WHY DRUMS DON’T ALWAYS LAST AS LONG……
WHY DRUMS DON’T ALWAYS LAST AS LONG……
2005-01-23 at 10:26:00 am #11436Why Drums Don’t Always Last as Long as They Should
Whether You are a salesperson or a technician, you will be confronted with questions about the lifespans of consumables. No one will ever complain if something lasts too long; and if you offer “all-inclusive” service contracts, the customer may never care how long anything lasts, as long as their equipment is running.
Nevertheless, it is part of your own cost structure, contract pricing, and service planning to know approximately what each machine will require to keep it running properly.
Manufacturers will nearly always have stated yields for certain “consumable” items. The most obvious is toner, of course. This is also the most controversial and the most costly and is best left for another discussion, especially since the technician’s work is unaffected by it, except in extreme cases. Developer (in dual-component machines), drums, drum cleaning blades, and fuser components (rollers, picker fingers, bearings, bushings, cleaner rollers, etc.) are the items that we are most concerned with.
Where the ratings come from
Manufacturers decide on the lifespan of such consumable items in several ways. No one oversees them. There is no EPA or any other government or international agency setting standards or running tests. These ratings are done on the “honor system.” If a manufacturer wants to tell people the drum lasts 100,000 copies and they know it only lasts 60,000, there is no one to stop them, nor is there any automatic penalty for the misstatement of facts.
Manufacturers do not blatantly lie. At least not in ways that are documented. However, selling machines in a highly competitive market requires “salesmanship.” The line between these two subjects (lying and salesmanship) is often a very large gray area.
In fact, some manufacturers do support their consumables yields with programs such as “guaranteed minimum drum life” figures.
For the most part, manufacturers base their stated yields on some limited testing done on their own premises by their own employees under their own management’s supervision. There are no watchdog agencies or federal inspectors.
How yields are determined
In my own limited personal experience, here is how yields were determined:
Two or three examples of a new-model copy machine were set up with a single test pattern on the platen glass (same one on each machine). Each machine was dialed to the maximum number of copies it could make in one run. The machine would be run all day and all week this way, replenishing toner and paper as needed and recording copy counts every time the machine was stopped or needed something.
Sample copies would be pulled from the exit tray periodically and compared to samples from when the machine began the test. “Fall-off” in copy quality would be noted and possibly investigated. Each machine’s samples copies would be carefully notated with date, copy count, and machine (remember several testing at once).
Using the above criteria and periodically opening up and inspecting the machines, a lab technician could eventually see the fuser rollers, drum, etc., start to fail (wear out). This information would be noted.
At some point the test is concluded and the results analyzed. If, for example, all three machines exhibited copy quality fall-off between 150,000 and 200,000 copies, the analysis might conclude that the full PM (preventive maintenance) should be performed at 120,000 copies to “ensure” no copy quality problems. Exactly what items the PM would include would likely be educated guesswork. Although some labs I have seen have the capability of examining drum blades under a microscope or viewing the inside of a machine with a fiber optic lens during operation, this is probably not usually done.
In addition to the relatively scientific conclusions reached by the above methods, there is the marketing aspect. Remember, to quote Steve Martin’s character in The Jerk, “It’s a profit deal.” If this particular machine does not show problems for over 120K and it is competing with similar machines that have a 30K PM schedule, the manufacturer has several considerations. He can give the machine a 120K PM schedule and blow away the competition in that category. On the other hand, his dealers may complain that the machine produces too little after-the-sale revenue. The dealer may say, in effect “Why should I sell your machine and do one PM every two years when I can sell the other manufacturer’s machine, make the same profit at sale, and do two PMs a year?”
What also may happen (and I certainly can’t prove or document any of this) is that the manufacturer is faced with machines that have very high PM schedules, compared to his own. He may then decide that instead of the recommended 120K PM cycle, he will rate the machine at 150K or even higher. His feeling is that if he doesn’t, in a competitive situation, the opposing salesman will point out to the customer that the 120K PM cycle will result in more expenses and/or down time for the customer.
But what about the machines?
Aha. Now we’re getting to my favorite subject. If you have a machine with a 120K PM cycle, including a 120K drum and blade, how come some are still going strong at 120K, but some fail much sooner? You will probably discover that, usually, the parts that fail sooner are on the lower volume machines, and here is why.
Low-volume machines tend to be used for short runs–one or two copies, maybe five or ten. High-volume machines tend to be run for hundreds of copies at a time.
Take a minute or two to do the following test with any machine. Run one copy and run 20 copies. From the moment you press the print button, start counting seconds. Stop counting when the last copy (even if it is the only copy) has landed in the exit tray and the machine has stopped completely (every motor has shut down, exposure lamp is off and ready light is lit again.) Jot down the amount of seconds for each.
You will discover that the average amount of time spent running the machine to make only one copy is 10-15 seconds. On the 20 cpm machine that I tested, it took 68 seconds to make 20 copies (because manufacturers, while not necessarily “lying,” don’t like to count the time it takes for the first copy to travel through the machine, since it makes their machines seem slower!) I guess that is not lying, but salesmanship, and besides, everybody does it. So…that makes it OK, right? Hmmm.
The math is pretty simple. One copy run means 10-15 seconds of running time per copy. A 20-copy run means 68/20= about 3.5 seconds of running time per copy. Some machines have simulations that allow you to check drum time, hours of operation, and so on. I don’t know of any technicians that do. But the fact remains that low volume machines work about three times as much, per copy, as higher volume machines. It would stand to reason, then, that their parts would have a substantially shorter lifespan.
Here is why it matters. In nearly all cases, the high mortality parts and consumables are being operated any time the machine is running. So, when the motors are running, the drum is turning (rubbing against the blade), the fuser rollers are turning (putting wear and tear on the rollers, bushings, bearings, separator fingers, and cleaner rollers).
Furthermore, all those motors are doing extra work. The fuser lamp keeps the rollers hot most of the day (energy saver minimizes this, but does not eliminate it). The heat of the fuser is a large factor in its lifespan, not just the amount of copies it runs. Heat causes the silicon press rollers and heat sleeves to dry out and crack and causes the non-stick coating on the heat roller to eventually bubble and peel off.
Also, every time customers use the machine, they press the print button, wearing out the switch and putting stresses on the operation panel, which eventually leads to cracked solder joints and worn out panels. Digital copiers usually only scan once per run, which means that a single copy run puts as much strain on the scan system, exposure lamp, and inverter board as a 999 copy run.
There is no way to accurately predict how long an item will last in any machine. You can “ballpark” pretty closely, and paying close attention to published yields as well as your customer’s usage can help you stay ahead of problems by replacing items before they fail or having them ready at the right time. But don’t ever expect to be able to accurately predict the lifespan of any item in any machine. As those stickers on new car windows state, “Your mileage may vary.”