My Samsung CLP-325 is printing four little vertical dots in the colour of the cartridges in the middle of the page and sometimes also at the top.

Delet the jobs in printer memory and turn OFF the printer and wait 1 minutes and turn ON.Delete the jobs on PC.

Laser, inkjet??? Model Make ??? You need to be more specific.it makes a difference on the type of ink used.

Spend a little time searching the topic on google and even this post. It appears that this has been a well documented problem since at least early 2008. The problem appears to be the imaging unit. According to several posts, Samsung has replaced several of the units. I purchased my CLP-300 in November 2008 and it worked with no problems until about 8 months in. The black text would print very lightly on the left side of the page about 1/4 of the way into the page. There was also a streak that ran down the page vertically that disrupted the text. I could change the font to any color and it would print just fine. After replacing several toner cartridges, I just began to print in a dark color for many months. After discovering all the posts on the internet this week, I contacted Samsung today with my documentation and evidence. They basically blew me off stating that I was outside of the 1 year warranty period and there was nothing they could do. I was even hung up on by a Samsung employee named Michael. Tonight I plan to take a hammer to it to relieve a little frustration. I cannot understand why Samsung chooses to ignore this well documented problem. Good luck.

you need to reassemble image unit and clean completely
if you dont know how to do just bring it your printer to technicians

yes you change it and buy new one because toner brush is not supply toner properly

Possible print alignment issue.
Check the toner and then go to properties of printer.
Clean heads etc and then print test page.
Wizard should assist to troubleshoot

black developer on drum worned out,need changing.

I suspect the problem is common. The Imaging unit requires a Black developer to be replaced. you may approach samsung service center for this.

The duplexer is bad or needs to be realigned, shake up the cyn color. it mostly likely low.

I have the same problem. Any solution?