Patent ID: 8414102

Claim:
An imaging device comprising: a media transport configured to move an image receiving member through a print zone in a process direction; a plurality of heated printheads arranged in the print zone to enable printing with a single color of phase change ink across the image receiving member in a cross-process direction; a first optical sensor located in the process direction from the plurality of heated printheads in the print zone, the first optical sensor being configured to generate signals corresponding to light reflected from ink drops ejected onto the image receiving member by the plurality of heated printheads; a spreader roller located in the process direction from the print zone, the spreader roller being configured to engage the image receiving member to spread ink drops ejected onto the image receiving member; a second optical sensor located in the process direction from the spreader roller, the second optical sensor being configured to generate signals corresponding to light reflected from spread ink drops on the image receiving member; and a controller operatively connected to the plurality of heated printheads, the first optical sensor, and the second optical sensor, the controller being configured to: operate one heated printhead in a plurality of heated printheads in the imaging device with one electrical signal in a plurality of electrical signals to eject ink drops onto the image receiving member to enable the one heated printhead in the plurality of heated printheads to produce a portion of a test pattern having a predetermined area coverage percentage on the image receiving member; identify an optical density measurement for the one heated printhead with reference to the portion of the test pattern produced by the one heated printhead and the signals generated by the second optical sensor; identify a difference between the optical density measurement for the one heated printhead and a predetermined optical density for the predetermined area coverage percentage of the test pattern and a color of ink ejected by the one heated printhead; and adjust the one electrical signal for the one heated printhead with reference to the identified difference in response to the identified difference exceeding a predetermined range about the predetermined optical density.