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The 8500, 8550 PEP Kit

16 Jan, 2002 By: Steve Geishirt imageSource

The 8500, 8550 PEP Kit

when there has been a problem area within a printer, the manufacturer will
publish a note to make technicians aware of the changes and also make the part
available to repair this problem or create a kit if the repair contains more
than one part. One kit in particular for the 8500 and 8550 color printers is
rather different than previous ones. This kit addresses several areas, some
problem areas and some making a good upgrade of the printer.  
This kit is called the P.E.P. kit (Product Enhancement Package kit). In
this article, I’d like to look at the multiple parts included in the P.E.P.
kit and why they have been included in the kit as this makes for an excellent
upgrade of the 8500 and 8550 printers.


areas addressed in the P.E.P. kit are:

Upgraded Toner Collection Tray

New ITD Guide

New ITD Lock Lever

Fuser Bumper Lever (left door)

Redesigned Transfer Charger

Toner Seal for the Fuser Area



of these names may seem foreign to you, so we will discuss what they are, their
purpose and why they have been upgraded.


Collection Tray

start off with the upgraded toner collection tray. The toner collection tray
sits below the toner carousel and collects toner that drops off of the toner
cartridges as they rotate (Figure
1). Most technicians I talk with, let alone customers, don’t even know
the toner collection tray exists. 
As the tray fills up with toner, the carousel begins to kick toner into
the paper path and onto the printing pages. 
This creates specks of toner on the page, typically one particular color
depending upon what color the customer tends to use more of. 
The reason for the upgrade of the tray isn’t just so people can now
find it, but for easier access. 
The door which covers the toner collection tray has a plastic cover that
looks like it is a part of the internal covers (Figure
2), is very difficult to remove. There is a clip that needs to be pried
back, but then another tool, such as needle nose pliers, is often required to
grab the door and pull it open. Most technicians got tired of this door and
began to leave it off which does not help the printer at all. 
The upgrade changed both the door and the tray. 
The door becomes a guide for the new tray which slides through it and
into the bottom of the carousel area. 
The fit is tight enough to keep the tray from sliding out, and it now
becomes obvious that there is an accessible part in the front of the machine.
Three trays are shipped with the kit so the customer can now dispose of the tray
along with the waste toner and replace it with a clean one.  
In the past, customers would often dump the toner into the waste basket,
causing a plume of waste toner to rise and float around the room. The three
trays come with plastic bags, which are used to encase the tray with the toner
so it can be disposed of as a whole unit. 


Transfer Drum

second upgrade is the ITD (Intermediate Transfer Drum) Guide which is the
plastic part that aligns one side of the transfer drum to the image drum, (see Figure
3). This allows the image to make a clean transfer off of the image drum
and onto the transfer drum to collect all four colors before transferring the
image to paper. 
The older plastic ITD guides would crack, allowing one side of the
transfer drum to drop away from the image drum. The results were distorted or
missing print from one side of the image (the part away from the drum), which
progresses across the drum into a clean image on the other side (the side making
good contact). The upgrade is a metal version of the ITD guide which should take
the stress better, (Figure 4).


Lock Lever

third upgrade is the ITD Lock Lever. This lever is located inside the front door
and locks the ITD drum into place aligning the transfer drum and image drum. 
The problem with this part has more to do with customers trying to remove
the transfer drum without unlocking it via the ITD lock lever, (Figures
5 and 6). Customers pulling on a locked drum unit to uninstall it put
a great amount of pressure not only on the ITD lock lever, but also the ITD
guide from the last upgrade item. The new lock lever has been reinforced to take
more stress so the customer is less likely to break it should they forget to
unlock it, (Figure 7). This is accompanied by a label so the customer can
see the correct way to uninstall the transfer drum when they open the right side



fourth upgrade is a bumper lever that has been added to the left door. This
lever essentially verifies the fuser lock lever is locked into place. 
The problem occurring here was that when the fuser was installed, it was
not always locked into place via the fuser lock levers. 
The 8500 fuser locks into place very much like it’s monochrome
component, the 8000. 
However, the 8500 version sits in the printer in a different manner from
the 8000.  On
the 8000, the fuser drops into place and even if it is not locked down, it is
unlikely to vibrate loose. 
The 8500 version sits on a plate that can allow the fuser to slide out of
position if it is not locked down. 
This can cause image defects, should one side of the fuser slide out
causing it to grab the paper at an angle, or even cause 50 service errors due to
poor connections. 
The fuser bumper lever will not allow the left door to close unless the
fuser lock lever is in proper position, (Figure 8). 



fifth upgrade is a redesigned transfer charger. The job of the transfer charger
is to help keep the paper in it’s path after the image has been transferred to
it from the transfer drum. Without the transfer charger, the paper could wrap
around the transfer drum causing a paper jam. 
There are small wheels on the transfer charger which help guide the paper
through the paper path. These rollers have occasionally fallen off of the unit
and into the paper path. 
Some of those wheels lay harmlessly in the printer, while others will get
pulled into the fuser, gouging the rollers. The new design keeps the small
wheels in place so they don’t fall off of the transfer charger, (Figure 9).



sixth upgrade is the toner seal for the fuser area. This seal is a felt covered
sticker which attaches to the printer above the fuser, (not shown). The problem occurring here was that if toner began
to build up in the toner collection tray, or even if it was working it’s way
down to it, there was a small crack between two plates that allowed that excess
toner to seep through. This toner would drop onto the paper after the fusing was
complete.  This
would cause a lot of confusion for the technicians when they found a fused page,
but unfused drops of toner. 
Cleaning would help for a short amount of time, but the unfused drops of
toner would reappear. More confusion occurs when a customer has a duplex unit
installed and the drops of toner were fused on one side, but not on the other. 
This toner seal closes that gap so excess toner cannot trickle into the
paper path after the fuser. 
There is one down side to this we might see as these machines age. 
Of the two plates that this toner seal sticks to, one side is the lower
delivery assembly, or Feeder Assembly. 
Should the lower delivery rollers fail at some point, the whole assembly
would need to be replaced, which would require the technician to destroy the
toner seal. If the technician does not know that they must install a new toner
seal, the unfused toner drops can reoccur. 
Also note, when installing the toner seal, you don’t want to cover the
cut out areas in the metal that the fuser tabs lock into.



seventh, and last part of the kit are the labels for the following:


A) Toner
labels better explain to the customer how to rotate the carousel to the low
toner cartridge for replacement, (shown in Figure 1). Do make a note, if your customer opens the
door to the carousel while the cartridges are spinning around, the printer will
display a 54.2 carousel error. This will require the customer to cycle the power
to clear the error. 

label explains how to install/uninstall the transfer drum so they don’t break
the ITD lever or ITD guide, (Figure 10). 

C) A
caution label – use only HP color laserjet transparencies – lets the end
user know other types of transparencies will not work on these printers, (Figure 11). More to the
point, I think, are for people who try to use inkjet transparencies which are
not designed for heat, and end up wrapping around the fuser rollers.



are a couple of other parts to the kit such as the bags for toner disposal, a
toner cloth that attracts toner and helps in the cleaning process. The toner
cloth will not perform the whole cleaning job and a proper toner vacuum should
be used by technicians who will be working on these color printers.
Recommendations are for a vacuum that will filter out parts to 0.3 microns in
size.  Also
included with the kit is the installation guide which covers in great detail how
to install the kit. 
Since the guide is so complete, we will not go into a step by step “how
to” at this point. The part number of the P.E.P. kit is RG9-1495-000, (see Figure 12). 


think it wise of HP to create a “complete” kit like this that takes care of
several issues all at one time. 
Often, a technician can find three or four kits for a particular printer
to upgrade different parts at different times. 
I suppose they could have done that and made more money, but this is
obviously the smarter way to go. 
Not just for their own efficiency, but particularly for the customer who
HP must ultimately satisfy.

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