Sharp Multifunctional Printer

Black spots on my print-outs – what causes them and how do I prevent them?

There are several reasons why your printer or photocopier could produce documents with black dots or smudges on them. This includes lack of moisture in the room, not telling your printer what paper type you’re using, a dodgy toner cartridge, if your printer hasn’t been serviced for a while, or if your photocopier has foreign material in it or has been damaged in some way.

This blog is going to explain why the above reasons can cause black spots and advise on how you can take steps to prevent them in the future.

Lack of Moisture

Laser photocopiers and printers require a certain level of static electricity to fuse the toner to the paper. If your printer is in a room that experiences low humidity levels, then it can interfere with the printer’s ability to bond toner effectively to the paper. To avoid this, investing in a Sharp Plasmacluster can help to improve print output in an environment that is too dry.

Incorrect Paper Selection

It is important that you tell the printer how thick the paper you are about to print on, or if it is a coated stock, such as gloss or silk. If the machine is expecting plain 80gsm paper to be used, but you are using 200gsm paper, for example, it will not heat the fuser to an appropriate temperature for thick paper, resulting in smudges and un-fused toner dust left on the surface.

Whenever you are printing on stocks that are not your standard office paper, be it a thicker paper or different paper stock, including envelopes or sheets of labels, you must be sure to change the paper tray settings, not just on the print driver window but on the actual machine itself. It is also advised that you use the bypass tray when printing on thick or coated stock, as it travels through the machine in the straightest route, which helps to prevent paper jamming. 

A Bad Toner Cartridge

Usually associated with compatible or re-filled cartridges, a leaky cartridge deposits toner inside your printer and onto your paper in places that it’s not intended, resulting in black spots. The easiest way to check if a cartridge has defects is to place it on a large piece of paper and tap it with a ruler, if toner is emitted from the cartridge, it is advised that you use a different cartridge, and dispose of the damaged one.

Check the Photocopier Glass

The glass on the photocopier may be to blame for black spots on printouts when copying documents. If there are specks of dust or dirt on the glass, then the photocopier will reproduce them on the printed outputs. To check if this is the cause, place a blank piece of paper on the glass and produce a copy, if there are black specks it is likely that the screen is dirty. Therefore, it is important that you make sure the glass surface is cleaned regularly to prevent this. After you have cleaned it, repeat the blank copy process and the printout should come out clear.

Foreign Material Causes Black Spots

Spots and streaks can be caused by foreign material finding its way inside the machine and sticking to or damaging the surface of the drum. The foreign material can be:

• Glue from labels
• Glue from envelopes
• Paper clips
• Staples

Toner builds up on the areas of the drum where the foreign objects are and creates black dots on the printed pages. The way to prevent this is to ensure that users don’t photocopy documents that contain paperclips or staples, and that when printing on labels or envelopes that the machine is told that is going to be printing on envelopes and labels (it will lower the temperature and prevent the glue from melting in the machine).

Needs Cleaning

Over time, the components inside copiers collect dust and dirt. Failure to properly clean inside a machine can affect its long-term performance. Sharp engineers carry out a preventative photocopier service as part of every visit to a customer. When they arrive at your offices, they will not only look at the broken-down machine, but all Sharp machines on-site and give them a good clean to remove any dust and dirt to prevent black marks on the printouts, and also prevent future breakdowns.

See more about Sharp Printers & Photocopiers.