The Xerox WorkCentre 7425, 7428, and 7435 are a very popular family of full color multi-function copiers. These machines have filled in where the WC-7328 family left off. The fusers on these machines are worthy of a good technician’s attention. A bit of a head start on the rebuild procedure on these fusers will probably be welcome since you have to dig pretty deep to get the heat roller out.
These fusers are wonder of mechanical ingenuity. That’s a compliment to the engineers but also a precaution to those who want to rebuild them… this type of fuser is not for the faint of heart. For one thing, you’ll likely find yourself wishing you had a Torx T-10 driver-bit.
Photo #1: Fuser Orientation
On a side-note, the newest models in this “style” (WC-7525 through 7556) are even more complex. Those have some seriously deviant technologies going on—toner that melts at unusually low temperatures, and instant-on inversion heating. They don’t have a heat lamp or element inside the heater roll; actually they don’t even use a traditional heat roll but instead use a sleeve. On those the thermistors are inside that sleeve. Pretty unusual stuff.
Luckily the 7425/7428/7435 models do have a regular Fuser Heat Roll that is just starting to show up in a good generic form. The Pressure sleeve is also out there.
Photo #2: Outer Face (remove 2 screw marked “1” and “2” on the photo)
The Phaser 7500 is a printer that has a fuser that is similar to the 7425 fuser. Although the two are not interchangeable, they do share the same heat roller and pressure sleeve. The procedure that follows will apply to the Phaser 7500 and WC-7425 fusers equally.
The fuser module for the 7425 is sold under the part number 8R13062. It has a stated yield of about 196,800 pages. At that point usually the Fuser Heat Roll is needed. The complete fuser retails for around $600, so they are worth rebuilding if you can handle them.
Let’s get oriented (see Photo #1) and then jump right into the disassembly procedure. We’ll call the end with the drive gear and the fuser connector the Rear End. The Outer Face (outer cover) is the side that faces you if you go to a machine to remove the fuser. It has a label with removal instructions on it. The Inner Cover is on the opposite face. Finally, the yellow exit guide is on the Top.
DISASSEMBLY PROCEDURE:
1. Remove the two Outer Covers: Remove 2 screws from the Outer Face, one at each end (see Photo #2). Then pull off the Small Outer Cover from near the rear end by pivoting it out of place (see Photo #3). Next unplug the connector from the Fuser Exit Sensor (see Photo #4) and remove another screw which retains the Long Outer Cover; that screw was hiding under the small Rear End Cover (see Photo #4). Now remove the Long Outer Cover by raising the yellow Exit guide and then lifting the Long Outer Cover’s front end up.
3. Free up the Fuser Heat Lamp at the front end: Unroute from its channels the two white wires from the front end of the Heat Lamp and the single black wire which the two white wires are crimped to. Remove 2 screws from the front Thermostat to free it up and then disconnect the spade lug where the Heat Lamp wire plugs into the front Thermostat (see Photos #7 & 8).
4. Finally, remove the Pressure Sleeve Assembly: First take notes and either measure or mark on the threads how far down the Pressure Tower Screws protrude below the metal frame (see Photo #9). Then you can back out the two Pressure Tower Screws. Take care not to lose the springs or the washers, which are up on top of the springs close to the screw heads. Next pivot the Pressure Sleeve Assembly up until it unhinges so it can be removed (see Photo #10).
Photo #3: Small Rear Outer Cover Removal
Photo #4: Long Outer Cover Removal
Photo #5: Preparing the Inner Cover for removal.
OK, we are out of space for this month’s article. I leave you till next month’s ENX article with this image of the fuser partially disassembled:
Photo #11: the Fuser with the Pressure Sleeve Assembly removed… half way there
For those of you who are adventurous and impatient, and want to tackle one of these fusers before the 2nd half of the article is released, the basics of it will be: removing the Fuser Exit Idler Gear Bracket, loosening up a bunch of stuff on the rear end to make enough room to sneak the front Heat Lamp wires out of the metal frame, releasing the Thermistor / Thermostat assembly, lifting the front end of the Heat Roll up so you can slide it out over the Heat Lamp, and of course reassembling everything! We’ll also take a closer look at the CRUM board with its picofuse for resetting the fuser counter. Have a great month everyone!
