Compensation for temperature dependent drop quantity variation

A method, comprising:

• receiving a first value, a second value, a third value, and a fourth value related to, respectively, a first temperature, a second temperature, a third temperature, and a fourth temperature of, respectively a first printhead, a second printhead, a third printhead, and a fourth printhead;
• determining a first ratio, a second ratio, a third ratio, and a fourth ratio of, respectively, a first nominal ink drop quantity value corresponding to a first nominal temperature, to a first ink drop quantity value corresponding to the first temperature, using the first value, a second nominal ink drop quantity value at a second nominal temperature, to a second ink drop quantity value corresponding to the second temperature, using the second value, a third nominal ink drop quantity value at a third nominal temperature, to a third ink drop quantity value corresponding to the third temperature, using the third value, and a fourth nominal ink drop quantity value at a fourth nominal temperature, to a fourth ink drop quantity value corresponding to the fourth temperature, using the fourth value;
• and
• forming a first transformed color value, a second transformed color value, a third transformed color value, and a fourth transformed color value using, respectively, a first color value, a second color value, a third color value, a fourth color value, the first ratio, the second ratio, the third ratio, and the fourth ratio.

A temperature compensation system, comprising:

• a first temperature sensor configured to provide a first signal related to a first temperature of a first printhead;
• a second temperature sensor configured to provide a second signal related to a second temperature of a second printhead;
• a third temperature sensor configured to provide a third signal related to a third temperature of a third printhead;
• a fourth temperature sensor configured to provide a fourth signal related to a fourth temperature of a fourth printhead;
• a controller arranged to receive the first signal, the second signal, the third signal, and the fourth signal, with the controller configured to determine a first ratio of a first nominal ink drop quantity value corresponding to a first predetermined temperature to a first ink drop quantity value corresponding to the first temperature using the first signal, to determine a second ratio of a second nominal ink drop quantity value corresponding to a second predetermined temperature to a second ink drop quantity value corresponding to the second temperature using the second signal, to determine a third ratio of a third nominal ink drop quantity value corresponding to a third predetermined temperature to a first ink drop quantity value corresponding to the first temperature using the third signal, to determine a fourth ratio of a fourth nominal ink drop quantity value corresponding to a fourth predetermined temperature to a fourth ink drop quantity value corresponding to the fourth temperature using the fourth signal, to determine a first transformed color value using the first ratio and a first color value, to determine a second transformed color value using the second ratio and a second color value, to determine a third transformed color value using the third ratio and a third color value, and to determine a fourth transformed color value using the fourth ratio and a fourth color value.

An inkjet imaging device to form an image on media corresponding to image data, comprising:

• a printhead arranged to receive drive signals and configured to eject ink onto the media according to the drive signals;
• a temperature sensor configured to provide a signal related to a temperature of the printhead;
• a controller arranged to receive the signal and the image data and configured to determine a ratio of a first ink drop quantity value corresponding to an ink drop quantity ejected by the printhead at a nominal temperature to a second ink drop quantity value corresponding to the temperature using the signal, configured to determine an intensity value from the image data, configured to determine a transformed intensity value using the ratio and the intensity value, and configured to generate data using the transformed intensity value;
• and
• a driver circuit arranged to receive the data and configured to generate the drive signals according to the data.

An inkjet imaging device to form an image on media corresponding to image data, comprising:

• a first printhead arranged to receive a first set of drive signals and configured to eject ink onto the media according to the first set of drive signals;
• a first temperature sensor configured to provide a first signal related to a first temperature of the first printhead;
• a second printhead arranged to receive a second set of drive signals and configured to eject ink onto the media according to the second set of drive signals;
• a second temperature sensor configured to provide a second signal related to a second temperature of the second printhead;
• a third printhead arranged to receive a third set of drive signals and configured to eject ink onto the media according to the third set of drive signals;
• a third temperature sensor configured to provide a third signal related to a third temperature of the third printhead;
• and
• a fourth printhead arranged to receive a fourth set or drive signals and configured to eject ink onto the media according to the fourth set of drive signals;
• a fourth temperature sensor configured to provide a fourth signal related to a fourth temperature of the fourth printhead;
• a controller arranged to receive the first signal, the second signal, the third signal, and the fourth signal and configured to determine a first ratio of a first nominal ink drop quantity value corresponding to a first nominal temperature to a first ink drop quantity value corresponding to the first temperature, to determine a second ratio of a second nominal ink drop quantity value corresponding to a second nominal temperature to a second ink drop quantity value corresponding to the second temperature, to determine a third ratio of a third nominal ink drop quantity value corresponding to a third nominal temperature to a third ink drop quantity value corresponding to the fourth temperature, to determine a first color value from the image data, to determine a second color value from the image date, to determine a third color value from the image data, to determine a fourth color value from the image data, to determine a first transformed color value using the first ratio and the first color value, to determine a second transformed color value using the second ratio and the second color value, to determine a third transformed color value using the third ratio and the third color value, and to determine a fourth transformed color value using the fourth ratio and the fourth color value;
• and
• a driver circuit configured to generate, the first set of drive signals, the second set of drive signals, the third set of drive signals, and the fourth set of drive signals from, respectively, the first transformed color value, the second transformed color value, the third transformed color value, and the fourth transformed color value.