Pre-Testing
When we receive a cartridge to be recharged we first test the cartridge to determine if the cartridge can be recharged without repair. By running tests we are able to determine if any of the major components will need to be replaced.
Several test sheets must be run. The first one or two are discarded as "cleaning paper", and the next few are examined for image quality. If a cartridge has been run completely empty a pretest won't be possible.

Diagnostics
If a pre-test is possible, various types of marks on the page will determine which components are worn. For instance:
1. Anything that occurs 3 times down the page, whether it be fading or black marks, is usually the sign of a worn drum.
2. 6 or more marks is usually the sign of a bad magnetic roller or charge roller.
3. Hazy vertical lines are usually the sign of a dirty charge assembly or one that is shorting out.
4. Straight vertical lines or repeated print are usually a sign of a worn wiper blade.

Cartridge assembly
The cartridge assembly must be disassembled and thoroughly inspected prior to recharge. A trained technician must determine by visual inspection combined with the results from the pretest, whether any of the components are worn and need replacement

Residual Toner
Any residual toner in the assembly must be dumped. Because of the dusty nature of the toner, protective clothing equipment must be worn including a dust mask and gloves. The toner dust must be controlled during this step. Both the hopper and dust bin should be thoroughly vacuumed If the wiper blade is still in the dust bin, care should be taken to avoid damaging. All parts should then be blown off with an air hose.

Magnetic Roller
Before the opening of the hopper is a magnetic roller that transports the toner to the drum. The charge that represents the image is transferred to the drum then the drum collects corresponding toner and transfers it to the paper. The "Doctor Blade" keeps the toner spread evenly across the roller. 1/3 of the page image is transferred per rotation.
When cleaning the magnetic roller must be wiped down. If toner is embedded in the surface of the roller. The entire roller must be cleaned with alcohol, this will keep print uniform. Toner should be rubbed into the surface, during refilling. This helps the roller carry the toner evenly. Check the magnetic roller for gouges, and replace if not in good condition.

The Charge Assembly
There are two types of charge assemblies, the newer type uses a charge roller, and the older types use a thin "Corona" or charge wire. The charge roller or wire is responsible for placing the charge on the drum or paper, some units use both.

Corona wire
A corona wire should first be cleaned as should the rest of the corona assembly and all contacts. The wire should then be burnished to remove any film left on it. The wire should then be tested for continuity if the continuity is not consistent the corona wire must be replaced or re-strung.

Charge roller
The surface of a charge roller should first be cleaned with water or peroxide and wiped dry. Conductive cream should then be applied to keep the surface pliable without hindering the charge. The metal roller ends should be cleaned with peroxide, then alcohol, and the cradle where the roller ends sit should also be cleaned with alcohol. Charge rollers should be checked for nicks, surface pealing, or flaking, and replace as necessary.

The Drum
The drum is a cylinder with an organic or synthetic photo conductor coating that carries the image, still in powdered toner form, to the paper. Most drums will rotate 3 times to cover a single letter size page. This means that only 1/3 of the image can be placed on the drum at one time.
After the other components are removed and cleaned, the Drum should be cleaned with water or peroxide. Any embedded toner should be removed with 99% alcohol. Depending upon the type of drum being cleaned, scuffs and minor scratches may sometimes be removed. The drum must be protected from exposure to light.

The Waste Bin
The opening to the waste bin is lined with the wiper blade on one side and the recovery blade on the other side. As the wiper blade scrapes residual toner from the drum, it drops onto the recovery blade that which directs it into the waste bin. Because the toner in the waste bin has been charged, it can no longer be used.

The Wiper Blade
The wiper blade, is a polyurethane strip with a fiber pad running the length that rides against the drum and covers the waste bin. Any residual toner left on the drum must be cleaned off before the next rotation. If it is not cleaned off, the first image will be repeated in a ghost-like background of the next image, and the second 1/3 of the image will also be repeated in a ghostlike background of the last image the wiper blade prevents this from happening.
To work properly the edge of the wiper blade must be precision sharp and smooth. The slightest little nick, scratch, or bow will allow residual toner to pass through and results in a ghosted background image, scratch marks, or lines on the page.

The Recovery Blade
The recovery blade is a thin Mylar strip that rests against the length of the drum and captures the excess toner falling from the wiper blade. If the recovery blade is rippled, bowed, nicked or scratched, or missing, the residual toner will fall onto the paper. The recovery blade must be carefully inspected. If it is not perfectly straight, and free of defects it must be replaced.
The wiper blade and recovery blade must be cleaned with water or peroxide, then wiped completely dry. To prevent dry rotting, a professional technician may coat the wiper blade with a protectant. Caution must be exercised this does not work well on all types of wiper blades, and may cause damage to some drums. Lastly the wiper should be dusted with lubricating powder.

Re-filling
The Drum or Cartridge is carefully filled with the proper measure of new toner in a carefully controlled environment where the excess toner dust can be properly contained. After filling, the hopper cap is immediately replaced. Excess toner is blown off with compressed air.
The drum should be checked for leaks prior to shipment. After tapping, turn the magnetic roller to see if any toner is on it. If your hopper is leak free, the magnet roller should be clean.

Reassembly
The cartridge should be should be dusted lightly with a lubricating powder, to prevent drum wear and keep the wiper blade from flipping. Once fastened, the drum should be rotated over the wiper blade to ensure proper operation of the wiper blade. The padding powder should be evenly cleaned off the drum as it is rotated. Once completely reassembled, the drum should be rotated to ensure that it is properly seated. If it is not, it will snap into place upon rotation.

Calibrations
The gap for the doctor blade must be set evenly on both sides using a gauge to ensure an even flow of toner to the magnetic roller in the correct thickness. The magnetic roller must be primed by placing an even amount of extra toner across the length of the roller. Rotate the magnetic roller, away from the doctor blade, until the heap of toner is all down under the doctor blade, and the roller is completely covered.

Final Testing
The cartridge should now be tested to ensure proper operation.
1. The first page is typically a text page. It should be examined for even printing throughout the entire page.
2. Then it should be carefully examined under a magnifying glass for broken or distorted letters.
3. The next page to be run is solid black page. For copiers, this would be accomplished by opening the copy-board cover and running a copy. A solid black page will print.
4. If you are using a laser or printer, you will have to prepare a solid page to be printed.
5. Check the solid black page for even print throughout. Light spots indicate a problem.
6. Next run a solid white sheet. Examine it for marks of any kind. Any flaws in the drum, charge roller, or magnetic roller will show up here.

Shipping toner seal
For locally delivery or pickup, seals are not typically used. For cartridges that are shipped, an adhesive seal is placed between the hopper and the magnetic roller where required. this seal keeps the toner in the hopper during transportation. Before shipping, the unit is checked for leaks by gently tapping it on a table at different angles, and tapping it on the sides by hand.

Outer-Housing Cleaning
After testing, all of the residual toner and finger marks are cleaned from the cartridge unit with alcohol. Care must be taken so that the drum is not touched through the shutter door while cleaning, especially if the drum was recoated. The alcohol might dissolve the coating and cause major print defects.

Packaging
The cartridge is then sealed in an air-tight, static free, foil bag with black inner lining to prevent light from getting in. Drums are photosensitive and can be damaged with prolonged exposure to light. The bag is then packed in a cartridge box with packing material to protect it during shipment.