Abstract: A method and apparatus to calculate the optical density of a fluid (110) traveling through a narrow gap (30) with a set width. Typically, a densitometer employs a light source (10) that is configured to transmit light across the gap and a detector, opposite the light source (10), configured to detect light transmitted from the light source, across the gap, for calculating the optical density of the fluid. The apparatus and method further include a transparent element (120), the transparent element part of a set of replaceable transparent elements, each replaceable transparent element having a particular width, the width less than the width of the gap. Typically, the transparent element is moved into the gap between the light source and the detector to narrow the effective sampling width of the gap for calculating the optical density of the fluid. In some examples, the transparent element is further configured to rotate in the gap to enhance the flow of the fluid through the gap.

Abstract: A method of calibrating an optical density sensor comprising calculating a first pigment solid density value of an ink solution using a current first electrical output signal value from a photodetector, a current second electrical output signal value from a photodetector, and a current lens gap value, calculating a second pigment solid density value of the ink solution using a previously measured first electrical output signal value, a previously measured second electrical output signal value, and a previously measured lens gap value, comparing the current first electrical output signal value, the current second electrical output signal value, and the current lens gap value with the previously measured first electrical output signal value, the previously measure second electrical output signal value, and the previously measured lens gap value, and comparing the first pigment solid density value with the second pigment solid density value.

Abstract: A method and apparatus to calculate the optical density of a fluid (110) traveling through a narrow gap (30) with a set width. Typically, a densitometer employs a light source (10) that is configured to transmit light across the gap and a detector, opposite the light source (10), configured to detect light transmitted from the light source, across the gap, for calculating the optical density of the fluid. The apparatus and method further include a transparent element (120), the transparent element part of a set of replaceable transparent elements, each replaceable transparent element having a particular width, the width less than the width of the gap. Typically, the transparent element is moved into the gap between the light source and the detector to narrow the effective sampling width of the gap for calculating the optical density of the fluid. In some examples, the transparent element is further configured to rotate in the gap to enhance the flow of the fluid through the gap.

Abstract: A device and method for measuring an optical characteristic of a fluid. The device, typically a densitometer includes a set of optical elements that include a light source, a collimating lens, a focusing lens, and a receiver, wherein a gap exists between the collimating lens and the focusing lens so as to allow the fluid to pass in between the lenses, and wherein at least one of the optical elements is tilted with respect to an optical axis.

Abstract: A system and method to calculate a concentration of solids in a fluid, the system including a light source to generate a light signal of predefined characteristics, a an optical detector, placed opposite the light source across a gap between the light source and the detector through which the fluid may flow and a processor to identify the light signal in a detection signal generated by the optical detector, and to calculate the concentration of solids in the fluid based on the identified light signal as related to the generated light signal.

Abstract: A device and method for measuring an optical characteristic of a fluid. The device, typically a densitometer includes a set of optical elements that include a light source, a collimating lens, a focusing lens, and a receiver, wherein a gap exists between the collimating lens and the focusing lens so as to allow the fluid to pass in between the lenses, and wherein at least one of the optical elements is tilted with respect to an optical axis.

Abstract: A method of calibrating an optical density sensor comprising calculating a first pigment solid density value of an ink solution using a current first electrical output signal value from a photodetector, a current second electrical output signal value from a photodetector, and a current lens gap value, calculating a second pigment solid density value of the ink solution using a previously measured first electrical output signal value, a previously measured second electrical output signal value, and a previously measured lens gap value, comparing the current first electrical output signal value, the current second electrical output signal value, and the current lens gap value with the previously measured first electrical output signal value, the previously measure second electrical output signal value, and the previously measured lens gap value, and comparing the first pigment solid density value with the second pigment solid density value.