Thermostat for laser printer fuser temp?

Are U sure? You could only indirectly control the fuser temp. if there was a continuous, unvarying , throughput of paper, no stopping and starting. Is it not just a general output , via air environment, over-temperature cut out ?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Make and model of hte printer, please.

Samsung SCX-4100

Thanks.

You're probably right. Now that I look at the fuser in the daylight (not in early hours of the morning) I see that there is what must be a small thermistor resting on the heated roller. *This* is most likely the feedback for the heater circuit.

The bimetallic switch must be a over-temp circuit breaker, as you say.

And I now see that they both come in contact with the heated roller, not the pinch roller (I thought the red roller was high-temp stuff...)

But as for replacement, it's all moot, yes? Or do you have a suggestion re. a work-around?

Thanks.

That looks like a very standard device. Just be sure to get the right temperature.

I am *guessing* that the E150 indicates the temperature. Take a look at Mouser part # 802-STO-160 to see if it will work for you. It is normally closed, and opens when the emperature rises above 155 to 165 F

Ed

ehsjr sez:

Thanks for your comments, Ed. I saw that one but would like to find a direct replacement without having to hack off tabs, etc (original has no separate mounting tabs; the connection tabs are use for screw mounting also).

Also, fuser assembly gets up to high 300f+ so I, too, am guessing at the temp rating. 150f seems a bit low for being in such proximity to the headed roller (few tenths of an inch). Maybe it's 150c (302f)? It *is* a Japanese printer...

The nearest Stancor product is 157f (315c)... too high?

Er... 157c (315f).

I dunno - but I can commiserate with your situation. When my toner ran low, I went to Staples to buy a replacement. 70 dollars! But, serendipity - they had an entire printer (Brother HL-2040) on sale for $110, and it's faster and better than the old one. (The price has dropped on them since I bought, so they are now $120 not on sale.) Anyway, it worked out well for me, but $70 for the toner still rankles! Interesting psychology - I didn't spend $70 and if I had I'd still be unhappy about it. I spent $110 - $40 more, and I'm pleased as punch. And it's actually more than $40 extra when you add in the tax.

Maybe the people who set the prices have an ulterior motive? (How do you make a "frowny face" icon with smoke coming out of its ears?)

Ed

Yeah, just now I looked on Office Depot for toner and it's $85!! And it's a

*tiny* cartridge. Will see what's on sale when this toner runs out (c:

But what kind of world are we making where the economy pushes us to fill landfills with this stuff? Maybe total recycle (what with RoHS regulation) every time toner runs out? Hmm... Are disposable computers (with removable data cartridge) next? Cars?

I use

to get toner for about $32 instead of staples $80 or so, and it works good. I won't buy a laser printer without checking to make sure I can get the toner cheap online somewhere :-)

If you are in the US or Canada call Premier Parts - Phone: 800-668-8778 or Fax: 800-668-8037

They are the Samsung dealer. The rating for the thermo-fuse is rated in Celius so it is 150C. I've got quite a few Samsung printers I use for parts so I'll look and see if I have a fuser or the thermister/thermo-fuse.

SparkyGuy wrote:

Usually these discount printers come with a toner cartridge that is about half full so you will be buying toner pretty soon anyway. Sometimes I believe they sell printers below cost just to create a market for toner. I am sure that is true for ink jets

150c thermal safety fuse. They're usually a single-shot unit, like a normal fuse, & must be replaced if they fail. If it fails, you need to find out why the fusing assembly is overheating in the first place. The most common cause is gunk building up on the thermistor used to sense the temperature on the hot roller. Look for a thin cable running to a small module pressed against the hot roller, situated under a cover. The module will have a heat-proof, non-stick film over it that is probably covered in cooked toner/dust. The film is quite easy to tear/cut, so scrape off the gunk with omething wooden or plastic. Before reassembling, make sure that the module is pressing firmly against the hot roller. It's also a good idea to check that the thermister is working correctly: connect an ohmmeter across the connector & verify that the resistance changes when you heat the module with hair-dryer. Alternatively, press the sensor against a cup of boiling water. Do not try to test the thermistor with a flame or soldering iron, or you will likely damage the internal connections.

Lionel sez:

I found most of what you say to be so.

I disassembled the "fuse" and it turns out to be a single pair of contacts with a bi-metallic dome (think kid's "cricket" sound toy that you pressed with your thumb) that opens the contacts. When it cools, the contacts are supposed to close again. Mine didn't seem to do that.

You're right: there was a buildup of gunk (toner) under the thin teflon (or whatever) strip that separated the thermistor from the roller. Cleaned that up with a blast of canned air. Luckily it wasn't sticky at all.

I put the thermal switch back together and installed it All seems to work OK but I won't put the printer into service until I replace the switch.

Where would you look for one?

Thanks.

Anybody know how do dial down the toner use on this printer? The white space on the pages seems to be a bit gray, and the build-up of toner under the thermistor also suggests a slightly "rich mixture".

If it was easy to remove the controller board (or just have access to it) I'd probably do a little exploring. But the pan that holds the controller PCB is basically the frame for all the plastic bits to bolt to. It's akin to the heater core in a car. It is suspected that the heater core is the first part placed on the assembly line, and the rest of the car is built around it.

Thanks.

In message , snipped-for-privacy@aol.com writes

ISTR reading somewhere that Xerox's business plan is to sell consumables and the hardware is only sold to create the market. Xerox used to give free printers to companies if they signed up to a contract for consumables. If toner and ink wasn't so profitable why would manufacturers go to lengths to prevent people cloning or refilling cartridges.

Kodak marketing: give away the camera and sell the film...

Worked well until there was no film!