UPS: "Do not connect laser printer..."

[notme]

What is it about laser printers that causes UPS manufacturers to recommend
they not be powered by a "stepped approximation to sine" UPS? It's a SMSP,
isn't it? What makes it special such that it needs sine-only? No such caution
re. computers, etc...

Thanks.

 

[Joerg]

What is it about laser printers that causes UPS manufacturers to recommend
they not be powered by a "stepped approximation to sine" UPS? It's a SMSP,
isn't it? What makes it special such that it needs sine-only? No such caution
re. computers, etc...

Modified sine is often just full peak on, pause, full negative peak,
pause, and so on. That can mess with PFC circuitry and also stresses
rectifiers at the line input more than a sine. However, RVers and
traveling sales folks do sometimes use modified sine inverters.

What really wreaks havoc is a printer that has a powerful fuser which
draws short but huge bursts of current. That can cause the inverter
inside the UPS to choke.

 

[Geoffrey S. Mendelson]

Possibly because some laser printers have 1000 watt fusing elements
and most home UPS units can't provide that much power?

They go out of their way to hide it. A friend of mine moved here with a 120
volt industrial strength HP laser printer. The specs said 325 watts, the
current draw was listed as 8 amps max on the last page of the manual.

My current small Samsung printer never actually says what it draws, but the
web page and manual made a big point about it drawing 6 watts in standby. Since
we print around 5 times a week, the standby current matters more than the
max draw, but I would not want to plug it into a UPS.

Geoff.

 

[PeterD]

They go out of their way to hide it. A friend of mine moved here with a 120
volt industrial strength HP laser printer. The specs said 325 watts, the
current draw was listed as 8 amps max on the last page of the manual.

Nothing much hidden there: 8 Amps, 120 volts, 960 watts. That's damned
close to a thousand watts, IMHO.

 

[Geoffrey S. Mendelson]

Nothing much hidden there: 8 Amps, 120 volts, 960 watts. That's damned
close to a thousand watts, IMHO.

My point was that the 8 amps was only on the last page of the manual, not
anywhere else, including the web page, sticker on the printer, specs page
at the begining of the manual and so on.

Geoff.

 

[Nobody]

So a heater of that sort takes its power directly from the line?

There's no reason to use DC, particularly if it means that you need a
1kW PSU instead of 200W.

 

[Geoffrey S. Mendelson]

Do inkjet printers handle the simily waveform well?

Inkjet printers use very low power stepper motors to move the head and paper,
and very tiny heaters to make the ink bubble up. They run off of low power DC.
The power supply in the printer (or external on most of my inkjets) very happily
converts the output of a UPS to the DC that it needs.

The difference with laser printers is that the toner only sticks to the paper
as long as there is an electrical charge. To keep it falling off of the paper
after a few minutes, it has to be melted onto the paper.

The technical term used is "fused" and the part of the printer is called
a "fuser". They could of as easily called it "ironing" and an "iron", (as in
an iron-on T shirt pattern) but that would have been too simple and
not sound important enough.

Geoff.

 

[PeterD]

My point was that the 8 amps was only on the last page of the manual, not
anywhere else, including the web page, sticker on the printer, specs page
at the begining of the manual and so on.

Geoff.

Ah, I see your point.

 

[Joerg]

chaCHING! Collect your prize at the door.

What did I win? Can one drink it?

 

[Joerg]

How about a bottle of Macallan 1926 single malt?

Nice! But a 1978 Montrachet or a nice bottle of Chateau d'Yquem would
also do

 

[Geoffrey S. Mendelson]

I had an Epson. Replacement ink cartridges were cheaper than other
brands too, because the piezos were permanent parts of the printer and
not built into the cartridges. I didn't use it often enough, and when
the nozzles clogged up, the printer's life was over.

You can clean them with a dilute solution of ammonia in water, but that's no
longer legal here. :-(

There are actually print head cleaning solutions, but I have not bought any
in a long time.

Geoff.

 

[Geoffrey S. Mendelson]

I have an Epson all-in-one, which works great except that if even one
ink colour is low, it won't let you do _anything_. On Saturday it
wouldn't even let me _scan_ until I replaced the yellow ink.

I had that same problem with an HP6100. It told me it was out of black ink
and when I put a new cartridge in, it did an alignment page. It printed out
some black lines and then failed.

It never told me that it was out of color ink too. I was about to throw it
away when I found an unopened set of catridges and replaced the color one
just because I had it. It did the alignment and now it is working.

I really did not care very much about the printing, I wanted to use it
as a black and white fax machine. Without two working cartridges (black
and color), it won't funtion at all. :-(

Geoff.

 

[Bob Larter]

What is it about laser printers that causes UPS manufacturers to recommend
they not be powered by a "stepped approximation to sine" UPS? It's a SMSP,
isn't it? What makes it special such that it needs sine-only? No such caution
re. computers, etc...

The big difference is that lasers usually have a mains powered quartz
lamp inside the fuser assembly to cook the toner onto the paper. My
guess would be that the lamp puts a huge current spike on the mains each
time it powers up, which is every minute or so. If so, that spike might
overload the UPS.

 

[Bob Larter]

How about a bottle of Macallan 1926 single malt?

Sounds good to me!

 

[Bob Larter]

Nice! But a 1978 Montrachet or a nice bottle of Chateau d'Yquem would
also do

I'd prefer the Scotch, myself.

 

[Bob Larter]

Possibly because some laser printers have 1000 watt fusing elements
and most home UPS units can't provide that much power?

IIRC, the fusing lamps are closer to 250W, but the element will draw a
lot more than that when it's cold.

 

[Bob Larter]

Do inkjet printers handle the simily waveform well?

It shouldn't be an issue at all for inkjets, only lasers.

 

[Bob Larter]

You can clean them with a dilute solution of ammonia in water, but that's no
longer legal here. :-(

You're kidding! Why not?

There are actually print head cleaning solutions, but I have not bought any
in a long time.

Betcha they're just water & ammonia.

 

[Geoffrey S. Mendelson]

You're kidding! Why not?

My guess is that someone thinks you can mix ammonia and various household
items to make a bomb, but what I think happened is that someone who
can't read the Hebrew warnings on the bottle cleaned their toilet with
ammonia and clorox and they had to evacuate the whole neighborhood.

Now the most exotic toilet cleaner you can buy is something called
"hot water" (may cham) which is a mild dilution of hydrochloric acid. So mild,
I don't think it will cause skin burns.

Geoff.

 

[Rich Grise]

Nice! But a 1978 Montrachet or a nice bottle of Chateau d'Yquem would
also do

I can get an "almost half-gallon" (1.75L) of Prestige Vodka for $8.99 plus
tax. ;-)

Cheers!
Rich