Printer Not Printing Black? Check Two Black Test Areas

First determine whether black is missing on the controlled test itself or only in one document/application. The Printer Vitals sheet gives black two independent checks.

Check the black line row

The line-continuity area shows whether known black elements are printing completely, partially or not at all. This is useful for a pattern-level comparison before and after maintenance.

Check the separate black field

The solid K field is measured independently from the line row. If both areas show severe black reduction, confidence in a broad black-channel issue is higher.

If the controlled sheet prints black normally

Do not keep cleaning the printer to fix a document-specific problem. Check the source file, application print options and driver settings first. HP support makes the same distinction in its diagnostic workflow: a clean print-quality diagnostic page points attention back toward the file or application rather than further printer cleaning.

If black is weak in both test areas

Follow the model-specific nozzle/print-quality diagnostic and normal cleaning instructions. Printer Vitals does not claim to distinguish cartridge, ink path, printhead or other hardware causes from a phone photo.

Manufacturer references: HP support