Issue #0208/1 - Part 1 - Lack of standards accounts for one of the most significant difficulties that users face when attempting to decide on new hard copy output devices if economy is near the top of their agenda. What the lack of standards means in practical terms is that figures quoted by the printer manufacturers for number of pages per cartridge are based on different metrics. Figures from a manufacturer for a printer in its range are only comparable against each of the other models in its own range and not against models from other manufacturers.
It may seem to be a simple matter to determine how many pages a cartridge produces – on the face of it, Yes, but in reality No! Debate has raged in the industry for many years over what constitutes a typical page, how yield should be measured, how it should be calculated and how it should be quoted.
This week TCPglobal begins a look at the various factors piece by piece, starting this week with a look at page coverage.
It would not be unfair to say that the majority of users are not fully aware of what page coverage means, what coverage any individual page may represent or what the implications are on toner consumption and costs. However, perhaps the most important of the unknowns is the question of how the manufacturer has produced the figure quoted in the literature. One element of the test procedure is the design of the test page, or pages, that are used to determine cartridge yield.
While for the majority of manufacturers it is impossible to know what sort of page the printer has been tested with, some manufacturers (e.g. Epson) do print a thumbnail image of the test pages used in the tests on the data sheet for the model. This is certainly very helpful but, because no user will be printing that page, it is still no guarantee that they will actually achieve the number of pages quoted and so can feel misled when they discover the true cost of printing. There is no simple solution to this conundrum but Epson does go one step further by alerting the user to the certainty of variance in yield by placing the following caveat in the relevant section of its data sheets, “(Ink cartridge yields may vary in accordance with print file size and type, print applications and media used.)”.
Yield figures for cartridges can only be produced by detailed testing of the product – which will be the topic of next week’s TCPglobal. While we talk about the need for standards and to have fully comparable and easily understood data, what we should actually be talking about in our testing is measuring ‘difference’ rather than trying to produce ‘normalised’ results. One of the areas in which this is significant is in the test pages used for testing.
Some test laboratories approach the question of yield testing with a test page that comprises a number of random characters, often grouped at the beginning or middle of the page, which they adjust for each printer by adding or removing characters to ensure that the page, as printed, measures exactly 5 percent (the accepted standard coverage for quoting printer cartridge yield). While this might seem to be providing a figure that will be truly comparable printer to printer, it does not actually provide a fully representative result.
There are two main issues here. Firstly, any test page must be as typical to the user as possible. And, secondly, as stated earlier, we need to measure the differences. This means that the input must always be identical no matter what the hard copy device being tested – allowing us to discover how the printer driver and the device itself handle the data and place the image on the paper in terms of how many pages of that document can be printed.
As every printer is liable to produce a page slightly differently from another printer, it is often recommended that fonts used in the document are embedded within that document itself – and this is not a standard way for documents to be created and saved. Having accepted that we should be measuring differences (because the average office user will not be carefully designing a page to be exactly 5 percent or embedding fonts in the document!), then there is a strong case specifically for NOT embedding fonts because that would be an instance of normalising the process – thus partially defeating the object of the exercise. If one printer handles the data in a different manner from another printer, then we want to know what effect that difference has on the printed output and the costs associated with that difference.
Returning to the fact that test pages should be designed to be typical to the type of page users would produce, they should be made available for users to view so that they can know what the coverage is, be able to visualise what that coverage means and then to know how many of that page to expect from each cartridge. In addition to Epson’s thumbnails published on the data sheets, several manufacturers publish examples of test pages, together with approximate coverage figures and (sometimes) cost per page. Note that these figures are manufacturer defined and produced and are not independently verified. Some of these examples (from Brother, Minolta, Oki and Xerox) can be viewed at http://www.charisco.com/tcpglobal/archive/images0208
Although the accepted norm for the printer industry is 5 percent, the copier industry has used a 6 percent cover standard and the fax industry a 3 percent cover standard (Slerex Letter). Just to complicate the matter further, the printer industry has also used the Dr Grauert Letter (ISO 10561), often misquoting it as 5 percent when it is actually measured at approximately 3.2 percent cover, a number of manufacturers have quoted yield at 4 percent and even at 2 percent (for IBM IPDS protocol). In a study undertaken by Oki a number of years ago, to find out what the average fax page coverage is within the general office environment, the resulting figure was 7.5 percent. No standard!!
So, this underlines that every manufacturer is approaching the testing and measurement process from its own angle and, of course, with its own interests at heart. Not only are the pages designed differently but measurement of the coverage will undoubtedly be undertaken in different ways so that even the coverage quoted cannot be guaranteed to be comparable let alone the yield figures and thus the cost.
To round off this brief look at the page coverage issue, if a user purchases supplies from a third party manufacturer, remanufacturer or refiller, then the situation becomes even more uncertain. The third party suppliers will usually state that their products at least match, or exceed, the yield of the original manufacturer’s products. We have already made mention in a previous issue of the fact that the third party industry in the US is not well regarded by the manufacturers, with suspect figures and claims being published. However, from the independence point of view, that situation merely adds to the overall uncertainty facing the user when making purchase decisions.
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