HP 8450 scratching issue

[espressogeek]

Hello all. I just bought an 8450 for its outstanding b&w output. However I have noticed at the end of the print (a4) and the begining there are marks from something mechanical in the printer. These marks are perpendicular to the print head action so its clearly the small roller guides or something else. Any ideas on what I can do to correct this?
Thanks

 

[parallax]

I think the marks are called 'pizza wheel' marks. Google on that and you might find some info.

 

[espressogeek]

Well, i spent an hour on the phone with hp yesterday. I had to escalate past the first level support person to get to someone who actually knew something about their printers. He says the paper I am using is to thin. But I tried the HP super premium photo plus whatever paper and the marks are more visible. I dont think its the pizza wheel either. I think its the feed roller in the back left side although it is perfectly clean. I tried to wear it down a bit by using a razor blade while letting the printer spin the wheel at high speed. I have not been brave enough to make a full print yet.

 

[jlw]

I'm not familiar with this particular HP printer model, but it's interesting that you say this happens only toward the end of the print.

I've had this kind of behavior on other printers caused by flexing of the sheet as it exits the printer. Toward the beginning of the sheet, there's not much paper sticking out past the printhead, so not much flex. Toward the end, when most of the sheet already has been printed, the weight of the paper causes it to bend slightly in the paper path, making it more likely to be scraped. (This may be why your HP tech suggested your paper was too thin: thinner paper is more likely to flex.)

You might check to make sure nothing is obstructing the exit of the paper, and that you have unfolded or extended all the pieces that support the sheet as it is coming out of the printer.

 

[Peter S]

I also had a similar problem with my HP8450. It turned out it came with HP paper with a tab. Don't know how to explain apart from the fact that the paper was partially precut. I never noticed it when I put the paper in the printer, but it was clear after printing. Had me puzzled for 30 minutes or so. Never had pizzawheel problems.

Good luck

Peter