Re: Turn off laser printer with power strip?

Thanks Tony,

It was a typo, and yes, it was supposed to read EEPROM.

Art

Tony wrote:

Many (most, in my experience) laser printers are isolated completely by the power switch, but some are not. If they are not then it is for a reason. I have no doubt at all that it is to dissipate heat from within the cabinet. The fuser may well be at 200 degrees Celsius and that heat has to go somewhere, I am sure that the the fans keep running to ensure that some of that heat is not applied to components that are not designed to withstand those temperatures without cooling.
There is no way that a fuser will cool down so it is safe to touch in only a minute or two, most manufacturers recommend that a cool down period of at least 20 minutes be applied before fuser removal; fusers have a high degree of thermal retention, they are designed that way. I do not believe that the short period of fan operation after power down is to make the printer safe for people to open since they can open it with power on in nearly all cases, and with many printers can get a slight burn (however there is always a degree of physical protection designed into the printer).
I am sure that Arthur meant to type EEPROM (similar to NVRAM), we all make typos don't we?
Tony

"w_tom" <w_tom1@xxxxxxx> wrote:

Ink jet printer manual warns a user to not switch off power.
Projector manufacturers with bulbs that require power down cooling also
provide the appropriate warning. No such warning is found with laser
printers.

Why would that extra seconds of cooling be installed in a laser
printer? So that bulb does not remain excessively hot when human hands
enter the machine.

However Arthur Entlich provides a first good reason for leaving a
printer powered until fan turns off. He notes damage that he
attributes to heat damage. A good reason for letting the cooling fan
first turn off before removing power. Once that fan turns off, then
still, laser printer can then be powered down by a switch.

EPROMs are not ever reset. EPROMs are read only devices - nothing to
reset. Furthermore, if a printer does not automatically reset itself
on power up, then we all want to know what printer to avoid as
defective by design.

Arthur Entlich wrote:

I am not speculating. I have repaired laser printers, and indeed, even
with "designed" heat removal via fans and heatsinks, parts do overheat
and permanently warp. There was one HP early color printer that had a
continual problem with this, causing parts of the case to warp and
eventually leading to an open door error developing because the case
form changed. Several other brands have had similar problems. I do not
know of any laser printer manufacturer that suggests regularly turning
off the printer after an activity before the unit's cooling fans go off.
Power bar switches are 3rd party products and switching a peripheral
off in that manner is equivalent to yanking the plug on it,

I have a better question... why do the engineers design there to be
cooling fans running on these devices if they want you to turn them off
at will?

Inkjet printer companies don't warn you that the printer may suddenly
stop working right in the middle of a project and have to be brought in
for a EPROM reset and change of the waste ink pads either, you just find
out when it happens. Nor do they warn that a clogged head on an inkjet
printer that uses a microchipped cartridge may falsely lower the ink
level it monitors even though the ink may not be leaving the cartridge
at all.

There are millions of things which appliance companies do not "warn" the
end user about, because they either don't wish them to know, or they
consider the action obtuse or not logical to engage in. Many designs
today especially use materials and systems that are designed just within
the known tolerances they can work at, and repeatedly pushing beyond
that will shorten their lives


.

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