HP d640 HP D640 High-Volume Printer - User Manual (Printer and Accessories), C - Page 182

Advanced Topics Managing Consumables Note The factory yield estimates for consumables are determined under operating conditions which are intended to model a large sample of customer installations. However, it is impossible to model every operating environment, and as result some installations may experience lower consumable yields than expected. Keep a log of actual consumable usage for each printer. This provides the most accurate data to plan consumable purchases. Toner Toner yields are primarily driven by the quantity of toner applied to each page. Large black areas, graphic images, gray backgrounds and forms outlines use more toner. If you print mostly or only a small amount of text, you will probably reach or exceed the estimated yield. Toner yield estimates are based on 4% toner coverage. This is a standard value used by the printer industry, which is based on the assumption that the "typical" A4 or letter-size business letter is 4% covered by black area. The D640 offers a number of features that, with some trade-offs, can extend toner yield. Density The density value is factory set to 10, approximately in the middle of its range. The density value can be set as low as 1 to reduce toner consumption. To the naked eye, solid area patterns will not appear any lighter under lower settings. Reducing the density will have the largest visual effect on gray scale patterns or the small text characters. Experiment to see if a lower density value can satisfy your print quality requirements. Actual toner savings will vary based on the types of images printed. The density setting can be found under the Maintenance Menu, described in "Density" on page 2-25. Economode Most printers simply print a lighter pattern when an economode setting is used. However, the D640 does not lighten the entire image. Instead, dots are turned off in strategic areas to reduce toner use while maintaining readability. When printing text in economode, the character outline is perfectly formed, while the inside uses fewer dots. The effects are nearly invisible to the naked eye at a 10 point character size, but may be more readily seen on large characters. Experiment to see if economode can be used for some, if not all of your printing. Large textonly reports may be able to use economode with no perceptible reduction in print quality. Economode can reduce toner consumption as much as 50%, depending on the printing pattern. The Economode setting can be found under the Configuration Menu, described in "Economode" on page 2-17. Advanced Topics 6-7