Ongoing Color Issues

Hi All,

I am looking for some help with a color issue. I believe with is a problem with the printheads but I work with networks and workstations more than I do large format printers so this is by no means an expert opinion. About two years ago we got two latex printers to replace our design jets. After coming back from COVID we started having color issues. I reached out to our vendor and they sent a tech out to help resolve these problems. The tech did not seem super familiar with the latex system. He recommended replacing the print heads after running a diagnostic print showing that we were getting really poor coverage from the 2nd black/blue head. He also said that he thought that the fact that the ink was expired was probably not an issue (I asked because I have no idea and the marketing team said they run expired ink through the old printers all the time). We started by replacing the one print head and then replaced the rest of them because we were still having issues. The problem persisted and the vendor escalated the problem their support center said that a whole host of issues can affect color and basically it's the way the printers work. This is an unsatisfactory answer the printers were working fine before covid. I was going to replace the ink but wanted to see if anyone had any more information so I called HP support. They recommended cleaning the encoder strip so I did. I also ran that diagnostic strip again and noticed that it was showing the 1st blue back printhead was again blocked. inspecting the print head I noticed that there was a difference in the look between the two nozzles. One had a thin line of color and the other a thicker line of color. I also noticed a sticky substance all over the gold contacts both on the printhead and where it interfaces with the printer. I am waiting to hear back from HP about these findings however I was wondering if anyone has seen this before. I am also wondering if anyone has any good info on the ink expiration if it may be my problem and if so why it was not a problem on the old printers.

Additionally, while it's not as bad 365 seems to be having similar color issues. I have not done much on it because I wanted to complete the 315 first. to the best of my knowlage they have been using the old design jet still without issue.

Hi @mikylec10333,

I understand that the printer was probably not used for a long period of time. It is important that the condition of the printer is good before starting production again.

As you mentioned there was a sticky substance in the printhead contacts, you should make sure that there isn’t any leakage that could be interfering with the printhead electronic contacts. You could clean the PH contacts carefully with a cloth dampened with alcohol.

If after cleaning the area you find any kind of substance there again, you should contact your support representative to look for the cause of the leakage.

As a general recommendation for all printheads:

Run a check and clean for all printheads and check the PH status by printing a nozzle health plot. If the printheads are not ok, try to recover the ones affected by running a hard clean on them. If the PH are still bad, you can clean a printhead manually with a soft, fiber-free cloth dampened with de-ionized water. Clean gently, with minimal pressure. If after all these steps the printhead is still in bad shape, please replace it.

If the nozzle check plot shows that all of the printheads are ok, please follow the correct color management workflow as stated below:

Remember: Color Calibration will ensure color consistency within a printer and media after the first calibration is launched when the color reference targets are set based on current printer conditions (temperature, humidity, PH DW, etc).

Regular Workflow for a single printer:

• Do a Color Calibration before beginning the job you want to keep consistency. Note the CLC is media-dependent.

• Re-do a Color Calibration whenever you see color change, the calibration is in “Recommended” or “Obsoleted” status.

Tips and tricks:

• Verify the calibration target is printed with good IQ (no nozzles out, banding, grain, advance is correct, etc).

• Launch the CLC when the printer is in the same state (e.g. if the machine has been printing for a while the system is hotter than if not, this may impact CLC).

• Note that in cloned substrates from generic the first time you launch color calibration that color is “saved” and next time you launch the color calibration you are calibrating it.

Is it possible I have bad ink in the tubes from the cartridges to the printheads still? Would obstruct contacts cause the print issues? I feel like that would probably result in the printhead not being detected.

Hi @mikylec10333,

If there is something obstructing the tubes and causing the nozzles to clog, you would see that there are nozzles out in the nozzle health plot. If that is the case, you should contact your support representative to check the lines affected and purge them if needed.

If the printhead is not being detected, it can happen when ink builds up on the electrical connections between the printhead and the printhead carriage (please check the User Guide on page 136).

It can also happen if there is any kind of leakage that could be affecting the printhead's electrical contacts, that is why we recommended cleaning the contacts carefully with a cloth dampened with alcohol.

If after cleaning the area the substance appears again, contact service support to check the printer for any possible leakage and take the corresponding actions to solve it.