X-rite Gmbh

Foresight Enterprises, Inc.

David R Bowden

Bernard J Berg

Douglas V Baker

Mark A Cargill

Lawrence D Zandstra

Steven Henry Peterson

Gary T Kalinka

Timothy R Friend

Thomas J Boes

Ross A Ouwinga

William R Given

A colorimeter for reading color bars of printed sheets or the like includes a longitudinally extending base including a paper stop along which a sheet to be tested for color may be positioned. An autonomously operating colorimeter head is moved along the base in a direction parallel to the edge of the sheet by means of an electric motor mounted on the base and driving an helical thread lead screw engaging an X-axis carriage supporting the head. The head is moved by operation of the lead screw in a direction parallel to the edge of the sheet, referred to as the direction of the X-axis. The head includes an electric motor and a Y-axis transport supporting an optics unit. The optics unit is moved within the head in a direction parallel to a Y-axis, extending perpendicularly to the X-axis. The optics unit is preferably a spectrophotometer including a rotating wheel provided with a plurality of individual filters, spaced apart along the periphery of the wheel. The individual filters each pass light of a predefined wavelength onto a single photodetector and the signal derived from the photodetector is integrated over a period of time to provide an output signal representative of the intensity of a particular wavelength.

Scanning colorimeter with x-y drive

A portable spectrophotometer includes a rotating wheel provided with a plurality of filters having filter characteristics in the 400 to 700 nanometer wavelength range. The filters are moved between an optical conduit and a photoelectric sensor as the wheel is rotated. In one embodiment, a lamp housing contains three object illuminating lamps circumferentially spaced apart by 120.degree. and projecting light onto the object sample at a 45.degree. angle to the object sample. Light reflected from the object sample is conducted through the optical conduit and focused on the optical sensor by means of a focusing lens. A blocking filter is interposed between the lens and the wheel and serves to block light outside of the 400 to 700 nanometer wavelength range. A side sensor receives light from one of the three lamps through the filters as the wheel is rotated and provides output signals which are used as reference signals for the individual filters. In another embodiment, the spectrophotometer includes an integrating sphere with an aperture for conducting specular-included light reflected from the object and an aperture for conducting specular-excluded light from the object. The integrating sphere spectrophotometer also includes a rotatable filter wheel, with a plurality of filters having filter characteristics in the 400 to 700 nanometers wave length range. A side sensor is also provided with the integrating sphere spectrophotometer. As the wheel is rotated, specular-included and specular-excluded light from an object sample to be tested is projected simultaneously through apertures of the sphere. Light detected by a side sensor is also simultaneously detected through one of the filters of the filter wheel. The integrating sphere spectrophotometer also includes an arrangement for providing calibration and compensation of reflectance measurements.

Compact spectrophotometer

A portable colorimeter housing has an upper portion which is mounted on a lower portion in a cantilever fashion and is adapted to receive sheets larger than the device for purposes of obtaining tri-stimulus color measurements. An adjustable paper guide determines the distance that a sheet is inserted between upper and lower plates. A sheet to be measured inserted in the opening will operate a micro switch which activates a motor operative to advance the sheet between a motor-driven drive wheel in the lower plate and an idler roller in the upper plate. Transmittance or reflectance measurements are taken by means of photodetector cells including colorimetric filters. A user programmable processor performs pattern recognition and control functions. An optical housing assembly mounted on the upper plate includes a substantially cylindrical body provided with a horizontally extending channel and a mounting bar disposed in the channel is insulated from the cylindrical housing by air space except in peripheral areas of the cylindrical portion, thereby conducting heat generated by the high intensity light source to an area away from heat sensitive filters.

Portable scanning colorimeter

A scanning densitometer is disclosed for obtaining color density measurements from colored samples, such as color bars and the like. The scanning densitometer includes a densitometer head (100) and a densitometer head transport system (101) having transport bars (102, 103). A sample sheet is positioned under the transport bars (102, 103) and the self-propelled head (100) moves over the sheet along the bars (102, 103) toward an end limit stop (105). During a return movement from the end limit stop (105) to a docking end housing (110), color measurement data is obtained. Upon docking at the docking end housing (110), an optical communications interface is provided so that data from the densitometer head (100) can be transmitted to a host computer.

Scanning densitometer

A densitometer apparatus (200) is disclosed and is adapted to provide color density measurements of opaque materials. The densitometer apparatus (200) comprises a light source unit (202) having a source light (204) projecting light through a collimating lens (206). Light rays transmitted through the collimating lens (206) project through an aperture (208). The rays are projected onto an irradiated area surface of an object sample (212) under test. Electromagnetic radiation in the form of reflected light rays (214) are reflected from the sample (212). The reflected light rays are directed through a spectral filter apparatus (216) and impinge on receptor surfaces of photo-voltaic sensor cells (232, 234, 236). The sensors (232, 234, 236) generate electrical currents having magnitudes proportional to the intensities of the sensed light rays. The electrical signals are applied as input signals to amplifiers (244, 246, 248), with the amplified signals applied as input signals to a multiplexer (256) for time multiplexing each of the output signals from the amplifiers. The resultant multiplexed signal is applied as an input signal to an A/D converter (264) to convert the analog multiplexed signal to a digital signal. The digital output signal from the A/D converter (264) is applied as a parallel set of binary information signals to a central processing unit (266). Actual measurements of color reference patches are processed so as to solve for unknown constants of a set of equations representing correction or compensation factors functionally dependent on actual reflectance measurements. The correction factors are then utilized by the densitometer apparatus (200) to compensate measurements of actual object samples.

Densitometer with error correction

A master computer of a controlled system is interrelated with the executory computer of a peripheral device via a standard serial interface. This relationship centers in the programming of the executory computer to make available on command from the master computer substantially all of the functions of the peripheral device, as well as the data stored in the executory computer, and also to lock out the keyboard of the peripheral device on command to prevent operator intrusion.

Growing community of inventors

Grandville, MI, United States of America

David R Bowden