanners use 24-bit color (with 16 million possible color variations) and higher to reproduce images, the monitor must dither (vary the pattern of dots to create the illusion of different colors or shades) some areas. This process results in a speckled area that some users mistake for imperfections on the scanned image.

Changing your monitor settings to display 24-bit color (true color) or higher will give you sharp, detailed images. To adjust color settings, click Start, select Settings, click Control Panel, and double-click the Display icon. In Display Properties, choose the Settings tab and in Colors (Color Palette for Win95), click the down arrow, choose the 24-bit or higher color setting, and click OK. Windows may prompt you to restart your computer for the settings to take effect. Before adjusting the color settings, make sure your graphics card can support the higher settings, or you'll have problems with your monitor.

Another common configuration problem, Walker says, is caused by "chaining [a low-end parallel port scanner] up with other devices." An example of this would be trying to have your printer and scanner (both of which use the computer's parallel port) plugged into and available for use on your computer.

To access more than one device using a computer's parallel port, Walker says, you can separate the devices by adding another parallel port or by connecting a switch box (a device that lets you connect two units to the computer using a single port), which lets you switch from unit to unit.

Problems arise from interrupt request line (IRQ) conflicts among hardware devices trying to communicate with the PC. But you can solve this problem yourself. Start by going to Device Manager. In the list of devices in Device Manager, you should see a yellow exclamation point next to your scanner or the device that conflicts with it. Scroll down to Imaging Device and click the plus sign. Highlight your scanner and click Properties. Under the Resources tab of the scanner's Properties window, you should see a list of the computer resources the scanner is using.

(NOTE: A parallel port scanner may be linked to the port it's plugged into and may not appear under Imaging Devices in Device Manager. Scroll down and click the plus sign next to Ports, highlight the port your scanner is using, and click the Properties button, then the Resources tab.)



Fixing IRQ Conflicts

After noting which resources the scanner is using, uncheck the Use Automatic Settings option so you can manually adjust settings. Click the down arrow next to Setting Based On and scroll through the Basic Configuration settings. As you experiment, pay attention to the Conflicting Device List at the bottom of the Device Properties window to be sure the new setting has free resources. After you've chosen the setting, click OK. Windows will give you a warning about changing the settings manually. Click Yes to change the settings.

Go through and choose configuration settings until the hardware conflict is resolved and the yellow exclamation point disappears from the Device Manager list. If, after trying all of the settings, your scanner still conflicts with other hardware, call the technical support number provided in the documentation that came with your scanner for assistance.

When dealing with resolution and file sizes, Walker says, "the trick is getting [customers] used to the idea that size is relative compared to the dpi level." For most users, he says, scanning at the lower dots per inch (dpi; a resolution measure) levels (100dpi to 300dpi) is sufficient for attaching images to e-mails, posting them to the Web, or printing, and it frees up a significant amount of memory on a PC.

For example, according to HP, scanning a 5- x 7-inch photograph into a computer at 1,200dpi with 24-bit color will give you a 100 megabyte (MB) file. With a two gigabyte (GB) drive, that means you'll only be able to store 20 images. And you'll need a lot of random-access memory (RAM), at least 128MB, to open and edit such files.

Often, though, a computer will crash or give you an Out Of Memory error when working with extremely large files. You can fix this problem by deleting the huge file and rescanning at a lower resolution or reducing the actual size of the scanned image itself through the scanner's software.

After rescanning or resizing your images, save the files you want to use as e-mail attachments and Web graphics in a high-compression Joint Photographic Experts Group (JPEG) format to further reduce the image's size. Because this format eliminates from the image what it sees as redundant data the first time it compresses it, JPEG is not recommended for users who want to archive images. For that, you'll want to compress the scanned images into a Tagged Image File Format (TIFF), which keeps the data intact but results in a larger file. You could also use a program such as WinZip to compress your files into more manageable sizes.

Walker says vertical streaks on a scanned copy are easy to fix. When an automatic document feeder, for example, drags a page across the glass and the scan head below, he says, anything, such as dust and particles, between the image and the scan head that's not getting pulled along will get scanned repeatedly and will appear as a vertical streak on the scanned page.

Cleaning the glass should solve that problem. Use a damp cloth to clean the glass, making sure to remove dirt, dust, and other particles.

For other image quality issues, Walker says, look at the original and how it was produced, because this affects how the scanner "sees" and scans it. For example, a magazine image is printed using very small dots, he says. A scanner also reproduces images using very small dots, called pixels. If the scanner's dot size is larger than the dots on the original, you'll get a repeating pattern of diagonal stripes or groups of blotches on your scanned image.

Fix this problem, Walker says, by scanning the image at a higher resolution and reducing the file size afterward by scaling down the image with the scanner software. Because the scanner uses smaller dots that more closely match the dots on the original image, the pattern will disappear.

The original condition of transparent images, such as film and slides, can also affect the quality of the scanned image. Even a slight amount of moisture on film or slides, Walker says, can result in a circular diffraction pattern on the scanned images. These "Newton rings" form when the scanner's light hits the moisture on the original images. Walker says that by raising the original off the scanner's glass, using a film or slide holder, you can prevent these rings from showing up on your scanned images.

The condition of the orginal document affects the ability of optical character recognition (OCR) software to interpret characters. OCR translates scanned text documents into computer-recognized characters that you can edit in a word processing program.



Keeping It Clean

OCR accuracy demands an original free of coffee stains, fingerprints, and other background imperfections that will distract the scanner, Walker says. Fancy, "busy" fonts and dark text on a dark background interfere with the scanner's ability to differentiate between text and background.

Jimmy Kuang, an engineer with Acer Peripherals, says some users choose settings that also affect the accuracy of the OCR. If the OCR produces accurate results only 50% of the time, he says, the scan settings may be too dark. Images for faxing or copying, Kuang says, can be set brighter to improve accuracy and prevent characters from blending during OCR translation. For less-than-perfect originals, Kuang suggests reducing the scale to 75% or even 50% to improve the OCR's overall accuracy.

Other imperfections, especially those affecting color reproduction, Kuang says, often come from incorrect settings in the scanner software. Although most software comes with default settings, some users experiment and change these color settings, he says.

"The problem is when they do that," Kuang says, "they forget how to get it back to the original settings." Depending on the software, users should be able to reset to the default options. Look for a default or factory setting in the software's image previewing or color-balancing window.

"Putting [the settings] back," Acer's Lee says, "to the default or the auto-adjustment function can fix a lot of the problems." But software settings aren't always the problem.

"If you have a lot of peripherals or computers in the area," Lee says, "it could create a lot of electronic noise that will affect the scanners," giving you scanned images with horizontal lines and/or dots.

However, Kuang says, a faulty CCD will produce similar distortions in the image. But if the problem is indeed the CCD element, he says, you should also find color variances, "a blue dot, for example, in the middle of a lot of green," in the copy. A scanner with a faulty CCD, Kuang says, must be shipped back to the manufacturer for repair.



A Healthy, Happy Scanner

Most scanners require minimal maintenance and may only need an occasional bulb change. Any problems that crop up while installing or using your scanner can usually be easily fixed, and your scanner, with proper care, should run for years.

by Lori Robison

Original	Scanned