Abstract: A measurement device is described for the quality control of printed products, having a pair of optical channels that differ in their properties and operate simultaneously. Each optical channel comprises an illumination channel for illuminating a measurement location and a reflection channel that picks up the light reflected from the measurement location. The reflected light is directed to an evaluation unit, which is connected to the reflection channel, that analyzes the reflected radiation spectrally. Polarization filters arranged in one of the pairs of channels provides the difference in the optical properties between the two pairs of channels. The measuring device provides an increased number of obtainable measured values for further processing in a way that requires only a modest increase in the metrological outlay compared to other measuring devices of this type.

Abstract: A measuring system for registering reflectances on printed products, the measuring system having at least one illumination channel for producing a scanning spot at a point on a measurement field on the printed material. The system includes scanning channels for registering the reflectances of the spot from the printed material. The measuring system moves relative to the printed material. Measuring devices supplying ink density and spectral, preferably colorimetric, measured values are combined with one another without additional outlay in terms of construction. The combination of the measuring principles (density and color) are optimally adapted to the task of a measuring strips on the printed material scanned in the longitudinal direction. The measuring system has a densitometer that produces a scanning spot on the printed material, and a spectrophotometer that produces a further scanning spot on the printed material.

Abstract: A description is given of a photoelectric measuring device by means of which the light reflected from a measuring point on a printed product is detected, and the corresponding measured signals are processed for the purpose of indicating quality data. A measuring instrument of this type, having at least one illumination device and measuring channels, is an improvement over the prior art in order to expand its possible uses, with a construction which is cost-effective and stable when handled. In accordance with the invention, this is achieved with an illumination device which has a spectral intensity distribution which corresponds to the number of spectral ranges provided for the irradiation of the measuring point. The light from the sequentially drivable illumination devices irradiates the measuring point. The light reflected from the measuring point is detected and converted into a reflective signal which is processed to determine ink density values.

Abstract: A photoelectric measuring head for the contactless scanning of measurement regions, particularly of measurement fields on a printing sheet resting flat. The measuring head having outlet orifices for compressed air on its underside to generated an air cushion between the measuring head and the printing sheet. A measuring head of this kind, suspended on an air cushion provides for high stability, and the least possible distance from the base. This is achieved in that the outlet orifice for the compressed air are formed from a plate which, by virtue of a microporous structure, is air-permeable.

Abstract: To prevent second-order like non-uniformities, that is, the cloud formation ffect on the image plane of a projected light source, projecting light in a film window, the reflector (3) has a profile (p) which is discontinuous and formed of a sequence of conical surface segments (F) which are successively placed on the reflector from the apex to the rim and which have different angles with respect to the axis or center line (CL) of the reflector. Each one of the areal segments, in cross section, has a length (1) which is so dimensioned that the overall length of the images of the projected filament (2) of the lamp in the plane of the film window is equal to or larger than the diagonal of the image field, and adjacent segments intersect in a discontinuous reflector or profile in intersection circles which lie on a curve (K) forming a continuous reflector profile, which continuous reflector profile may be in accordance with any standard arrangement.

Abstract: To reduce the accuracy requirements and permit greater tolerance in placing f a filament of a halogen cycle incandescent lamp (2) of low wattage, for examle 200 W, within a reflector, particularly to provide a source for projection of super-8 mm film on a ground-glass screen surface, the reflector is positioned in a range in accordance with the hyperbolic equations:A: 0.1477x.sup.2 +1.2617xy+y.sup.2 -31.461x+58.119y-1577.1=0 andB: 0.1201x.sup.2 +1.2503xy+y.sup.2 -30.554x+56.082y-1449.7=0.Preferably, the curvature of the hyperbola equation isC: 0.1339x.sup.2 +1.2570xy+y.sup.2 -31.028x+57.140y-1513.4=0.

Abstract: To provide for uniformity of illumination across a film window, for example or super-8 mm film, the reflector has at least two contours whose generatrices follow conical sections which have a common optical axis in the direction of radiation emission, and which are so arranged that the sections are formed as sectors, with adjacent sectors having different contours. At least four sectors are used, and preferably the focal point of the generatrices are displaced relative to each other either in the reflector axis or on a parallel thereto, the conical section are identical, and two such conical sections are used, with surface areas at a ratio of between 4:6 or about even.