Officejet 4500 G510n is printing shadows with images

[BerndF]

After being forced to upgrade from Windows 7 to Windows 10 by Microsoft I noticed shadows in my prints. It is only the black color, even printing a multi color page. I replaced the black cartridge with a new original one, cleaned and adjusted everything.
Nothing helped. So I started to trace down the problem.

- Printing a selftest directly from the printer looks good.
- Printing a plain text from LibreOffice looks good.
- Printing a PDF looks is bad and has shadows.

To get all Windows stuff out of the way I switched to Linux Mint for further testing.

- Text printing looks good.
- Printing a PDF shows that the text (if it is really text within the PDF) is printed good and clear, but if there is an image in the PDF the image has shadows of the black color.
- If the PDF has text and image then the text is printed good and the image has shadows of black.

- The same PDF with text and image printed in Photo Mode has no shadows (but takes very long time to print).
- I tried print mode Normal, Draft, FastDraft and Photo Mode. Only Photo Mode has no shadows.

Any advise how to proceed?

[BerndF]

I just did some tests with Windows 10 64-bit.
Removed any HP component and printer driver and rebooted, then installed Windows 10 built-in printer driver.

Windows 10 found and identified my network printer and installed all its driver.

I started LibreOffice, wrote some text and also added  3 rectangular symbols. One blue, one black, one red.

The printed page has clear printed text, the blue and red symbols are good, the black symbol has a shadow below. 😠

I exported the page as PDF and printed this.

Result, all black text and the black symbol have shadows below, the blue and red symbol are fine.

Symptoms for Windows 10 and Linux Mint are the same, with the only difference that the PDF export seams to

export the text as image and therefore the printed PDF text has shadows.

What else to test?

[BerndF]

Another test.

After using Windows 10 and Linux Mint I tested with Samsung Smartphone and HP print service and printed a PDF.

Result, the black text has shadows. 😠

Conclusion, it is not any driver because the problem remains under Windows 10, Linux Mint and Android Smartphone???

It can not be the black printer cartridge because I replaced with original new and re-adjusted. 

What else is left?

How to update the Printer Firmware and is it possible to update at all???

It looks like the printer selftest does not include any real images, why?