JPS6015534A - Roll pressure measuring apparatus - Google Patents

Abstract

PURPOSE:To measure the roll pressure and the nip width quickly and accurately by inserting between rolls a pressure sensor equipped in parallel with long and thin electrodes on both sides of a sheet made of a piezo-electric organic high polymer material at the specified pitch. CONSTITUTION:A pressure sensor 1 is equipped with electrodes 5-a and 5-b on both sides of a sheet 4 made of a piezo-electric organic high polymer material in such a manner that long and thin electrodes are arranged at least on one side thereof in parallel at the specified pitch. An computation circuit 2 integrates signals of electrodes of the sensor 1 by time individually. An output section 3 indicates a pressure value based on the output of the circuit 2. Then, the sensor 1 is brought into contact with rolls 7-a and 7-b to be measured to measure the pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a roll pressure measuring device, and more particularly to a device for measuring roll pressure in a device that pinches a strip.

In a printing press, a strip is sandwiched between rolls and a predetermined pressure is applied. In other words, in all of the 3-plate printing, such as letterpress printing, lithographic printing, and intaglio printing, although the format of the printing plate and the structure of the printing machine are different, basically the printing ink on the plate is transferred to printing paper, film, etc. Transfer to printing material. Therefore, the pressure of the roll during transfer has a large effect on print quality. Therefore, setting and managing the roll pressure in an optimal state is an important issue in ensuring print quality.

Most current printing machines have a structure in which pressure is applied to the printing plate by a roll called an impression cylinder, but various problems occur due to inappropriate pressure on the impression cylinder roll.

For example, if the pressure on the impression roll is higher than the optimum value, the ink will be transferred to the paper in a heavier state than the reproduced image on the printing plate. On the other hand, if the pressure is lower than the optimum value, the ink will not be transferred sufficiently to the paper, resulting in fading or blurring. Furthermore, if the pressure distribution in the axial direction of the impression roll is uneven, uneven printed matter will be produced.

Therefore, several methods have been used to measure roll pressure.

The first method is to calculate the axial pressure or roll pressure.

However, this method requires a complicated mechanical structure for measuring the axial pressure, and requires measuring the area under pressure in advance, making it impossible to easily determine the roll pressure. Another problem is that it is not possible to adjust the pressure distribution in the circumferential direction.

The second method uses pressure-sensitive paper coated with microcapsules, and examines the phenomenon in which the microcapsules break down due to pressure and the substance inside the microcapsules develops color. This method is advantageous in that the pressure distribution and the nip width of the rolls can be investigated by measuring the concentration in the pressure area.

However, because it is an irreversible reaction, it cannot be used for practical purposes.

In addition, pressure measurement requires the use of a reflection densitometer, which is time consuming and requires accurate management of the time during which pressure is applied.

Under such circumstances, it is currently impossible to measure roll pressure comprehensively and quickly.

The present invention has been made in consideration of the above points, and an object of the present invention is to provide an apparatus that can quickly and accurately measure roll pressure and nip width.

In order to achieve this objective, in the present invention, a sheet-like pressure sensor is inserted between rolls, and each electrode of this pressure sensor has an output of The roll pressure is measured by supplying k to the calculation section.

This makes it possible to accurately and quickly measure the inter-roll pressure and nip width, and to provide an apparatus that has good reproducibility even after repeated use.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Inventive embodiments will now be described with reference to the accompanying drawings.

FIG. 1 shows the overall circuit configuration of the device according to the present invention, in which a pressure sensor 1 is inserted into the roll to be measured, extracts a plurality of detection signals from various parts of the roll surface, and takes out a plurality of detection signals from various parts of the roll surface. 1. Give to each of 2-2...2-n. Each integrating circuit integrates the detection signal and provides its output to the output section 3.

FIG. 2 shows the cross-sectional structure of the pressure sensor 1 in the thickness direction and the relationship between the pressure sensor 1 and the printing roll. The pressure sensor 1 is composed of electrodes 5-a and 5-b sandwiching a sheet 4 of piezoelectric organic polymer material, and each electrode is connected to a corresponding one of the arithmetic circuit 2 via leads 56-a and 6-b. connected to an integrating circuit.

A suitable piezoelectric organic polymer material is, for example, a polyvinylidene fluoride film, and electrodes are formed by coating both sides of this film with a conductive metal such as aluminum or nickel by vapor deposition, plating, or the like. - It is preferable to measure the roll pressure using the pressure sensor 1 in a state close to that in which the printing roll is printing, and therefore it is preferable that the thickness of the pressure sensor is the same as that of the printing material. Therefore, it is preferable that the thickness of the film coated with the electrode is 5 to 50 pm, and the total thickness of the film coated with the surface protection film is 10 to 150 .mu.m.

The electrodes 5-a and 5-b of the pressure sensor 1 configured as described above are connected to the corresponding integrating circuit of the arithmetic circuit 2 via lead wires 6-a and 6-b.

The pressure sensor 1 and the lead wires may be connected directly, or a known structure using a conductive rubber sheet may be used.

FIG. 3 shows the overall shape of the pressure sensor 1, in which electrodes 5 provided on both sides of a piezoelectric organic polymer material sheet 40 are shown.
-a and 5-b are made up of a plurality of elongated electrodes arranged in parallel at a predetermined pitch as shown in the figure. This pitch is 0.1 to 20 mm, taking into account the nip width of the printing press roll, which is 2 to 20 mm.
2mm is selected.

Therefore, the width of the electrodes should be an appropriate size that matches the above pitch. Moreover, the thickness of the electrode may be selected so as to satisfy the thickness of 5 to 50 μm including the above-mentioned film. Note that either one of the electrodes 5-a and 5-b may be a planar large-area electrode.

FIG. 4 shows the response 6 to the pressure of the pressure sensor 1 and the measured output obtained from this response result. A pressure sensor using this piezoelectric organic polymer material generates a charge signal according to the pressure gradient. When the pressure gradient is positive, that is, the pressure is increasing, there is a positive charge, and when the pressure gradient is negative, the pressure is increasing. If the pressure decreases, a negative charge is generated, and if there is no pressure change, the charge becomes O.

'1- That is, as shown in the figure, a positive charge is generated during the period when the pressure gradient is positive (t-12), and during the period when the pressure gradient is negative (t3
~14) and (1, ~16) generate negative charges. and the period (12-13) where the pressure does not change and (t4
~t5) becomes a charge O. Then, by time-integrating the charge signal that changes depending on the pressure in this way, a signal corresponding to the applied pressure is obtained.

FIG. 5 shows one method for measuring roll pressure using the pressure sensor, in which the pressure sensor 1 is placed on the roll 7-a in such a way that the longitudinal direction of the elongated electrode of the pressure sensor is perpendicular to the axial direction of the roll. , 7-b. As a result, the electrodes of the pressure sensor 1 are arranged between the rolls 7a and 7b in the axial direction of the rolls, and each electrode generates a charge corresponding to the pressure applied by the rolls. The electric charge generated at each electrode is applied to the arithmetic circuit 2 via the lead wire 6, and the arithmetic result is sent to the output section 3.

FIG. 6 shows the measurement results obtained by the measuring method shown in FIG. 5, in which the roll pressure in the roll width direction shows a curve that dips from the center. This is thought to be due to roll wear or deformation.

FIG. 7 shows another method for measuring roll pressure using the pressure sensor, in which the pressure sensor 1 is placed on the roll 7- in such a direction that the longitudinal direction of the elongated electrode of the pressure sensor coincides with the axial direction of the roll. a.

It is sandwiched between 7-b. As a result, each electrode of the pressure sensor 1 is arranged between the rolls 7-a, 7-t in parallel to the roll tangent.

FIG. 8 shows the measurement results obtained by the measurement method shown in FIG. 7, and the roll pressure shows a curve with a bulge at the center in the roll circumferential direction. This shows the contact surfaces of the rolls 7-a and 7-b.

In the above embodiment, an example of printing pressure measurement was shown, but it is also applicable to measurement of inter-roll pressure, roll contact pressure on a flat surface, etc.

As described above, the present invention inserts a sheet-like pressure sensor made of a piezoelectric organic polymer material sheet with elongated electrodes arranged on both sides at a predetermined pitch between rolls, and calculates the output of each electrode of this pressure sensor. Since the pressure between the rolls is measured by applying pressure to the roll, a pressure sensor is placed between the rolls so that the longitudinal direction of the electrode is perpendicular to the roll axis direction, and the pressure distribution in the roll width direction is measured. By sandwiching a pressure sensor between the rolls so that the longitudinal crystal of the electrode coincides with the axial direction of the roll, the pressure distribution in the circumferential direction of the roll can be accurately and quickly measured. Since the roll pressure can be adjusted using the obtained pressure distribution, the roll pressure can always be optimized. Automatic roll pressure adjustment is possible by feeding back the obtained pressure distribution to the printing pressure control device.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the schematic circuit configuration of the device according to the present invention, Fig. 2 is an explanatory diagram showing the cross-sectional structure in the thickness direction of the pressure sensor used in the device of the present invention, and Fig. 3 is a block diagram showing the schematic circuit configuration of the device according to the present invention. FIG. 4 is an explanatory diagram showing the overall shape, FIG. 4 is an explanatory diagram of the pressure response of the sensor and measurement results based on this, and FIGS. 5 and 6 are explanatory diagrams of the method for measuring the pressure distribution in the width direction of a roll using the device of the present invention. , FIG. 7, and FIG. 8 are explanatory diagrams of a method for measuring the circumferential pressure distribution of the roll. 1... Pressure sensor, 4... Piezoelectric organic polymer material sheet, 5... Electrode, 6... Lead wire, 7... Roll. Applicant's agent Kiyoshi Inomata Figure 1 Figure 5

Claims (1)

[Claims] A pressure sensor has electrodes on both sides of a sheet made of piezoelectric organic polymer material. A roll that is equipped with an arithmetic circuit that time-integrates each signal from the electrodes and an output section that displays a pressure value based on the output of this arithmetic circuit, and that measures the pressure by bringing the pressure sensor into contact with the roll to be measured. Pressure measuring device.