First, when the printed paper has a significant black on the back, clean up the waste toner box.
After the printer cartridge refill the ink, when the printed paper has a significant black on the back, the direct reason is that the soft scraper under the toner cartridge box has been filled, and the waste powder overflow. Under normal circumstances, each print only need about 5 to 20% of the toner transferred to the paper, the corresponding roller on the corresponding part of the paper toner is a soft scraper collected the overflow toner into the waste toner box, when the waste toner box is full and the spill toner will pollute the paper. Clear waste powder is not difficult, different brands of toner cartridge's waste toner box design is slightly different, the need for users hands-on assembly and dis-assembly, there are many detailed steps on the waste toner warehouse cleaning on the internet, the user can do it according to the internet step. We need to pay attention to the waste powder can not be recycled, because the waste powder loss he effective after it make the reaction with the magnetic stick and drum core.

Second, if the the font fades or appear white lines on the print paper, the problem is coming from the magnetic stick
After the cartridge filling powder, if the font appears to be too light or some of the word is not clear with white line, then we should check the powder on the stick first. The common situation is that your new brand of cartridge ink is different from the original cartridge ink,the two different brands of toner will appear to affect each other to let the faint situation. The solution is to clean the original powder on the magnetic stick and then fill the powder. It should be noted when we remove the drum core that we should pay attention to protect the drum core, because the drum core can not see the light, including sunlight and glare light, and finally placed in a black bag for cleaning.If all those step is difficult for you that you can change the ink cartridge by yourself and the operate is so easy, just need to purchase a cartridge ink according to your printer model, my printer brand is Brother and then I can choose the brother tn 660 to replace the original ink cartridge. The print paper quality is good and it can printer about 2600 pages for one package.

Third, print the paper appears black pot or black line, the problem come from the drum core.
After the toner be filled and the printed with black pot or black line,under normal circumstances is the drum core dirty or wear, drum core dirty is easier to handle, you can move the drum core along the rotation, Clean with a cotton wool when the drum core rolling, after you clean the drum core and the print will return to normal.Another situation is drum core wear, such as put the drum on the ground when you filling the toner or hit a hard knife like a screwdriver. Because the drum is made of photosensitive material, so the repair method is to use a photosensitive drum polishing detergent repeatedly rub the photosensitive drum surface 3-4 times, please do not to let the photosensitive drum surface cleaning agent and then back to the drum that can be used again.
Of course, if the drum core wear too much, then it is necessary to replace the drum core. Drum core price is not so expensive,as generally speaking, each drum core may add three to five times the powder, but we should pay attention to model and quality in advance and do not casually substitute.