12a cartridge gives 4 horizontal line - HP LaserJet 1020 Printer

Try a different cartridge, blank horizontal would point towards a possible drum issue. Does the defect repeat down the page?

If you are getting smearing then likely the drum is dragging. If you simply added more toner without emptying the waste bin that would be the reason.

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.

This sort if thing is acually caused by a mark on the drum. Check to see if it comes out on this printer and see if it is scratched. Drums are usually a user replaceable part that can be purchased from HP or other HP stockist

change wiper blade (drum cleaning blade )

Hi
Replace the ink cartridge with another

User manual page 6.17 says:
Horizontal streaks indicate improperly installed or defective toner cartridge. Try re-installing the cartridge.

http://downloadcenter.samsung.com/content/UM/200607/20060712143739406_ML-1710_English.pdf

Hi,

Based on what you described the problem may be with your toner cartridge. The green photosensitve drum has become faulty somehow. I'd suggest trying another toner cartridge, it's the easiest way to determine what the problem is.

Another part that could be at fault is the scanner. It "etches' the image to the drum inside the cartridge, so if the scanner is bad it can make it look as if the toner cartridge is bad.

Hi ,
try the following link:
http://tinyurl.com/dyz9bj
or else here is the price list:
HP 12A (Q2612A) Compatible 2,200 Yield Black Toner Cartridge - HP LaserJet 1012, 1018, 1020, 1022, 1022N, 1022NW, 3050, M1319F 
Price: $24.99
Sale Price: $24.99 Quantity: 
3-PACK HP 12A (Q2612A) Compatible 2,200 Yield Black Toner Cartridge - HP LaserJet 1012, 1018, 1020, 1022, 1022N, 1022NW, 3050, 3052, 3055, M1319F 
Price: $62.99
Sale Price: $62.99 Quantity: 
HP 12A (Q2612A) OEM Original 2,000 Yield Black Toner Cartridge - HP LaserJet 1012, 1018, 1020, 1022, 1022N, 1022NW, 3050, 3052, 3055, M1319F
Sale Price: $72.99

hwo to reffil hp 12A cartridge