CA2298376C

CA2298376C - Ink fountain blade for a printing machine

Info

Publication number: CA2298376C
Application number: CA002298376A
Authority: CA
Inventors: Raffaele Fina
Original assignee: De la Rue Giori SA
Current assignee: KBA Notasys SA
Priority date: 1999-02-23
Filing date: 2000-02-14
Publication date: 2008-06-03
Anticipated expiration: 2020-02-14
Also published as: DE60021932T2; EP1031419A1; CA2298376A1; UA69388C2; EP1031419B1; DE60021932D1; AU1752400A; AU769060B2; JP2000246875A; KR100668031B1; CN1222410C; CN1264645A; RU2226153C2; ATE302117T1; KR20000058115A

Abstract

The blade at the bottom of an ink fountain is split into several adjacent sectors (11) that can be shifted so as to vary the distance between the edge (12) of the blade and the circumference of the ink fountain roller (6). The sectors (11) can be shifted in the plane of the blade, parallel to each other.

Description

Ink fountain blade for a printing machine FIELD OF THE INVENTION

The present invention relates to a blade for an ink fountain for a printing machine, the edge of which blade is intended to maintain a determined thickness of ink on an ink fountain roller, said blade being split into several adjacent sectors that can be shifted so as to vary the distance between the edge of the blade and the circumference of the ink fountain roller.

The present invention also relates to an ink fountain for a printing machine, said ink fountain comprising an ink fountain roller, a bottom in the form of a blade, the edge of which is close to the ink fountain roller circumference, and two side walls in contact with the bottom of the ink fountain and sealing the sides of the ink fountain.
These blades and ink fountains are used mainly in intaglio printing machines in which the amount of ink applied to the ink fountain roller is great, so as to adequately ink the intaglio cuts in the printing plates.

PRIOR ART

Ink fountain blades and ink fountains of this type are known in the state of the art. For example, patent DD 110 632 discloses an ink fountain, the bottom of which has a blade which is close to the circumference of the ink fountain roller. In order to vary the distance between the edge of the blade and the roller, that is to say the thickness of ink applied to the roller, the blade is deformed elastically by screws which press against the blade, on the other side thereof with respect to the ink fountain roller.

The major disadvantage of this system lies in the fact that the deformation of the blade does not allow a constant thickness of ink to be applied. This is because the profile of the deformed blade has, roughly speaking, a rounded shape because the screws press at a point location on the blade, which means that the metering of the ink is thus inaccurate.

Another system is described in patent application EP 0 600 435. In this system, the ink fountain blade is formed of several adjacent bladelets which can be elastically deformed in order to modify the thickness of ink applied to the ink fountain roller. To obtain this deformation, use is here too made of a lever on the other side of the bladelets with respect to the ink fountain roller in order to move them closer to this roller and thus alter the distance between the edge of each bladelet and the circumference of the ink fountain roller and thus the thickness of ink applied.

This system has several drawbacks, particularly the fact that the deformation of the bladelets occurs toward the ink fountain roller. Thus, in the event of an error of manipulation, there is the risk that the blade will come into contact with the roller and damage it. The deformation of the blades also leads to fatigue in the material and this may create problems of premature wear.
SIJMMARY OF THE INVENTION

The purpose of the invention is to improve the known systems.

More specifically, the purpose of the invention is to propose a system which has a fine adjustment to allow a constant thickness of ink to be applied to the ink fountain roller, precisely, repeatably and without risk of damaging the roller.

The invention is characterized by the fact that the sectors forming the blade at the bottom of the ink fountain can be moved in the plane of the blade parallel to one another.

The advantages afforded by the use of a blade split into sectors according to the invention are many. Mention may, in particular, be made of the fact that the movement of the sectors is linear, which means that it is easier to control and to measure. Specifically, any arbitrary point on a blade sector according to the invention has the same movement, whereas in the case of the bladelets known from the prior art, a precise measurement of the movement could be made only on the actual edge of each bladelet.

The invention provides a blade at the bottom of an ink fountain for a printing machine, the blade being divided into several sectors having respective edges for maintaining a determined thickness of ink on an ink fountain roller, the sectors being adjacent and shiftable to vary the distance between the edge of each sector and the circumference of the ink fountain roller, wherein the edge of each sector comprises a reinforcement.

The invention will be better understood from the description of one embodiment thereof and from the figures pertaining thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 diagrammatically shows an inking device comprising two ink fountains;

Figure 2 shows a detailed view in part section of the bottom of an ink fountain, Figure 3 shows a view from above of part of the ink fountain, and Figure 4 depicts a dividing wall suitable for mounting in an ink fountain including a blade according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Depicted diagrammatically in Figure 1 is an inking device with two superposed ink fountains, of the type used in intaglio printing machines. This device is made up mainly of a mobile inking carriage 1, comprising two superposed mounts 2, each mount 2 being fitted with an ink fountain 3 formed of a bottom 4 and of two side walls 5 collaborating with the ink fountain roller 6. The bottom 4 is formed of a blade, the front edge of which touches the ink fountain roller 6. To illustrate one application of this ink fountain 3, Figure 1 also diagrammatically depicts inking rollers 7 which, for example, ink impression plates (not depicted) mounted on a plate cylinder 8.

The bottom 4 of the ink fountain is described in detail with reference to Figures 2 and 3. This bottom 4 is mounted on a transverse spindle 10 parallel to the axis of the ink fountain roller 6 and pivots about this spindle 10 toward the ink fountain roller 6 as the ink fountain is brought into operation. Blade segments 11 are mounted on the bottom 4. These segments 11 are connected to the bottom 4 by transverse slideways 13, 14 parallel to the spindle 10 supporting the bottom 4 and which are themselves fixed to said bottom 4 by means of screws 15 and 16. These transverse slideways 13, 14 have the overall shape of a T, the top of which is held in a corresponding slot 32, 33 cut in the segments 11. All the segments 11 may thus be mounted on the bottom 4 of the ink fountain by introducing them sideways into the transverse slideways 13 and 14 and, once they are all in place, they can then be moved at right angles to the spindle 10 of the ink fountain by virtue of the clearance that there is between the T-shaped top of the slideways 13, 14 and the corresponding slot 32, 33 of the segments.

At right angles to the slideways 13, 14, each segment 11 has housings 19, 20, in each of which a return spring 17, 18 is placed. These springs 17, 18, which work in compression, serve to keep the segment 11 in the position in which the edge of the segments 11 is closest to the ink fountain roller 6. This position may thus be defined as being a reference position, and the movement of the segments 11 in order to alter the thickness of ink applied to the roller 6 is performed by moving the sector 11 away from the roller 6.

The edge of the sector 11 is reinforced 12, for example by a wafer of hard material such as metal or ceramic which allows the life of each sector to be lengthened considerably. This is because the inks used have abrasive properties which wear the edge of the blade away. However, in order to maintain application of a precise thickness of ink to the roller 6, it is necessary for the blade to be sharp-edged. The use of reinforced sectors according to the present invention thus makes it possible, on the one hand, to reduce the wear on the edge and, on the other hand, for just one sector to be changed in the event of premature wear, rather than the entire blade, thus resulting in an appreciable saving.

There is a specific system provided for shifting each sector 11. This system comprises a cam 23 which, in Figure 2, is associated with a motor 21. The cam 23 is placed in a corresponding slot 24 in the sector 11 and mounted on the spindle 22 of the motor 21. The motor 21 itself is mounted iri the bottom of the ink fountain 4 and is fixed in by screws 25 and 26. The use of a motor as depicted in Figure 2 in particular allows the movement of the sectors 11 to be controlled remotely. Thus, using an appropriate device, the position of each sector can be adjusted constantly to suit the quality of print produced, by combining the system described with computerized control means, for example. Of course, it is not necessary for the movement of the cams 23 to be motorized and it is possible to replace the motors 21 with a manual control acting on each cam 23.
Figure 3 diagrammatically depicts six adjacent sectors 11, 11' of an ink fountain. For a better understanding of the invention, the middle sector, referenced with the number 11, is depicted with an exaggerated offset. This offset thus allows the application over a determined width of a constant thickness of ink which is different than the thickness of ink applied by the adjacent sectors 11. According to the size of the pattern which requires a determined amount of ink, it is, of course, possible to shift more than one sector 11 at a time, if the width of the pattern exceeds the width of one sector 11.

Advantageously, a blade with sectors 11 according to the invention can be used in an ink fountain comprising ink dividers. Such dividers are used to separate the colors when the ink fountain is used for multicolor printing. Patent EP 0 374 092, for example, the content of which is incorporated in the present application by reference, describes an ink fountain including at least one such divider allowing inking with at least two different colors.

By attaching a divider directly to a sector 11, there is obtained a modular system in which any arbitrary sector as described hereinabove can be fitted with a divider so that the assembly allows numerous combinations.

Figure 4 diagrammatically depicts a divider 27 mounted directly on a sector 11 according to the invention. The elements which are common to Figures 2 and 4 are identified with the same references. The divider 27, known per se for example from patent EP 0 374 092, comprises an intermediate plate 28 made of plastic, for example nylatron, which is kept in contact with the periphery of the ink fountain roller 6 by press means (not depicted) such as springs, so that the contact remains leaktight.

If the divider 27 is not as wide as the segment 11 on which it is mounted, then the edge of the segment 11 on the same side as the ink fountain roller 6 needs to be reinforced, for example using a wafer of hard material 31 similar to the wafers 12 depicted in Figures 2 and 3. A wafer 31 of this kind will in fact be placed on each side of the intermediate plate 28. It will thus be possible to shift the segment so as to precisely adjust the thickness of ink applied in the vicinity of the intermediate plate 28 while at the same time maintaining sealed contact of this plate against the ink fountain roller 6, by virtue of the press means.

The system of segments 11 may also be used advantageously for mounting the ink fountain side walls 5, these being placed on the two end segments of the blade at the bottom 4 of the ink fountain. Such side walls are described in patent EP 0 374 092 mentioned hereinabove, and also in Swiss patent application No.
105/99 filed on January 20, 1999 and not published at the present time, the content of which is incorporated in the present application by reference.

The embodiments of the invention are described by way of example and variations are possible within the scope of the claimed protection. For example, the number of slideways 13, 14 may be increased. It is also possible to envisage return means other than the springs 17, 18. Likewise, use may be made of another system equivalent to the system of cams used for moving the segments 11.

Claims

1. A blade at the bottom of an ink fountain for a printing machine, the blade being divided into several sectors having respective edges for maintaining a determined thickness of ink on an ink fountain roller, the sectors being adjacent and shiftable to vary the distance between the edge of each sector and the circumference of the ink fountain roller, wherein the edge of each sector comprises a reinforcement.

2. The blade according to claim 1, wherein the reinforcement comprises a part made of a hard material.

3. The blade according to claim 1 or 2, wherein the distance is adjusted by moving the edge of each sector away from the circumference of the ink fountain roller.

4. The blade according to any one of claims 1 to 4, wherein the sector is moved using a cam.

5. The blade according to claim 4, wherein the movement of the cam is controlled manually or by a motor.

6. The blade according to any one of claims 1 to 5, wherein at least one return spring returns each sector toward the ink fountain roller.

7. An ink fountain for a printing machine having an ink fountain roller, a bottom in the form of a blade, the edge of which is close to the ink fountain roller, and two side walls in contact with the bottom of the ink fountain, wherein the blade is a blade as defined in any one of claims 1 to 6.

8. The ink fountain according to claim 7, which comprises at least one dividing wall mounted on one of the sectors of the blade.

9. The ink fountain according to claim 7 or 8, wherein the side walls are mounted on end sectors of the blade.