printing quality issues

[pinky-swirl]

good day ! our printer smart tank 615 series has some print quality issues that we cant seem to fix by cleaning the printheads. before this happened, our printer cant proceed to print any files as the printhead (iirc colored) is not installed properly, so we go to our nearest hp support store and have them fix it. at first, there was no more occuring problems, but weeks later i noticed that there seemed to be a banded rows of smudge/noise of the print output, then months later whenever we photocopy (b&w, plain paper), there's a severe white lines in the print output. this also happens now when we print pictures on plain papers. is there a way to fix this issue ? attach below is an image of our print output.  thank you so much (please excuse my grammatical errors, english is not my first language)

[Hawks_Eye]

Hi @pinky-swirl 

Welcome to the HP Support Community! We're here to help you get back up and running.

Thank you for the detailed explanation and for sharing the print sample. I understand the print quality concern with your HP Smart Tank 615. From the image and the symptoms you described, the severe white lines, banding, and missing sections in copies and prints typically point to printhead nozzle performance or printhead alignment issues, especially since cleaning alone has not resolved the problem.

As a next step, please try the following:

Print a Print Quality Diagnostic Page from the printer control panel and check if any color blocks or black areas show gaps, streaks, or missing lines.

Perform all three levels of Printhead Cleaning from the printer menu. If only the first level has been run previously, continue with the second and third cleaning stages, allowing the printer to complete each cycle.

After cleaning, run Printhead Alignment:

• Printer control panel > Setup > Tools > Align Printhead

Ensure all ink tanks contain sufficient ink and that there are no air gaps visible in the ink tubes.

Since the color printhead was previously serviced, gently reseat both printheads:

• Turn the printer on.
• Open the printhead access door.
• Remove and reinstall the black and tri-color printheads securely.
• Close the access door and allow the printer to initialize.

Make a fresh black-and-white copy directly from the scanner glass. If the white lines appear even on standalone copies, the issue is likely originating from the print system rather than the computer or print driver.

If the Print Quality Diagnostic Page still shows the same missing lines or gaps after the alignment and all cleaning levels, please share a clear photo of that diagnostic page so we can review the printhead pattern more closely and guide you further.

Take care, and have an amazing day!

Regards, 

Hawks_Eye