7425 style - Drum Cartridge Rebuilding Instructions

Xerox^® 7425 style Drum Cartridges Reconditioning Information… for Xerox WorkCentre^® 7425, 7428, 7435 (013R00647), WC-7525, 7530, 7535, 7545, 7556 (013R00662),  Phaser^® 7500 (108R00861),

& Phaser^® 7800 (106R01582)

            Let’s have a crack at one and see how they come apart for servicing.

            This cartridge appears four times in each machine… the same cartridge will serve in any of the 4 color stations.  The WC-7425, 7428, & 7435 use 013R00647 in all market regions.  The cartridge is extremely similar to the Phaser 7500 (108R00861), WC7525 (13R662), & Phaser 7800 (106R01582) drum cartridges, although they are not interchangeable because of differences in the chip onboard each cartridge and also a few subtle physical differences on the front end cover.  If you learn one, you know how to tackle any of them… but try not to mix up which cartridge you have in hand so you don’t run into problems.  They come with a rectangular Installation Sleeve as shown in Photo #1.

            The 7425 style Drum Cartridges use a Drum Reset CRUM (Customer Replaceable Unit Monitor) to keep track of how many copies a cartridge has run (see Photo #2).  This chip limits the cartridge’s running life and will “time out” once the machine hits a limit of copies.  The yield varies depending on how much volume the machine is running.  A machine which runs an average of 6 pages per copy job or print job will yield approximately 60K before it calls for a new cartridge.  If the customer runs shorter jobs (under 6 pages per run on average), the yield will be reduced down as low as 32K.  If a machine runs longer runs, its yield will increase to yields as high as 80K impressions.  I know… it’s kind of confusing.  The important thing about this is that a machine in a low volume office will call for new drum cartridges long before the drums are actually worn out.  When a replacement CRUM becomes available, replacing the CRUM will allow the cartridge to run a lot longer without much else being necessary.  Drums, Blades, & Charge Rolls are now available.

            If previous, similar types of drum cartridges are any indication, the Charge Rollers will also be an important consumable in these cartridges.  Usually impacted toner on the Charge Rollers will affect copy quality long before the drums themselves get worn out.  Washing the Charge Roll gently in soap and water to remove any impacted toner material will extend the roller’s life considerably assuming it is not actually damaged or worn out.   Make sure not to get fingerprints on the Charge Roller.  Replacing the Charge Roll will certainly be a good option too once aftermarket rollers become available (not yet).

            Now to it… Lets see how one of these things comes apart.   

Reconditioning  Procedure:

• Remove the Front End Cover which houses the Drum Reset CRUM chip (2 screws from the front… #1 phillips, machine thread). See Photo #2 for a picture of what the original CRUM looks like).  To remove the CRUM from the Front end Cover, you can slide a tiny flat-head screwdriver under one side of the CRUM and very gently pry upward to release the little clips in the two holes on top of the CRUM and then slide the CRUM out (see Photo #4).
       
  
       
• Next Remove the Charge Roller Assembly. Refer to Photo #3.  It is held on by two screws (#1 phillips).  The two screws are labeled on the photo in white numerals: 1 & 2.  Note that there is grease on the ends of the Charge Roll to lubricate the roller’s bearings.  Take care not to get any grease or fingerprints on the Charge Roller’s surface. 
       
  
       
• Clean the Charge Roller. It is mounted in a pair of white plastic line-bearings with a soft white foam cleaning roll beneath it.  If you find impacted toner on the surface of this roller, we’ve been finding this type of roller responds well to gentle cleaning with a soft cloth, soap, and luke-warm water.  Make sure to rinse it off thoroughly, avoid leaving any fingerprints, and allow it to dry completely before you reinstall it.  Use a tab of conductive grease when you reassemble it.  The conductivity of the grease is important at the rear end where the Charge Roller’s bias clip makes contact with the exposed metal at the end of the roller. 
       
  
       
• Release the Rear Drum Bearing’s cradle clip. Here’s how to get that off:  Place the cartridge so that the Waste Auger Tube is underneath the unit (See Photo#’s 6 & 7).  Press gently with the tip of a tiny flat-head screwdriver into the recessed clip-release as shown in the photo.  Prying in other places on the clip is likely to end up damaging it.  Once you release it, you can pivot it up and off. 
      
  
       
• Remove the Rear End Cover / Collar (1 screw, #1 phillips) (see Photo #8)
  
  
• Then go to the Front End and remove the Front Metal Plate (2 screws, #1 phillips). Refer to Photo #9. The metal plate has the Drum’s front end shaft attached to it.  The plate also has two little holes which hold a pair of plastic nubs on the curved part of the Toner Waste Auger Tube steady…. So be careful, because once the plate is off, the auger tube will be able to move around a lot.  It looks fragile and the waste toner may start spilling out… things can get rather messy.
      
  
       
• Lift the Drum and its Bearings out of its cradles and shift it forward to remove it from the unit. This type of drum has a spiny-looking drive coupling (4 dogs) at the rear end.  It rides on ball bearings.  The Drum ground is a clip inside the rear end of the drum which touches the drive shaft / coupling in the machine when the drum is installed. 
      
  
        
• Remove the Drum Cleaning Blade (2 screws, #1 phillips). Below the blade, adhered to the metal of the blade, is a mylar sheet with a row of finger-like protrusions which help to keep the waste auger from clogging up. 
  
  
• Clean out the waste toner using a shop-vac with a toner-rated filter. Be very careful around the mylar recovery blade which is adhered to the Waste Auger Tube opposite of where the Drum Cleaning Blade mounts. 
  
  
• Replace the Drum Reset CRUM chip in the Front End Cover to reset the drum count for the machine. (Refer back to Photo #4)
  
  
• Reassemble everything. Pay attention to the rear auger drive coupling’s plastic bearing as it is keyed to fit a slot in the rear frame of the cartridge (see Photo #10). 

That’s it !

            Hopefully the instructions will help the cartridge feel familiar from the start. 

Author: Britt Horvat, with special thanks to Kurt for his expertise and thanks also for support from whole Partsdrop gang. Originally published as an Article in the marvelous ENX Magazine - www.enxmag.com :)

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