To improve poor black and white print quality, it's important to control the dynamic range, which is the range of tones from the blackest black to the whitest white in an image. In a black and white photograph, you want to make full use of the entire dynamic range. One way to do this is to remove the black ink cartridge and print only with the tricolor ink cartridge. This allows the printer to operate in single-cartridge mode, which creates composite black from the tricolor ink cartridge.
Another way to improve print quality is to update the printer settings for the highest quality printing. This can be done by adjusting the printer settings for a single print, or by using the printer's automatic servicing routine to clear up any print quality problems with black ink. Additionally, making sure the printable side of the paper is face up in the sheet feeder and running the Print Head Alignment utility check box in the Advanced dialog box can help to improve print quality. It's also important to use genuine HP cartridges and to perform software and hardware upgrades to improve printer quality. Finally, aligning the printer cartridge or head can help to improve print quality, as misalignment can occur over time.