Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sdd.hp.com!hp-pcd!hp-vcd!kevinh
From: kevinh@hp-vcd.HP.COM (Kevin Hudson)
Newsgroups: comp.periphs.printers
Subject: Re: Laser Printer duty cycles
Message-ID: <980010@hp-vcd.HP.COM>
Date: 16 May 91 20:45:39 GMT
References: <1991May15.151221.25684@beach.csulb.edu>
Organization: Hewlett Packard, Vancouver, WA
Lines: 24

/ hp-vcd:comp.periphs.printers / sichermn@beach.csulb.edu (Jeff Sicherman) /  8:12 am  May 15, 1991 /

>>  Also, what is the real significance of these figures in actual use. How
>>closely should they be followed in operation ? Are they true monthly (or
>>even daily) based or monthly averages based upon some expected MTBF (or
>>mean copies between failures) ? What are the risks of exceeding them ?
----------

I'm simplifying things a bit, but the pages per month (PPM) numbers
are basically derived by taking the expected lifetime of the mechanism
(in pages) and dividing by the number of months someone might be expected
to own and use the machine.

For instance, if the machine is determined to have a lifetime of 1,000,000
pages, and the expected "time-to-obsolescence" is 5 years, you get about
17,000 PPM. If you exceed this, the "risk" you take is that your mechanism
has a chance of not making it to the ripe old age of 5.

Kevin Hudson

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The above is not HP-stated policy or procedure, but my own opinion
or explanation.
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