Man Roland Druckmaschinen Ag

Man Roland Druckmaschinen

Peter Rakitsch

Karsten Wendt

Franz Lampersberger

Hans Joachim Six

Rainer Tutsch

Hans Zehentbauer

Bernd Tieleb&ouml;rger

J&ouml;rg Sierks

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.

Measuring device for the quality control of printed products

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. The densitometer and the spectrophotometer are arranged one behind the other in the measuring head. The scanning spot of the densitometer and the scanning spot of the spectrophotometer are spaced apart from each other by a distance determined by the speed of the measuring system in the scanning direction and by the computational speed of the evaluation electronics, which are connected downstream of the densitometer and the spectrophotometer. The measured values from the densitometer may trigger the measurements and/or evaluations of the measured values obtained by the spectrophotometer.

Measuring system for registering reflectances on printed products

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. The photoelectric measuring device is designed, in particular, as a densitometer, preferably being made using light-emitting diodes (LEDs). Interference filters are additionally used in order to match the spectral intensities of the diodes to the spectral ranges which are provided for obtaining ink density values.

Photoelectric densitometer

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.

Growing community of inventors

Moosburg, Germany

Peter Rakitsch