Patent ID: 9114626
Filing Date: 2015-08-25
Classification: B41J

Abstract:
1. A method of operating a printer comprising: combining at least two inks of different colors in a reservoir in the printer to form a mixed ink, each ink of the at least two inks forming the mixed ink having a color other than black; identifying with a controller in the printer a value of an optical characteristic of the mixed ink by applying an electrical current to a first electrode positioned in the mixed ink within the reservoir, identifying a conductivity of the mixed ink with reference to an amount of the electrical current received at a second electrode positioned in the mixed ink within the reservoir, and identifying the value of the optical characteristic of the mixed ink with reference to the identified conductivity; identifying with the controller a difference between the value of the optical characteristic of the mixed ink and a predetermined value of the optical characteristic for black ink; and adjusting operation of the printer with the controller by adding black ink to the mixed ink in the reservoir in a proportion that produces an ink having a value of the optical characteristic that is closer to the predetermined value of the optical characteristic for black ink than the value of the optical characteristic of the mixed ink before the black ink is added to enable the printer to form an ink image with the mixed ink, the ink image formed with the mixed ink having the value of the optical characteristic that is closer to the predetermined value of the optical characteristic for black ink than the value of the optical characteristic of the mixed ink before the black ink is added.