Fuser disabled

[SikaStag]

Hi Guys
Not sure if this has been asked here before, having trouble getting information on the net.
I would like to use a Laser-jet printer to put an image to be transferred to a metal plate using transparencies to put the toner on to.
My problem is, I do not want the toner to be heated to melting point and sticking to transparency. Is there any way possible of Modifying a printer to have the heat controlled by a rheostat that could be put in line, So it will leave the toner sitting on the transparency and when you swipe your finger over the toner it comes away easily on to your finger.

I would like to use this method to transfer images and lettering to be engraved in metal. The benefit of the transparencies is that you can take a mirror image of the intended transfer and when placing on the work piece you are able to see through the transparency and centre the transfer accordingly.

My other problem is that I need a printer that will be compatible with Mac OSX.

I have had a demonstration via cam online showing me an HP L6 printer that was modified to do this, it is the only way the engraver said he transfers images.

I have had a chance to buy a HP 4200N, Not sure if this would be able to be modified.

I am hoping that you guys can help me out here. I am at my wits end trying to find out how to do this.

The person that showed me the method, Is in Belgium and speaks very little English. I am in the Scottish Borders. I speak no Belgian.

Help Please
Ian

[Big Al]

I'm kind of outside my comfort and competency zone here. There are three thermostats in the fuser. One is the low temp and turns the heater on if it is too cool. Another turns the heater off when it gets too hot. The third one shuts the fuser down if the temp goes too high and might cause a fire. This is the old style fuser, not the newer ones with a ceramic heater or a flashlamp.

You should be able to put a variable transformer in series with the 110/220 volt supply to the fuser. You are probably using 220? These are the round transformers with a big knob on top.

You would need an older printer that you can feed straight through. You might have to remove the back cover and disable the interlock. Then you could rig up a tray to catch the plate/transparency when it comes out. Maybe an HP4, 4+ or 5N. They are quite inexpensive, parts are still available, free service manual on the Internet.

Any chance you could ask the guy in Belgium what temperature he uses or did he just use trial and error? Most folks in Belgium speak both German and French. Maybe you could find an interpreter?

You might also be able to do this with a heat lamp and an homemade enclosure, plus a thermometer to watch the temperature or a thermostat? Restaurant equipment like deep fryers use high temperature thermostats, some are adjustable. Maybe a tempered glass plate to keep even pressure on the transparency?

Let us know what you figure out!

Al

[SikaStag]

Hi Al
As far as I was aware there was no heat to the toner, it can be wiped cleanly away leaving nothing behind.

I honestly know nothing about printers, way over my head. This is the type of transferring that I would like to do, therefore I have to come up to speed fast on the subject.
I had seen a post on somewhere else on the net and basically what you have described is what was suggested. I have to firstly find a printer that this mod can be done to easily and it has to be compatible with a Mac computer.

I really appreciate your input, thank you.

Ian

[cs_steve]

One simple way to do this would be a "halfway test" :-)

http://www.printertechs.com/tech/print-defects/halfwaytest.php

You basically send the print job to the printer, and then as the transparency passes under the toner, you lift the lid to freeze the paper in its place, before it can reach the fuser and bond/melt :-)

With a little practice you can time the halfway test to stop in the correct position fairly accurately; but this won't work well if you are planning on your prints covering the entire transparency rather than just portions of the page...

[Big Al]

OK, I see a little better what you are up against now. You want to run the transparency through and just put the toner on it without fusing it. I guess it would be possible to rewire the fuser so the printer thinks it is up to temperature without running the heater. This is probably what the guy in Belgium did. If you disconnect the power cable going to the heater and jumper the thermostat that tells the printer the fuser is up to temp then that might do it. You might even be able to rewire it so the fuser is not even in the printer. You are going to need the schematics for the printer and maybe an electronics technician to make this happen.

Al

[Big Al]

Working on repairing a fuser today, for an HP 2200. The Thermister controls the heater strip. It read .360 Meg Ohms at room temperature. I heated it with my heat gun and as the temperature went up the resistance went down. At some lower resistance level the control circuitry will turn the heater off. You could try disconnecting the wires going to the thermister and substitute a variable resistor in its place. Crank down the resistance slowly until the fuser stops heating? I heated the thermister for several seconds and it only dropped a few ohms. The wires going to the thermister are very small so a light duty, maybe 1/4 watt, variable resistor should work fine.

Al