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UPS and laser printer

First: I am well aware of the limitations on UPS devices and laser printers.

Client is a financial firm that prints complex documents as part of their production activities. No documents printed = no fulfillment, no money. A critical business function.

These are large documents, like 200 pages. Currently they print out on an HP LaserJet 41xx with several paper trays/handlers attached. As I mentioned this is a critical business function.

The power grid has been problematic in their area recently. I just finished installing heavy-duty UPS devices on all their computers and VoIP phones. But what about the laser printer? If they can't print, then the whole thing is a bit of a waste.

Unfortunately they are located in a large office building that has no whole-building generator, and it would be impractical for them to get their own generator.

Some sort of UPS device for the laser printer? If so, how to size it? Is this practical? It was suggested to me that I use a marine battery and a power inverter. I've seen that done with certain powerful radio equipment. But is that the best solution?

Any input welcomed. Thanks in advance.
3 Solutions
John HurstBusiness Consultant (Owner)Commented:
I just finished installing heavy-duty UPS devices on all their computers and VoIP phones

I read this to mean multiple UPS machines - one per computer and one for the VOIP system. If this is wrong, how big (watts) is heavy duty.

Easily an APC Smart UPS 500 or 750 that is a true UPS (not a battery backup) should run a LaserJet 41xx with no issue. You want the UPS to be always supplying so as to accept the surges easily.

I think the issue with Laser Printers is that people were using small UPS units. A decent UPS will do just fine.

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milhouse537Author Commented:
I read this to mean multiple UPS machines - one per computer and one for the VOIP system. If this is wrong, how big (watts) is heavy duty.

You assume correctly. APC BR1500G units on each workstation, and an APC SUA1000XL with an additional two SUA24XLBP auxiliary packs attached for the phone system.

The specifications for their printer say that it consumes 450 watts during printing, which: sure, there are units that supply that kind of power. But I was under the impression that the first jolt of power as it starts printing is beyond that, and would blow out the UPS, or damage it, or whatever. Maybe I'm mistaken on that?

And are you saying that the Smart-UPS (whichever exact model) would be preferable in this case, because it will handle the initial load more easily?
Gary CaseRetiredCommented:
Yes, the initial surge current of a Laser is significant -- typically several times the printing load.    For example, the HP 3200 specifications (I couldn't find these details for a 4100) shows an operating load of 210 watts, with a maximum of 700 watts during printing ... but an "inrush current" when turned on of as much as 23 amps (that's over 2500 watts !).

A UPS is not designed to sustain that kind of a load.    I do not know what the "surge" capability is for a APC UPS unit -- I suspect as long as it's not operating on battery, a 2000 watt unit would sustain a 25% overload for a few milliseconds ... but don't know for certain.

This would PROBABLY be okay:  http://www.newegg.com/Product/Product.aspx?Item=N82E16842101483

... but a 3000 watt or higher unit would be safer.   You may want to call APC to discuss this.
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Gary CaseRetiredCommented:
FWIW I do not folks who have used 1500 watts UPS units with "personal" laser printers and have not had a problem.    I don't recommend it ... but clearly it can work with relatively low power lasers.
John HurstBusiness Consultant (Owner)Commented:
Here is a short list of decent APC Smart UPS Units.

I agree with the caveats above, but small laser printers should be able to manage.


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Tony GiangrecoCommented:
Here are the power consumption specs from the HP site on the LJ4100.

Power consumption (average, in watts)
Printer State       HP LaserJet 4100 printers      HP LaserJet 4100N, 4100TN, 4100DTN printers
Printing      465 watts      465 watts
Standby      21 watts      21 watts
PowerSave      20 watts (EPA Energy Star)      20 watts (EPA Energy Star)
Off      0 watts      0 watts

Min recommended circuit capacity
100-127 Volts      8 amps
220-240 Volts      4 amps

I agree the start up wattage demand is always higher on a laser.  Assuming there is only one laser printer plugged into each UPS, I'd say use a 2000 Wt UPS. We only use APC because of their quality and support. I've tried other and left them due to quality issues.

A great way to test this is to connect it to a wattage meter and turn it on. If you don't have a testing meter, your electrician should have the equipment.

Hope this helps!
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