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Automatic Take up unit for print and cut applications
Been trying to create a solution to automatically take up print and cut jobs.
I have almost come up with a system but I think I’ll need to add some electronics and modify it a bit.
Basically what I’d done is added two extra tubes infront of the printer. The higher black one is fixed. The one in the yellow area is free to move up and down within the yellow area. What happens is when the materials sags below the yellow box so that tube is no longer putting weight in the material the tension between the fixed tube and the take up unit is reduced so it winds up the media.
My problem is the weight the take up unit puts on the media needs to be counteracted with the tube in the yellow area. This causes a problem on too much weight being put on the media when it pulls the media back through for print and cut and stuffs up the cuts.
I basically need the tube in the yellow area to be light as possible.
I’m thinking of making this tube touch a switch at the bottom which then activates the take up roller to a point where the tube is lifted and no longer touching the switch. I wouldn’t then need the dancer bar to be used thus not needing something heavy to pull down the material.
Any input appreciated.
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20 Replies
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I want to pinch you idea, love it!
I would only want to use it for print only jobs though so it should work as it is… any chance of a tutorial or even just a few photographs of how you put it together?
Cheers
Gavin
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Gavin the stock take up unit works with print only jobs. I’m trying to modify the setup so print and cut jobs work. Print and cut jobs need the job to print say 50cm then this material pulled back through the printer to be able to cut then its spat out again.
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Ahh ok, i thought you had made you own take up roll as I have been thinking of doing this.
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Gavin is you want a simple system just get a pully or a rope and tie it around the flange of where your media is before it enters the printer and tie it to a tube at the front of the printer. When the media unwinds it should wind that tube. Its simple might not work without problems but it should work.
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Good plan Jason, that should work fine for long vinyl runs. The more complicated bit is getting something to work for banner as I reel this of the roll first.
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This is close to the take up roll works on our Summa DC3. Only diffrence is that when the material sags it blocks 2 optical sensors causing the machine to start the rollers and roll up the material until the sensor isn’t blocked anymore.
That’s the idea atleast. Problem is that the DC3 has to weak motors doing the rolling up, so it can’t rotate the rollers. Good idea, poor execution. 🙂
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Hey Tobias,
Do you know what kind of sensors the take up mechanism employs. I’m thinking of creating a sensor that is attached to a servo that pushes the button on my take up unit.
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It’s just a photo sensor. When the sagging media blocks the sensor, the circuit closes and the motor start. Once the motors lift the material enough the photo sensor isn’t blocked anymore and thus breaks the circuit and stopping the motor.
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Hi Jason,
Just trying to understand the basic system first to see if I can offer any help.
What activates the take-up motor … to start .. and then to stop?
How much torque does it have?
Is the motor a 240v one or only a low voltage one .. eg 9 or 12 volt?
How heavy is the movable roller you’re using now?
What is the dancer bar that you refer to .. is that the roller that moves up and down in the area designated by the yellow box?
Regards, Roger
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Hey Roger,
The dancer bar is part of the take up unit that comes with the machine. This is what keeps the media taught as it comes out of the printer on a print only application.
The take up unit works by once that dancer roller gets lowered to a certain point it winds back up.
You can see how the default setup works in this video
http://www.youtube.com/watch?v=wXQTqAQ8sjM
This doesnt allow the printer to pull back the media in a print and cut application.
So I’m trying to create a system where I have some or slack in the media before it gets upto the take up unit and where there is an excess of slack the take up unit kicks it.
That’s why I have that black roller up the top to keep the tension between that roller and the take up unit constant. When the slack under the roller in the yellow area increases the media should move over that upper roller causing less tension between the upper roller and the take up unit thus winding it up.
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Have you got a semi working version of this additional roller system as if not then they may be a couple of fundemental flaws.
1 Since the roller will be resting on the print side of the vinyl directly after printing I can see potential issues with marking of the face. Its one of the reasons that all take up systems allow a large sag of material before rolling up.
2 The natural curve of the vinyl will be in the opposite direction to the slack roller so a lightweight roller may not overcome the tension in the material when near the top.
3 If the roller does make it to the bottom, by counter rolling the vinyl it will billow out at the top where entering and exiting the additional drop and if they touch it will be ink to ink and is likely to stick together.
Don’t want to pour cold water on your idea but didn’t know if these concerns might affect your design.
Colin
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Hi Jason,
Not discounting what Colin has raised above, I think the control side should be a piece of cake.
A picture tells a thousand words .. so I put together a couple of quick and dirty graphics to show what I mean.
Never used Imageshack before .. so hope it works. 🙂
Regards, Roger
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Hey Roger,
Ive actually just purchased the same micro switch 🙂
I’m going to try it over the weekend.
Collin I’ve tried my current setup the only problem was that the weight of the roller was to great.
I’m going to try the micro switch method and report back.
Jason
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No worries Jason,
Hope you get some good results.
I started off making it too complicated with opto couplers and all sorts of electronics … but simple is best .. usually 🙂
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Hey Roger,
Here it is. The NEW AND IMPROVED take up roller attachment switch.
I bought another power supply. I had to jam the manual take up switch button so it was always on. I didn’t really want to hack my take up unit internally. So jammed the take up switch to always on.
I hacked the new power supply I bought so when I want print and cut take up roller I can just switch the power supplies around.
I need to build a more permanent holder and roller but this was just a test.
Here is the video: http://www.mediapoint.com.au/uksb/takeuproller.wmv
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This seems to work fine and doesn’t have any of the problems I mentioned so well done.
I know if it was me though I would still be using the prototype 2 years down the line 🙂
Colin
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Well done Jason … looks like it works well.
Bit of fine tuning and pretty it up, and you’ll be able to sell it as an add-on kit for other users. 🙂
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Hey Collin and Roger,
I’m just going to build a case for it like one of those bolts with the plastic handle on the end so you can slide it across the top of the take up roller unit rail like the end holder currently does and just mount the switch on top of this.
The only concern I have is the switch might get jammed. What I was thinking is using two switches in series so both would have to get jammed for it to stuff up. Both switches would also have to be activated for it to work also.
I will play so more and post my results.
I’ve been doing tones of sticker runs lately and manually winding up the take up unit drives me nuts. Hopefully this works and I can run my longer sticker runs over night.
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I’ve just done a ten metre run of print and cut stickers. Worked without a hitch and I didn’t have to baby sit the printer.
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It was worth persevering then, especially if it’s going to free you up and save you some time. 🙂
Why do you think the switch might jam? They are pretty reliable devices, and the whole thing is pretty simple ….
Regards, Roger
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