horizontal lines in some colors

[Thermo22]

I recently replaced a several year old 8100 printer with a new 8100 printer.  Everything seemed fine until printing a picture. On plain paper normal mode there were fine horizontal lines about an inch or so apart.  I do not remember ever seeing this on the old printer.  Printing at higer quality muted the effect but still there.  Printing a spreadsheet with vertical blue, yellow, magenta bars clearly shows that yellow does not have the problem, only black, blue and magenta.  I have cleaned several times includeing the 2nd and 3rd level cleaning (which went quickly despite their notice it would take 5 minutes) and the head allignment procedure as well.  Any suggestions?

[Rainbow23]

@Thermo22,

Welcome to HP Forums, this is a great place to get support, find answers and tips.

Thank you for posting your query, I'll be more than glad to help you.

I understand that you are facing print quality issues with your HP Officejet Pro 8100 ePrinter.

This issue could occur if the printhead is not aligned properly or damaged.

Let's go through a few steps to resolve this issue.

And here's the step by step guide for you in the link: Troubleshooting Print Quality Issues

You may also check the link: http://hp.care/2nis44z

Let me know how this works.
 

You have a good day ahead.

[Thermo22]

This morning I printed the quality diagnostic page (on plain paper).  I frankly don't understand what I am supposed to be looking for in Test Pattern 1.  The three vertical lines are not the same length.  The box surrounding the cross is not of even weight such that the box is not actually a continuous perimeter.  There are no horizontal lines in Test Pattern 2, but in the upper blue and red rectangles it appears there was erratic printing along the lower left hand edge so it looks like a mouse ate part of the rectangle.  I then ran the allignment and cleaning (through stage 3) and found no real difference in the quality diagnostic page.  I printed my test spreadsheet bar chart in normal and best quality (on plain paper).  There were slightly fuzzy white lines (or perhaps very closely spaced narrow lines) in normal mode which were barely noticable in best mode.  I hope these tests give some clues.

[Rainbow23 · Accepted solution]

@Thermo22,

Thank you for your reply, I'll be more than glad to help you.

I understand that the issue still persists after following the steps provided in the previous interaction.

This issue could occur if the printhead is defective.

Hence, you may contact HP phone support for further assistance at the link: www.hp.com/contacthp

You have a good day ahead.