JPS624643B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring ink layer thickness using a densitometer.

Devices for measuring ink density in inking units of printing presses are known. Devices for measuring ink density on monitoring strips of printed paper are likewise known.

These measurements are carried out to ensure that the ink density does not exceed or fall short of a predetermined value, or to ensure uniform print quality.

A device for repeatedly measuring the ink concentration along an ink monitoring strip is known from DE 2632017 A1. For this purpose a truck is provided with an ink density meter covering the ink monitoring strip. The values obtained from the ink densitometer are evaluated and recorded numerically on paper tape.

The disadvantage of this device is, inter alia, that the printing paper must be brought into a certain position or removed from the printing press for the ink density measurement.

A device for measuring the ink layer concentration in the inking unit of a printing press is described in German Patent No. 2649010. In this device, the ink layer is measured in the gap between two adjacent light-transmissive rollers. The disadvantage of this device is that it can only measure a certain range over the length of the inking roller. Differences in the amount of ink existing in bands or over the entire length of the roller cannot be detected with this device. Similarly, neither of the two devices allows the ink monitoring strip to be scanned during machine operation.

It is therefore an object of the invention to scan a longitudinally arranged zone with one stationary measuring head and to measure, for example, the ink layer thickness on an ink roller during mechanical operation or on a print monitoring strip. It is to measure the ink density on or printed image.

This purpose comprises a rotatably arranged measuring roller, on the wall of which light-transparent measuring ranges are arranged in the form of a single helical line in the axial direction of the roller, in each case at the spacing of the ink zones, through which A device for measuring the ink layer thickness by means of a densitometer is solved, in which the light energy emanating from the measuring position is transmitted via a light guide to a stationary densitometer.

Depending on its design, this type of device offers significant advantages over conventional devices. For example, it is possible to measure the ink layer thickness on the inking roller directly in the inking unit. Similarly, with this device it is possible to measure the ink density on an ink monitoring strip that is printed on printed paper at any time. Depending on the arrangement and configuration of the device, the printing sheets can be scanned or measured during machine operation without removing them from the machine.

Next, the present invention will be explained with reference to the drawings.

The embodiment of FIG. 1 has a measuring roller 2 on which a densitometer 6 is arranged. The measuring roller 2 has transparent measuring areas 3 arranged on its circumferential surface in a linear manner in the axial direction of the roller, each at the same distance as the ink zone.
Equipped with. Depending on the design, a light guide 5 and a light source 8 are arranged on this measuring roller 2 . In this case, the light guide 5 is arranged within the measuring roller 2 and the light source 8 is arranged outside the roller, although the reverse arrangement is also possible. Depending on the position of use, the measuring roller 2 is driven in rotation, so that during one rotation of the measuring roller 2 a monitoring area extending over the length of the measuring roller 2 is scanned by means of a linearly arranged measuring range 3 . The light energy of the individual measuring regions 7 projected one after another from the individual measuring regions 3 onto the light guide 5 is guided, as the light guide 5 forms, to a densitometer 6, where it is processed and evaluated using known methods.

According to the sectional view in FIG. 2, all measuring areas 3 are shown rotated into the plane of the figure. Depending on the direction of rotation of the measuring roller 2 and the helical arrangement of the measuring field 3, the measuring field 7 is scanned from left to right or from right to left. The light guide 5 shown in FIG. 2 is a mirror system having mirrors 12 corresponding to the number of measurement ranges 3,
This mirror reflects the light energy of the individual measurement area 7 onto a mirror designed as a concave mirror 13 . The light energy is measured from the concave mirror 13 to the densitometer 6
reach. Depending on the position of the densitometer 6 and the measuring roller 2, the transmission of the light energy takes place by means of known optical fibers, which makes the device according to the invention even more widely applicable.

If the measuring roller 2 is arranged outside the printing press 10, for example as shown in FIG. 3, the measuring roller 2 can be rotated by hand. If arranged inside the printing press 10, a separate drive 11 must be provided which can drive the measuring roller 2 in rotation depending on the machine speed. In FIG. 4, the measuring roller 2 is arranged inside the printing press 10. In FIG. In this case, the measuring roller 2 is suitably placed behind the final printing zone 14. All inks in the individual printing zones can thereby be detected.

As shown in FIG. 5, the inking device 9 of the printing press 10
By arranging the measuring roller 2 within the inking device, the thickness of the ink layer on the inking roller of the inking device can be determined band-wise. All light guides 5 can then be switched into a common densitometer 6 by means of a light guide switch (not shown).

In the embodiment of the invention according to FIG. 6, the measuring roller 2 enters onto the stack of sheets 14 from the trailing edge of the sheet.
For this purpose, it is necessary that the printing paper 15 fed during the measuring time does not fall onto the measuring roller 2. To ensure this, a known paper delivery holder 16 with the measuring roller 2 extends onto the paper stack 14 and the sheets 15 fed into this holder are temporarily supported. The embodiment of FIG. 6 can also be combined with the embodiment of FIG. 5, so that both the values from the inking device and the values from the printing paper can be sent to the densitometer 6 for evaluation.

[Brief explanation of the drawing]

FIG. 1 is a side view of the device according to the invention, FIG. 2 is a sectional view of the measuring roller, and FIGS. 3 to 6 are diagrams showing various ways of arranging the device according to the invention. 2... Measuring roller, 3... Measuring range, 5... Light guide, 6... Densitometer, 7... Measuring area, 8... Light source.

Claims (1)

[Scope of Claims] 1. An apparatus for measuring ink layer thickness using a densitometer, which includes a rotatably arranged measuring roller 2, and includes ink zones arranged in a single row on the wall surface of the roller in the axial direction of the roller. Light-transmissive measuring ranges 3 are arranged at intervals of , through which the light energy emanating from the measuring position is transmitted via a light guide 15 to a stationary densitometer 6. A device that measures ink layer thickness using a densitometer. 2. The light source 8 is arranged inside the measuring roller 2, and the light guide 5 for guiding the light source energy is arranged at a constant distance with respect to the measuring roller 2.
Apparatus described in section. 3. Device according to claim 1, in which the light source 8 is arranged outside the measuring roller 2 and the light guide 5 is arranged inside the measuring roller 2. 4. Device according to one of the claims 1 to 3, characterized in that the measuring roller 2 is designed as an inking roller and is arranged in an inking device 9 of the printing press 10. 5. Device according to claim 4, in which the measuring roller 2 has a drive 11 which is controlled in dependence on the speed of the printing press. 6. Device according to claim 1, in which the light guide 5 is formed by mirrors 12 and 13.