HP Designjet 500 'juddering'

[Guest]

HI, Hoping someone can help.

I bought a second hand designjet 500, and I am struggling with the print quality. As the carriage travels across it makes a 'juddering' sound like it is jumping or sticking on something, when I look at the printing it isn't lining up properly, and has over-printed so that the text and lines look blurry.

So far I have: cleaned the service station
Cleaned the white (data cable?) that curls up at the back and the surface it lies on (this was filthy and it got a bit better after)- this seems to hit on the black plastic clips that hold it down when the carriage is 2/3 of the way across should it do this?
Checked the belt for defects/bit stuck in it. The belt looks pretty new, removed a few bits of fluff but nothing major
Checked the pulleys the belt runs on - can't see anything but I haven't taken it totally apart
Cleaned the metal rod it travels on and oiled it with a wee bit of sewing machine oil
Have run a print head alignment and cleaned the print heads

It seems to be worse when it is travelling quickly, but even with the printer set on best and optimised for lines and text it is still doing it. It seems to be worse when printing blocks of colour than when printing just lines and text. I really need it to print my degree drawings!

Any suggestions would be gratefully received
Thanks

[theengel]

Re: HP Designjet 500 'juddering'

Is is possible that the carriage isn't seated properly?

You said the print looks blurry. Can you attach a sample. I would say check the encoder, but it sounds more like something is just physically off in the carriage.

[CJane]

Re: HP Designjet 500 'juddering'

11150825_886318651429080_7145677131968317038_n.jpg
sorry, thisis the wrong way up. The top part printed fine, then the red dashed line and text 'foul water drainage' are what it is doing, it should be a single red dashed line, but it has printed 2. the next line down isn't quite as bad, but it looks like it is 'bold' when it shouldn't be.

[fixthecopier]

Re: HP Designjet 500 'juddering'

Print quality issues can come from the printheads not being used and drying up. The juddering can come from the rail you put oil on. It should be cleaned to get the old crap off, then lubed with something slick. I use Tri- Flow. Can be found at auto parts stores. Make sure the rod is slick. Move the carriage back and forth. Spray the oil on the felt bushings on the carriage. Clean the encoder strip, that runs through the carriage like the belt. Clean it with soft cleaner, like windex and a cloth. that is hoe the carriage reads where to be. Check the dates on the printheads.

[theengel]

Re: HP Designjet 500 'juddering'

How is this orented coming out of the printer? From what I understand, this looks not at all like an encoder or carriage issue. It looks more like an X axis problem instead of a Y axis problem.

[Kiran Otter]

Re: HP Designjet 500 'juddering'

Make sure the carriage bushing isn't missing. 9 out of 10 times when someone replaces a belt and doesn't know what they're doing, they break off the carriage bushing.

Rear carriage bushing.jpgClipboard01.png

It's part number Q5669-60687. I'll betcha this is the issue.

It's also possible someone either removed, or incorrectly re-installed the carriage rail bushings in the carriage. I don't know why people insist on removing them in the first place! But I've seen them either removed and missing entirely (though I don't think it will successfully slide on the carriage rail; it will get caught on the rail mounts,) or they remove them and reinstall them upside down, which changes the height of the carriage. Hopefully this isn't the problem.

The trailing cable (your white ribbon cable) should have a tan, stiff plastic 'follower'.. HP calls it a 'foil'.. that keeps the cable from flopping around and getting caught under the carriage assembly. Original model 500/800s did not come with this piece, and HP later added it. It's also included on new trailing cables. (Well, it's supposed to be included! I went through a huge debacle with HP because the 42" cables were missing the foil. I finally got it escalated to their engineers but who knows how long it will take to get them to fix it.) The 24" cable had the foil, the 42" should too. At any rate, if the trailing cable is worn and does not have the foil, I would replace it with a new one, with the foil.

Also I'd advise against using any sort of petroleum-based lubricant on the carriage rails. The bushings in the carriage are plastic, and petroleum oils will dissolve the plastic. What HP supplies is called 'Nye Oil'.. it's synthetic. You can get it from just about anywhere, including HP. 6040-0855 is a 3.5oz bottle for $32. The one I have has lasted me about 8 years.

Kiran

[fixthecopier]

Re: HP Designjet 500 'juddering'

Make sure the carriage bushing isn't missing. 9 out of 10 times when someone replaces a belt and doesn't know what they're doing, they break off the carriage bushing.

[ATTACH=CONFIG]29056[/ATTACH][ATTACH=CONFIG]29057[/ATTACH]

It's part number Q5669-60687. I'll betcha this is the issue.

It's also possible someone either removed, or incorrectly re-installed the carriage rail bushings in the carriage. I don't know why people insist on removing them in the first place! But I've seen them either removed and missing entirely (though I don't think it will successfully slide on the carriage rail; it will get caught on the rail mounts,) or they remove them and reinstall them upside down, which changes the height of the carriage. Hopefully this isn't the problem.

The trailing cable (your white ribbon cable) should have a tan, stiff plastic 'follower'.. HP calls it a 'foil'.. that keeps the cable from flopping around and getting caught under the carriage assembly. Original model 500/800s did not come with this piece, and HP later added it. It's also included on new trailing cables. (Well, it's supposed to be included! I went through a huge debacle with HP because the 42" cables were missing the foil. I finally got it escalated to their engineers but who knows how long it will take to get them to fix it.) The 24" cable had the foil, the 42" should too. At any rate, if the trailing cable is worn and does not have the foil, I would replace it with a new one, with the foil.

Also I'd advise against using any sort of petroleum-based lubricant on the carriage rails. The bushings in the carriage are plastic, and petroleum oils will dissolve the plastic. What HP supplies is called 'Nye Oil'.. it's synthetic. You can get it from just about anywhere, including HP. 6040-0855 is a 3.5oz bottle for $32. The one I have has lasted me about 8 years.

Kiran

Good point about the bushing. I keep an extra one with me. Experience says you can't make it work with electrical tape. Well, for a little while anyway, til the new one comes in. My oil suggestion is what I prefer over HP oil. After having a 5500 that I rebuilt, keep showing paper path jams, no matter how many times I cleaned and oiled the rod, my support guy told me to use Tri -Flo for problem cases. I bought a can for $22 and one coating brought the machine to life.

[Kiran Otter]

Re: HP Designjet 500 'juddering'

That Tri-Flow is akin to WD-40, from what I can tell. It has heavy solvents, acetate and petroleum oils. It might be ok for cleaning the carriage rails, but I wouldn't use it as a lubricant.

I assume you meant carriage path errors, not paper path. When you get those it's usually a dirty encoder strip, a bad encoder, bad carriage, bad belt, bad motor, etc. But hey, if that stuff solved a problem.. that's good. I just wouldn't use it on a regular basis.

Most Designjets come with a user maintenance kit, which includes among other things, a bottle of oil. Always try to instruct the end user on how to check if the carriage rail is dry and how to oil the machine. I tell them it will prolong the life of the belt (which it should!) and that I charge $595 to replace it; that usually gets their attention.

If they've lost or misplaced the maintenance kit, offer to get them another one. They're not expensive. And on some models (the 4000 series, probably others) the only way to get that little sponge/spittoon on the left side is in the maintenance kit.

Will they do it? My experience is that they won't. Will it matter? Probably not. You can lead a horse to water, etc. And if end users could fix their machines, I wouldn't have a business.

I did have a user that mixed graphite with 3-in-1 oil, and put it on the carriage rail with a brush. I kid you not. It made an incredible mess. I think the guy was a rocket scientist at Lockheed.

Kiran

[Kiran Otter]

Re: HP Designjet 500 'juddering'

OP.. btw, make sure that spring-loaded tensioner on the back of the carriage isn't missing, either. It pushes down (tilting the carriage forward.) The carriage will have some play in it when everything is in order, but if it has an excessive amount of play, check the carriage bushings.

You can take them out without removing the carriage. They're C shaped, plastic. Just turn them over and put them back in, and note the difference.

I think techs with no experience think the way to get the carriage out is to remove the bushings, because they see screws there.

Kiran

[Kiran Otter]

Re: HP Designjet 500 'juddering'

And not to put too fine a point on it.. (too late, right?) This is from HP's service notes:

Special Lubricant is available for the slider rods to eliminate squeaking or excessive friction. Parts required: Synthetic Lubricant P/N 6040-0854 (1/2 ounce)

Note: The is highly specialized lubricant. The use of other lubricants can cause the carriage bushings to deteriorate.

[CJane]

Re: HP Designjet 500 'juddering'

How is this orented coming out of the printer? From what I understand, this looks not at all like an encoder or carriage issue. It looks more like an X axis problem instead of a Y axis problem.

The picture should be turned by 90 degrees (took it with my phone and it automatically puts photos in portrait, sorry).

Thank you so much for your advise, everyone, I will see where I get. Although it is going to have to wait until the end of next week now as my finals start on Monday. Going to have to pay to print at uni Will let you know how I get on.

Thanks

[Kiran Otter]

Re: HP Designjet 500 'juddering'

I did a belt on 500 Friday and took some pictures of those bushings.. even if it's not the issue it might help someone in the future.

This is the correct orientation of the bushing (note the screw and washer are removed. If there isn't a screw and washer holding it in, there needs to be one.)
bushing correct.jpg

This is the incorrect orientation. Note that the bushing does not seat flush when upside down.
bushing wrong.jpg

I took a little video to show the correct play in the carriage when it's mounted correctly.

https://youtu.be/o2wpyBlM_EM

Here's a picture of the lower rear bushing that's spring loaded:
rear bushing.jpg

And one other thing that's always an issue with these printers, is the tape that holds the trailing cable foil together with the trailing cable. After time it usually comes lose, and the foil no longer stays with the trailing cable, causing a fake paper jam error because the cable and foil no longer pass through the window above the service station. I tried electrical tape once, and that lasted about a month. Then I found what's called 'book binding tape'. It's kind of like duct tape, but it seems to be exactly the same as what HP used originally. In this picture, I had put the tape on there back in 2012 when I replaced the belt last, and it hasn't budged.

Also, the black plastic clip to the left of the tape; it inevitably breaks or will be partially missing (try to locate the bits of it so they don't cause a problem later.) These come with a new trailing cable, and in fact they often give you several of them. But, if you don't have one.. you can probably get away without replacing it. The trailing cable is held in that channel pretty securely.

trailing cable.jpg

All this goes for the 510 and 800 too.

Kiran