Xerox Color 550 & DCP 700: Rebuilding the Second BTR Roll Assemblies (DC250 style) – Time and Patience

Xerox Docucolor 240, 250, 242, 252, 260, WorkCentre 7655, 7665, 7675, 7655, 7665, 7675, Xerox Color 550/560/570, C60/C70, DCP-700/700i/770, Color Press C75/J75

A bit of time and a healthy dose of patience (as well as a few replacement parts) are all that’s needed to rebuild one of the DCP700 or Color 550 2nd BTR roller (transfer roll) assemblies.  The first few techs who rebuilt these reported that what at first looked like an easy repair turned out to be quite complicated. I have been wanting to write an article on one for some time now.  For this article I recruited my brother Kurt’s help.  He showed me how the assembly comes apart and with his guidance the repair became far more approachable.

As is true with most things, the repair gets easier with experience.  There are a few tidbits of knowledge which make this procedure go a lot smoother.  One of the keys is to slide the pivot shaft out through the front end of the unit rather than the rear. The temptation is to leave a pair of e-clips on the shaft and slide it out through the rear end—but as it turns out, there’s a ground clip inside which you need to sneak the shaft past.  The rear end of the shaft is rounded to help get it by that ground point.  You’ll also see there are parts which don’t need to be removed at all, in particular the cam shaft and all the hardware on that part of the assembly.

There are two types of screws on this assembly: long plastic thread screws and short metal thread screws.  It’s important to put the correct kind of screws back in the right spots or you’ll run into problems.  The instructions below will mention which type of screw is in each position.

There are four versions of this assembly depending on which model machine you’re working on. Though all are similar, they are not completely interchangeable.DC250 version:

  • 059K45987 / 059K88420 (for: DC240/DC242/DC250/DC252/DC260, WC-7655/7665/7675, WC-7755/7765/7775)
  • 550 version: 059K68395 (for 550/560/570, C60/C70)
  • 700 version: 059K55905 / 059K78323 (for DCP 700/700i/770)
  • J75 version: 059K79314 (for J75 / C75)

For this month’s article, we’re going to tackle the bulk of the rebuild procedure. We’ll use the 550 version as the guinea pig.  Note that the 700 and J75 versions are extremely similar in their complexity. I’m told the DC250 version is easier to take apart.   We will get all the way through freeing up the sub-assembly which has the transfer roll / blade / brush and wax bar so that it can be lifted out of the unit.  Then, next month, we’ll finish the procedure and look at the differences between the four versions.

You’ll want to keep the following tools handy:

  • Philips head screwdriver (or 5.5 mm nutdriver)
  • Small flat-bladed screwdriver
  • Needle-nosed pliers or a spring hook.

PROCEDURE:

Photo #1: Remove tension springs

1. Use a spring hook or needle-nosed pliers to remove the two tension springs at the bottom of the unit (one each at the front and rear ends, see photo #1)

Photo #2: Notice the location of the markings on the cam adjust collar

2. Take notice of the position of the 2 “dashes” on the cam adjust collars (see photo #2).  In this example and on all of the ones we’ve seen so far, these two dashes are positioned at the very top of the unit (at the 12:00 position).  This is true for both the front and rear cam adjust collars.

Important NOTE: the two cam adjust collars are not identical.  Instead, they are mirror images of one another.  You can tell them apart because the one at the front end is the thicker of the two.

Photo #3: Front end

3. Remove the front-end cover (1 screw at the upper left corner: short machine thread), then shift cover to your right and let it hang by its wiring harnesses. (see photo #3)

Photo #4: Top entrance baffle: One screw from the front, one up top near the front and another near the rear end.

4. Take off the top entrance baffle (the metal baffle). Remove 2 screws from the top and 1 from the front end (see photo #4).

Photo #5: Front indexing bracket (4 screws, #2 is the only machine-thread of the 4)

5. Next the front inner bracket can come off (4 screws from the front. Of these, 3 are long plastic thread screws.  The one on the lower left is a short metal thread screw)

Photo #6: One screw to remove the front inner cam plate.

6. Next, take off the large front gear (1 e-clip) and then the front cam adjust collar can also slide off (but see the important note in step #2!)

Photo #7: Front inner cam plate shown removed from the unit. Be careful not to lose the Indexing Finger from either end of the unit. They are spring loaded and not captive.

7. Also pop off the small front gear (1 e-clip)

Photo #8: Rear end

8. The front inner cam plate can now come off. Extract it from around the BTR roll’s shaft. Be careful with the little cam indexing finger, though. This finger is spring loaded and not captive, so it can easily fall off if you’re not paying close attention.  NEXT for the rear end (see photo #8):

Photo #9: Rear cam plate (4 screws)

9. Remove the BTR drive gear (DC250BTRDG) from the end of the BTR roller’s shaft (it is just pushed onto the D-shaft and will pop off fairly easily).

Photo #10: Extract pivot shaft out front end

10. Also remove the BTR drive idler gear (DC250BTRDIG or DC700BTRDIG) from its shaft (1 e-clip) and then remove 2 other e-clips from the same shaft behind where the gear was mounted.  (see Photo #8)

11. Remove the rear BTR roll bias contact (1 screw – short machine thread)

12. Next take off the rear plastic plate. This plate is black plastic and had the bias contact attached to it. It also holds the cam adjust collar’s indexing pin (as with the one on the front end, this piece is spring loaded. Be very careful as the indexing finger can pop or slide off and get lost). There are 3 screws. The bottom screw has long plastic threads and the two upper screws have short machine threads.

13. Now you can remove the cam adjust collar and its bearing from the BTR roll’s shaft (1 e-clip).

14. Extract the rear cam inner collar from the BTR roll’s shaft as well.

15. Slide the pivot shaft out through the front end.

Important NOTE: When reassembling, you will need to insert the pivot shaft in again through the front end so that the rounded rear end will make it past a ground clip inside the pivot frame.

Ok… so I hate to leave you all hanging!  But we’ll need to wait till next month to do the honors of actually lifting the BTR roll / brush / blade / wax bar assembly out of the unit (hint: you’ll be lifting the front end out first and you’ll want to be gentle with the mylar seal blade on the unit).  Next month we’ll also take a good look at the various versions and what makes them different from one another. We’ll take an especially close look at the gears on each version.

Britt Horvat
About the Author
Britt works for The Parts Drop, a company whose primary business is providing parts, supplies and information for Xerox brand copiers, printers and fax machines. You can find more information, including many of Britt’s past ENX articles on their website, www.partsdrop.com . If you’d like to read more about Xerox brand office equipment, there’s also a complete listing of past articles under contributing writers on the ENX website (www.ENXMAG.com).