As more printer manufacturers shy away from giving details of how many ml’s of ink is contained in aninkjet cartridge it has become more important to understand page yields and how they are measured.

Page yield is the total number of pages that you can print with a given ink cartridge. Traditionally each printer manufacturer would run their own differing tests to determine page yields and customers ran the risk of comparing “apples to oranges” when determining the printer page yields from different manufacturers.

Now, fortunately printer manufacturers work with the International Organisation for Standardisation (ISO) and have developed a set of industry standard tests to measure inkjet cartridge page yields.

What is ISO?

ISO is a network of the national standards institutes of 156 countries, on the basis of one member per country, with a Central Secretariat in Geneva, Switzerland, that coordinates the system.

ISO is a non-governmental organization: its members are not delegations of national governments, as they are in the United Nations. Rather, ISO occupies a special position between the public and private sectors. Some of its member institutes are part of the governmental structure of their countries, or are mandated by their governments, while others represent national partnerships of private-sector industry associations.

Therefore, ISO is able to act as a bridging organization in which consensus can be reached on solutions that meet both the requirements of business and the broader needs of society, such as the needs of stakeholder groups like consumers and users.

These tests consist of printing a standard set of five pages, continuously, until the ink cartridge has reached

the end of its life. This continuous method of testing is obviously less time consuming and expensive for the manufacturers to perform and whilst may allow an “apples to apples” comparison, bears little resemblance to real life situations.

The five pages chosen for example are unlikely to be replicated in actual day to day print situations and industry experts estimate that ink printer users only print a few pages at a time and that hours, if not days can pass before another print job is requisitioned. This type of start/stop printing can dramatically reduce the page yield obtained from a cartridge. Inkjet printers use some ink to keep the printhead nozzles clear to allow the ink to flow smoothly and most printers perform a maintenance operation on startup which also depletes the volume of ink in the cartridge.

Some page tests are measured on page coverage of only 5% for black print, the standard letter test, and areas of solid black or areas of grayscale on the page will have an effect.

Canon are now alone amongst the major printer manufacturers to continue to display the volume of ink contained in their cartridges and it is unlikely they will continue to do so if their competitors have abandoned the practice. HP and Epson until recently had this information available, however on the latest HP packaging only a page yield figure is given and the latest Epson packaging contains no information at all to aid the consumer in a choice. Lexmark have had a tradition of vagueness when it comes to page yield information on packaging and they have reached new levels of ambiguity with their latest XL cartridges, stating “2x More pages” and in the small print telling you that the cartridge will last twice as long as another Lexmark cartridge.

It is true that different printer models would yield differing page yields with the same volume of ink, but it is clear this latest trend sheds little more light on the thorny question of how long an ink cartridge should last.