HP d640 HP D640 High-Volume Printer - User Manual (Printer and Accessories), C - Page 181

Managing Consumables Repetitive Defects Repetitive marks appear repeatedly on the printed side of the page. • Replace the drum unit in the printer with a new drum unit. (See "Drum Kit - Replacing Drum and Transfer Assembly" on page 4-18.) • Replace the fuser unit in the printer with a new fuser unit. (See "Fuser Kit - Replacing the Fuser" on page 4-29.) • If you are still having this print quality problem, contact your authorized HP service representative. Managing Consumables Use the following checklist to identify actions you can take to maximize consumable yields. Further detailed information is provided later in this section. 1. Keep the printer clean. Follow all the maintenance procedures listed in Chapter 5. Accumulations of toner and paper dust affect the yields of all consumables. 2. Use high-quality media. Factors such as paper chemicals or scratches from unsupported media can damage the drum and fuser. See Appendix A for a description of supported media. 3. Handle all consumables and print media with care. Protect the drum from light and abrasion. Avoid dropping or rough handling of consumables after they are removed from their cartons. Store the consumables and media in a clean, stable environment, preferably at the same location or under the same environmental conditions as the printer. 4. Use the toner management features discussed on page 6-7. The D640 printer supports several features that maximize toner usage. 5. Monitor and, if possible, manage print job sizes. Single-page print jobs are the least efficient for consumable usage. Longer, multiple-page jobs are more efficient. 6. Monitor and, if possible, manage the complexity of printed images. Images which are too complex to print at rated speed (for example, a large, complex PostScript image) reduce the life of the drum and developer. Also, printing repetitive images can wear the fuser rollers unevenly. 7. Avoid frequent lapses into power save mode or frequent power cycling. The start-up process uses some of the life of the drum and developer. 8. Avoid prolonged periods of inactivity with the power switched on. Hewlett-Packard recommends you switch off printers that are inactive overnight if the power save feature isn't used. 6-6 Advanced Topics