Remanufacturing of the HP LaserJet 4250/4350 Toner Cartridge
 

 

Remanufacturing the HP LaserJet 4250/4350 Toner Cartridges
 0358

Overview

First introduced in October 2004, the HP LaserJet 4250 engine is a 45ppm, 1200 dpi engine, the HP LaserJet 4350 is a 55ppm, 1200 dpi engine, both made by Canon. The Q5942A cartridge is rated for 10,000 pages at 5%, the Q5942X cartridge is rated for 20,000 pages at 5%. As with the HP-4200 the chip is mainly controlling the toner low functions and of course the HP/Non HP cartridge message.

These instructions cover both the “A” and “X” cartridges. Unlike the 4200 and 4300 cartridges, these are interchangeable. Both the A and X cartridges can go into either machine. They will not however fit into the 4200/4300 machines. Many changes have been made to prevent this. The only major exception is removing the wiper blade on the 42X cartridge. The 42X cartridge has a plastic shelf that must be removed in order to remove the wiper blade. The 42A cartridge does not have this shelf.

At first glance, these cartridges look very similar to the 38A/39A cartridges, but upon closer inspection, there are many subtle differences. There have also been many changes made to make opening up the cartridge more difficult. HP may publicly tout that they are friendly to our industry, but more and more their cartridge design is proving other wise. The following Figures (1-8) show the difference between the four cartridges.

Figure 1: Top of 38A Figure 2: Top of 42A
Figure 3: Bottom of 38A Figure 4: Bottom of 42A
Figure 5: right side of 38A Figure 6: right side of 42A
Figure 7: left side of 38A Figure 8: left side of 42A
Figure 9: top of 39A Figure 10: top of 42X
Figure 11: bottom of 39A Figure 12: bottom of 42X
Figure 13: right side of 39A Figure 14: right side of 42X
Figure 13: left side of 39A Figure 14: left side of 42X

As you can see, HP and Canon seem to have gone out of their way to design them so that they cannot be made interchangeable with the 38X/39X cartridges.
Testing is ongoing to see which if any cartridge components fro the 38A/39A cartridges can be used in these cartridges.
The current machines that use these new cartridges are as follows:

HP-LaserJet 4250
HP-LaserJet 4250n
HP-LaserJet 4250tn
HP-LaserJet 4250dtn
HP-LaserJet 4250dtnsl
HP-LaserJet 4350n
HP-LaserJet 4350tn
HP-LaserJet 4350dtn
HP-LaserJet 4350dtnsl

There is one new setting available in the printer menu, the “OPTIMIZE” mode. There are three settings possible in this mode.
HIGH TRANSFER: This should be set to “ON” if the paper being used is of a low quality. The manual does not indicate what this setting actually does. From the name, it sounds like the settings of the power supply are changed for the transfer roller, but it could also be the fuser setting. Hopefully the Service manual when released will clear this up.


LINE DETAIL: This should be set to “ON” to improve the appearance of lines on the page.

Supplies Required

Polyester based toner; weights to be determined

Replacement drum

Wiper Blade

Doctor Blade

PCR

Magnetic roller sleeve

  • Conductive Grease
  • Tube of silicon for sealing wiper blade gap. (See Text)
Tools Required

Toner approved vacuum.

A small Common screwdriver

A Phillips head screwdriver

Needle Nose Pliers

Dremel tool for removing Wiper Blade

shelf on 42X cartridges

Magnetic roller press

Disassembly

1) Place the cartridge with the toner hopper facing up and away from you. This will orient the cartridge for right and left sides.

2) Remove the four screws on the left side end cap. See Figure 17

3) Open the drum cover towards the back of the cartridge. Remove the left side metal bar. See Figure 18

4) Carefully pry off the drum cover plastic arm. The spring will probably pop off, take care not to loose it. We will go over the installation at the end of this article. See Figure 19

5) Remove the metal bar from the right side, and remove the entire drum cover assembly. Make sure you put the spring in a safe place. See Figure 20
      Figure 17
      Figure 18
      Figure 19
      Figure 20

6) Drill out the two plastic rivets as shown Just drill enough now to allow the end cap to come free. The rest of the hole will be drilled later. Do not remove the screw that is holding the recessed metal drum axle pin. See Figures 21 & 22
The rest of the right side end cap is held in place by three melted plastic posts. See Figure 23.
Although there are tools to aid in removing this end cap, we have found it not necessary. After removing and replacing the waste chamber a few times, a technician will be much faster than going through the trouble to remove the end cap.


7) Remove the left side end cap from the cartridge. See Figure 24

      		•
        Figure 21
        Figure 22
        Figure 23
        Figure 24

8) Carefully work the waste chamber loose from the right side end cap. Press in on the metal drum axle pin to help free it. See Figure 25

9) Remove the metal drum axle pin screw and the axle pin. See Figure 26

10) Remove the drum. See Figure 27

11) Remove the PCR. See Figure 28

      		•
        Figure 25
        Figure 26
        Figure 27
        Figure 28

12) Remove the two screws from the wiper blade. See Figure 29

13) With a razor knife, carefully lift up the seal foam and cut away. This is very sticky stuff, the best way to remove it is to cut and lift. The wiper blade can be resealed with a good quality silicon caulk. Make sure you use the type that never dries (Cannot be painted). See Figure 30
This foam seal is apparently a cheaper way to seal the cartridge instead of using a foam gasket. Although it is a real pain to remove, replacing it with silicon will allow you to easily peel it of the next cycle.

14) At first glance, the 42A/X wiper blade is the same as the 38A/39A. Further testing is ongoing to confirm this. Due to the high speed and page counts of these cartridges, we recommend that they be replaced. *It should be noted that the 42X cartridge has a plastic shelf across the wiper blade that prevents it from being removed and replaced. This shelf is best removed by a Dremel type tool with a grinding bit, or a circular blade bit. We do not recommend that a knife be used as it is easy to slip and cut yourself. This is identical to the 39A cartridge. See Figure 31

15) Remove the wiper blade from the cartridge, and clean out the waste toner.

16) Clean the PCR with your standard PCR cleaner.

17) Install the wiper blade and two screws. See Figure 32

      		•
        Figure 29
        Figure 30
        Figure 31
        Figure 32

18) Seal the back edge of the wiper blade with a good quality silicon caulk. Use the type that never dries. (Cannot be painted). Let the caulk dry for a few hours before doing anything else. See Figure 33


19) 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! See Figure 34

20) Install the drum, drum axle pin and screws. Make sure that the plastic pin is centered in the oblong hole of the metal axle pin. (Just like the HP-4000 cartridges) See Figure 35

 

21) On the supply chamber, carefully pry off the Magnetic roller (MRS) cover, and remove.
See Figure 36

      		•
        Figure 33
        Figure 34
        Figure 35
        Figure 36

22) Remove the small metal pin from the MRS holder. See Figure 37

23) Remove the MRS drive gear. See Figure 38

24) Note the location of the spring that sits between the MRS holder and the hopper. Remove the screw, spring and the holder. See Figure’s 39 & 40

      		•
        Figure 37
        Figure 38
        Figure 39
        Figure 40

25) Remove the MRS assembly. See Figure 41


26) Remove the two Dr. Blade screws and the DR. Blade. Note the clear spacer that fits in between the blade and the white plastic spacer. Do not loose this spacer or light print will occur. See Figure’s 42 & 43

27) Clean out all the remaining toner in the supply hopper.


28) Note the magnetic seals on the MRS and the DB sealing foam. Make sure both are clean.
See Figure 44

      		•
        Figure 41
        Figure 42
        Figure 43
        Figure 44

29) Note also the new style magnetic roller contact. There are two copper fingers that fit top and bottom on the Magnetic roller. This when combined with the new larger diameter of the roller, allow the cartridge to run at the higher speeds that both machines are capable of. See Figure 45

 

30) There are three 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 46

31) The entire upper half of the toner hopper is different in that is “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 as our testing continues.

32) Install the doctor blade and two screws (Make sure that all the spacers both clear and white are seated correctly!). See Figure 47


33) On the MRS 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 Figure’s 48 & 49

      		•
        Figure 45
        Figure 46
        Figure 47
        Figure 48

34) Install the holder and spring. See Figure 50

35) Install the screw and the small metal pin. See Figure 51


36) Install the MRS drive gear. See Figure 52

      • Figure 49
        Figure 50
        Figure 51
        Figure 52

37) 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. See Figure 53


38) Fill with appropriate amount of Polyester based toner. See Figure 54

39) Install the waste section into the fixed end cap on the supply hopper. This is a tricky process the first few times, but gets much easier. The best way to do it is to carefully pull the end cap out, and slide the waste up and in, until everything aligns. For the first few times, this is definitely easier said than done, but you will get the hang of it. See Figure 55

 


40) Install the two screws into the end cap in the holes that were drilled out previously. See Figure 56

 

      		•
        Figure 53
        Figure 54
        Figure 55
        Figure 56

41) Install the left side end cap. See Figure 57


42) Install the four screws. See Figure 58

43) Install the metal bars from the drum cover on both sides of the cartridge. You will have to turn the bars so that the flattened end of the bars fit into the keyed slots. See Figure 59

 

44) Install the spring into the drum cover arm as shown. Pull the upper tail of the spring until it fits into the notch in the arm hub. See Figure 60

      		•
        Figure 57
        Figure 58
        Figure 59
        Figure 60

45) Install the arm onto the cartridge. Release the spring from the notch so that the tail fits as shown. See Figure 61


46) 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 62

      		•
        Figure 61
        Figure 62

         

 
Reset Procedure

Resetting the Maintenance Kit Counter
Every 200,000 pages, the machine will call for a new maintenance kit. This kit consists of the Fuser assembly, Transfer roller, paper pickup rollers, and the paper feed rollers. Once the kit has been replaced, the counter must be reset.

Turn the printer off and then on.
When “XXX” appears on the display, press and hold the “SELECT” button. Continue holding the “SELECT” button until all three control panel lights flash once, and then stay on. This process can take as much as 10 seconds.

Release the “SELECT” button and press the “UP” button until NEW MAINTENANCE KIT appears on the display

Press the “SELECT” button to reset the counter

Troubleshooting

Common Cartridge Problems

OPC Drum: 94mm
Magnetic Roller Sleeve: 55mm
PCR: 38mm

Dirty or Bad Primary Charge Roller (PCR); A bad PCR will normally cause a gray background, or ghosting. Small defects from the PCR will repeat every 38mm.

Dirty PCR Connection; This will show as horizontal dark black bars across the page, or as shadingthroughout the page.

Scratched Drum; This is shown by a very thin, perfectly straight line that runs from the top to the bottom of the test page.

Chipped Drum; This will show as a dot or series of dots that repeat 3 times per page or every 95mm. Any drum defects will repeat 3 times per page (94mm).

Light Damaged Drum; This will show up as a shaded area on the test print that should be white. Again this will repeat 3 times per page.

Tire Tracks; This is normally caused by a bad drum, they normally show up on the right edge of the page.

Damaged Magnetic Roller Sleeve; A damaged Magnetic Roller Sleeve will leave a mark that repeats every 55mm.

Printer error Codes

With these machines, HP has started to move away from number only codes, most of them are self explanatory in text. There are still a few however that are part text, and part number. It is those codes that we will list here.

10.XX.YY Supply Memory Error: An error has occurred in one or more of the printers supplies. Values of XX and YY are listed below.

XX00 Memory is defective
XX01 memory is missing
YY00 Black print cartridge

This seems to indicate that other supplies such as the staple cartridge will be chipped also. No other products were available at the time of this writing to see if they do.

10.32.00 Unauthorized Supply. The printer has detected that a printer supply is not a genuine HP supply.
No more “Non-HP” message, now it is “Unauthorized Supply”!!

Error 13.XX.YY: All the error 13 codes deal with paper jams. There will always be a text message under the number code tell you where the jam is.

Error 41.X: This code is a Printer error.
Error 50.X: This code is a Fuser error.
Error 51.X: This code is a Printer error.
Error 52.X: This code is a Printer error.
Error 53.XY.ZZ: This code is a Printer Memory error.
Error 59.XY: This code is a Temporary Printer error.

Many of the codes also have sub codes for the “X” and “Y” values. We will update this instruction as soon as the service manual is released by HP.

all other codes are self explanatory

Running The Cleaning Page

Press the “MENU” Button
Press the “DOWN ARROW” until CONFIGURE DEVICE appears
Press the “SELECT” Button
Press the “DOWN ARROW” until PRINT QUALITY appears
Press the “SELECT” Button
Press the “DOWN ARROW” until PROCESS CLEANING PAGE appears
Press the “SELECT” Button
Follow the instructions on the cleaning page to complete.

Running Test Pages

Press the “SELECT” Button
Press the “DOWN ARROW” until INFORMATION appears
Press the “SELECT” Button
Press the “DOWN ARROW” until either:
PRINT MENU MAP,
CONFIGURATION PAGE,
SUPPLIES STATUS PAGE, or
PS or PCL FONT LIST appears
Choose the page(s) desired, and
Press the “SELECT” Button