GB1560160A

GB1560160A - Ink duct for offset or relief printing presses

Info

Publication number: GB1560160A
Application number: GB48608/77A
Authority: GB
Original assignee: Heidelberger Druckmaschinen AG
Current assignee: Heidelberger Druckmaschinen AG
Priority date: 1977-03-17
Filing date: 1977-11-22
Publication date: 1980-01-30
Also published as: AT361513B; BR7801054A; SE7800672L; AU3069177A; CA1119885A; JPS53116904A; IT1156922B; NL7713218A; ZA776496B; MX147002A; DE2711553A1; CH626005A5; ES465787A1; JPS5617233B2; NO780930L; ATA808477A; AR220119A1; BE863996A; IT7867582A0; AU509516B2

Abstract

The ink duct has an ink metering device with adjusting elements. Using the latter, the gap opposite the ductor roller can be adjusted differently in zones. The ink duct (1) is covered by an elastic film (11) which is easily removable; the film is fixed in the upper region (12) of the ink duct (1), for example by an adhesive film (23) or clamping means. This dispenses with complicated cleaning of the ink duct; it is sufficient to exchange the film for a new one. <IMAGE>

Description

(54) INKDUCT FOR OFFSET OR RELIEF PRINTING PRESSES (71) We, HEIDELBERGER DRUCKMASCHINEN AKTIENGESELLSCHAFT, a company organised under the laws of the Federal Republic of Germany of Alte Eppelheimer Str. 15-21, Postfach 102940, 69 Heidelberg, Federal Republic of Germany, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to inkducts for offset or relief printing presses.

In constructions hitherto known, means for wiping off ink and for adjusting the quantity of ink on a ductor roller of a printing press are normally firmly screwed to the inkduct of the press. In this context it is irrelevant whether a foil or a spring-steel blade is used. So-called fountain screws of an elastic material are removed from the inkduct only when they require reconditioning or when they have to be exchanged for a new fountain screw. Independently of this, the inkduct must be cleaned more frequently, including more particularly when changing colours. These cleaning operations are complicated because ink which has dried on is difficult to remove with solvents.

According to the present invention there is provided an inkduct for an offset or relief printing press, the inkduct including an ink dosing device adjustable to form a gap in relation to a ductor roller using adjusting elements by which the gap is adjustable differentially by zones, the adjusting elements being juxtaposed axially of the ductor roller and adjustable to various distances with reference to the ductor roller so that their respective distances from the ductor roller determine the ink gap in that zone, and the ink dosing device is covered by an elastic foil fixed to the inkduct, the elastic foil being fixed only in an upper region of the inkduct so as to be easily removable.

The invention further provides printing presses including such inkducts.

The present invention uses an ink dosing device with an elastic foil. It has been found that reconditioning or cleaning of the foils can be dispensed with in the case of wear or fouling, since they can simply be exchanged for a new foil.

The elastic foil is preferably fixed by means of an adhesive film or clamping means. An easy and simply fixing, and an easy removal of the foil from the inkduct, avoids reconditioning or complicated cleaning of the fountain screw when changing colours, and it replaces the more expensive fountain screw by a disposable foil. The latter can easily be torn off an adhesive film, e.g.

when changing colours, and with equal cases a new foil, which has merely been cut to length, can be inserted.

Inkducts embodying the invention will now be described by way of example, with reference to the accompanying diagrammatic drawings wherein: Fig. 1 shows a side elevation of one inkduct with a foil fixed by being stuck on; Fig. 2 shows a further inkduct to a larger scale, the foil fixed by being firmly clamped; Fig. 3 is a vertical section through the foil and an adjusting element; Fig. 4 shows a vertical section through a further inkduct having pressure bars fixing the foil; and Fig. 5 shows a section on line 5-5 of Fig. 4.

The illustrated offset or relief printing press (Fig. 1) has a ductor roller 2 associated with an inkduct 1, between which ink 3 is filled into a wedge-shaped space. The ink is fed in a thin film from the ductor roller 2 via a lifting roller 4 to an inking unit roller 5, from where it is transferred into an inking unit not shown. During this, the ink film can be adapted to particular requirements by an ink dosing device 6. To enable the inkduct 1 to be cleaned, it can be pivoted away from roller 2 about a pivot joint 7. The lengths of the rollers and inkduct 1 axially of the rollers are dimensioned according to the paper format to be printed. Both ends of the mkduct 1 and the rollers are mounted in known manner in inking unit side walls, (not shown).

The ink dosing device 6 includes adjusting elements 8 of zone widths which are arranged closely juxtaposed and extend across the width of the inkduct 1. As illustrated in Fig. 2, the adjusting elements 8 are cylindrical and are rotatable in a peripheral direction. Associated with each adjusting element 8 is a spring 9 which partially surrounds the same and urges it against the ductor roller 2. The springs 9 are fixed to the inkduct 1 by means of a cover strip 10 which serves as a stop for the spring 9 in the out-ofservice state of the inkduct 1. The adjusting elements 8 are covered by an elastic foil 11, only an upper region 12 of the foil 11 being secured to the inkduct 1. The pressure of the spring 9 is thus transmitted through the adjusting elements 8 and the foil 11 to the ductor roller 2.

Considered axially of the ductor roller 2, bracing regions 13 and dosing regions 14 are juxtaposed on the adjusting elements 8 (Fig.

3). The bracing regions 13 are always in contact, through the foil 11, with the ductor roller 2 even when the adjusting elements 8 are adjusted. The dosing regions 14 are adjustable to variable distances with reference to the ductor roller 2, so that their particular distances from the ductor roller determine the ink gap in that zone. The elastic foil 11 is then lifted off the surface of the ductor roller 2 by the static pressure of the ink 3 and urged against the dosing region 14.

In order to rotate the adjusting elements 8, a bifurcate arm 15 is fixed to them. Arm 15 is coupled through a slot 16 to a bolt 17 of a set nut 18. The set nut 18 is in turn fixed on a screw-threaded portion 19 of a set screw 20 which is rotatable in the inkduct 1. By rotating the set screw 20, the set nut 18 can be displaced and the arm 15 can thus be pivoted through an angle a. The arm 15 then pivots in a slot 21 of the spring 9. The pivoting range of the arm 15 thus determines the range of adjustment of the adjusting elements 8.

The foil 11 extends along the length of the inkduct 1 and extends at both ends beneath closure pieces 22, likewise easily removable, for the wedge-shaped space of the ink 3. The foil 11 is therefore longer than the actual ink space of the inkduct 1, and it is additionally clamped by the closure pieces 22 at the ends of the inkduct 1.

In Fig. 1, the foil 11 is fixed to the inkduct 1 by means of an adhesive film 23 in the upper region 12. The fixing is effected by pressing the foil into place, and it is so dimensioned that the foil 11 can be pulled off easily.

In Fig. 2, the foil 11 is firmly clamped in the upper region 12 of the inkduct 1 by a clamping strip 24, clamping with the clamping strip 24 being effected by screws 25.

After releasing the screws 25, the foil 11 can easily be drawn out under the clamp strip 24 and exchanged for a new one. The foil 11 consists of a high-grade and wear-resistant plastics material, and it is disposable, i.e.

reconditioning or complicated cleaning operations are not required owing to the low cost of the foil.

The inkduct 1 shown in Fig. 4 employs pressure strips 26 for urging the adjusting elements 8, the strips 26 having a recess 27 in a front region thereof for the adjusting elements 8. The pressure strips 26 are held loosely by means of screws 28 and are supported by compression springs 29. The pressure of the compression springs 29 is transmitted through the adjusting elements 8 and the foil 11 to the ductor roller 2. The elastic foil 11 covers the pressure strips 26 and is fixed to the latter by an adhesive film 23.

The elastic foil 11 extends along the length of the inkduct 1 and is continued at both ends beneath the closure pieces 22, by which it is firmly clamped upon the inkduct 1 (Fig. 5).

The closure pieces 22 and the foil 11 can easily be removed by means of screws 31 arranged in a block 30.

Obviously, the invention is not restricted to the embodiments described. Thus, for example, a disposable foil can be employed on all types of inkducts, e.g. including divided fountain screws.

WHAT WE CLAIM IS: 1. An inkduct for an offset or relief printing press, the inkduct including an ink dosing device adjustable to form a gap in relation to a ductor roller using adjusting elements by which the gap is adjustable differentially by zones, the adjusting elements being juxtaposed axially of the ductor roller and adjustable to various distances with reference to the ductor roller so that their respective distances from the ductor roller determine the ink gap in that zone, and the ink dosing device is covered by an elastic foil fixed to the inkduct, and the elastic foil being fixed only in an upper region of the inkduct so as to be easily removable.

2. An inkduct according to claim 1, wherein the elastic foil is fixed by means of an adhesive film or clamping means.

3. An inkduct according to claim 1 or claim 2, wherein the elastic foil extends along the length of the inkduct and extends beneath closure pieces at both ends thereof, and the foil is firmly clamped to the closure pieces.

4. An inkduct according to any one of claims 1 to 3, wherein the elastic foil covers pressure bars defining zones, the bars having a recess for the adjusting elements in a front

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Claims

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be cleaned, it can be pivoted away from roller 2 about a pivot joint 7. The lengths of the rollers and inkduct 1 axially of the rollers are dimensioned according to the paper format to be printed. Both ends of the mkduct 1 and the rollers are mounted in known manner in inking unit side walls, (not shown).

The ink dosing device 6 includes adjusting elements 8 of zone widths which are arranged closely juxtaposed and extend across the width of the inkduct 1. As illustrated in Fig. 2, the adjusting elements 8 are cylindrical and are rotatable in a peripheral direction. Associated with each adjusting element 8 is a spring 9 which partially surrounds the same and urges it against the ductor roller 2. The springs 9 are fixed to the inkduct 1 by means of a cover strip 10 which serves as a stop for the spring 9 in the out-ofservice state of the inkduct 1. The adjusting elements 8 are covered by an elastic foil 11, only an upper region 12 of the foil 11 being secured to the inkduct 1. The pressure of the spring 9 is thus transmitted through the adjusting elements 8 and the foil 11 to the ductor roller 2.

Considered axially of the ductor roller 2, bracing regions 13 and dosing regions 14 are juxtaposed on the adjusting elements 8 (Fig.

3). The bracing regions 13 are always in contact, through the foil 11, with the ductor roller 2 even when the adjusting elements 8 are adjusted. The dosing regions 14 are adjustable to variable distances with reference to the ductor roller 2, so that their particular distances from the ductor roller determine the ink gap in that zone. The elastic foil 11 is then lifted off the surface of the ductor roller 2 by the static pressure of the ink 3 and urged against the dosing region 14.

In order to rotate the adjusting elements 8, a bifurcate arm 15 is fixed to them. Arm 15 is coupled through a slot 16 to a bolt 17 of a set nut 18. The set nut 18 is in turn fixed on a screw-threaded portion 19 of a set screw 20 which is rotatable in the inkduct 1. By rotating the set screw 20, the set nut 18 can be displaced and the arm 15 can thus be pivoted through an angle a. The arm 15 then pivots in a slot 21 of the spring 9. The pivoting range of the arm 15 thus determines the range of adjustment of the adjusting elements 8.

The foil 11 extends along the length of the inkduct 1 and extends at both ends beneath closure pieces 22, likewise easily removable, for the wedge-shaped space of the ink 3. The foil 11 is therefore longer than the actual ink space of the inkduct 1, and it is additionally clamped by the closure pieces 22 at the ends of the inkduct 1.

In Fig. 1, the foil 11 is fixed to the inkduct 1 by means of an adhesive film 23 in the upper region 12. The fixing is effected by pressing the foil into place, and it is so dimensioned that the foil 11 can be pulled off easily.

In Fig. 2, the foil 11 is firmly clamped in the upper region 12 of the inkduct 1 by a clamping strip 24, clamping with the clamping strip 24 being effected by screws 25.

After releasing the screws 25, the foil 11 can easily be drawn out under the clamp strip 24 and exchanged for a new one. The foil 11 consists of a high-grade and wear-resistant plastics material, and it is disposable, i.e.

reconditioning or complicated cleaning operations are not required owing to the low cost of the foil.

The inkduct 1 shown in Fig. 4 employs pressure strips 26 for urging the adjusting elements 8, the strips 26 having a recess 27 in a front region thereof for the adjusting elements 8. The pressure strips 26 are held loosely by means of screws 28 and are supported by compression springs 29. The pressure of the compression springs 29 is transmitted through the adjusting elements 8 and the foil 11 to the ductor roller 2. The elastic foil 11 covers the pressure strips 26 and is fixed to the latter by an adhesive film 23.

The elastic foil 11 extends along the length of the inkduct 1 and is continued at both ends beneath the closure pieces 22, by which it is firmly clamped upon the inkduct 1 (Fig. 5).

The closure pieces 22 and the foil 11 can easily be removed by means of screws 31 arranged in a block 30.

Obviously, the invention is not restricted to the embodiments described. Thus, for example, a disposable foil can be employed on all types of inkducts, e.g. including divided fountain screws.

WHAT WE CLAIM IS: 1. An inkduct for an offset or relief printing press, the inkduct including an ink dosing device adjustable to form a gap in relation to a ductor roller using adjusting elements by which the gap is adjustable differentially by zones, the adjusting elements being juxtaposed axially of the ductor roller and adjustable to various distances with reference to the ductor roller so that their respective distances from the ductor roller determine the ink gap in that zone, and the ink dosing device is covered by an elastic foil fixed to the inkduct, and the elastic foil being fixed only in an upper region of the inkduct so as to be easily removable.
2. An inkduct according to claim 1, wherein the elastic foil is fixed by means of an adhesive film or clamping means.
3. An inkduct according to claim 1 or claim 2, wherein the elastic foil extends along the length of the inkduct and extends beneath closure pieces at both ends thereof, and the foil is firmly clamped to the closure pieces.
4. An inkduct according to any one of claims 1 to 3, wherein the elastic foil covers pressure bars defining zones, the bars having a recess for the adjusting elements in a front

region of the bars, and the bars are supported by compression springs.
5. An inkduct for an offset or relief printing press, the inkduct being substantially as herein described with reference to the accompanying drawings.
6. A printing press including an inkduct according to any one of the preceding claims.