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Author Topic: Can a single starwheel be removed?  (Read 510 times)

simplesimon

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Can a single starwheel be removed?
« on: January 04, 2019, 11:49:09 pm »

There is one wheel on my Z3200 that fairly consistently leaves a faint scratch on platine or baryta papers. It is on the inboard row of wheels, clearly visible with the window open. The wheels are set to up in the paper profiles. I have cleaned it with isopropyl alcohol, and have checked the movement separately by nudging wheels around with a small screwdriver. It is not quite as free turning as the other wheels, but it is not tight. I also work a piece of cardboard between the wheels before starting a print to make sure they're moving first, but the line is still there for the first four or five inches of paper feed. The scratch is at best only noticeable from certain angles, at worst it leaves a clearly visible white line in areas of printed color.
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Ernst Dinkla

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Re: Can a single starwheel be removed?
« Reply #1 on: January 05, 2019, 04:22:38 am »

Yes. Last week a corner fold at the end of a sheet knocked out a starwheel here and deformed the spring axle. I removed the starwheel bar and folded the spring axle it runs on upwards so it could not touch the media surface. Printed other things afterwards without issue. I have an extra bar here left over from an HP upgrade for the Z3100 a decade ago so I can use parts of it when there is time to do it. I think some HP desktop models have similar starwheels but not the same spring axles. If you use wide rolls not that often you might exchnage a wheel from the eother side if you get issues with one wheel less. Kind of delicate operation though.

Met vriendelijke groet, Ernst

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simplesimon

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Re: Can a single starwheel be removed?
« Reply #2 on: January 05, 2019, 01:17:06 pm »

Thank you. After losing seven prints to the scratching, I felt more comfortable in doing something from reading your post. I removed the two torx head screws holding the rail to the printer, and the spring clip retaining the wheel sections on the rail. I identified three sections that had a little tension when turning starwheels, and soaked them in isopropyl alcohol. After that, I popped out the spring axles, inspected the center of the wheels (which all looked clean at this point) and reinstalled the wheels. They all seem to be turning quite well now. Had I known it was such a simple operation, I would have done it much sooner. I was concerned I could throw something with the wheels or rubber rollers underneath, but nothing seems to be adjustable in what I did, as it's just held in by those two screws threaded into plastic bosses. If it still scratches, I will either completely remove the offending wheel, or take it off, grind down the very tips of the teeth on a diamond plate, and put it back with that reduced profile.
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deanwork

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Re: Can a single starwheel be removed?
« Reply #3 on: January 06, 2019, 04:10:32 pm »

I had this happen a few weeks ago with a bad paper jam printing on curled hand made hemp paper. It was a very bad train wreck and I almost messed things up big time with the ribbon cable on the carrage assembly getting the torn up paper out. Afterward I was getting black marks on my roll prints. I saw ink on a couple of star wheels and one was bent. I cleaned them with alcohol and straightened one that was bent with needle nose pliers right in the printer ( with a good work light ) . Everything was fine after that, but scary. Don’t take chances with warped paper or paper with frayed organic edges that can get caught in the star wheels. Since the very beginning of the z series the star wheels are one of the weak points of the printer. But they did fix the scratching on gloss media that was epidemic on the first two years of the z3100. I’ve had very few problems since then, but I treat my printers like little babies and try to avoid warped media. If you are careless you can end up with a costly service bill because of those star wheels.

John


quote author=simplesimon link=topic=128393.msg1087261#msg1087261 date=1546712226]
Thank you. After losing seven prints to the scratching, I felt more comfortable in doing something from reading your post. I removed the two torx head screws holding the rail to the printer, and the spring clip retaining the wheel sections on the rail. I identified three sections that had a little tension when turning starwheels, and soaked them in isopropyl alcohol. After that, I popped out the spring axles, inspected the center of the wheels (which all looked clean at this point) and reinstalled the wheels. They all seem to be turning quite well now. Had I known it was such a simple operation, I would have done it much sooner. I was concerned I could throw something with the wheels or rubber rollers underneath, but nothing seems to be adjustable in what I did, as it's just held in by those two screws threaded into plastic bosses. If it still scratches, I will either completely remove the offending wheel, or take it off, grind down the very tips of the teeth on a diamond plate, and put it back with that reduced profile.
[/quote]
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