Remanufacturing HP LaserJet Enterprise M4555 MFP Toner Cartridges
- By Mike Josiah
- Dec 01, 2011
First introduced in March 2011, the HP LaserJet M4555 engine is a 55-ppm, 1,200-dpi multifunction engine. The new CE390A and CE390X cartridges are rated for 10,000 and 24,000 pages, respectively. As with all mono black HP cartridges to date, the chip mainly controls the “toner low” functions and, of course, the HP/non-HP cartridge message.
These are nice cartridges to do, in that there are no plastic rivets to cut or drill, all the screws are the same size, and no glue-type seals are used anywhere inside.
The configuration of the base LaserJet M4555 MFP machine is as follows:
Touch-screen control panel
50-sheet duplexing ADF
100-sheet multipurpose tray
Four 500-sheet input trays
HP Jetdirect 1 GB embedded print server
1,280 MB RAM
Embedded hard drive
One available EIO slot
Walk-up USB port
900-sheet, three-bin stapling mailbox
High-speed color scanner.
The current machines that use these new cartridges are as follows:
HP LaserJet M4555h MFP
HP LaserJet M4555f MFP
HP LaserJet M4555fskm MFP.
These cartridges are also very profitable to remanufacture. As of October 2011, the retail price for the CE390A was $238.50, and the CE390X was $398.56.
Figure 1 shows the shipping seals in place on a new OEM cartridge. The main seal separates the two halves of the cartridge, relieving some of the pressure on the various spring-loaded and foam assemblies.

Printer usage as well as some common printer/cartridge problems will be covered at the end of this article.
1) Place the cartridge with the toner hopper facing up and toward you. This will orient the cartridge for right and left sides.
2) Remove the five screws on the right-side end cap. See Figure 2.

3) Open the drum cover toward the back of the cartridge. Remove the right-side metal bar by pressing it out of the small clip. See Figure 3.

4) On the opposite side of the cartridge, carefully pry off the drum cover plastic arm. The spring will probably pop off, so take care not to lose it. We will go over the installation at the end of this article. See Figure 4.

5) Remove the metal bar from the left side and remove the entire drum cover assembly. Make sure you put the spring in a safe place. See Figure 5.

6) Remove the five screws from the left end cap. See Figure 6.

7) Remove the right-side end cap from the cartridge. Note that the gears do not come off the end cap. See Figure 7.

8) Remove the left-side end cap. Both halves will come apart easily. Be careful not to damage the drum or mag roller sleeve. See Figure 8.

9) Remove the plastic drum bushing/gear train assembly and screw. See Figures 9 and 10.


10) Remove the drum. Lift it up from the large gear side, pull it over and remove it. There is no need to remove the drum axle pin. If it is removed, there is a chance that the hole in the plastic wall it sits in will become enlarged, allowing the axle and drum to move slightly, which will cause banding. See Figures 11 and 12.

11) Remove the PCR. See Figure 13.

12) Remove the two screws from the wiper blade. See Figure 14.

13) Due to the high speed and page counts of these cartridges, we recommend that the wiper blades be replaced.
14) Note that there is not any type of sticky sealant on the wiper blade. There is just normal foam and felt seals under the blade. Remove the wiper blade from the cartridge and clean out the waste toner. Be careful not to damage the spring coming out from the black PCR holder. See Figure 15.

15) Clean the PCR with your standard PCR cleaner.
16) Clean the flet and foam seals under the wiper blade. make sure they are not compressed, or they may leak. See Figure 16.

17) Install the wiper blade and two screws. Be careful not to damage the small contact that comes off the PCR spring on the black holder side. See Figure 17.

18) Install the cleaned PCR. Place a small amount of conductive grease on the black PCR saddle. Remember, when using conductive grease, more is not better. Also place a small amount of white lithium grease on the white holder side. See Figure 18.

19) Install the drum, drum bushing assembly and screw. Make sure the gears from the bushing assembly align with the drive gear on the hopper. See Figures 19 and 20. Place the waste chamber aside.

20) On the supply chamber, carefully pry off the magnetic roller (MRS) cover and remove. See Figure 21.

21) Remove the MRS drive gear. See Figure 22.

22) Note the location of the spring that sits between the MRS holder and the hopper. Remove the two screws, the spring and the holder. See Figures 23, 24 and 25.

23) Remove the MRS assembly. The left (nongear) bushings may come off with the roller. If they do not, remove them so they are not lost or damaged. See Figures 26 and 27.

24) Lift up on the clear scraper covers and remove the two doctor blade screws. Remove the two scrapers and the doctor blade. See Figures 28, 29 and 30.

25) Remove the fill plug from the hopper. See Figure 31.

26) Clean out all the remaining toner in the supply hopper.
27) Note the magnetic seals on the MRS and the doctor blade sealing foam. Make sure both are clean. See Figure 32.

28) There are two separate mixing blades in the toner hopper. The largest is on the bottom, with the smallest on the top. Each is driven by its own separate drive gear. See Figure 33.

29) The upper mag roller section of the toner hopper “floats” on a series of foam seals. The upper half can be removed from the hopper, but some of the seals will be destroyed. This may become necessary in order to seal the cartridge. We will keep you informed on the availability of a seal system and how to install it as our testing continues. The foam isolates the mag roller from the vibrations of the mixing augers and allows smoother prints.
30) Clean the mag roller contacts and replace the conductive grease. If the plating on the contact is worn, it should be replaced, or banding will most likely occur. See Figure 34.

31) Install the doctor blade, being careful of the alignment pins. For now, do not install the scrapers or screws. See Figure 35.

32) Clean the mag roller with a dedicated mag roller cleaner. On the left side of the mag roller, there is a small hub that is keyed into the MRS holder. Align the hub with its slot and install the hub as well as the entire MRS assembly. See Figures 36, 37 and 38.

33) Install the two doctor blade scrapers and screws. The clear scraper covers must sit on top of the roller. Installing them now will lessen the chance of damaging them or getting any grease on them. See Figure 39.

34) Install the holder and spring. Make sure that the spring is compressed so it fits into its slot. This is easily done with a small screwdriver as the holder is pressed in place. If you are having a hard time getting the holder in place, take a moment to look at the angles of the plastic holder. They have to align with the corresponding angles in the hopper for it to fit. Install the two screws. See Figures 40, 41 and 42.

35) Install the MRS drive gear. See Figure 43.

36) Install the keyed MRS cover. Make sure that the keyed hole in the cover matches the keyed end of the magnet in the MRS assembly. Note that the post on the front or DB side is longer than the back post. See Figures 44 and 45.

37) Fill with the appropriate amount of M4555 toner and replace the fill plug. See Figures 46 and 47.

38) Install the left-side end cap onto the toner hopper. It is easier to install the end cap on the supply hopper first, install one screw, then slide the waste chamber into the end cap. Install another screw from the end cap into the waste hopper to hold it in place. See Figures 48 and 49.

39) Install the right-side end cap and five screws. See Figure 50.

40) Install the remaining three screws on the left-side end cap. See Figure 51.

41) Install the metal bars from the drum cover on both sides of the cartridge. Place the bars in front of their slots and press them in place with a small screwdriver. See Figure 52.

42) Install the spring into the drum cover arm as shown. Pull the upper tail of the spring until it fits into the notch un the arm hub. See Figure 53.

43) Install the arm onto the cartridge. Pull back all the way and release the spring from the notch so that the tail fits as shown. See Figure 54.

44) Replace the chip on the top of the cartridge. Replacing this chip will enable the “toner low” functions of both the cartridge and the machine again. See Figure 55.

45) Install the plastic separator seal. This seal keeps the two halves slightly separated, relieving the pressure of the various foam and spring assemblies. See Figures 56 and 57.


Repetitive Defect Chart:
OPC drum 94 mm
Upper fuser sleeve 94 mm
Lower fuser pressure roller 94 mm
Cassette feed and separation rollers 79 mm
Tray 1 feed roller, separation roller 79 mm
Magnetic roller sleeve 63 mm
Tray 1 pickup roller 63 mm
Preregistration roller 50 mm
Feed roller 50 mm
Transfer roller 47 mm
PCR 38 mm
Running the cleaning page
From the home screen, touch the “Device Maintenance” button.
Open the following menus: 1) “Calibrate/Cleaning,” 2) “Cleaning Page.”
Touch the “Print” button to run the page.
This process can take a few minutes to complete.
Running test pages
From the home screen, touch the “Administration” button.
Open the following menus: 1) “Reports,” 2) “Configuration/Status” pages.
Choose the “Configuration” page, “Administration Menu” map, “Current Settings” page or “Status” page (your choice).
Touch the “Print” button to run the report.
Printer error codes
There are literally hundreds of error codes listed in the service manual on these machines. I have listed just the more common cartridge and paper jam codes here:
10.XX.YY — Supply memory error: An error has occurred in one or more of the printer’s supplies. HP again calls the chip a “memory tag,” and the machine cannot communicate with one of them.
10.XX.33 — Used supply in use (chip not changed).
10.XX.40 — Genuine HP supplies installed.
10.XX.41 — Unsupported supply in use (wrong chip installed).
10.YY.35 — Incompatible supply in use.
Error 13.XX.YY — All the error 13 codes deal with paper jams or an open door. There will always be a text message under the number code to tell you where the jam is. These messages are very specific.
This article originally appeared in the December 2011 issue of Recharger.
About the Author
Mike Josiah is East Coast Technical Director at UniNet East Coast, a global distributor of toner, OPC drums, wiper blades and other supplies. He and his technical support team regularly contribute articles to Recharger Magazine and teach seminars at association meetings and trade shows.