Portable scanning spectrophotometer

Abstract

The specification discloses a portable spectrophotometer (10) providing improved movement and control of the sample (S) during analysis. The unit (10) includes a base (12) and an upper assembly (14) supported on the base (12) for floating movement. Both a spectral measurement engine (20) and drive rollers (104) are contained within the upper assembly. The base (12) includes independently suspended idler rollers (16), and the drive rollers (104) engage the idler wheels (16), so that at least a portion of the weight of the upper assembly (14) is borne by the engaging drive rollers (104) and idler rollers (16). The upper assembly (14) therefore floats up and down with samples (S) of varying thickness moving between the rollers (104 and 16). Additional upstream idler rollers (18 and 24) on the base and the upper assembly engage one another and bear a portion of the weight of the upper assembly (14) to create tension in opposition to the drive rollers (104) to hold the sample (S) taut. A planar media guide (130) is located on the underside of the upper assembly (14) and surrounds the spectral engine (20) to engage the sample (S) and reduce flexing and bowing of the sample (S). A manually actuated backer (30) is supported by the base (12) to selectively present to the spectral engine (20) one of two areas (32a and 52b) with different reflective properties. The unit (10) may include a fast light source (21) in the spectral engine and a second light source (60) in the backer (30) so that the spectrophotometer (10) is capable of both reflective and transmissive analysis.

Description

TECHNICAL FIELD[0001]The present invention relates to color measurement instruments, and more particularly, to spectrophotometers.BACKGROUND ART[0002]Color measurement instruments for many and varied applications are well known. Them instruments are used, for example, to determine color consistency in primed material, photographic material, textiles, and plastics. The most comprehensive color measurements are obtained by instruments known as spectrophotometers, which measure the spectral distribution of light and give a percentage reflection or transmission at many segments in the visible color spectrum.[0003]The field of desk top publishing has expanded greatly in recent years, and color output devices such as color printers, plotters, proofers have become widely used. The color output devices are often controlled by computer software, which transmits control signals to the printer defining color to be produced. To assure color quality, it is desirable to be able to calibrate color...

AI Technical Summary

Benefits of technology

The present invention provides an improved portable spectrophotometer that can better register and move samples. The instrument includes a mechanical drive system that transports samples with precision. The drive mechanism includes a plurality of drive wheels and independently suspended idler rollers that flex to accommodate samples of varying thicknesses. The drive rollers are located downstream from the color measurement engine to improve consistent sample registration and movement. A planar, low-friction media guide is located on the upper assembly to improve sample registration and riding the top surface of the sample. A two-position backer is provided in the base for both reflective and transmissive analysis. The spectrophotometer is capable of both reflective and transmissive analysis and includes a first light source for reflective analysis and a second tight source for transmissive analysis.

Problems solved by technology

Only mail changes in the distance between the sample and the measurement engine can create significant errors and inconsistencies in the color measurement.

Because these two primary components are located in different housings, there is the possibility that sample registration and movement is not as precisely controlled as required for present day measurement.

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