Need Help Smudge when print head changes direction

[Dale D]

Any ideas what is causing my print head to leave marks like this only on the left side of the print when the print head changes direction? The print head is approx 1 yr old and it does this even after a cleaning

 

[Dale D]

Sorry, its a Roland VersaExpress 640 printer

 

[Solventinkjet]

Could be media buckling. Make sure the vacuum is up all the way. Check to see if the media is buckling during printing. If it is, turn the heat settings down. Then just check the bottom of the head to make sure there are no inkcicles forming and dragging along the media.

 

[Dale D]

Media is tight, not buckling. It even happens with the edge clamps on it. Ill check the vacuum. We have never changed the settings ion vacuum in 7 yrs and this just showed up about a week ago.

 

[Dale D]

If there is Inkcicles, what is the cause? Ill look shortly at the bottom of the head.

 

[Solventinkjet]

If there is Inkcicles, what is the cause? Ill look shortly at the bottom of the head.

If you print a lot of banner or other fibrous media, those little fibers can get stuck to the ink on the head. Over time ink drips down and solidifies little by little until it starts to touch the media while printing. It's always a good idea to take a look at the bottom of the head once a month or so just to make sure they aren't building up and clean them as necessary.

 

[Dale D]

I dont do banners much. Possibly 1 a month or 2. Most is printed on IJ180, 35, or 40

 

[Dale D]

What is odd, it that it only leaves a mark when the head stops and changes direction. No where else on the print.

 

[Jester1167]

Try cleaning your outfeed surfaces because it looks like every time the media advances, it raises up and hits the head. Usually with just the weight of that much media hanging over you won't have that problem.

You could also solve it by making the carriage go the full width, not just the width of the print. You will also get more consistent dry times before it hits the take-up reel.

 

[MelloImagingTechnologies]

Do a really good cleaning and inspect under an around printheads.
Typically this is caused by something minimally hanging under carriage and looks like its dropping down when carriage changes direction.
Bruce
melloimaging.com

 

[rjssigns]

Fuzz on the head. Quite possible to only show up on one side. There is a physics principle involved but my last physics class was decades ago.
Basically the "inkcicle" bends back against the direction of travel keeping it off the print.
When the head changes direction this causes the "inkcicle" to swing through an arc thus dragging it across the media until the force of acceleration causes it to swing up and off the media.

 

[Alebaba]

I had this exact problem on a Canon printer. I would clean the bottom of the printhead and found it dirty every single time. Even after printing a little bit. Whenever the printhead would change directions it would leak ink into the substrate. My suspicion was that the printhead was leaking ink. Printhead was 3 years old. I even tried putting some tape on the printhead's corner to hold up the ink. Didnt work. I changed the printhead and the problem was gone. Expensive solution but couldn't find any other way.

 

[Jester1167]

Every time you clean the head the wiper will leave a little ink on the backside of the head. The older the wiper the worse it will be.

In reality, the head should never contact the print. As before, I think the most likely scenario is, when the media advances, it buckles up for a split second and touches the head. On the right side, the media advances when the print head is off the media. on the left, it happens when the head is over the media if you don't have it set to full width scan. You should be able to shine a light in there and observe what is happening. Typically I would use a flashlight to get a better look.

My buddy claims if you turn your print heater off and dryer heater on it will stop. He does this for banner and calandard media.

 

[Jester1167]

I zoomed in and you have other problems going on. There are ink drops at the left side of the printed area that appear to correspond to the lines in the unprinted area. The consistency of the location and size is strange. I don't remember lint on the head doesn't make that constant of a pattern.

 

[Alebaba]

You can also setup the printhead to travel the entire width of the media and will change directions outside of your printable area - hence throwing off ink somewhere else.

I had a similar problem with a Mimaki printer that for some reason when printing yellow the first centimeter of solid yellow ink would have contaminated black on it. Something about the printhead changing directions that was causing the color to migrate. I changed my designs to include a solid yellow block on the left side so the printer would print/clean out the contaminated yellow before it prints the actual image. Not a full fix but worked.

 

[cstone94]

Clean the linear encoder with 99% isopropanol. From our years of printing experience, when we were running our Mimaki JV5's, we started spraying the front surface where the media travels (the post heated area) with anti-static spray. We found that the static buildup from the media was causing the media to slightly buckle, and cause head strikes that resemble what you've photographed.

Link to AntiStatic Spray: http://clairemfg.com/content/multi-purpose-anti-static-spray

 

[Dale D]

Thank you guys. Static electricity has been an issue in our new location this year. I have been shocked a few times when unrolling my vinyl after I laminated it. I also just toasted a touch screen on 1 of my Summa plotters when static electricity hit when I touched the screen. Lucky I had a spare.