HP 8550 Service Manual - Page 123

Copy module adjustments Note EN End-user adjustments These adjustments and tests should be attempted before service is performed on the hardware to remedy copy quality complaints. For instructions about how to perform these adjustments, see the Copy Module User Guide. l Clean the glass, ADF belts and rollers, standard white plate, mirrors, and lenses. l Inspect the original. Defects and imperfections of the original often cause copy quality complaints. Check to see if the copier is simply making an accurate reproduction of a bad original. Also examine the original to see if the source of the complaints is simply a limitation of a four-color process printer. l Determine whether the image adjustment is required for all copies or only for a specific original. Don't make adjustments to the default settings of the copier for a single original that is uniquely difficult to copy. l Try a different original-type setting (printed image, photo, or black text) to better match the original. l Manually lighten or darken the exposure with the arrow keys on the main menu. l Adjust sharpness. Increase to sharpen edges and add contrast, or decrease to soften contrast and reduce granularity of photos. l Adjust color balance. Increase or decrease relative strengths of primary colors YMCK to achieve best reproduction. l Use the density fine adjust to control the relative lightness or darkness of each primary color in high, medium, or low density areas. l Use the background color adjustment to eliminate the color that appears on copies as a result of the copy module trying to reproduce the color or texture of the original media. l Use second-side elimination to reduce the image from the back side of a lightweight original that appears on the copy. l Perform auto gradation to calibrate the scanner to match the condition of printer (consumables, lamp, etc.). l Perform zoom fine adjustment to adjust for small deviations between original and copy size. l Use exposure recalibration to change the medium value of light/ dark if the print on all copies is too light or too dark. Copy module adjustments 121