Disassembly Instructions:Brother HL-1240 Toner Cartridges
Released in September 1999, the Brother HL-1240 printer engine is the latest, and possibly best, engine Brother has released to date. With all the problems seen in the 630 and 720 engines, the 1240 engine is by far Brother's best effort. The toner cartridge is simple,
and easy to remanufacture. The drum cartridge, other than a few simple quirks, seems the same so far.
Brother has released a lot of machines with this engine. Some are laser printers, some are fax machines and some are a combination. Unlike past versions, there is only one part number for either the laser or fax version. The TN-6300/6600 are the part numbers
for cartridges sold outside North and South America. To date, we have not seen or heard of any differences between the domestic and overseas cartridges. Testing has been favorable worldwide.
Table 1 lists the machines currently using the HL-1240 engine.
There are two versions of cartridges for these machines. The standard yield cartridge holds 150 grams and is rated for 3,000 pages. The high yield cartridge holds 220 grams and is rated for 6,000 pages. The reason the high yield cartridge achieves double the yield
while using only 50 percent more toner has to do with this engine's unique toner sensing system. These cartridges routinely leave as much as 80 grams of toner in the supply chamber, all the while reporting that the toner is depleted and refusing to print! Shaking the cartridge
at this point will only get you another 25 to 30 pages before the printer shuts down again.
Our testing has seen a maximum of 2,200 pages from an OEM standard cartridge, leaving 72 grams left in the supply hopper. In order to get the "OEM stated yield" of 3,000 and 6,000 pages, we recommend using 160 grams for the regular cartridge,
and 240 grams in the high yield version. TN-430 cartridges can easily be upgraded to a high yield by using the 240-gram load.
The tools needed to successfully and safely remanufacture toner cartridges are as follows:
- Toner-approved vacuum. We recommend the Atrix HCTV canister-type toner vac, or the Atrix AAA/Omega-style toner vacuum. Some type of approved toner vacuuming system is important. The toner consists of very fine particles that will pass right through a
normal vacuum filter and blow out the exhaust, creating a real mess.
- Phillips head screwdriver
- Small common screwdriver
- Needlenose pliers
- Black toner for the Brother 1240 (160g for TN430, TN-6300; 240g for TN460, TN-6600)
- Lint-free cotton cloths
- Toner magnet cloths
- White Lithium Grease
Before proceeding, you should have a work area available with clear space of about four feet by three feet. It should be covered with some disposable paper since toner will spill on this area. Taping brown craft paper to the workspace works well.
Also, an empty garbage can with a strong plastic liner should be adjacent to the work area to empty used toner. It should be at least two feet deep to prevent toner from clouding up and over the top of the bag during disposal. Have a few rags available and some
disposable paper towels. Toner magnet cloths are perfect for this task. Finally, the work area should well ventilated in case toner becomes dispersed into the air. An exhaust fan in one window is recommended for ventilation.
This following procedure details the complete disassembly of the cartridge. Although the cartridge can be refilled by simply pulling the fill plug, we recommend that the static roller be removed and cleaned. In our tests, density went up from 1.44 to 1.49 after
simply wiping the roller!
Figure 1.
- Vacuum the exterior of the cartridge.
- Remove the fill plug from the toner cartridge. Dump the remaining toner into the garbage, and vacuum clean. Make sure that the gear area is clean (Fig. 1).
- On the NON-GEAR SIDE of the static roller, pry off the white spring-loaded plastic axle (Fig. 2).
Figure 2.
- Locate the three tabs on the static roller end plate and pry off (Fig. 3).
Figure 3.
- On the GEAR SIDE, remove the two screws and cover plate (Fig. 4).
- Pry off the white plastic axle (Fig. 5).
- Remove the E-Ring and small gear (Fig. 6).
Figure 4.
Figure 5.
Figure 6.
- On the doctor blade side of the static roller, another small plate is located on the end of the roller and inside the plastic wall of the cartridge. From the outside of the wall, locate a small round hole. Press in the round tab located inside the hole. While pressing in, turn
the plate up so that the plate and roller are free (Figs. 7 and 8).
Figure 7.
Figure 8.
- Remove the static roller assembly (Fig. 9).
- Vacuum the doctor blade and foam feed roller. We do not recommend removing the doctor blade as the static roller felt seals will be disturbed. Once a new blade is available, great care must be taken not to tear the seals, causing a leak. Blowing the excess toner off and wiping with a lint-free cloth easily cleans the doctor blade. Be very careful not to leave any lint behind (Fig. 10).
Figure 9.
Figure 10.
- Clean the gears, making sure that the fine-toothed gears have no toner on them. This is a good time to also check the gear shafts to make sure there is enough grease. If the shafts appear dry or the grease is contaminated with toner clean the shaft and inside of the gear. Replace the grease with a product designed for this use (Fig. 11).
- Clean the static roller with a lint-free cloth. Do not use any chemicals to clean the roller. A dry, clean cloth works fine (Fig. 12).
Figure 11.
Figure 12.
- Reinstall the static roller, inside end plate first. Turn the inside plate so that it locks in place (Fig. 13).
Figure 13.
- Install the small outside end plate, and both the spring-loaded white axle and the non-spring axle (refer back to Figs. 2, 3 & 5).
- Install the static roller gear, and c-ring. Make sure all the other gears are meshing properly ( refer back to Fig. 6).
- Install the gear cover plate, and two screws (refer back to Fig. 4).
- Fill the cartridge with Brother 1240 toner (Fig. 14).
Figure 14.
- Replace the fill plug (refer back to Fig. 1).
- Wipe the cartridge down to remove any remaining toner dust.
Note: There are no reset fuses or procedures for this cartridge.
The cartridge printing process is best explained as a series of steps or stages.
In the first stage, the primary charge roller (PCR) places a uniform negative DC Bias voltage on the OPC drum surface. The amount of the negative DC Bias placed on the drum is controlled by the printer's intensity setting. This process is called conditioning.
In the second stage (also called the imaging section), the laser beam will discharge this DC voltage to ground wherever it strikes the OPC's surface, leaving a latent electrostatic image on the drum. The OPC drum's circumference is approximately a third of
a page and therefore makes three revolutions for each 11-inch printed page.
The third stage is where the toner image is developed on the drum by the developing section, or supply chamber, which contains the toner particles. The toner is held to the static roller by the DC Bias voltage that is supplied by the high voltage power supply.
This DC Bias voltage is controlled by the printer's intensity setting and causes either more or less toner to be attracted to the drum. This, in turn, will either increase or decrease the print density. The DC Bias voltages of both the primary charge roller and static roller
are controlled by the printer's intensity setting. The amount of toner on the static roller sleeve is controlled by the metal doctor blade, which uses pressure to keep the amount of toner constant on the static roller sleeve. This blade also causes a static charge to build up
on the toner, which helps keep the coating of toner even and allows easy transfer to the OPC drum.
As the laser-exposed areas of the OPC drum approach the static roller, the toner particles are attracted to the drums surface due to the opposite voltage potentials of the toner and laser-exposed surface of the OPC drum.
This image is then transferred to the paper as it passes below the drum by the transfer charge roller, which places a positive charge on the back of the paper. This positive charge causes the negatively charged toner on the drum's surface to be attracted to the
page. The small diameter of the drum, combined with the stiffness of the paper causes the paper to peel away from the drum. The static charge eliminator weakens the attractive forces between the negatively charged drum surface and the positively charged paper.
Without this help, thin paper may wrap itself around the drum.
The image is then fused onto the paper by the fuser assembly, which is comprised of the upper and lower fuser rollers. The lower rubber roller presses the page up into the upper roller, which then melts the toner into the paper.
The fourth stage is where the OPC drum is cleaned. For this engine, approximately 99 percent of the toner is transferred to the paper during the print cycle. The remaining 1 percent remains on the OPC drum and is cleaned off the drum by the wiper blade,
guided into the waste chamber by the recovery blade and stored in the waste chamber.
Once the print cycle has been completed, the primary charge roller will then place an AC voltage across the drum surface, erasing any residual charge left on the drum surface. The OPC drum is now ready to be conditioned by the primary charge roller using
the negative DC Bias voltage, and the print cycle starts again.
The primary charge roller operates at a lower voltage than the old-style corona wire, which generated ozone. The PCR also replaces the erase lamps that were present in older laser printers. The drawback to this technology is that if this roller becomes dirty,
or contaminated in any way, the printed pages will have the problems. Since the primary charge roller is not accessible from the outside of the cartridge, it cannot be cleaned by the user as the primary corona wires could be in older style cartridges.
— Technical Support Team, Summit Laser
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For further information, Mike Josiah and the technical staff at Summit Laser can be reached at 800-221-3516, 631-467-3205 or fax 631-467-3223. The company website can be accessed at www.summitlaser.com.
This article originally appeared in the October 2000 issue of Recharger.