EP0594536A1 - Segmented ductor knife - Google Patents

Abstract

A knife (12), designed as a flexible steel plate, for the ink fountain of an offset printing machine has segments (42) in the region of the working edge (38), which are bendable in zones to a varied extent relative to an ink ductor (34) by means of individually adjustable setting elements. The segmented ductor knife (10) is designed as an autonomous installation unit. It comprises two-part lateral jaws (14), attached on both sides of a knife carrier (16), each having an outer metal jaw (18) and an inner plastic jaw (26) which can be engaged resiliently against the end faces of the ink ductor (34) and against the knife (12). Said plastic jaw expediently has a groove which is recessed at least in the region of the knife (12) immersed in an ink bath and which is filled with an elastic sealing compound. At least the segments (42) of a knife (12) designed as a flexible metal plate, also in an autonomous installation unit, are completely covered on the top side with a glued-on flexible metal strip. <IMAGE>

Description

The invention relates to a lamella ink knife for the ink fountain of an offset printing machine, a knife designed as a flexible steel plate being bendable in different zones against an ink duct by adjusting elements arranged on each lamella, and to a knife designed as a flexible steel plate.

Lamellar color meters are known for example from CH, A5 602345, which are referred to as color meters for the ink fountain roller. This color knife has cutouts in the area of the working edge, which are distributed on both sides of adjoining set screws. The lamellae formed in this way can be adjusted individually, influencing the neighboring knife areas is excluded or at least considerably reduced. The thickness of the ink layer can be adjusted with the adjusting screws on each lamella, individual colors in the different ink zones can be adjusted as required by the print image in the various width ranges. A disadvantage of this solution is the spaces between the lamellae, which allow the color to pass through and create ring beads on the color duct.

The passage of paint between the slats is prevented, for example, according to CH, A5 658626, in that the slat color meter, called a metering knife, is divided into at least 3 mm thick slats that can be bent parallel to a roller, and groove-shaped spaces with a membrane-like web. With such a metering knife, the individual slats can be individually adjusted via actuators, but the space remains impermeable to color thanks to the web. However, creating the grooves between the slats appears to be very complex and expensive.

EP, A1 052196 describes an ink fountain for a printing press, in which the ink knife is longer than the ink fountain roller. The side walls each consist of a fixed part and a part which rests elastically on the end faces of the ink fountain roller and which is pressed on with resilient set screws. The inner part of the side walls can be pressed laterally against the longitudinal sides of the extended color knife by a further resilient element.

Each individual slat of a color knife can be regulated quickly, precisely and reproducibly with an actuator designed in the simplest case as an adjusting screw. The color dosage can be adjusted manually or automatically, any influence on neighboring zones is prevented.

The ink fountain of an offset printing machine is sealed in the axial direction of the ink duct by side jaws attached to the machine frame. This sealing function must be created every time when the knife is inserted, according to the known state of the art. The running surface of the duct is fitted into a corresponding recess in the side jaws attached to the machine frame and thus largely prevents the outflow of paint.

In view of the manufacturing tolerances with regard to the length of the ink duct and knife, which can be a few tenths of a millimeter, and the ease of use, the known systems with exchangeable slat color knives and side jaws rigidly attached to the machine frame are not satisfactory.

The inventor has therefore set himself the task of creating a slat color meter of the type mentioned which, in addition to a clean, zone-by-color metering, allows simple assembly with good sealing in the side area and in the area between the slats.

With regard to the lateral seal, the object is achieved according to the invention in that the lamella color knife is designed as an autonomous installation unit with two-part side jaws fastened on both sides to a knife carrier, which side jaws each have an outer metal jaw and an inner one, resiliently on the end faces of the color ductor and also on the end face on the Knife adjustable plastic jaw. Special and further developing embodiments of the slat color meter are the subject of dependent patent claims.

For the purposes of the present invention, the autonomous installation unit with two-part side jaws, which can be inserted into a paint box, is referred to simply as a slat color meter according to its main functional component.

A perfect seal on the face of the ink duct is made possible by the spring-mounted plastic jaws, which easily compensate for deviations in the manufacturing tolerances mentioned. The annoying lateral running down of the paint is completely eliminated. Each slat color knife has dense and individually adjustable side jaws, which can be installed in and removed from the autonomous installation unit, for example for regrinding the knives and / or rollers.

An optimal seal is preferably achieved on the end face of the ductor and on the knife, in that a groove in the area of the knife in the plastic jaw is filled with an elastic sealing compound. The knife can be pressed more or less deeply into this sealing compound.

The elastic sealing compound can be cast in, but can also be profile-shaped and can be inserted into or removed from the groove.

The groove and the corresponding elastic sealing compound are preferably 1 to 2 mm wider than the knife. The sealing compound is preferably approximately flush, but can also protrude up to approximately 1 mm or be lower. The sealing compound expediently consists of rubber or a white Chen plastic, which is easily deformable and chemically resistant.

With regard to the sealing in the area between the lamellae, the object is achieved according to the invention in that at least the lamellae of the color knife are completely covered on the top with a glued-on flexible metal band. Standard adhesives can be used for fastening in metal construction, which ensure shear-resistant and permanent connections.

Like the lamellae themselves, the metal strip is expediently made of steel, in particular spring steel, and has a thickness of approximately 0.2 mm.

The flexibility of the individual lamellae can be improved with at least one weakening groove running parallel to the working edge. A weakening groove that preferably does not exceed half the thickness of the flexible metal plate of the slat color knife, or knife for short, improves the flexibility of the individual slats without loss of performance. A weakening groove is preferably arranged in the area of the lamellar lugs. Two weakening grooves are expediently also recessed in this area, opposite one another and correspondingly less deep.

With the lamella color meter according to the invention, noticeable cost savings are achieved through shorter set-up times, constant color guidance, reliable continued printing and thereby a massive reduction in the amount of waste. The resilient plastic jaws do not have to be adjusted on the machine and prevent the ink from running down completely, especially with an elastic sealing compound in the area of the knife. The metal band on the slats does not affect their elasticity, but prevents the passage of color between the slats.

A slat color meter, which is designed as an autonomous installation unit, also allows conversion in the shortest possible time, which is so simple that it can be installed by the offset printer without any special knowledge or tools. There is no need to explain further that this entails considerable cost savings.

The lamella color knife, which is designed as an autonomous installation unit, and / or the knife, which is designed as a flexible steel plate, is as suitable for the new equipment of offset printing machines as it is for machines to be converted.

The combination of an autonomous installation unit and a knife covered with a metal band is a particularly impressive advantage.

• - Fig. 1 eine Draufsicht auf ein verkürzt dargestelltes Lamellenfarbmesser als autonome Einbaueinheit,
• - Fig. 2 eine teilweise aufgeschnittene Seitenansicht einer Einbaueinheit in Arbeitsposition,
• - Fig. 3 eine Draufsicht auf ein Lamellenfarbmesser ohne Seitenbacken,
• - Fig. 3a eine Seitenansicht von Fig. 3,
• - Fig. 4 einen Schnitt durch eine Hakenklammer,
• - Fig. 5 eine Ansicht der Hakenklammer gemäss Fig. 4,
• - Fig. 6 einen Schnitt durch eine Niederhalteklammer,
• - Fig. 7 eine Ansicht der Niederhalteklammer gemäss Fig. 6,
• - Fig. 8 eine Ansicht einer Kunststoffbacke,
• - Fig. 9 eine Seitenansicht der Kunststoffbacke von Fig. 8,
• - Fig. 10 eine Ansicht einer Metallbacke,
• - Fig. 11 eine Seitenansicht der Metallbacke von Fig. 10,
• - Fig. 12 ein Detail der Verhakung von Metall-und Kunststoffbacke,
• - Fig. 13 ein Detail der Abdichtung des Messers,
• - Fig. 14 einen Längsschnitt durch die mit einem Stahlband abgedeckten Lamellen eines Messers,
• - Fig. 15 eine Ansicht einer Variante einer Kunststoffbacke,
• - Fig. 16 eine Ansicht einer Variante einer Metallbacke, und
• - Fig. 17 eine Seitenansicht der verbundenen Kunststoff- und Metallbacke gemäss Fig. 16 und 17.

The invention is explained in more detail with reference to exemplary embodiments shown in the drawing, which are also the subject of dependent claims. They show schematically:

• 1 is a top view of a lamellar color meter shown in abbreviated form as an autonomous installation unit,
• 2 is a partially cut-away side view of an installation unit in the working position,
• 3 shows a top view of a slat color meter without side jaws,
• 3a shows a side view of FIG. 3,
• 4 shows a section through a hook clip,
• 5 shows a view of the hook clip according to FIG. 4,
• 6 shows a section through a hold-down clamp,
• 7 shows a view of the hold-down clamp according to FIG. 6,
• 8 is a view of a plastic jaw,
• 9 is a side view of the plastic jaw of FIG. 8,
• 10 is a view of a metal jaw,
• 11 is a side view of the metal jaw of FIG. 10,
• 12 shows a detail of the hooking of the metal and plastic jaw,
• 13 shows a detail of the sealing of the knife,
• 14 shows a longitudinal section through the slats of a knife covered with a steel strip,
• 15 is a view of a variant of a plastic jaw,
• 16 is a view of a variant of a metal jaw, and
• 17 shows a side view of the connected plastic and metal jaw according to FIGS. 16 and 17.

A slat color knife 10 shown in FIGS. 1 and 2 as an autonomous installation unit essentially comprises a flexible metal plate 12, otherwise also called a knife, and two-part side jaws 14 on both sides. The knife 12 and the side jaws 14 are connected to a knife carrier 16 (FIG. 3a) connected.

The metal jaws 18 of the side jaws 14 are each connected to the knife carrier 16 by two countersunk screws 20. A plastic jaw 26 is resiliently held on each metal jaw 18 via hook clips 22 and hold-down clips 24. The brackets 22, 24 are connected to the metal jaw 18 by means of screws 28.

1, the plastic jaw 26 is held on the metal jaw 18 with resilient ball screws 30. The four resilient ball screws 30, the position of which can be seen in FIG. 2, maintain a distance a of, for example, approximately 1 mm. If the autonomous installation unit is inserted into the offset printing machine, the plastic jaws 26 are displaced by less than the distance a against the associated metal jaw 18, the resistance of the resilient ball screws 30 having to be overcome. As a result, the plastic jaws 26 are pressed against the end faces 32 of the ink duct 34, which is a perfect seal allowed. In the present case, the four resilient ball screws 30 press the plastic jaw 26 against the ink duct 34 with a total force of approximately 1 kp.

The metal plate 12 of the slat color knife 10, the knife, is divided into slats 42 in the area of the working edge 38 placed against the running surface 36 of the ink ductor 34 or pressed in the vicinity thereof by right-angled cuts 40 of equal length. The individual slats 42, which are expediently of equal width, can be elastically bent by a respective adjusting element along the dash-dotted lines 43. The support area 41 of an actuator located below the knife 12 is indicated in a lamella 42. Simple adjusting screws or further developed, known manual or automatic adjusting elements can be used as adjusting elements.

It can be seen from FIG. 2 that the side jaw consisting of metal jaw 18 and plastic jaw 26 has free space in the region of the roller neck 44 of the ink duct 34. The visible subsegment of the plastic jaw 26 lies on the end face 32 of the ductor 34 and is responsible for lateral sealing. Wear of the stretched plastic jaw 26 is compensated for by the resilient ball screws 30 pressing the plate.

In the area of the knife 12 with the fins 42, the plastic jaw 26 has a groove with a sealing compound 62 on which the knife 12 rests.

• - innerhalb des Toleranzbereiches Längenunterschiede zwischen Farbduktor 34 und Messer 12 bei gleichbleibend guter Abdichtung ausgleichen kann, und
• - Abnützungen der nur auf den Stirnseiten 32 des Farbduktors gleitenden Kunststoffbacken 26 automatisch ausgleicht.

In the lowest area of the built-in unit, a dye bath 46 is indicated, which according to the invention is cleanly sealed. Overall, in the area of the side jaws 14 there is a perfect seal, which has never been achieved even anywhere

• - Can compensate for differences in length between ink duct 34 and knife 12 within the tolerance range while maintaining a good seal, and
• - Wear of the plastic jaws 26 sliding only on the end faces 32 of the ink ductor is automatically compensated.

The lamella color knife 10, which is designed as an autonomous installation unit, can be folded down by pivoting about an axis A until the knife 12 lies approximately horizontally. 1 is shown in this folded position.

A knife 12 with 16 slats 42 is drawn in FIG. The knife carrier 16 is visible on both end faces, with screw holes 17 for fastening the side jaws 14 (FIG. 1). The knife 12 and the knife carrier 16 are screwed together, which is indicated by five screw holes 48.

A weakening groove 50 runs parallel to the working edge 38, at the level of the lamellae lugs. This facilitates the individual elastic bending of lamellae 42. However, the remaining wall thickness ensures sufficient static strength.

In FIG. 3a it can be seen that the weakening groove 50 is arranged directly next to the knife carrier 16.

The hook clip 22 shown in FIGS. 4, 5 has an angled leg 54 in the area of the screw holes 52. A latching lug 56 is formed at a distance corresponding to the thickness of the metal jaw 18 and the plastic jaw 26 and the space a.

6, 7 also has an angled leg 54 with screw holes 52, but does not have a latching lug 56. Instead, the hold-down leg 58 is bent outwards at the free end.

As already mentioned, the plastic jaw 26 shown in FIGS. 8, 9 has a groove 60 for receiving a soft sealing compound 62 (FIG. 2). For design reasons, the groove 60 only extends up to a recess 64 in which the knife carrier 16 (FIG. 2) of the autonomous installation unit is received.

In the metal jaw 18 shown in FIGS. 10, 11 all screw holes are shown which are left open for the screws not shown, the screw holes 66 for the hook and hold-down clamps, the screw holes 68 for the resilient ball screws and the screw holes running parallel to the metal jaw 18 70 for the screws for attachment to the knife carrier 16.

The function of a hook clip 22, which is screwed to a metal jaw 18, is shown in FIG. 12. The plastic jaw 26 is held by the latching lug 56 when it is held at a distance a from the metal jaw 18 by resilient means. Resilient ball screws 30 act on the plastic jaw 26.

When the installation unit is inserted, the end face 32 of the ink duct 34 (FIG. 2) presses against the surface 74 of the plastic jaw 26, as a result of which the distance a is somewhat reduced.

In the embodiment according to FIG. 13, the metal jaw 18 and the plastic jaw 26 are connected to one another with screws 78 freewheeling in the area of the metal jaw 18 with the interposition of an elastically compressible layer 76, for example made of a closed-pore elastic plastic.

The knife 12 lies on the sealing compound 62, which is inserted in the groove 60 (FIG. 8) of the plastic jaw 26. As shown, the sealing compound 62 is flush with the surface 74, but it can also protrude or be slightly lowered, e.g. up to about 1 mm. In this way, the knife 12 can lie absolutely tight against the side jaws 14.

In addition to the sealing of the ink bath 46 according to the invention (FIG. 2) in the side area The spaces b between the lamellae 42 are also expediently sealed in accordance with FIG. 14, so that no color really runs out. This can be done in a manner known per se. However, a flexible metal strip 80 is preferably applied in a sealing manner on the top of the generally 1 to 3 mm, in particular 1.5 to 2.5 mm thick slats 42, preferably by means of an adhesive 82. Each slat 42 can be counteracted by means of an indicated actuator 84 the tread 36 of the ink ductor 34 are pressed, so that the ink flow is reduced in zones or even prevented. The flexible, for example 0.2 mm thick, spring steel band can compensate for this displacement without having any significant effect on the adjacent slats 42 and prevents color leakage between the slats 42.

The plastic jaw 26 shown in FIG. 15 largely corresponds to that according to FIG. 8. A step 86 forms a support surface 88 for a hook clip 22 (FIG. 17).

A groove (60 in FIG. 8) for supporting a knife end face is filled with a sealing compound 62. A guide groove 90 for a guide plate 92 (FIG. 16) is cut out on the back.

The metal jaw 18 according to FIG. 16 essentially corresponds to that of FIG. 10. A step 86 forms a contact surface 88 which corresponds to that of the plastic jaw 26, i.e. the distance from the base 94 is the same in both cases. The screw holes 70 are used for the frontal fastening of the metal jaw 18 to the knife carrier 16 (FIG. 3). The resilient screws 30 hold the unloaded plastic jaw 26 at a distance a from the metal jaw 18, but yield under pressure. The round plate 92 is pushed into the guide groove 90 of the plastic jaw 26 during assembly. The stepped blind hole 96 serves to receive a threaded rod for the manually actuated corrugated screw 98 shown in FIG. 17.

17 shows the resilient fastening of the plastic jaw 26 to the metal jaw 18 by pushing the metallic guide plate 92 as far as possible into the guide groove 90 and the two contact surfaces 88 being placed flush against one another. The hook clip 22 with a hole for the threaded rod in the blind hole 96 (FIG. 16) is fastened with the corrugated screw 98. A single hook clip 22 is thus sufficient for the resilient fastening of the plastic jaw 26.

Claims (10)

1. lamella ink knife (10) for the ink fountain of an offset printing press, a knife (12) designed as a flexible steel plate being bendable zone by zone against an ink duct (34) by actuators (84) arranged on each lamella (42),
characterized in that
the slat color knife (10) is designed as an autonomous installation unit with two-part side jaws (14) fastened on both sides to a knife carrier (16), which side jaws (14) each have an outer metal jaw (18) and an inner one that resiliently rests against the end faces (32) of the Color ductor (34) and also on the front side of the knife (12) adjustable plastic jaw (26). 2. Lamellar color knife (10) according to claim 1, characterized in that the plastic jaws (26) on the inside a groove (60) filled at least in the area of the knife (12) immersed in a color bath (46) and filled by an elastic sealing compound (62). exhibit. 3. slat color knife (10) according to claim 1 or 2, characterized in that the plastic jaws (26) with elastic clips (22,24) are held and pressed. 4. slat color meter (10) according to any one of claims 1 to 3, characterized in that the distance (a) of the plastic jaws (26) from the corresponding metal jaw (18) with resilient ball screws (30) or a compressible intermediate layer (76) maintained is. 5. slat color meter (10) according to any one of claims 1 to 4, characterized in that the elastic sealing compound (62) in the groove (60) is replaceable. 6. slat color knife (10) according to any one of claims 1 to 5, characterized in that the groove (60) with the elastic sealing compound (62) is 1 to 2 mm wider than the knife (12). 7. slat color meter (10) according to any one of claims 1 to 6, characterized in that the elastic sealing compound (62) consists of rubber or a soft plastic. 8. Knife (12) designed as a flexible steel plate for the ink fountain of an offset printing press, which knife can be bent differently zone by zone against an ink duct (34) by adjusting elements (84) arranged on each lamella (42), characterized in that at least the lamellae (42 ) are completely covered on the top with a sealingly applied flexible metal band (80). 9. Knife (12) according to claim 8, characterized in that the preferably glued metal band (80) consists of spring steel and is about 0.2 mm thick. 10. Knife (12) according to claim 8 or 9, characterized in that it has at least on one side a parallel to the working edge (38) extending weakening groove (50), preferably along the approaches of the lamellae (42).

Images