Strange Fuser Question

[Mired]

I have a strange request. One way to put images on ceramic pottery is to print something using an older laserjet printer. To make sure the image transfers well, the fuser needs to be disabled so the image is not bonded to the paper and will transfer to the wet clay.

I have an old HP 1200 (still working) that I want to use for this. I need to disable the fuser without allowing the printer to know so it doesn't disable the print function. I can unplug the fuser power connector and the printer will print a couple of pages before the printer stops functioning. (In a less than ideal situation, that could work since it isn't likely that many copies will be made at any one time.)

I would like to get a copy of the schematic for the fuser circuitry so I can figure out how to make the printer think the fuser is up to temperature when it is in fact disabled. ....Or if anyone already know how to do that please let me know.

Thanks.

[Big Al]

Most newer fusers have a single varistor that tells the electronics when the fuser heater is too hot
or too cold. This resistor is under the fixing sleeve. You would need to experiment with a variable
resistor in series or in parallel with the varistor to fool the printer. In the older printers, like the
HP4, 4+ and 5n they used three thermostats. Shorting the high temperature might keep the
fuser from warming up. Not likely you will get hold of a schematic, that is proprietary and not available
to us do it your selfers. I do not think the 1200 is a good candidate for this. The printers with easily
removable fusers would be better. I have seen 4's and 5's go for a few dollars at yard sales and
second hand stores. If you could take the pressure off the rollers by removing the springs or
shimming them apart you might be able to get what you need that way.

Al

[Mired]

Good thought about the fuser spacing. I will look into that.