The input ppi is determined by the printer driver setting.
I think the printer you use is an excellent printer with a very high input ppi.
Qimage on Max will accept that highest ppi as its target. If you set the resolution in Qimage to High, it cuts that number in half. Low is half of that.
So if you start with 1200 ppi which I think that HP does, half is 600, and half is 300.
To achieve the 150 number, you need to go into the HP driver and lower the quality setting a notch. I don't have any HP drivers so I cannot tell you where.
Maybe Ernst, or someone with a similar driver can point to the location of the setting.

Fred

"...my printer driver (HP B9180) can't handle large images at high resolution."

Please tell us more.  How large is the image?

Example of image sizes are 3000x934 pixels and 9450x3780 pixels.

The problem is very similar to that previously discussed on this forum:
http://ddisoftware.com/tech/printers/hp9180-short-prints/
As this did not result in a clear resolution I thought that I would not bother everyone with the details of my problem. However, if anyone has more suggestions I would be very pleased to hear them.

Below is a copy of a posting that I made on the dpreview forum.

Previously I have used this printer and Windows XP to make many panorama prints 32x80cm but under Win 7 the print job disappears from the print queue and the paper ejects. The print ends with a sharp edge to the photo and not a fuzzy (partly printed) edge. In other words, it is as if Windows 7 thinks the print job has finished when it has not. There are no error messages.

Generally a given print ends at the same place. 10-30cm into a print that is 32cm wide. Decreasing the print resolution gets me further but not a complete print.

I have had extensive email communication with HP technical support. While they had some good diagnostic suggestions to start with, I think they are now out of ideas. I have also tried suggestions from the Qimage website.

Some details about my system are:
Windows 7 32 bit (fresh install, not Vista upgrade)
Intel i7 CPU (also tried on old Pentium 4 system)
4GB RAM
Windows managed page file. (also tried forcing a larger page file)
About 40Gb available on the system disk where the print queue writes to.
Latest Win 7 printer driver from HP

Latest printer firmware (27A) from HP (also observed problem before I updated the firmware)
Printing from Qimage. (also observed problem with HP Photosmart Essentials)
Image size about 32cmx80cm
Using special media tray but have also tried main tray
Connected by USB but have also observed same problem with Ethernet connection.

Some of the other troubleshooting that I have tried is:

Put a blank HDD into my “old” computer where the printing worked under Win XP and freshly installed Win 7 on it along with the full printer driver (freshly downloaded) and the version of QImage which worked under Win XP. No other software was installed. This showed the same problem of incomplete prints so it can not be attributed to new hardware. Repeated this again with a laptop with the same result.

Tried printing to a PDF file with Cute PDF. The whole photo appeared in the file without problems. So it is not a problem just due to say Qimage sending an incomplete picture to the print driver.

Tried printing using HP Photosmart Essentials software but the print was still only 50% complete when it was ejected. So it is not a problem attributable to Qimage alone.

Tried disabling Enable advanced printing features from within Win 7 (this was a suggestion from the QImage people). This resulted in smaller files in the print queue (as expected) but the print still did not complete. In fact it stopped in the same place.

Tried printing though the network but the prints are still incomplete.

Replaced the printer driver with the Win Vista printer driver but still running under Win 7. However, I still got incomplete prints.