Grainy print and different ink coverage along print lines

[petej1728]

Not too sure what is happening. Up until a couple of weeks ago everything was running fine. Prints were good and the machine was troublefree.

Then suddenly, everything just started to go wrong. At first, some colours of the print started to look washed out, or in some cases pinkish.

I went through the usual test prints, head cleaning, head alignments etc. All of the general maintenance options. Then the prints started to get very grainy.

I am unable to change the curing temparutres in either the RIP (Wasatch) or the printer front panel. It appears to be the max temp in the RIP and the front panel icons show a padlock as opposed the the right facing arrow that allows you to access the next menu.

I have replaced all but 2 printheads that were changed only a couple of months ago. The 2 printheads I didn't swap out have only fired 807ml and 670ml. All of the other printheads have fired less than 70ml.

I also replaced the PH maintenance kit about 4 or 5 weeks ago.

Here are the latest test prints I made;

And the other issue that has now started is that when the printheads travel over a large patch of white and then continues to print another colour, the ink density increases creating faint stripes in the print (see below)

Hopefully, just in between the 2 black lines I have drawn, you can see that the blue is slightly darker where the printheads have not been printing (the white part that runs horizontally and to the right edge of the image) and then started printing again. Or possibly, all of the other part of the blue isn't printing with as much ink.

Any help would be greatly appreciated.

[petej1728]

It's a few days on since my original post and no responses as yet.

I have still been testing. I have tried all manner of variations of configurations to see if I can get rid of these issues;

reduced total ink but increased ink level

increased total ink but reduced ink level

increased the number of passes to slow printing speed

increased curing temp

Still grainy and still getting the 'striped' effect.

Have even re-installed the RIP in case it was somehow corrupt.

Without any other suggestions, looks like I'm going to have to replace all of the inks and see if that cures it.