While printing while lines are appearing what is the problem. I changed Drum also. But the same was repeating.

I guess you talk about Ricoh MP 1800.
The Black lines on the bottom appear because the copier has made more than 60,000 prints or more if new.
If it's bought used, than it has made 60,000 or more prints from the last change of the drum and the drum cleaning blade. For the print to be clean again, it will need to be changed the drum and drum cleaning blade. This copier as all other copiers have parts that have a yield.

Horisontal line: I assume you mean a line across the paper movement direction. Please, inspect if the line is repeating on exact distance from one to the other. Measure the distance, divide by Pi (3.14) and you'll get the diameter of the faulty roller. Also, please, make a half print test page (open the cover in the middle of the printing process). Inspect if the line is appearing before the fusing unit or after it.
Try printing with different cartridge, just to be sure the cartrige is causing the problem.
Primary charge roller and its bearrings can be dirty and not charging enough the drum, causing black lines
Weared stripe on the OPC drum caused by friction with jammed paper improperly pulled out can also be the root of the problem. Faulty laser-scanner unit can also write black lines randomly. Weared teflon sleeve on the fusing unit can accumulate toner and print repetitive defects.

If you are seeing vertical streaks/black lines your primary corona wire is dirty and or the fax scanner may be dirty.
1)To clean the corona wire you take the drum unit and toner cartridge and place it on disposable paper to avoid spilling.
2) Clean the primary corona wire inside the drum unit by sliding the blue tab from right to left several times.
3) Return the blue tab and snap it into the home position.
4) Reinstall the drum unit and toner cartridge.
5) Close the front cover.
Caution: if you do not return the blue tab to the home position it may repeat the black lines.

There will be a flap at the back that drops out and down to give access to the fuser for clearing jams and "straight through" printing. Four lines repeating down the page is equally likely to be be a mark on the cartridge drum, possibly from the Primary Charge Roller if the unit has been very hot or not used for a period of time in higher temperatures. Remove the toner cartridge and in LOW light manually rotate the drum using the gear at one end of the cylinder. Look for a scuff mark right across the drum or a black/grey line. You may be able to clean the drum with a cotton ball and alcohol. Try the print again and see if there is any improvement. If you have another cartridge in hand you might try that to verify cartridge or fuser.

If the lines repeat in a regular fashion, with a consistent distance from each other, you need to replace the imaging drum. I would take a print out with the horizontal lines on it, then fold the paper up until two of the lines overlap each other; this will tell you the general diameter of the drum and give you an idea of what to look for inside the machine.

-David.

Try to stop the copier (by jamming a sensor or opening a cover) mid-way through the printing cycle. Remove the 1/2 copied document out from the drum area. Look to see if you have the double printing. This will eliminate the fuser as the problem. If you don't have the double printing then the fuser's cleaning roller may be shot causing repeat image. If it is in the drum area it will be hard to determine since you already replaced the drum(?). But there is a "cleaning" lamp or charge wire on the drum to check.

From the service manual:


Vertical lines or streaks

Check for a leak where light might be entering the printer.

Check for circumferential scars on the photosensitive drum. If scars are present, replace the
drum cartridge if the line goes through all colors.

Check for circumferential scars on the upper fusing roller. If scars are present, replace the upper
fusing roller if the line goes through all colors.

Remove the imaging drum and inspect main charger or imaging drum for a contaminant, such as
a fiber, if the line goes through all colors.
CAUTION Do not expose the imaging drum to light for more than 15 seconds. The drum is light sensitive, and
exposure to light can cause permanent damage.
Vertical black lines

The toner cartridge is defective.

The toner cartridge is not seated properly.

The fuser entrance is dirty.

The fuser has scratches on it.

This might be a repetitive defect. If so, the lines will repeat at a consistent interval down the page.

The printer needs to be cleaned.

There is a problem in the heating element.
Vertical white lines

If white lines or streaks appear only in the black areas of the printed media, print several
configuration pages to clear the anomaly. If this does not clear the problem, check the sleeve
surface to confirm the defect, then replace the black toner cartridge.

If white lines appear only in a particular color, try printing several configuration pages to clear the
error. If the error does not clear, check the sleeve surface to confirm the defect, then replace the
defective toner cartridge.

There is a lack of toner or the toner cartridge is faulty.

There is dirt in the laser path.

The fuser is defective.

A mirror in the laser scanner is dirty.

your color laser printer pink vertical line appear on the roller and film drum,
1) you need check the pink drum surface, it got damage if you find there is a different color vertival line on the drum surface, so you need change the pink drum.
2) check the pink drum cleaner (call brush to return the waste toner), it can not clean well sometimes, if the drum surface good.

if the drum already been scratched out,so there is no solution to repair it,u have to change the drum.before change the drum check the copier glass surface if any dry up material,wipe it with dry cloth.

the drum life is over, change PC drum, also you may clean laser glass whats under the pc drum