My drum was exposed to light it now prints black sport on the paper

It sounds like the corona wire in the drum unit has broken or the drum is overloading toner. It is also possible that light is getting into the printer an exposing the whole drum to light.
Last and least likely is the toner powder could be the wrong type for your machine. This may have happened if your cartridge is a compatible or has been refilled, and may also happen to an original if it is very old ie more than two years since manufacture.

If you replaced the drums and the cartridges and still get white lines it means there is something obstructing the imager. I believe this printer has LED imagers, In the printing process areas that are exposed to the light are printed as black on the paper and areas that are not exposed are left white. I would look for some dirt or debris on the scanners or some LED are faulty. If it has a laser scanner there may be dirt on a mirror

If this a P2035 printer using a toner cart with a drum in it. The drum has been exposed to light or has a smudge on it. take the cart out and look at the drum. This is a round light blue tube located at the bottom of the cart. It is the drum because it is the only thing in the printer that will print a defect three times on the paper. You could also print about 0 black sheets of paper through the printer and it will go away. This is because the drum coating is in layers like an onion. You must get rid of the exposed layer to get to on that has not been exposed to light.

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Try to print a document and see if you will be getting same issue. Try to copy a document and see if same thing will happen also. Check if the cartridges are not running out of ink.

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Depending on what model of printer it is this can be a couple of causes. However they are more often than not caused by a fault somewhere in the cartridge.

The most common cause is a Drum fault in the cartridge. This particular fault is where the Drum has been exposed to Ultraviolet light. If the cartridge is at fault you can prove this by putting in another cartridge and trying again. This can be an empty cartridge as all you are trying to prove is that the cartridge is faulty. It could also be a stripped drum where the coating on the drum has worn or been scraped free from one side of the drum.

Other causes can be a faulty Wiper Blade (Also in the cartridge) this would normally show as a grey panel on the printout rather than solid Black. Faulty PCR also grey rather than solid black.

If it is printing completely blank on one half of the page but completely black on the other when trying to print a solid black page then I would suggest that you have toner settled on one end of the cartridge. Give the cartridge a shake if this is the case to free up the toner.

If the jam is consistent with exiting the drum, there's a chance the drum isn't secure and is the paper is getting caught on the exposed area of the drum. If this isn't the case, there may be paper caught in the feeder wheels.

The drum is a very sensitive part. Should not touch with bare hand, expose to light for long, etc. With what did you clean,it.

1. Charge – Print Quality (PQ) -- The charge roller evenly distributes a negative charge on the photoconductor (PC) drum. This evenly distributed charge acts as the film that is discharged (exposed) by the laser to create the latent image.
a. Print Quality effected: Faint, Entire Black background, Grey Fog/Haze
b. Parts Involved:
i. Drum -- A drum cartridge is coated with a photoconductive material that allows electricity to pass when exposed to light. As an example of why this can be the failure, if you leave a drum out in light long enough, you will get dark backgrounds or just black pages. However, drums do wear out over time too; specifically the photo material the drum is coated with. As this degrades, more of the positive electricity on the inside of the drum gets through and grabs toner, as if the laser wrote to every square inch of it. A damaged or defective PC drum can cause black streaks/lines, voids, speckles and various other print quality problems.
ii. Charge Roller – Also known as the BCR or Bias Charge Roll. The charge roller pulls double duty. It energizes the outside of the drum with negative energy and as a result it cleans any previous latent images. If the charge roller were failing to energize either due to the HVPS or the charge roller itself, it wouldn’t clean any previous unused toner deposits from the last revolution would start to accumulate and appear on paper more and more causing haze. A missing charge roller causes completely black pages.

iii. HVPS – High Voltage Power Supply -- Responsible for charging components such as the inside of the drum, the charge roller, and transfer roller. If the HVPS does not give enough to the charge roller it can fail in erasing the drum, causing entirely Black pages to be printed.

The drum is one of the most important major part of a laser printer. This part of the printer is so sensitive that fingerprints on it will ruin it and will cause poor print quality. If this is damaged then you will definitely need to have it replaced. This may cost a bit because it is a major component of a printer.

Laser printers works this way. A laser beam projects an image of the page to be printed onto an electrically charged rotating drum coated with selenium. Photoconductivity removes charge from the areas exposed to light. Dry ink (toner) particles are then electrostatically picked up by the drum's charged areas. The drum then prints the image onto paper by direct contact and heat, which fuses the ink to the paper.