HP Laserjet "Powersave" mode.

[b33k34]

I stuck a power meter on my Laserjet 4000 yesterday. The HP specs are
accurate and sure enough it sits at about 30watts when idle and up to
about 600 when printing.

What surprised me, however, was that there was seemingly no difference
at all when the printer went into what the display calls "powersave".
This turns off the backlight on the display but the power drawn by the
printer remains at 30 watts.

Is this a fault or is HP's Powersave a load of greenwash?

 

[Warren Block]

I stuck a power meter on my Laserjet 4000 yesterday. The HP specs are
accurate and sure enough it sits at about 30watts when idle and up to
about 600 when printing.

What surprised me, however, was that there was seemingly no difference
at all when the printer went into what the display calls "powersave".
This turns off the backlight on the display but the power drawn by the
printer remains at 30 watts.

Is this a fault or is HP's Powersave a load of greenwash?

It's probably not a fault, just that the backlight doesn't draw enough
current to show on your meter.

Like much power "saving" circuitry, it still uses more than simply
turning the device off.

 

[Silicon Sam]

I stuck a power meter on my Laserjet 4000 yesterday. The HP specs are
accurate and sure enough it sits at about 30watts when idle and up to
about 600 when printing.

What surprised me, however, was that there was seemingly no difference
at all when the printer went into what the display calls "powersave".
This turns off the backlight on the display but the power drawn by the
printer remains at 30 watts.

Is this a fault or is HP's Powersave a load of greenwash?

On my LJ5000, I think I read where it was 360W while printing, 30W
while standing by, and 24W while in Powersave mode, so yeah, not a lot
of difference.

Sure beats the old LaserJet's where the fuser stayed hot the entire
time the printer is on....

Raymond

 

[Splork]

It's probably not a fault, just that the backlight doesn't draw enough
current to show on your meter.

Like much power "saving" circuitry, it still uses more than simply
turning the device off.

I thought it was only to save the backlight, not power (4050).

 

[Mushroom]

I thought it was only to save the backlight, not power (4050).

The LJ4000 was the very first device to have an instant-on fuser.
Instead of using a halogen bulb inside a teflon-coated aluminium shell,
it uses a rotating plastic sleeve and a ceramic-encased resistor. The
advantage is that you don't have to wait two minutes from cold for a
first page out and then don't have to keep the bulb on in case you print
another page soon after. The instant-on fuser is either on or off and
saves you significant amounts of power and time. The backlight draws
virtually nothing and therefore won't register.

 

[b33k34]

On 5 Dec 2006, 15:43, "Silicon Sam" <
On my LJ5000, I think I read where it was 360W while printing, 30W

while standing by, and 24W while in Powersave mode, so yeah, not a lot
of difference.

Most disappointing is that the printer consumes 4watts when switched
OFF at the power switch but still plugged in. That's shocking!

 

[Silicon Sam]

The LJ4000 was the very first device to have an instant-on fuser.
Instead of using a halogen bulb inside a teflon-coated aluminium shell,
it uses a rotating plastic sleeve and a ceramic-encased resistor. The
advantage is that you don't have to wait two minutes from cold for a
first page out and then don't have to keep the bulb on in case you print
another page soon after. The instant-on fuser is either on or off and
saves you significant amounts of power and time. The backlight draws
virtually nothing and therefore won't register.

The 4000 (November 1997) may have been the first "real" HP Laser
with instant-on, but the HP LaserJet 5L beat it by 2 years (Late
1995). I am pretty sure the 5L was the first HP laser with a fuser
sleeve.

Raymond