Thermostat for laser printer fuser temp?

It should be okay to snip off the mounting tabs with tinsnips or whatever.

That's correct, the original part is rated at 150c.

You mean 315F/157c. ;)

No, that should be correct. The thermoswitch is intended to trip if the temperature exceeds the working temperature. The original part specifies the working temperature, but the Stancor part specifies the trip temperature.

That's exactly what they do.

It depends very much on the engine model. Look for a green plastic dial somewhere in the guts (EHT controller assembly, specifically) of the printer. It should be visible with the lid open, but without needing to remove any screws. If your printer has an LCD on the control panel, there should also be a density setting somewhere in the configuration menu. OTOH, see below:

Is the grey on the blank areas consistant in density, or does it contain very faint ghost images of the previous page? If the latter, you have a problem with the drum-cleaning system, which is often due to a bad cartridge. If you're getting streaks down the page, you likely have dirty corona (high voltage) wires, that're preventing the drum from getting an even charge across its full width. Another possibity is dirt/dust bunnies in the window between the laser-scanning unit & the slot on the top of the toner cartridge. It's safe to dust out the window & mirror with a clean, dry paintbrush.

That's not the part you need to be looking at anyway. (And on the bigger laser engines, you access the controller boards from underneath the printer, not from the top.)

Leftist weenies are alive only because it is illegal to kill them ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

It's not only true, they also have a separate "drum cartridge" (rather than the old system of toner and drum as one). This would be fine, except that the pricing there is literally insane: I recently purchased two complete printers, because the price of the complete printer with drum cartridge and half-full toner cartridge was _less_ than the drum cartridge alone. I have two complete chassis for spare parts and/or the junkyard...I'd offer to send the OP a thermostat, but it's clearly a different printer (this one reads the hot roller) and there are no visible markings on it at all (I have not fully disassembled the fuser assembly to see if there are any on the backside of it, but the visible parts have no markings).

Brother, at least, has also been working to reduce the capacity of their toners and drums - the 51XX series costs significantly less per page than the newer 20XX series. Both have the nasty and undesirable behavior of simply stopping printing when THEY think the toner is low, or the drum is shot (as does the newer HP we have) rather than advising you that the toner is low and continuing to print until you don't like the prints (more evidence that it's all a scam to sell more toner).

It gets worse with color laser printers. Saw one on sale recently for $300, priced a set of toner, $600, drum was another $200-300...and the "starter toner", upon investigation, was not even half-full - more like

Mate, if it were legal to kill right-wing weinies, I'd have a /lot/ of notches on my weapon-of-choice. ;)

It seems that the thermo shut-off is positioned in close proximity to -- but not touching -- the heated roller. It's designed to open when the temperature (within about 1/8 inch of the roller) reaches 150c.

Yeah, that's how it is in this one.

Thanks.

Close, but not quite correct. It's designed for a hot roller operating temperature of 150c, & opens if it goes significantly higher than that. ;)

Good. That version of the design is easier to fix than the version where the thermal cutout touches the roller, which used a special cutout that had an indentation in it that matched the shape of the roller. (We fixed the older version by bending the tabs on a standard cutout so that they match the roller distance of the newer type.)

My pleasure. It's nice to know that my hard-earned experience with laser engines isn't just wasting space in my brain. ;^)

Mouser gives the ratings in both F and C. If he needs 150 C then the part I posted is wrong. The closest part # would be

Ed

Yep, that's the one I suggested after reading your post. ;)

Not wasted - it is very interesting! I take it that most of the time this type of failure is caused by the build up of crud in there? Is it a fool's errand to try to do preventive maintenance - maybe just as likely to cause a problem as to prevent it? Also, when these printers start "smudging" the non-printed area, is that a sign of impending toner replacement? The prior printer did that for a long while before the printing became light & toner needed replacement. I tried to clean it on a number of occasions, but was not successful in clearing the problem. So either I wasn't cleaning the right things, or it wasn't an issue of cleaning.

Ed

Thanks! Glad you picked up on the error. It would be a bummer if he put in the wrong part, to say the least. And I've enjoyed reading & learning from your posts on this. :-)

Ed

Thanks. :)

Not if you know what you're doing, but it's enough of a pain to get at the relevant part of the fuser that I've never bothered doing it unless I run into symptoms like the OP's, or am opening up the printer for some other reason, in which case I'll give it a clean up while I'm in there. BTW, a tiny squirt of silicon spray on the woolly, removable wiper on top of the hot roller for every ream of paper you put through the printer will greatly extend the life of the teflon coating on the hot roller, which is hard to obtain, & a pain to replace. It's also good to clean the accumulated gunk of the separation claws (that 'scrape' the paper off the hot roller in its way out), because they're prone to causing paper jams on exit, & can scratch gouges in the teflon hot-roller coating.

It totally depends on the cause, of which there several for that particular symptom. (And there are unrelated problems that cause symptoms that look very similar to the inexperienced.) But yes, the most common cause of dirty backgrounds is a cartridge on its last legs. At a site where they have more than one printer of the same type, the easiest, quickest way to detect a bad cartridge is to swap cartridges with another unit, then do a test print from both.

Most likely the latter. If it came good when you put in the new cartridge, you've got the answer to your question. ;)

Thanks again. It's always nice when one's advice is appreciated. ;)

I was mistaken -- the thermal cut-out safety switch in the Samsung 4100 I'm trying to fix does monitor thet hot roller (I always though the red-coated one was the hot one... apparently not).

Well if it looks like this:

(the black end of it with the two mounting/electrical tabs is visible from the exterior of the fuser) please consider it.

Thanks, Sparky

Lionel,

Thanks. Good info, as usual!

Ed

just gotta love the tricks these marketing moguls use to extract our money from our wallets.

they are not concerened with conservation, re-use or longevity. they only seek to enrich themselves by selling us time limited and sales strategic devices that require extreme cost to service or replenish. the initial purchase is a come-on

the HP deskjet cartridge, (yes that tiny little ink thing) has probably generated more profit for HP than most all its gear combined.

no one in business for profit ever cares about resource depletion until their own kids die from it.. & even then, they figure they will leave THAT problem for their kids to solve. "if it aint broke,doan figz it"

direct

separate

temp

roller

wrote in news:8NpLh.1277$ snipped-for-privacy@newssvr23.news.prodigy.net:

Don't kid yourself. They don't think of it AT ALL. Period. There are two ways to think things like this, unless you're no longer sane, in which case all bets are off:

1. You assume it IS relevent to you, and all that you care about, in which case it nags at you till you eventually do something, ANYTHING, to appease the nagging sense of doubt, in order to make yourself feel more secure. OR
2. You assume your security is ALREADY assured, thus you don't think of doing anything to change what others appear to be whinging about as a perceived threat.

Given that the firms doing this ARE amongst the most secure, financially, politically, and socially, their arrogance is the cause. This is not mere ignorance, it is WILLFUL ignorance, the worst and most dangerous kind. It also the kind that is hardest to forgive, and if resources become low enough to make a majority of people start to begrudge this and DO something about the way they choose to spend their money, it will carry on. There are firms that will sell cheap refills, but these aren't the cure, they DEPEND on the problem to exist.

Now, as I'm saying my small rant in the presence of electronics engineers, some of which are considering their own business management as well as electronics details, I won't try to tell them solutions they probably know more about themselves, it's enough to point out tht there will be a market for products that don't fleece the buying public at unacceptable expense.

I do have one small suggestion, I guess. Innovation is the ONLY way a small firm can get ahead. After all, it;s buying up innovators that makes the big firms get ahead, right? So, if small firms patent their stuff precisely instead of in the aggressive way large firms do to try to stop others, instead of just protecting themselves, this can help, it can prevent a large firm from muying and burying innovation that threatens their own wasteful empires, and it can also prevent them from revising history to try to force their exploitation of your ideas. Patent it under your own name if you invent it. A firm can't claim your idea even if you thought it up on their time! Do they OWN your mind? I think not. At least copyright it by sending yourself signed sealed copies. Do this before it becomes valuable to someone else.

There may be all kinds of better ideas to erode the tech society that wastes so heavily, but I'm not inside it enough to think of much more than I have said here.

Lostgallifreyan wrote in news:Xns98F84BEDD36A4zoodlewurdle@140.99.99.130:

Correction, "...it will stop."