Panasonic® KX-P4420 Drum Unit

Reference Information:

Approximate Remanufacturing

OEM PN: KX-PDM2

Time: 30 min.

OEM Yield: 18,000 (5.5% image area)

(10 pgs. repetitive printing)

Operational Theory:

The main components of the drum unit are the OPC drum, charge corona unit,

and cleaning unit. The charge corona applies a high, uniform negative charge to

the surface of the OPC drum. The negative charge dissipates where the laser

beam is applied. As a result, the OPC drum electrically retains the image gen-

erated by the laser beam. Where the magnetic brush lightly touches the drum,

the negatively charged toner is attracted to the latent image on the drum. As the

paper is fed between the drum and the transfer corona, a high positive charge is

applied to the back-side of the paper. The negatively charged toner are attracted

from the drum surface to the paper. After transfer, the curvature of the drum sep-

arates the paper from the OPC drum. The cleaning blade scrapes residual toner

from the drum surface and the spiral rod sends the toner to the toner disposal

Figure 1

bottle.

The drum first-use sensor is used to tell the CPU when a new drum unit is in-

stalled. An electronic counter on the logic board tracks drum life. At 18,000 prints;

CHANGE DRUM U27 is displayed.

Recommended Tools:

Phillips head screwdriver

Flat head (3mm) screwdriver

Steel dowel (3/16 diameter/16-20 length)

CAUTION: Do not test your unit with the new first-use sensor installed or

your printer will blow the fuse. Test the unit with the old sensor and then

install the new first-use sensor. This will insure that your customer's page

counts are properly reset.

Figure 2

Instructions:

1. Remove the flange (3 screws - Fig. 1). Be careful not to spill waste toner

from spiral rod.

2. Remove the E-ring from the drum shaft.

3. Slide the drum shaft to the flange side and remove the keeper.

4. Remove the drum. Clean, inspect and lubricate the drum (with padding

powder) and store in a dark place. Replace if necessary. If replacement is re-

quired, then perform the following to remove the OEM gears:

a. Insert a steel dowel (3/16 diameter/20 length) through the non-contact

gear and lightly tap the edge of the opposite gear until it becomes dis-

lodged.

b. Perform step a. on the remaining gear.

5. Remove the upper drum unit cover by unattaching the 3 hooks (Fig. 2).

Clean and inspect the charge corona unit located in the lower drum unit cover.

6. Remove the cleaning blade (3 screws - Fig. 3) and clean the spiral rod of

all waste toner. Be sure to remove all the old toner. Clean, inspect and

Figure 3

lubricate the wiper blade with padding powder. Replace if necessary.

7. Install the cleaning blade.

8. Replace the upper drum unit cover by attaching the 3 hooks on the rear of the

drum unit.

9. Install the OPC drum.

10. Replace the flange (3 screws).

11. Install a new drum first-use sensor.

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Products, Inc. may result in legal action. All registered trademarks are the property of their respective owners.

Oasis Imaging Products, Inc. Technical Support: (888) 627-6555