Any experience with Designjet 4500 printers?

[D Hook]

Seem to be having trouble with the lower roll loading on the Designjet 4500. If there is a lot of slack in the paper it loads just fine but a soon as the slack tightens the paper doesn't move through the printer and throws a error message about paper jam. Of course, it isn't a paper jam since it completes the loading process as long as there's slack in the paper. It seems like the roller tension can't overcome the rewinder on tray 2.
This is the first time I've run into a problem like this with the rewinder not allowing the paper to move forward. Is there an adjustment to be made to either the rewinder or to the pinch rollers that move the paper forward?
Thanks!

[blackcat4866]

Re: Any experience with Designjet 4500 printers?

I've seen something like this on the T3500 (newer model).

The paper slips back about 2" then overprints the 2" of image. Then it pulls an error (not a jam) ... sorry, I can't remember the code. At first I thought the takeup was too strong, but it was just the hard foamy registration roller dirty. Just cleaning the roller took care of it.

It did take some disassembly to get to the reg roller. =^..^=

[D Hook]

Re: Any experience with Designjet 4500 printers?

I've run into that problem with dirty rollers on smaller printers where paper dust gets on the rollers and they lose their grip. Cleaning is free so I'll try that first.

Thanks!

[Kiran Otter]

Re: Any experience with Designjet 4500 printers?

I don't quite why that would be but I have a couple questions:

Has the 2nd roll feed module ever been removed from the printer and reattached?

And what kind of paper is it, specifically? Have you tried any other kind of paper?

Kiran

[D Hook]

Re: Any experience with Designjet 4500 printers?

Printer is new to me so don't know if it's been removed or not.

Tried a couple different types from regular 20# bond to thicker photo but same result. Have yet to try some 42" wide to see if that might load better.

I unrolled a length of the bond paper and manually fed it through, watching the paper path to see (or feel) if there was anything pinching the paper but couldn't see or feel anything. So no obstruction.

I'm not certain how those rewinders work. I don't see any wires running to the left side but there must be something that allows the spindle to turn freely and then something that adds the resistance. So I took off the small plate that holds in the pin that engages the spindle when the drawer is pushed in and held the pin out
w/a pair of vise grips so it doesn't engage the spindle when the drawer is pushed in. It loaded the paper just fine but of course the rewinder wasn't pulling any tension on the paper.

So is there maybe an adjustment on the rewinder mechanism to reduce the tension or on the pinch roller to be made to give more "pinch" on the paper?

Thanks!

[Kiran Otter]

Re: Any experience with Designjet 4500 printers?

There is a Media Drive Test in the diagnostics. It's very lengthy but it does test the 2 roll feeds. That might shed some light on the problem.

I don't recall there being any mechanism that toggles the tension... but I haven't looked at one in years. As far as I know the roll should be free to turn at all times. I don't think there's a rewinder motor either that turns the spindle backwards, looking at the service manual. All I do recall is that BT (back tension) arm assembly and encoder being a problem on one I repaired. That #3 in the exploded view in the manual is the the encoder disk. I don't know how the tension would be related but it does give feedback to the printer about the paper moving or not.

Kiran

[D Hook]

Re: Any experience with Designjet 4500 printers?

Great. That will give me another way to look at this thing.

I have the service manual so will run those tests next.

Thanks!

[D Hook]

Re: Any experience with Designjet 4500 printers?

There is definetly something that turns the roll backwards to keep tension on the paper but it feels spring loaded rather than a motor. I disabled the mechanical device on the tensioner and it lets the roll free wheel while loading and the paper loads just fine. I tried using a 24" roll of plain 20# bond, a roll of 36" heavy coated and a roll of 42" coated. The 24" slips during loading, throws an error, when the tensioner is enabled. Without the tensioner it loads fine. Same for the 36". I did get the 42" to load with the tensioner engaged once. Didn't try it a second time yet but will try again today to see if the wider paper is more likely to load than the narrower paper. This might indicate that SOME of the rollers are worn (reducing their diameter) but not all.

When the tensioner is engaged you can turn the spindle to unwind paper but then, when you let go of the spindle, it rewinds, creating tension on the paper. This allows the paper to load without skewing. Disengage the tensioner and it's almost impossible to load paper without skewing.

After taking off the left end cover, you can see the gear assembly that drives the spindle but whatever drives those gears is hidden. It is keyed to give a positive lock when the drawer is pushed in and releases the gear mechanism when the drawer is pulled out to allow the spindle to free wheel. I think it also free wheels after pushing the drawer in before hitting the button that starts the load process and moves the paper. After that, the spindle is engaged and will rewind the slack during the loading and parking process to prevent the paper from skewing.

My next thing to try (after doing the tests you suggested) is to use a light spray of Stickum (stuff football players use on their hands to give grip on the ball) but just a dusting to see if it adds enough traction to load the paper. But only on one of the rubber rollers. Also been researching what could be used to treat the neoprene (?) that's on the roller that might make the neoprene swell slightly and create more grip against the pinch rollers. That would help narrow down the cause of the slipping. It's possible the roller is just worn out I guess and needs to be replaced to give the grip it once had. Just didn't think those things would wear out enough to make them slip. It's also possible I could rough up the surface with emery cloth or sand paper to remove whatever gunk has accumulated on the surface of the roller. (Already tried cleaning but with just some generic glass cleaner.) From the Useage Report it's run about 17,000 sq. ft. of paper through the printer, which seems like a lot. And that's of just the bond paper. More if you count all the other different papers. Maybe not all of it has gone through drawer #2 though. Drawer #1 has no slippage problem and loads/unloads/parks and reloads just fine. Paper useage is not broken down by drawer # though.

I'll update as to what I find.

[Kiran Otter]

Re: Any experience with Designjet 4500 printers?

That's right about the spring-loaded thing.. I totally forgot about that. I'm really surprised that's creating that much tension but I do recall it being pretty strong when trying to pull the paper off the roll.

It's been extremely rare that I've had to do anything to the rollers in any Designjet, but I have used Rubber Renew with success. It's nasty stuff but it worked. It's available on Amazon.

Let us know what happens.

Kiran

MG Chemicals 408A-125ML Rubber Renue, 125 ml Liquid Bottle

[D Hook]

Re: Any experience with Designjet 4500 printers?

Thanks Kiran. Just placed an order for both the Rubber Renu and also a spray can of platten/roller cleaner. Amazon shows mostly good reviews for both products but must use care when applying so an not to get on other parts. Someone else suggested carb cleaner since ingredients are similar but I'll try these first.

Yes, this is the first time I've ever had a paper slippage problem too on any Designjets.

Thanks again and I'll let you know how it works.

[blackcat4866]

Re: Any experience with Designjet 4500 printers?

I've seen something like this on the T3500 (newer model).

The paper slips back about 2" then overprints the 2" of image. Then it pulls an error (not a jam) ... sorry, I can't remember the code. At first I thought the takeup was too strong, but it was just the hard foamy registration roller dirty. Just cleaning the roller took care of it.

It did take some disassembly to get to the reg roller. =^..^=

Here is the database entry, if it's helpful:

[theengel]

Re: Any experience with Designjet 4500 printers?

I've had problems with the rollers slipping on several of these. Actually, all their bigger designjets. There's some kind of mode in the utility menu to clean the roller. Once you set it, it just rolls the roller very slowly, so you can use something like the mentioned chemical to clean it (I use Goof Off, or some generic version of it, found in Krogers).

[D Hook]

Re: Any experience with Designjet 4500 printers?

I used some "MaxPro Rubber Rejuvenator" spray. Sprayed it on the rollers while they were turning, let it sit for about 30 seconds and the problem is gone. Switches paper rolls now very reliably. Bought off Amazon for about $9. Highly recommend.

Thanks for all the input guys. Much appreciated.

[D Hook]

Re: Any experience with Designjet 4500 printers?

Update:

Well, the spray worked for awhile but then the slipping started again. So I went for this product instead:

https://www.amazon.com/gp/product/B008O9X3KS/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

[D Hook]

Re: Any experience with Designjet 4500 printers?

UPDATE:

The chemical applications worked well for a while but needed to be reapplied every few weeks or so to be reliable. Eventually the problem returned and the #2 roll refused to load reliably.

So I ordered some grip tape made for the tops of skateboards. It's about 80-90 grit with adhesive backing. I cut three equal length pieces just long enough to fit the circumference of the neoprene rollers and applied using the command to turn the rollers continuously. All three went on just fine. I put one on the center roller and the other two towards the ends but not to the far-end roller so at least tow of the rollers with the grip tape will catch all sizes of paper widths.

I loaded and unloaded the bottom roller about a half-dozen times and it completed the action successfully everytime, using 42" heavy coated paper. No slips at all. I then loaded some gloss photo paper, 36", and printed a photo and could see no evidence of the grip tape damaging the front of the paper or marring the print.

The printer was idle for about 3 months and came in today to do a large print from roll #2. It loaded and printed with no problem so the grip tape seems to be okay for a long-term application.

So I'm calling this "fixed" for now.