CJV150-160 Possible Damper problem?

[Prairie Portable]

So I have a CJV150-160 I just bought used. The dampers were changed back in 2017. I am having an issue with missing nozzles on test prints only immediately after cleaning cycles. If I do a test print first thing in the morning after the printer has been sitting I get almost a perfect test print. If I do a normal clean or nozzle wash I have a bunch of missing nozzles on my following test print. Eventually they get better after a few more test prints without cleanings or just running a print job.

Here are the things I have noticed. First my wiper was not touching the head when it came across to do a wipe. Initially I thought this would be my problem so I put a new OEM wiper and had the same issue of the wiper not touching the head at all. I removed the pump cover and found two screws that allow adjustment of the wiper height and I now have the wiper contacting the head surface and completing a wipe. What I notice is that after a wipe ink seems to still come out of the head and form droplets on the underside of the head surface. These droplets are what seem to cause the missing nozzles on test prints as the areas missing on the print are always in the areas where the droplets have formed.

If I bring the head over to the service station and manually clean the head surface with a foam swab and remove these ink droplets on the underside I immediately get a great test print. But if I run a cleaning cycle the ink comes back onto the underside of the head again and causes missing nozzles on the print. I really have no clue what dampers do, but if they go bad can they allow ink to seep out of the nozzles enough that it doesn't drip onto the platten but stays on the underside of the head? Thus blocking ink from firing easily in that area of the head? I have attached a photo of the underside of the head with some of the droplets formed. Sometimes the size of the droplets can be larger.

Is this a temperature issue of the environment my printer is in? I usually drop my shop temps to 10c(50f) when I am not there. And when we are at the shop it's regular room temp of 19c(66f)


I have replaced the wiper and cap so far. Any tips or next things to look for would be helpful.

 

[Prairie Portable]

How's the height of my wiper look during a wipe? Just want to make sure I have it set right and not applying too much pressure to the head surface?

 

[Solventinkjet]

I would say it need to be slightly more up. The wiper should bend backwards slightly as it drags across.

 

[Prairie Portable]

I would say it need to be slightly more up. The wiper should bend backwards slightly as it drags across.

Ok I will adjust. Everything you read says not to touch heads so I'm surprised at the amount of contact a head takes from a wiper without causing damage? Do you have any thoughts on my possible damper issue? Is ink supposed to hang under the head like that? I ordered 4 dampers and they will be here today so we'll see what that does.

 

[Solventinkjet]

Ok I will adjust. Everything you read says not to touch heads so I'm surprised at the amount of contact a head takes from a wiper without causing damage? Do you have any thoughts on my possible damper issue? Is ink supposed to hang under the head like that? I ordered 4 dampers and they will be here today so we'll see what that does.

The wiper is soft enough that it doesn't damage the head. You just don't want to touch it with something hard which could damage the nozzles or something that might push debris up into the nozzles so it's a good idea to avoid it in general. As far as ink dripping from the head, it could be dampers for sure. If you are using a bulk system it could be that too. It might even just be the wiper not getting it all off. Also, keep an eye on your cap top and make sure it drains. If ink stays in it, that could be the issue as well.

 

[Prairie Portable]

The wiper is soft enough that it doesn't damage the head. You just don't want to touch it with something hard which could damage the nozzles or something that might push debris up into the nozzles so it's a good idea to avoid it in general. As far as ink dripping from the head, it could be dampers for sure. If you are using a bulk system it could be that too. It might even just be the wiper not getting it all off. Also, keep an eye on your cap top and make sure it drains. If ink stays in it, that could be the issue as well.

Thanks for the info. No bulk system, Cap top drains. Now that the wiper actually touches the head it seems to take off all the ink even where it's set now, but ink seems to come out of the head immediately after the wipe. Fingers crossed these dampers improve something, they ain't cheap.

 

[hand851]

Change the cap top and the pump.

 

[Prairie Portable]

Change the cap top and the pump.

Cap is 2 weeks old. What's your reasoning for pump replacement?

 

[Prairie Portable]

The wiper is soft enough that it doesn't damage the head. You just don't want to touch it with something hard which could damage the nozzles or something that might push debris up into the nozzles so it's a good idea to avoid it in general. As far as ink dripping from the head, it could be dampers for sure. If you are using a bulk system it could be that too. It might even just be the wiper not getting it all off. Also, keep an eye on your cap top and make sure it drains. If ink stays in it, that could be the issue as well.

So I’ve changed dampers. I’ve got ink in all channels except the furthest right magenta I got nothing. Can barely get ink to the damper. I’ve burned through almost an entire set of cartridges doing ink fills. There’s gotta be a better way? What am I doing wrong. I’ve got yellow in that same right side damper but can’t get magenta into it.

 

[Prairie Portable]

Update. I was able to get some of the nozzles on the furthest right magenta side to fire but not all. They come and go with each cleaning. I swapped the farthest right damper to the left side and took the left one and put it into the right side to see if the issue followed dampers and it did not. I swapped ink lines on the furthest right damper to see what would happen and the issue stayed in the same channel. What I'm noticing on the furthest right damper is the ink line at the rear of that damper no matter what color I have going to it doesn't seem to draw ink in as well as the other dampers do. If I swap the lines on the same damper, the front side of the damper pulls ink through nicely and changes colours quickly but the rear side does not. I have attached some photos showing my test prints. I've run out of ink so have installed flushing carts instead to keep cleanings going. I'm currently doing my second overnight nozzle wash and I'll see what happens on Monday.


Test print after damper change



Test print after a few hours of cleanings and ink fill procedures basically draining all my carts


Today after an over night nozzle wash


Before I swapped Magenta and Yellow lines on right damper


After Swapping lines (You can see yellow changed to magenta with only 3 normal cleans but yellow did not flush the magenta in the same time period.


Before Moving left side damper to right side and right side to left side


After damper position swap


Many more cleanings. Slowly yellow is beginning to replace the cyan


More cleanings. Yellow and black slowly being replaced by flushing liquid which is why color is faint.


Current ink configuration.

 

[Alan Menhennet]

Is the cap top you replaced original Mimaki parts?
Ive used Chinese parts and a brand new cap top had a crack in the rubber.
Original parts are way better.
I would say dampers are the issue.
With regards to the far right colour not being there. The cap is either not alligned correctly or not sealing enough to suck ink