By: Mike Josiah and the Technical Staff at Uninet
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First introduced in September 2015, the LaserJet Pro M402series of laser printers is based on 40ppm, 600dpi engine that comes standard with 128MbMemory (256Mb on the M426).The first page out is stated to be as fast as 5.4 seconds.
Two different cartridges are available for this series, the CF226A rated at 3,100 pages, and the CF226X rated for 9,000 pages.
The cartridges are similar in design to the P400 series, but are not interchangeable.There are some significant changes. The drum drive gear is a new very small type. See Figure 1. They are both easier and a bit harder to take apart than previous versions.
The printers released in this series so far are as follows:
LaserJet Pro M402dn
LaserJet Pro MFP M426
Supplies required
LYtoner for use in HP-M402 toner for the CF226A cartridge (3,100 pages)(Amount to be determined)
HYtoner for use in HP-M402 toner for the CF226X cartridge (9,000 pages)(Amount to be determined)
Replacement Chip
New Drum (Optional)
Wiper Blade (Optional)
Dr. Blade (Optional)
Magnetic roller (Optional)
Sealing Strip (Optional)
Cotton Swabs
Isopropyl Alcohol
Drum Padding Powder
Tools Required
Jeweler’s screwdriver
Phillips head screw driver.
Small Common screw driver
X-Actotype razor knife
Flush Cutting wire cutters
Tools required to remove and install used OEM gears
Metal 1/16” rod about 18” long.(From local hardware store)
Needle nose Pliers
Super glue or equivalent
Rubber mallet
Ohm (Continuity)meter
1) Remove the drum cover by prying up on each end. Note the spring position so that it can be replaced later. See Figures 2&3
There are two pins that need to be removed to open the cartridge. The best and easiest way to remove them without damaging the cartridge is to cut two small slots in the plastic next to each of them.
2) Thereare two small slots on opposite sides of each pin. See Figures 4 & 5.
3) Grab the pins with a pair of pointed flush cutting wire cutters, and remove. Flush cutting wire cutters have blades that are flat on the bottom side. Normal wire cutters have curved blades. The flush cutting kind are better for grabbing recessed pins.Note that the pins for both sides are the same. See Figures 6, 7 & 8
4) Separate the two halves. See Figure 9
5) With a flat head screwdriver, press the drum axle pin out from the inside of the cartridge wall as shown. There is NOT a small shoulder as in older versions. Press the axle out just enough so that you can grab it with the flush cutting wire cutters. You may have to make two small cuts on each dies of the pin from the outside in order for the cutters to be able to grab it. See Figures10, 11& 12.
The drum hub on the opposite side is welded. The weld can be broken or drilled out, but there is a good chance that the hub will either warp if pried off, or will be hard to align if drilled out. See Figure 13
6) The drum dongle gear has a spring that holds it off to one side. (Necessary for it to engage the printer). Release the tail of the spring off the gear and remove the drum. See Figures14& 15.
7) Remove the PCR and clean with your standard PCR cleaner. See Figure 16
8) Remove the 2 screws and the Wiper Blade, there is an adhesive seal that hold the blade in place. Carefully lift it up. See Figure 17
9) Clean out the waste toner, make sure the seals are clean. If toner gets on the blade seal it can be cleaned with alcohol to activate the adhesive again See Figure 18.
10) Coat the wiper blade with your preferred lubricant. Install the blade and 2 screws. See Figure 19.
11) Re-install the cleaned PCR. Note that a new OEM PCR has a small amount of conductive grease on the black (contact) side. See Figure20.
12) Re-Install the OEM OPC Drum and metal axle pin. The metal axle pin should have a small amount of conductive grease on the tip. Remove the old grease and replace before inserting the pin.Make sure the axle pin is fully inserted. See Figures 21& 22
If you are replacing the OEM drum, follow this procedure to remove the gears and install them on the new drum:
13) Slide a 1/16″ metal rod about 18″ long along the drum wall until it meets the side wall of the dongle gear. Lightly tap the rod a few times with a hammer, rotate the drum, do the same until it comes loose. Normally it will take three to four taps for the gear to come loose. Do the same for the contact side taking care not to place the rod anywhere near the copper contacts that bite into the drum. See Figure 23
14) Straighten out the contacts on the contact gear. See Figure 24
15) Lightly sand the inside of the new drum where you will be installing the contact gear. This will help ensure good electrical contact. See Figure 25
16) Apply a few drops of super glue around the inside of the new drum about 1/8” in from the edge. Make sure you leave space with no glue present for the contacts to touch the metal drum wall. These contacts must be metal to metal with no glue in between them. If any glue is in between the contacts and drum wall, there will be drum ground issues (solid black pages). Install the contact gear. See Figure 26
17) On the opposite side, place a few drops of medium or thick super glue on the inside wall of the drum about 1/8”in from the edge. This will prevent the glue from overflowing into the drum coating when the drive gear is installed. See Figure 27
18) Install the drive gear. Place the drum onto a flat surface and gently tap the gear with a rubber mallet until the gears sits flush. (Do not hit the dongle gear!) See Figure 28
19) Check the drum ground with an ohm meter. Place the probes into the drum contact and drum (very edge on the drum where there is no coating), and check for continuity. Be very careful to keep the one lead on the edge of the drum. The top metal part has a clear protective coating on it and is easily scratched. Do not press in hard or the lead will slide across the drum ruining it. Allow the glue to dry for about a couple of minutes and the drum should be ready to use. See Figure 29
20) On the supply chamber, remove the two screws from the end cap on the gear side of the cartridge. See Figure30
21) Remove the end cap. See Figure 31
22) Remove the magnetic roller assembly. See Figure 32
23) Remove the Doctor Blade and two screws. See Figure 33.
24) Clean out any remaining toner from the hopper. Note the Dr. Blade seal. It is a sticky substance that can be clean with alcohol if toner gets on it. If this seal becomes damaged, replace it with 100% silicon caulk. See Figure 34.
25) Remove the remnants of the old seal. These cartridges use a self-removing seal system. This picture shows a new cartridge with the seal starting to remove from right to left. See Figure 35
At this time no new seals are available.
26) Fill through the Mag roller opening with *g of toner for use in the HP CF226A or X series toner cartridges.There is not a fill plug in these cartridges.See Figure 36
* Amount to be determined
27) Re-install the doctor Blade and two screws.Make sure the contact sprint is touching the blade! This is a new type of contact for HP to use on this blade. See Figures37 & 38
28) Install the magnetic roller. Turn the roller until the keyed end fits into the keyed slot in the end cap. This can be tricky to do until you get the hang of it. The keyed magnet is shown extended from the sleeve. The proper orientation for the keyed side is facing down. See Figure 39
29) Install the end cap and two screws. See Figure40
30) Place the two halves together, make sure that the two springs are aligned, and insert the two pins. Make sure that the pins are slightly pushed in so that they do not interfere with installing the cartridge in the printer. See Figures 41 and 42.
31) Install the drum cover; make sure the spring is situated correctly, and the slot on the cover fits into the tab on the cartridge See Figures43, 44&45
32) Replace the chip by slicing off the top two corners of melted plastic and sliding the chip out. After replacing the chip if it seems a little loose in the slot, place a dab of hot glue on each of the corners that you sliced off. The hot glue is easily removed when recycling the cartridge again, but will firmly hold the chip in place. See Figures46, 47&48
