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Remanufacturing the Samsung SCX-4725 Toner Cartridge

• Dec 01, 2008

These cartridges do not have a built-in drum cover, but do come new with a plastic form fitting drum cover. For these cartridges Samsung has stopped using the heavy paper wrap.

While we will not be going into the printing theory on this cartridge, it should be noted that the printer uses a Pre-Transfer Lamp (PTL). This lamp basically shines a light onto the OPC drum, which lowers the charge on the drum’s surface and improves the transfer efficiency.

Another interesting fact about these machines is that in addition to the normal Toner Low and Toner Empty messages there is also a "Drum Warning” message. This message first appears when a cartridge is nearing 14,000 pages. The service manual states that after 15,000 pages, the waste hopper may overflow. The cartridge will shut down at this point regardless of the amount of toner left. The HY cartridges are rated for 3,000 pages so reaching that point is doubtful. Once toner empty state has been reached the cartridge will shut down so the only way for a cartridge to get that high a page count is if very little if any toner is used per page.

The HY replacement cartridge is rated for 3,000 pages at 5 percent coverage (ISO 19752). The starter cartridge (SCX-4525FN) is rated for 1,000 pages.

The HY cartridge I have seen listed with two different part numbers. The Samsung Web site shows it as SCX-D4725A/XAA, the service manual lists the SCX-4725D3 number.

From what I can find the SCX-D4725A/XAA is the correct number, but in case you come across the D3#, you’ll know what it is.

So far there are two machines in this series. The SCX-4725FN and the SCX-4725F.

Remanufacturing instructions

[1] Place the cartridge with the handle facing away from you. Remove the two screws on left end cap. See Figure 1.

[2] Gently pry off the left end cap. See Figure 2.

[3] On the front edge of the cartridge, there are two screws, remove them. See Figure 3.

[4] Lift up and remove the waste chamber from the cartridge. Make sure the tabs on the left and right sides slide out of the slot. If you try to lift the cover off without sliding the tab out, they will break off. See Figure 4.

[5] Remove the two screws and wiper blade from the waste chamber. See Figures 5 & 6.

[6] Clean out any remaining toner from the waste chamber.

[7] Re-install the wiper blade and two screws. Place the waste chamber aside. See Figure 7.

[8] Remove the two screws from the right side end cap. Carefully pry off the end cap. See Figure 8.

[9] Remove the four gears, and place aside. See Figure 9.

[10] Slide the PCR away from the contact side, lift up and remove. See Figure 10. Clean the PCR with your normal PCR cleaner.

WARNING: Do not clean the OEM PCR with alcohol, as this will remove the conductive coating from the roller. If the PCR is an aftermarket, follow the cleaning methods recommended by the manufacturer. If the PCR is an OEM, we recommend it be cleaned with your standard PCR cleaner.

[11] Remove the OPC drum. See Figure 11.

[12] Carefully pry out the fill plug. It fits tight and is easily damaged. Work a small jeweler’s screwdriver around the edge until the plug comes free. See Figure 12.

[13] Clean out any remaining toner from the hopper.

[14] Gently pry out the roller plate from the cartridge by pressing in on a tab located on the bottom of the cartridge. There is a spring that is in contact with the developer roller shaft. Move the tail of the spring up so that as the plate is lifted out, it will fall behind it. See Figures 13 & 14.

[15] Remove the developer roller by lifting it out. See Figure 15.

[16] Remove the two screws on the doctor blade. On the fill plug side of the blade, there is the other tail of the spring. Lift it up while removing the doctor blade so it is not damaged. See Figures 16 & 17.

Note: It is highly recommended that the doctor blade be cleaned. Failure to do so will cause streaking. Dampen a cotton swab with alcohol, and clean the blade. Be careful not to press too hard and damage the blade. If the blade has a heavy buildup of toner on it, clean it with acetone and then alcohol.

[17] Clean the feed roller and any remaining toner from the hopper. See Figure 18.

[18) Re-install the doctor blade and two screws. Make sure the tail of the spring fits into the proper slot. See Figures 19 & 20.

[19] Install the developer roller, keyed end to the gear side of the cartridge. See Figure 21.

[20] Install the roller plate. Route the tail of the spring so that it sits on top of the plate and is in contact with the shaft of the developer roller. Lock the plate in place with the tab. See Figures 22 & 23.

[21] Install the four gears as shown. See Figure 24.

[22] Install the drum in place. See Figure 25.

[23] Clean out the old conductive grease from the PCR contact hub and replace with new. A small amount of grease is fine, more is not better when it comes to conductive grease. See Figure 26.

[24] Install the PCR by sliding it through the non-contact side, and into the contact hub. See Figure 27.

[25] Fill the hopper with the appropriate toner. Replace the fill plug, check for leaks. See Figure 28.

[26] Install the gear side end cap, and two screws. Make sure the PCR fits correctly in its holder, and all the gears are aligned. See Figure 29.

[27] Install the waste chamber by sliding the tab through the slot in the end cap. Rotate it down, and install the two screws. See Figure 30 & 31.

28) On the non-gear end cap, the chip needs to be replaced before it is installed back on the cartridge. There are two tabs that lock the chip housing in. Carefully pry up the two tabs. Remove and replace the chip. Snap the chip housing back in place. See Figures 32, 33, & 34.

[29] Install the non-gear end cap and two screws. Make sure the end cap sits flush with the rest of the cartridge. See Figures 35 & 36.

Printing Test Pages

As these machines are also copiers, a simply copy of a good test page should be all you need.

Running the Drum Cleaning Page

Press the "Menu” button until MAINTENANCE appears on the display.

Press "Enter”

Press the "Left” or "Right” arrows until CLEAN DRUM appears on the display

Press "Enter”

Press the "Left” or "Right” arrows until YES appears on the display

Press "Enter”

Repetitive Defect Chart

OPC drum  — 75.5mm

Lower fuser roller — 75.4mm

Upper fuser roller — 63.9mm

Supply roller — 47.5mm

Transfer roller — 46.2mm

PCR — 37.7mm

Developer roller — 35.2mm

Machine Error Codes

These machines use plain English error messages so there is no need to go into them here.

Mike Josiah is technical director at Summit Technologies, a division of UniNet Imaging Inc., a global distributor of toner, OPC drums, wiper blades and other supplies. Josiah has been with the company since 1987. He and his technical support team regularly contribute articles and teach seminars at association meetings and trade shows. Contact him at 631-218-8376 or mjosiah@uninetimaging.com.