Measurex Corporation

Honeywell-measurex Corporation

Mark J Alguard

Daniel A Gordon

Lee M Chase

John D Goss

Steve Axelrod

John J Howarth

Harriss T King

Len Anderson

Peter Herzlinger

Disclosed is an apparatus for measuring on-line the color and color-related properties of a moving sheet. Contrast ratio reflectance measurements are made for providing opacity corrections substantially in real time for a full color spectrum. An optical color sensor in accordance with the invention includes a pair of synchronized spectrometers, the first spectrometer being aligned to view a region of the sheet backed with a highly reflective ('white') material and the second spectrometer being aligned to view a region of the sheet backed with a highly absorptive ('black') material. The use of two spectrometers permits substantially simultaneous 'black' and 'white' measurements for a full color spectrum. The optical color sensing system further includes two light sources, a flashlamp and a continuously energized tungsten filament lamp. Light beams from the two sources are combined to form a sheet-illuminating third beam approximating the D65 standard source. The intensity of the flashlamp is electronically controlled to maintain the balance of UV to visible light that characterizes the standard source. The color sensor further includes a sheet backing system including a rotatable standard wheel carrying a white standard tile. Provision is made to permit rotation of the standard wheel and to standardize the sensor off-sheet while maintaining isolation of the white standard tile from the paper mill environment. The sheet backing system includes a paper guide plate defining an annular vortex space into which air is introduced from a pressurized source. A low pressure region thereby produced in the vortex space draws the paper sheet toward the guide plate. At the same time, circulating air spirals outwardly from the vortex space to form a thin air film or air bearing between the sheet and the paper guide. Sheet flutter is thereby minimized and damage to the sheet is prevented.

Dual spectrometer color sensor

A two-dimensional position detector, in combination with dynamic z and/or flutter sensors, provides dynamic misalignment detection and correction of a measuring head, thereby allowing accurate determinations to be made of properties of a sheet material, such as basis weight.

Method and apparatus for optical alignment of a measuring head in an X-Y

Color sensor simulating standard source illuminant

Disclosed is an apparatus for measuring on-line the color and color-related properties of a moving sheet. Contrast ratio reflectance measurements are made for providing opacity corrections substantially in real time for a full color spectrum. An optical color sensor in accordance with the invention includes a pair of synchronized spectrometers, the first spectrometer being aligned to view a region of the sheet backed with a highly reflective ('white') material and the second spectrometer being aligned to view a region of the sheet backed with a highly absorptive ('black') material. The use of two spectrometers permits substantially simultaneous 'black' and 'white' measurements for a full color spectrum. The optical color sensing system further includes two light sources, a flashlamp and a continuously energized tungsten filament lamp. The color sensor further includes a sheet backing system including a rotatable standard wheel carrying a white standard tile. Provision is made to permit rotation of the standard wheel and to standardize the sensor off-sheet while maintaining isolation of the white standard tile from the paper mill environment. The sheet backing system includes a paper guide plate defining an annular vortex space into which air is introduced from a pressurized source. A low pressure region thereby produced in the vortex space draws the paper sheet toward the guide plate. At the same time, circulating air spirals outwardly from the vortex space to form a thin air film or air bearing between the sheet and the paper guide.

A system is provided for measuring the color of a sample material, and the system includes means for illuminating the sample and a sensor to measure light from the sample. The system also includes sample backing means to receive light transmitted by the sample and reflect the light back to the sample.

System for measuring the color of a material

An improved color sensor is provided having two sources of illumination, one source being modulated on and off while the other source remains on. Data taken while the modulated source is on is compared with data taken while the modulated source is off to compute the effective fluorescence of the sample. A corrected color spectrum can then be determined for a defined source.

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Palo Alto, CA, United States of America

Mark J Alguard