Xerox Docutech and 5090 Family Service Cost Reduction Strategy

By Raymond Cote

In the past few months, I have had several requests from self-maintainers, concerning the high costs of parts and services. The lingering question was often the same: What can I do to reduce the cost of operating my copier?  In the late 1980’s, Xerox took a hard look at the copier family and tried to evaluate what was happening. One of the biggest concerns was the photoreceptor belt (1R88). For some reason, it was being replaced prematurely at about 250,000 to 300,000 copies, when in fact it should have lasted to well over 500,000 impressions.

After the study was completed, there were a number of changes implemented to extend the service life of the photoreceptor belt and other internal components. Two recommendations were made: (1) the spots blade and (2) a new PR Life Kit was introduced. This extended the average PR service life to about 450,000 impressions.

In the early 1990’s, field engineering developed a new strategy that would directly address the service reduction costs. They looked at all the HSFI items, and evaluated each and every one of them with an eye on improving them, or the application in some way. After the evaluation, they discovered that the parts and strategies worked, and that the life expectancy of many of the High Frequency Service Items could have their service life extended. 

Replacing the new parts only went just so far in reducing the service costs. Technicians (and self-maintainers) have to rely on the service strategy as well. You are the key to reducing costs and making this a total success. If you use these procedures, (outlined in this article) your cost for service parts will go down, and as a result, save hundreds of dollars in maintenance.

There are 4 main areas that we will be looking at in the Docutech (and 5090) copiers:

(A) Dicorotrons and the charging system life extension 

(B) Stray light reduction in the optics cavity (5090)

(C) Flash lamp extended life (5090)

(D) Photoreceptor belt life extension

As we examine these four main topics, keep in mind that cleanliness is important in the efficiency of any copier. If your copier is contaminated with toner, it is recommended that you perform a Preventative Maintenance (PM) on the copier, and replace all HSFI’s at this time.

Charging System   

The charging system usually accounts for about 10% of the total service cost; this is usually the first place you would look at for copy quality issues. There are eight components that are directly related to the charging system:

1) High Voltage DC PWB (140K16823)

2) High Voltage AC PWB (140K5221)

3) Ozac hose assembly (5090/119K86   DT135/119K109)

4)Dicorotrons (125K1081 chopped Dicorotrons 125K1450)

5) MIN ADA PWB’s 1 and 2  (140K7341)

6) MIN DIO PWB (140K7353)

7) High Voltage Cable assembly (the DC spider Connection)  (117K6371)

8) High Voltage AC Output Module

All of these parts and assemblies work in harmony to provide the proper current flow to the photoreceptor belt, to transfer the latent image to the paper, and lastly, to provide a Preclean charge to prepare the photoreceptor belt for the next impression. 

Keep in mind, that the harder the charging system has to work to do its job, the sooner the parts and assemblies in the charging system will fail. When the system is “working harder”, that usually means the system is generating more power (voltage) to do its job. Conversely, if the charging system could operate at a lower voltage, all of the parts will last longer. This in my opinion, is a no-brainer.      

TAG 199 Charge (Chopped) Dicorotrons and the Air Dam TAG 222 retrofits will reduce contamination, and reduce the amount of voltage to the photoreceptor belt. Most, if not all copiers in the field should have these retrofits; all we have to do is make sure that they are within factory specifications. Check the adjustment section of the 5090 and Docutech service manuals for the procedure.

CHOPPED DICOROTRONS  

The Chopped Dicorotrons have a yellow body (125K1450) to distinguish them from the regular dicorotrons (125K1080). The Chopped Dicorotrons are actually closer to the photoreceptor belt, that way, it could work more efficiently with a lower charge current. The changes were developed to raise the charge efficiency, and thereby reducing contamination.  When you re-wire any dicorotrons, use compressed air to clean them, and then use a slightly damp soft cloth to clean the dicorotrons assembly. Pay particular attention to the special coating on the dicorotrons to see if the coating is not contaminated with any ozone damage. When in doubt, throw it out. Use a fresh Dicorotron because the plastic housing will retain the ozone damage and contaminate the new photoreceptor belt. The reason they are called “chopped” is because about 1.55 mm has been shaved off the bottom. The Docutech family does NOT use the Chopped Dicorotrons in the charge locations. The only position for Chopped Dicorotrons in the Docutech family is in the preclean position. Exactly one Chopped Dicorotorn is used.

When making the adjustment for the Chopped Dicorotron assembly, the adjustment specification will be 1.55 mm + or – 20 mm between the photoreceptor and the charge assembly.  In all actuality, the new Chopped Dicorotrons will be 2 mm closer to the photoreceptor belt. The Preclean (chopped) Dicorotron’s new position is now 4.00 mm from the photoreceptor belt.     

Now that the coronode is much closer to the photoreceptor belt, the charging system is more efficient because it is working with a lower voltage. The efficiency of the device will increase the life expectancy of all electrical parts in the charging system, and this is especially true with the Dicorotrons and the photoreceptor belt.

The HSFI Service replacement has been increased for the Chopped Dicorotrons because the service life can be extended. The Charge 1 dicorotron HSFI will be increased to two million copies, and Charge 2 Dicorotron will be increased to three million copies. The Preclean dicorotron will remain at one million copies because of the dirt contamination. The Preclean dicorotron’s life was not extended, but the efficiency will have an impact on copy quality when it comes to cleaning the photoreceptor belt.

In summary, when the dicorotrons are moved closer to the photoreceptor belt, it will increase the charge efficiency; that means the photoreceptor belt and dicorotrons will have a longer service life. Over time, you will notice that 09-203 and 09-204 system faults will not come back to haunt you as they did when the system had the old configuration (charge dicorotrons).

STEP ONE (1)    

Fix the charge Dicorotrons height adjustment correctly first. The adjustment can be found in the adjustment section of the service manual in section 9.6. If you need the adjustment procedure, contact my office for a free copy. Keep in mind, if the height is not adjusted properly, the charging will not be efficient; parts will fail prematurely and your service costs will go through the ceiling. 

For those that would like to try the adjustment without the book, please keep in mind there are two basic adjustments for the dicorotron height: (1) Inboard (rear) adjustment (2) outboard

(front) adjustment. In my experience, I have always had trouble adjusting the inboard height. Your arms never seem to be long enough, and if you’re adjusting a 5090, you can’t see what it is you’re doing.  Not only that, but your knees seem to be the brunt end of a painful experience.  After setting the inboard height, you can use a test pattern 82E2770 to adjust the outboard end by making copies and folding the copy to compare the dark patches.

Next, check for TAG 222, the Air Dam. If you don’t have it, I would strongly recommend that you order the kit from your supplier. The Air Dam retrofit will divert unclean air away from the coronode wire. When the Air Dam is installed on the preclean dicorotron assembly, it will divert the air that is contaminated with contaminants from the charge dicorotrons. It will also help to control the air that is sucked down behind the stripper bar and into the preclean dicorotron assembly. With this retrofit, 09-328’s are almost eliminated in the 5090.  Next month, we will explore ways we can reduce stray light in the optics cavity, and eliminate most (if not all) 09-363 and related system faults. Meanwhile, if you have a specific question or a specific machine situation that you are concerned with, please do not hesitate to e-mail me with your concerns. I can be reached at: VillageCopierNY@AOL.COM. u