Aficio 2075 Fusing Problems

[Zia Graphy]

Hi everyone.

I'm working on a Ricoh Aficio 2075 with some fusing problems. The SC History shows recent SC545 (Overheating code, possible thermistor) and SC555 codes (Fusing lamp error or thermistor). When inspecting the machine I found that one of the 192C thermostats was blown. Thankfully I had a replacement thermostat. Upon running test copies I found that after about 7 copies the toner would no longer fuse to the paper and a jam would occur due to the build up of loose toner on the hot and pressure rollers. The jam occurs before the fuser throws a fuser code, so I haven't been able to reproduce the SC545 and 555. Checking the fusing temperature display during test copies reveals that the temperature drops from ~195C down to ~144C during a run of 10+ copies before the machine jams.

The thermistors are clean, and the hot roller and pressure roller are in good shape. The lamps show continuity and light up appropriately during test copies. I don't know how long it's been since any of the fuser parts have been replaced. I suspect that the thermistors might be the problem so I've ordered replacements. However during test copies I also got an SC569, which is a pressure roller release motor error. This threw me for a loop.

I inspected the pressure roller release mechanism and position of the pressure roller and everything appeared to be normal - none of the gears transmitting drive from the release motor have any damage or wear and the cam rotates normally and the home position sensor is clean and correctly identifies the home position. The code has not returned. I only mention this because the SC569 seemed totally unrelated to the other codes which will hopefully be fixed by replacing the thermistors.

Has anyone run into multiple fusing codes like this or have any idea if the problem could be deeper than a couple of thermistors - like a controller board or something? Is there anything else I should think about replacing while I'm at it? Thanks for your consideration.

[allan]

Check to see if there is proper pressure between the rollers.

[rthonpm]

Check and see if the machine has the updated thermistor brackets from a few years back. They bring the thermistors into closer contact with the heat tube.

[slimslob]

Check that you have the proper lamps. If the 550W lamp, applies heat to the ends of the hot roller, is a 220 volt lamp temperature of the ends will drop during copying. This will also happen if the connections of the 550W lamp and the 280W lamp are reversed.

[Codex]

I had some issue with the Fusing Unit conector, (Piece of paper inside)

[Zia Graphy]

Thanks for the ideas everyone. Pressure between the rollers looked good when I was out there. Not sure if the new style thermistor brackets are on the machine, but I'll check that and double check the lamps to see if they are the correct wattage and that they are plugged in correctly.

I'll let you guys know what I find when it is fixed!

[Zia Graphy]

Check and see if the machine has the updated thermistor brackets from a few years back. They bring the thermistors into closer contact with the heat tube.

My parts catalog shows 2 different thermistor brackets for that model B140 4196 Inner Back Thermistor Bracket and B140 4197 Middle Thermistor Bracket.
Are those the up to date version?

Replaced the thermistors and hot roller today with no change. Checked the fusing lamps as slimslob suggested, and they are the correct lamps - there's a 650W, 550W and a 280W. The green connects to green, blue to blue, and white to white. Out of curiousity I checked the fusing temperature on a known working machine and saw that the temp does drop down to ~145C - 150C during the course of copying - so it looks like those temps are normal. I also checked the power outlet the machine is plugged into and everything checks out normal there, even in the middle of copying.

Now I'm actually at a bit of a loss. It doesn't seem like the temperature is a problem since the thermistors, hot roller, thermostats, and lamps are good - yet the toner is not fusing to the page as if the temperature is dropping during a run of copies. I double checked and confirmed that the pressure roller is being engaged by the pressure roller cam. The cam turns and the little flag stops when it reaches the home position sensor. Scratching my head now. Any thoughts? Oh, and the machine is running OEM toner, it's at about 1.6 million copies. And the stuff that's rubbing off of the page definitely feels like toner, not developer.

Thanks for all the help thus far! You guys are great

[Tonerbomb]

Sc 555 is a huge nuisance code, the 569 code usually comes from a broken sensor or connector that wasn't unplugged before removing the fuser. Also if the lamps are not in the correct positions in the lamp holders you can have codes or bad fusing. Also clean the pins and springs on the machine side of the fuser connector in the rear of the machine. again power,power,power............

[mikadonovan]

You ought to go ahead and rebuild the fuser to start.That way you know for sure that the hot and pressure rollers are in good shape, instead of chasing your tail assuming they are ok. The only poor-fusing issue I have had on this model was because of non-OEM toner, which you said was not the case. The toner I refer to worked fine in the 2051, but the 75 cpm speed of the 2075 wouldn't fuse the aftermarket toner properly.

[Oze]

Check those lamps right where the glass meets the white plastic.
This isn't exactly a modern box and those lamp ends can get brittle and crack or break and cause intermittent issues...especially when you're trying to wrestle them back into the brackets at either end.