Streaks appear on prints when hitting the print carriage

HP Latex 300 Series

#1 pideas1 8 years ago

Marc, I think what Graphikal is referring to is very common issue with some stocks. I have experienced it mutliple times. When I run a standard glossy or matte poster stock, the media hits the bottom of the print carriage as it advances causing streaks on the prints. It's more evident with heavy solid prints. This usually occurs before the media reaches the heater. The ink on the media bubbles up a little so it hits the bottom of the carriage causing streaks to appear on the pre-dried print. This is one of the other common flaws of the latex machine along with the head crashes/strikes. This usually occurs when not using the TUR. I don't always use the TUR if I have shorter runs because I have to waste 5-10 feet of media if I connect to the TUR. As a fix, I increase the vacuum pressure for that particular media. Also, if I have a very short run, I have pull down on the media as it exits to flatten it out the media so it doesn't hit the bottom of the carriage.

#2 Graphikal 8 years ago

Yes, this is exactly what I was referring to. We had a true 'head strike' for the first time a couple of days ago - I realize I was using the wrong terminology. I'm going to try your vacuum adjustment idea, and we've begun using a longer leader on the media, advancing it beyond the platen into the heater area. That seems to mitigate the problem. The premium poster paper, being a thicker media, tends to have a stronger 'memory' and retains some cupping or curl if it sits in the machine, so the leading edge needs to be advance considerably to get beyond the problem area to avoid these drag marks. Thanks for your post!

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#3 HP-MarcM 8 years ago

Hi again, My recommendation is to use the Take-up-reel. Just for you to know, you can use the "Bypass start job safety" (you can find it in the user guide) in order to optimize the media advancement until the exit of the impinging.

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#4 pideas1 8 years ago

Marc, The take up reel is not always an option especially when you have a short run. If I were to use the take up reel, i would have to waste 3-4 feet of media on every run. Not necessarily cost efficient unless I have a 15-20+ foot run. The take up reel is also an option on the 110 and 310 so it's not an ideal solution.

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#5 HP-MarcM 8 years ago

Hi pideas, I know that the TUR is not always the a valid solution due to the media waste. For that reason I was purposing you the "Bypass start job safety" (page 78 of the user guide). Did you tried?

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#6 PrintReadyFile 8 years ago

should this feature just be turned off as the default then? i cant think of a time when i have the paper not either hanging from the front or on a TUR... what is the feature essentially doing?

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#7 HP-MarcM 8 years ago

Hi PrintReadyFile, The job start safety mode is activated by default so that the leading edge of the substrate does not crash under the curing system. This mode basically reduces the velocity of the leading edge when entering in the curing zone in order to avoid the media to rise from the platen due to the air streams generated in the curing zone. Once the leading edge comes out from the curing zone this feature is deactivated itself. If you print with the substrate hanging from the front of the printer, or using the TUR, you may want to deactivate this option. Hope this helps

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