There could be a few potential culprits if your scanner is producing blurry images.
First, you should check to ensure that the paper being scanned is placed correctly on the scanning surface of the scanner. If it is not properly aligned or if the paper is curled or bent, then the resulting scan will likely appear blurry. To ensure an accurate and clear scan, be sure to place the paper flat on the scanner with no bends or creases. This is true for both sheet-fed scanners and flatbed scanners.
Second, be sure to double-check your scanner settings. It is important to make sure that the correct settings are selected for the type of scan you are attempting. Make sure that the image resolution (e.g. DPI) and other pertinent settings are set appropriately for your task.
Third, if you are using a sheet-fed scanner, check to see if the rollers in the scanner are clean or need replacing. The rollers help to move the paper through the scanner, and over time they may become dusty and dirty. The dust and dirt can affect the quality of the scan, so ensure that they are routinely cleaned or replaced as needed.
Fourth, make sure that the scanner is not too far away from the computer. If there is too much distance between the scanner and the computer, this can affect the quality of the scan. Make sure that the cables connecting the two are not too long and kept free from tangling.
Finally, check to see if your scanner software is up-to-date. Outdated software can cause a range of technical issues, which may include a decrease in scan quality. It is recommended to regularly check for software updates and update your scanner software as needed.
By ensuring that these suggested steps are completed, you should have better success at obtaining clearer scans. If your scanner continues to produce blurry images, then it might be time to consider purchasing a new scanner.