Introduction

This document discusses the following printer functions:

• How to optimize cost-per-page if printing mostly black-only pages
• What happens to printer performance when optimizing the MOSTLY BLACK PAGES option
• The effect of grayscale job printing on performance and cost-per-page

Information

The HP Color LaserJet 3500, 3550, and 3700 printers have four-color print cartridges (cyan, magenta, yellow, and black). After printing approximately 8,000 pages at 5 percent coverage on a cyan, yellow, or magenta cartridge, the printer will require that you replace that cartridge. This is true for most customer workloads where the rate of replacement for each color cartridge is affected by how much of each print cartridge's toner is used when printing pages.

Issue:

If you print primarily black-only pages, the printer may require that you replace the cyan, magenta, and yellow cartridges before exhausting its toner. The color print cartridges may be replaced more often than expected based on the number of color pages being printed. This happens because the life of each toner cartridge is dependent not only on toner, but also on a photoconductive drum and developer that can wear during the printing process, even when not printing with that particular color.

SOLUTION:

Use the MOSTLY BLACK PAGES option in the printer's control panel options to optimize the life of the color cartridges when printing primarily black-only pages. To locate this option, do the following on the control panel:

1. Press (check mark) to enter menus.
2. Press (down arrow) to highlight CONFIGURE DEVICE.
3. Press (Check mark) to select CONFIGURE DEVICE.
4. Press (down arrow) to highlight SYSTEM SETUP.
5. Press (check mark) to select SYSTEM SETUP.
6. Press (check mark) to select COLOR/BLACK MIX.
7. Press (down arrow) to highlight MOSTLY BLACK PAGES.
8. Press (check mark) to select MOSTLY BLACK PAGES.

The printer includes the MOSTLY BLACK PAGES option to optimize the life of the color cartridges if you are printing primarily black-only pages. Do not select this option if the printer is printing primarily color pages, as this option, with that type of workload may slow performance throughput without optimizing cost-per-page. This option is not recommended when printing greater than 35 percent color pages.

What happens when the MOSTLY BLACK PAGES option is selected?

The HP Color LaserJet 3500, 3550, and 3700 printers employ a mechanism for partially disengaging color cartridges from the printing process in order to prevent wear of the color photoconductive drums and developers during black-only printing.

What about grayscale print jobs?

If the Print in Grayscale option is selected in the printer driver for a particular print job, the printer will disengage the color cartridges for the extent of the print job. The color cartridges will disengage regardless of how the COLOR/BLACK MIX option is configured on the printer's control panel.

Usually, no performance penalty will be seen when the grayscale option is used, and cost-per-page is minimized for the duration of the job. Print speed may be affected when grayscale jobs and non-grayscale jobs are printed back-to-back. In that case, a pause of up to six seconds may be seen between print jobs.

Tips for using grayscale print jobs

Control of cost of color printing by implementing the grayscale print job option in the print server, forcing jobs from certain users or at certain times of the day or week to print as black-only.

When should I use the MOSTLY BLACK PAGES option?

Use the MOSTLY BLACK PAGES option as the default setting when printing more than 65 percent black-only pages.