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Laser Printer Power Usage

#1 User is offline   LiveBrianD 

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Posted 12 March 2012 - 12:01 PM

Out of curiosity, I plugged my Brother MFC-9840CDW into my watts up meter. I was getting about 100-900W usage while it was warming up and then printing (perhaps the spike is when it's running the fuser?) and about 30W idle (well, a moment after I had just printed; I set it to go into sleep after 2 minutes, default was 5). What makes these draw that much? I mean, part of the time when printing all it's doing is pulling paper from the tray! Also, what's typical of these?

Edit: Even 20 minutes after I printed, at which point the fan had stopped running, it was still drawing 30W. What the heck is it doing? Keeping the fuser warm? After all, it still has to spend a little while warming up when I print something.

This post has been edited by LiveBrianD: 12 March 2012 - 12:24 PM

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#2 User is offline   smax013 

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Posted 12 March 2012 - 05:14 PM

View PostLiveBrianD, on 12 March 2012 - 12:01 PM, said:

Out of curiosity, I plugged my Brother MFC-9840CDW into my watts up meter. I was getting about 100-900W usage while it was warming up and then printing (perhaps the spike is when it's running the fuser?) and about 30W idle (well, a moment after I had just printed; I set it to go into sleep after 2 minutes, default was 5). What makes these draw that much? I mean, part of the time when printing all it's doing is pulling paper from the tray! Also, what's typical of these?

Edit: Even 20 minutes after I printed, at which point the fan had stopped running, it was still drawing 30W. What the heck is it doing? Keeping the fuser warm? After all, it still has to spend a little while warming up when I print something.


It is due to heating up the fuser when you print and it must keep the fuser as some slightly warned temperature so that when you print something, it does not take as long to heat up the fuser. The fuser must be at around 400 deg F in order to properly fuse the toner to the paper and it takes a lot of power to do that. It is like an electric stove...it takes a lot of power to get that stove to heat up to 400 deg.
Good riddance PCWorld.
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#3 User is offline   LiveBrianD 

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Posted 12 March 2012 - 05:18 PM

It still takes quite a while to warm up if it's been idle for a while though. I wonder why toner can't have a lower bonding temperature than that.
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#4 User is offline   smax013 

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Posted 12 March 2012 - 05:21 PM

View PostLiveBrianD, on 12 March 2012 - 05:18 PM, said:

It still takes quite a while to warm up if it's been idle for a while though. I wonder why toner can't have a lower bonding temperature than that.


Might as well wonder why water can't have a lower boiling temperature or why steel can't have a lower melting point. It is a function of physics & material properties of the toner.

This is the one downside of a laser printer...the power requirements. You likely still save money compared to what you would pay to print the same amount with an inkjet.
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#5 User is offline   LiveBrianD 

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Posted 12 March 2012 - 05:25 PM

But, what I mean is can the formula of the toner be changed slightly?
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#6 User is offline   smax013 

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Posted 13 March 2012 - 12:49 AM

View PostLiveBrianD, on 12 March 2012 - 05:25 PM, said:

But, what I mean is can the formula of the toner be changed slightly?


Considering that laser printers have been around for at least a couple decades, they likely have it as good as it is gonna get. While it is always possible that there could be some break through, the length of time that laser printers have been around tends to suggest that it is unlikely... presumably, someone would have thought about it by now.
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#7 User is offline   LincolnSpector 

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Posted 13 March 2012 - 07:01 AM

Now I feel like getting a meter and trying out my printers.

30w when idle is unacceptable IMHO. I'd rather it took a couple more minutes to print the first page than burn power 24/7.

It could also just be poor design.

Lincoln
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#8 User is offline   LiveBrianD 

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Posted 13 March 2012 - 04:10 PM

I think poor design may be part of it. I timed it once, and it took 2 minutes to warm up and then print one page. (Once it's actually printing, it gets a pretty good speed; rated at 20 or so ppm single-sided which seems about right; for duplex maybe half that) If it's been idle for a while, maybe a bit over 1 minute. If I just used it a minute ago, it still takes about 10 seconds before it starts feeding paper though, maybe 15 seconds until the page comes out. How is it that lots of other lasers I've seen don't take anywhere near that long to warm up?
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#9 User is offline   mjd420nova 

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Posted 13 March 2012 - 05:23 PM

LBD: Yes, laser printers are power hogs, the color units even more so. Whats a toaster, some I've seen up to 900 watts. Smaller toasters down to 350 watt. That fuzer takes the biggest it when printing, initialization and standby. The color source, whether toner attaction or burned from a substrate with a laser. Keeping the fuzer clean helps but high volume machines rely on the fresh sheets to carry most of the heat away. Teflon coated rollers have been know to get fried off, so cleanliness will save in the long run.
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#10 User is offline   LiveBrianD 

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Posted 13 March 2012 - 05:42 PM

Dang... mine's a color duplex unit!
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#11 User is offline   smax013 

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Posted 13 March 2012 - 06:14 PM

View PostLiveBrianD, on 13 March 2012 - 04:10 PM, said:

I think poor design may be part of it. I timed it once, and it took 2 minutes to warm up and then print one page. (Once it's actually printing, it gets a pretty good speed; rated at 20 or so ppm single-sided which seems about right; for duplex maybe half that) If it's been idle for a while, maybe a bit over 1 minute. If I just used it a minute ago, it still takes about 10 seconds before it starts feeding paper though, maybe 15 seconds until the page comes out. How is it that lots of other lasers I've seen don't take anywhere near that long to warm up?


Yes, designs will vary. Some will use more power than others.

For example, my LaseerJet 6MP supposedly using about 175 watts when in use and 8 watts when in standby (according to the HP Specs...I have not had a chance to test it myself yet...never really had any reason to test it to date, but I am curious now).
Good riddance PCWorld.
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#12 User is offline   LiveBrianD 

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Posted 13 March 2012 - 07:00 PM

How much time does that printer take to warm up though? Oddly, this printer is rated for 38W sleep, 100W ready, 515W copying. The sleep figure is a bit high, the ready one is about right, and the copying one.... more like an average.
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#13 User is offline   smax013 

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Posted 13 March 2012 - 08:05 PM

View PostLiveBrianD, on 13 March 2012 - 07:00 PM, said:

How much time does that printer take to warm up though? Oddly, this printer is rated for 38W sleep, 100W ready, 515W copying. The sleep figure is a bit high, the ready one is about right, and the copying one.... more like an average.


I did a quick test with one page. I connected the printer to one of the battery ports of my APC UPS that has a built-in "watt meter". Prior to the printer being plugged into that battery port, there was about 10 watts being used by the devices connected to the batter ports (my router, my cable modem, a desktop phone, and my Vonage device). After I plugged in the laser printer, about 17 to 18 watts was being consistently drawn, which is consistent with HP's 8 watt value for standby/idle. When I then printed one page, it took about 5 to 10 second before the printer starting the warm-up and print process (the processor in that printer is OLD and SLOW, so it can take a while for the process a file for printing) at which point the watt level jumped initially very briefly to about 500 watts, but very quickly leveled back off to about 250 to 300 watts (higher than the 175 watts that HP said). It took about 10 seconds for the whole warm-up, print, and wind-down process to complete at which point it went back to only 17 to 18 of watts being drawn (only about 7 or 8 of that the printer). So, all told, my printer was using about 250 to 300 watts for about 10 seconds (remember only one page) and then rest of the time was about 8 watts. FWIW, the laserjet 6MP is listed as "Energy Star complaint".

When I have time, I will do a test by printing several pages. Doing only one page definitely resulted in significant variation as there was the initial spike for the warm-up. It will interesting to see if the wattage stays more level for a longer printing job.

The end result is that my printer has a VERY short high wattage draw...only for the time to actually print...and it seems to warm up very quickly...it was about a second or two from the time that the processing by the printer completed and the warmup (and wattage spike occurred) and the page of paper started to be pulled from the tray to complete the print process. For an rather old printer, it seems to be rather energy efficient...but it is SLOW...only 8 ppm.

FWIW, here is the performance "specs" for the LaserJet 6MP:

http://h20000.www2.h...ID=bpl04055#A11

Note that for warm-up time it says "instant-on" fuser...which is consistant with my test.
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#14 User is offline   LiveBrianD 

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Posted 13 March 2012 - 08:25 PM

Man, yours is downright efficient (and for a single page, including warmup, fast) compared to mine. lol... and mine's only 2 years old and yours is what, a decade or more? Oddly enough, mine is energy star compliant (how'd it get that?). And how does yours have an instant-on fuser when those have to heat to hundreds of degrees? (On the other hand, my school has a bunch of hp printers and those don't seem to spend a while warming up, just a few seconds maybe.) Honestly, the ppm doesn't matter to me much, as I usually only print one or two pages anyway (though I always use duplex). The warmup time is what really bothers me.
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#15 User is offline   BIGFLY 

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Posted 21 March 2012 - 12:48 PM

I know that the HP 4200 series printers require absolutely no warmup time. When selecting a printer it is good to investigate this stuff and to find out how many pages per minute it prints, as most would prefer a little speed.
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#16 User is offline   WinfieldZenith 

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Posted 28 March 2012 - 10:34 PM

Power consumption is most important thing in these days. Laser printer is very helpful for saving the power. Thanks!
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