Panasonic® KX-P4420 Developer Unit Remanufacturing Instructions...
Panasonic ® KX- 4420 Developer Unit
Reference Information:
Approximate Remanufacturing
OEM PN:
KX-PDP2
Time: 30 min.
OEM Yield: 18,000 prints (5.5% image area)
Recommended Tools:
Phillips head screwdriver
Flat head (3mm) screwdriver
Soldering iron and wick
Operational Theory (Figure 1):
The developer unit holds approximately 300 grams of developer in the mixing
unit. The developer is a mixture of toner and carrier. The mixing paddle rotates
clockwise to stir the developer which creates a friction charge called a tribo-
electric charge. The toner is negatively charged and the carrier is positively
charged. The magnetic roller consists of magnets mounted inside a rotating
aluminum sleeve. The sleeve rotates at 98.7rpm and the magnets inside attract
the developer to the surface of the sleeve, forming a magnetic brush. A doctor
blade mounted in the developer housing trims the brush to 1.0mm. Where the
magnetic brush lightly touches the drum, the negatively charged toner is attracted
to the latent image on the drum. The latent image is then converted to a visible
image on the OPC drum. A bias voltage is applied to the sleeve to achieve max-
imum print quality. Any developer remaining on the sleeve is removed by the
Figure 1
scraper and returned to the mixing paddle for new toner. A toner barrier catches
loose developer which is then re-attracted to the magnetic roller.
The developer first-use sensor is used to tell the CPU when a new developer
unit is installed. An electronic counter on the logic board tracks developer life. At
8,000 prints, CHANGE DEV U26 is displayed. The toner density sensor detects
when the toner quantity in the developer unit is lowered and signals the CPU to
supply toner from the toner cartridge. Additionally, a developer detection sensor
signals the CPU when the developer unit is installed with the toner cartridge. The
toner cartridge is mounted on the developer unit. The toner cartridge first-use
sensor tells the CPU when a new toner cartridge unit is installed. Also, a toner
cartridge detection sensor signals the CPU if a toner cartridge is present.
Figure 2
CAUTION: Do not test your unit with the new fuse installed. Your printer
will blow the fuse. Test with the old fuse then install the new fuse. This will
insure that your customer's page counts are properly reset.
Instructions:
1. Separate the toner cartridge from the developer unit by lifting the green lever
on the developer unit.
2. Remove the old developer from the mixing paddle area and the magnetic
roller sleeve. Be sure to remove all the old developer.
Figure 3
3. Refill the developer unit with new developer. Pour developer into top cavity
opening. Spin the magnetic roller sleeve gear to coat the sleeve. (Note:
Spin the roller so that it comes out of the top and into the bottom of the unit.)
4. Re-attach the toner cartridge to the developer unit.
Note: The magnetic roller has an angle of graduation adjustment for print density.
Figure 4
When using Oasis 4420 developer perform the following steps: (Fig. 2).
a. Use as is.
b. Set the pointer to the mid-scale position.
c. Tighten the screw ( be sure that the pointer does not move).
d. Watch your test prints very carefully.
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2
Panasonic® KX-P4420 Developer Unit Remanufacturing Instructions continued...
4. Locate the developer detection sensor/developer unit first-use sensor unit on
the top of the developer unit (fig. 3). Remove the cover. De-solder
the two center leads on the green circuit board (fig. 4). Flip the green
circuit board over and remove the old fuse. Insert and solder new fuse.
Secure green circuit board to developer unit. Replace the cover.
If you notice a grainy feeling to the paper or any scattered dumping on the page,
stop the test immediately. Remove the developer unit and adjust the pointer
again (clean the printer if necessary). Move the scale so that the pointer is one
notch to the right of center. Continue this process, making fine adjustments until
you are able to run 20 to 25 clean crisp prints. It is very common to print 75 to
100 test pages per developer unit. Be sure to make your adjustments in small
increments (no more than one notch at a time).
© 2001 Oasis Imaging Products, Inc. Any attempt to reproduce any part of these instructions without the written consent of Oasis Imaging
Products, Inc, may result in legal action. All registered trademarks are the property of their respective owners.