This application is the U.S. National phase, under 35 U.S.C. 371, of PCT/EP2007/053701, filed Apr. 17, 2007; published as WO 2007/134919 on Nov. 29, 2007 and claiming priority to DE 10 2006 024 029.4, filed May 23, 2006; to DE 10 2006 030 057.2, filed Jun. 29, 2006 and to DE 2006 042 590.1, filed Sep. 11, 2006, the disclosures of which are expressly incorporated herein by reference.
The present invention is directed to an inking unit of a rotary printing press comprising a film roller. The film roller has a structured circumferential surface that has a hardness of at least 60 Shore D. The surface has a stochastic structure which is imparted to the surface using shot peening.
An inking unit of a rotary printing press comprising a film roller is known from JP 2005 271407A. The film roller has a circumferential surface with a coating of an 11-polyamide/12-polyamide or of copper.
An inking roller of a printing press having a stochastic structure formed on its circumferential surface is known from GB 729561A1. The stochastic structure is produce via shot peening.
An inking unit of a rotary printing press is known from DE 44 39 144 C2. It comprises an ink fountain roller which picks up ink from an ink reservoir, and a plurality of ink forme rollers which apply ink to a printing couple cylinder. An ink dividing roller is provided, which divides an ink flow coming from the ink fountain roller into a primary flow and a secondary flow. A distribution roller, which transfers ink from the ink dividing roller to at least one of the ink forme rollers, is provided in the primary flow and in the secondary flow. The roller train between the ink fountain roller and the ink dividing roller comprises four rollers arranged in a row, and is therefore relatively long. When the ink forme rollers are to apply a very specific quantity of ink to the printing couple cylinder, a relatively thick layer of ink is applied to the roller which is situated downstream from the ink fountain roller in the roller train. Following each gap position between two adjacent rollers in the roller train which transfer ink, the layer of ink is thinner on the roller situated downstream from the gap position. However, the respective ink layer is necessarily relatively thick, at least on the first of the four rollers situated near the ink reservoir, due to the many gap positions between that at least first roller and the printing couple cylinder. This results in increased ink misting in the case of a high-speed rotary printing press.
An inking unit of a rotary printing press is known from WO 2004/024451 A1. It is comprised of an ink fountain roller, which picks up ink from an ink reservoir, and a plurality of ink forme rollers which apply ink to a printing couple cylinder. An ink dividing roller, which divides an ink flow coming from the ink fountain roller into a primary flow and a secondary flow, is provided. A distribution roller, which transfers ink from the ink dividing roller to at least one of the ink forme rollers, is also provided in the primary flow and in the secondary flow. The ink, which is to be fed into the roller train, is applied directly to the ink dividing roller by an ink chamber blade. In this prior device, the ink dividing roller is configured as an anilox roller. A short ink train of this type has no provision for metering ink quantity by zones. It is suitable for use only in connection with a dry offset printing process which does not employ dampening agent.
A method is known from DE 10 2004 004 665 A1 in which each of the rollers of an inking unit and/or a dampening unit is equipped with a device for executing a remotely actuable radial movement of the respective roller. This can be done, for example, to adjust the roller's contact pressure against an adjacent rotational body.
A device, for use in mounting a cylinder of a printing unit using a bearing block, and which is capable of moving in linear bearings along an adjustment path and which has a rotary bearing, is known from DE 10 2004 037 889 A1. The bearing assembly is embodied as a bearing unit in the manner of a structural assembly which can be mounted as a complete unit, which, in addition to the rotary bearing, comprises both cooperating bearing elements which enable the relative movement of the bearing block.
An inking roller with a jacket piece configured as a sleeve made of a microporous elastomeric material is known from DE 27 23 582 B. In the jacket piece, which is made, for example, of foam rubber, a plurality of cavities are formed. The cavities are of substantially different sizes within a predetermined size range. The purpose of this inking roller is to prevent ink mist from being thrown off of the inking roller, especially at higher circumferential speeds of the inking roller of at least 305 m/min.
A fluid roller with a hard surface is known from DE 30 04 295 A1. A hard metal coating, such as, for example, chromium, for example having a thickness of up to 0.5 mm, is applied to the outer surface of the cylindrical core. In this coating, a random pattern of interconnected gaps, with separate islands lying between them, is created via etching. The interconnected gaps occupy up to 30% of the surface of the fluid roller. The gaps have a depth, for example, of up to 0.075 mm. This fluid roller cooperates with another roller to transport the fluid. The additional roller has a soft circumferential surface. These two rollers are engaged against one another.
An inking roller, which is made of steel, is known from U.S. Pat. No. 4,537,127A. The circumferential surface of this inking roller is preferably structured with intersecting lines in a cell pattern via engraving, is boundary hardened in a nitration process, and is then subjected to an oxidation process. The oxidation process forms an outer layer, comprised primarily of Fe3O4, on the circumferential surface of the roller.
A printing unit, with an inking unit having at least one ink dividing roller, is known from DE 10 2004 040 150 A1. Only a single roller is positioned in the inking unit between an ink fountain roller, which picks up ink from an ink reservoir, and the ink dividing roller. This single roller is configured as a film roller. The film roller has a structured circumferential surface.
A film roller for inking units of rotary printing presses is known from DE 69 10 823 U. The surface of that film roller is equipped with a thin layer of hard rubber. The hard rubber layer has a Shore hardness of 80 to 85°.
A method of producing an anilox roller, made preferably of steel, is known from DE 100 28 478 A1. This anilox roller is equipped, on its outer surface, with small depressions. The depressions are preferably generated via shot peening. A limitation of this prior anilox roller is that a circumferential surface made of steel will create a discontinuity in ink transport after only a short period of operation, especially when used in a wet offset printing process. This is because such a circumferential surface tends to run out of ink rapidly.
The object of the present invention is to provide an inking unit of a rotary printing press comprising a film roller. The inking unit in accordance with the present invention is wear resistant at a transport speed of a print substrate printed in this rotary printing press of more than 10 m/s. It also tends less toward ink misting, and can be used to produce a high quality printed product.
The object of the present invention is attained, according to the present invention with the provision of a film roller with a structured circumferential surface having a hardness of at least 60 Shore D. This structured surface has a stochastic structure which in imparted via shot peening. The circumferential surface has irregularly distributed depressions ranging in depth from 50 μm to 400 μm. The open depressions on the circumferential surface of the film roller make up a maximum vacant space ratio of 35%, relative to a closed, cylindrical surface of the film roller.
The benefits to be achieved with the present invention consist especially in that a film roller having a circumferential surface with a hardness of at least 60 Shore D, and preferably with a surface hardness of more than 70 Shore D, and especially within the hardness range of 80 to 90 Shore D, is more wear resistant than a traditional film roller, such as, for example, a film roller having an outer surface with a hard rubber layer, under the conditions of use that are present in a high-speed rotary printing press which is operating at a transport speed of more than 10 m/s of the print substrate to be printed. This increased wear resistance is because the desirable high values for the hardness of the circumferential surface of such a film roller cannot be achieved using rubber materials. To provide a circumferential surface that will be wear resistant under the above-described operating conditions, it is advantageous to select a polyamide or a polyacrylate or copper as the material for the circumferential surface of the film roller. These materials are characterized by a high resistance to wear and by resistance to aging, while also possessing very beneficial ink absorption and ink delivery properties due to their ink affinity. Particularly advantageous, in accordance with the present invention, is the use of Rilsan®, which is a polyamide made of 11-aminoundecanoic acid (Rilsan B, PA 11) or of ω-laurolactam (Rilsan A, PA 12). These polyamide materials have a hardness of at least 60 Shore D, and preferably have a hardness of more than 70 Shore D. Particularly high hardness values are achieved by reinforcing the relevant polyamide material with glass fibers. It is significant that in an inking unit there is a very great difference between the respective circumferential speeds of the ink fountain roller and of the ink dividing roller. The circumferential surface of the film roller, which is situated between the ink fountain roller and the ink dividing roller, is subjected to a high mechanical stress and, if applicable, is also subjected to a high thermal stress.
It is advantageous, in accordance with the present invention, to configure the circumferential surface of a film roller with a stochastic structure. This is because a film roller having such a circumferential surface with a stochastic structure has a very favorable ink transport capability, which ink transport capability contributes to the production of a high quality printed product. Moreover, the method of imparting the stochastic structure to the circumferential surface of the film roller, in accordance with the present invention, is highly advantageous. This is because shot peening is a very cost-effective processing method.
It is further advantageous, in accordance with the present invention, that, due to the shortness of the roller train which transports ink to the printing couple cylinder, and thus, due to the low number of ink gap positions, the ink fountain roller needs to pick up only a comparatively thin layer of ink from the ink reservoir and to apply it to the roller that is situated downstream from the ink fountain roller in order to provide the requisite quantity of ink to the printing couple cylinder. Consequently, the ink layers on the rollers, which ink layers are the main causes of ink misting, which is especially true on the film roller, are relatively thin. Therefore, the inking unit in accordance with the present invention tends toward less ink misting, even when it is used in a high-speed rotary printing press in which the substrate being printed is transported at a speed of more than 10 m/s.
The combination of features of the present invention accordingly results in a film roller which, under the operating conditions imposed on it in a high-speed rotary printing press, has a long service life and also has a highly beneficial ink transport capability, together with a low level of ink misting. The film roller of the present invention is also cost-effective to produce.
A further advantage of the inking unit, with the ink film roller of the present invention, consists in that, because of the short roller train, the inking unit reacts rapidly to ink metering adjustments made, for example, to one or more ink zones during an ongoing production run. Such a rapid reactions result in the reduction of the amount of waste paper that is produced before the new ink quantity has become stabilized.
Added to this is the advantage that the inking unit, in accordance with the present invention, holds only a relatively low volume of ink in its relatively short roller train. This low ink volume allows the washing times, which are associated with a cleaning of the inking unit, to also be kept short. Short washing times help meet the demand for short set-up times. This is especially important among customers involved in newspaper printing, because the washing times are included in the setup times.
A front-loaded inking unit with a plurality of ink forme rollers, such as, for example, with at least three ink forme rollers, as is provided by the present invention, generates an even ink application on the printing couple cylinder against which the ink forme rollers are engaged, or on the at least one printing forme which is arranged on this printing couple cylinder. This is a fundamental criterion for the quality of the printed product which is to be produced in the printing press that comprises the inking unit in accordance with the present invention. Classic newspaper printing presses have usually had only two ink forme rollers. However, three ink forme rollers even out the ink application better than can be accomplished through the provision of only two ink forme rollers. There ink forme rollers are also better at evening out a pattern that forms on the ink forme rollers with respect to their respective ink film. The result is that an inking unit having three or more ink forme rollers tends less toward ghosting.
Ghosting refers to the presence of a shadow-like, repeating, undesirable imaging of a part of a print image, which is formed in the printing direction of the printing couple cylinder. The imaging is characterized by the presence of a greater or lesser inking, as compared with the surrounding area. Ghosting is affected by the distribution of ink in the inking unit, and is especially affected by the distribution of ink on the ink forme rollers. If a previously impressed ink profile is not adequately broken down, or is not evened out, through ink resplitting, based upon the image on the printing forme before the next inking up, or before the next rotation of the ink forme roller, then the image segment that already been printed will be partially transferred to, or ghosted onto another image segment to be printed on the substrate.
In addition, and in accordance with the present invention, by mounting at least the film roller and/or the ink dividing roller and/or the ink forme rollers of the inking unit so as to allow radial movement, an improvement in the quality of the printed product produced in connection with this inking unit is possible. This quality improvement is because the contact pressure that is exerted by the respective roller can be adjusted and can be corrected as needed. With this adjustment, the transport of ink can be controlled and thereby can be optimized.
One preferred embodiment of the present invention is represented in the set of drawings and will be specified in greater detail in what follows.
The drawings show:
Referring initially to
The inking unit which is shown in
Primary ink flow B is the part of the ink flow A, that is coming from the ink fountain roller 08, which is picked up by the ink dividing roller 11, which is directed in the direction of rotation of that ink dividing roller 11 and which is forwarded as the first ink flow in the direction of the forme cylinder 02 via the distribution roller 12 that is situated in this primary flow B. The part of the ink flow A, which is coming from the ink fountain roller 08, and which is picked up by the ink dividing roller 11, in the direction of rotation of that ink dividing roller 11, downstream from the primary flow B and which is forwarded in the direction of the forme cylinder 02, is referred to as the secondary flow C of the ink which is picked up from the ink reservoir 07. The secondary flow C can, in turn, be divided into additional partial ink flows D; E, if a plurality, and especially if two, of the ink forme rollers 03; 04; 06 are engaged against the distribution roller 13, which is positioned in the secondary flow C. Because the primary flow B of the ink flow A coming from the ink fountain roller 08 is the first to reach the forme cylinder 02, in the direction of rotation of the forme cylinder 02, and is at least spatially in front of the secondary ink flow C and its partial ink flows D; E, this type of inking unit depicted in
The ink reservoir 07, from which the ink fountain roller 08 picks up the ink which is to be transported to the forme cylinder 02, is embodied, for example, as an ink fountain 07 or as an ink trough 07. A plurality of ink blades, which are not specifically shown, such as, for example, thirty to sixty ink blades, are provided in a row on the ink fountain 07 or on the ink trough 07 in the axial direction of the ink fountain roller 08. Each of these ink blades can be adjusted, in terms of its respective engagement against the ink fountain roller 08, and is actually engaged against that ink fountain roller, preferably remotely, via an adjustment mechanism, which is not specifically shown, thereby allowing a zonal metering of the ink which is picked up by the ink fountain roller 08 from the ink reservoir 07. The metering of the quantity of ink, which is performed by adjusting the respective ink blade, is expressed in an ink film thickness, which ink film thickness is proportional to this adjustment in the relevant zone on the circumferential surface of the ink fountain roller 08. Accordingly, in the preferred embodiment of the present invention, the inking unit is structured as a zonal inking unit.
The lengths of the rollers 03; 04; 06; 08; 09; 11; 12; 13 of the inking unit, in their respective axial directions range, for example, from 500 mm to 2,600 mm, and especially range from 1,400 mm to 2,400 mm. Their outer diameters range, for example, from 50 mm to 300 mm, and preferably range from 80 mm to 250 mm.
The circumferential surface of the ink dividing roller 11 is preferably made of a flexible material, such as, for example, a rubber material. The layer thickness of the elastomeric material on the circumferential surface of the ink dividing roller 11 can range, for example, from 1 mm to 20 mm, and preferably can range from 5 mm to 15 mm. The circumferential surface of the ink dividing roller 11 is preferably structured with a hardness ranging from 40 to 80 Shore A, and especially with a hardness ranging from 50 to 60 Shore A, with this measurement of hardness being defined according to DIN 53505. The higher the value of this hardness indicator, the greater the hardness of the material, which, in this case, is used for the circumferential surface of the ink dividing roller 11.
As a special characteristic of its circumferential surface, the ink film roller 09 has a circumferential surface with a stochastic structure, or in other words, is configured with a circumferential surface with an irregular distribution of elements which structure this circumferential surface, and which irregular distribution of elements generally have an irregular form and further have no specific preferred direction or orientation. The circumferential surface of the ink film roller 09 is preferably such as made of a plastic, preferably a polyacrylate or polyamide, and especially is name of Rilsan® or, in an alternative embodiment, is made of copper. The circumferential surface of the film roller 09 is relatively hard in structure, having a hardness of at least 60 Shore D, and preferably having a hardness of more than 70 Shore D, and especially having a hardness ranging from 80 to 90 Shore D, with this measurement of hardness also being defined according to DIN 53505. In the preferred embodiment of the ink film roller 09, the stochastic structure is produced on an initially smooth and homogeneous circumferential surface of the ink film roller 09 using a shot peening procedure, which shot peening procedure represents a particularly simple and therefore a cost-effective production procedure of the circumferential surface of this ink film roller 09, which is advantageous for the transport of ink. It is important to note that there is no linear correlation between the hardness testing processes in accordance with Shore A and Shore D. For purely informational purposes, an addendum to DIN 53505 states that a hardness of 80 Shore A corresponds to a hardness of approximately 30 Shore D. A hardness measurement of at least 60 Shore D, preferably of more than 70 Shore D, and especially of 80 to 90 Shore D is therefore characteristic of a relatively very hard surface.
The circumferential surface of each of the distribution rollers 12; 13 can also be made of plastic, preferably a polyamide, and especially Rilsan®. The circumferential surface of each of the distribution rollers 12; 13 is smooth and has no stochastic structure. Each of the ink forme rollers 03; 04; 06 preferably has a circumferential surface which is also made of an elastomeric material, preferably a rubber, with the hardness of these circumferential surfaces, as defined according to DIN 53505, preferably ranging from 35 to 60 Shore A. The circumferential surface of the ink fountain roller 08, which is preferably dipped into ink in the ink reservoir 07, can be steel or can be a ceramic layer which is applied to a material that forms the core of the ink fountain roller 08.
The stochastic structure of the circumferential surface of the ink film roller 09 is preferably embodied by cavities and depressions that have been imparted to this circumferential surface by the shot peening procedure discussed above, which form the structural elements. Depths of the cavities and depressions, measured in the radial direction of the ink film roller 09, can range, for example, from 50 μm to 400 μm. This depth is non-uniform with respect to the structural elements which are distributed over the circumferential surface of the film roller 09. The roughness of the cylindrical surface which actually delimits the ink film roller 09 as a rotational body has an absolute roughness depth Rt ranging, for example, from 100 μm to 120 μm and a mean roughness depth Rz ranging, for example, from 60 μm to 80 μm. These values can be determined, for example, using a perthometer, which is typically a tracing stylus instrument, preferably operating according to pertinent standards, such as, for example, DIN EN ISO 4287. A smallest material ratio Mr1 of the circumferential surface of the film roller 09, corresponding to a percentage of contact area of the peaks, and determined according to DIN 4776 from an Abbott curve, ranges, for example, from 7% to 13%, and preferably ranges from 9% to 11%. A greatest material ratio Mr2 of the circumferential surface of the film roller 09, corresponding to a percentage of contact area of the ridging, as determined according to DIN 4776 using the same Abbott curve, ranges, for example, from 80% to 95%, and preferably ranges from 85% to 90%.
Each of the open cavities and/or the depressions, which are formed on the circumferential surface of the ink film roller 09, forms a vacant space with respect to the cylindrical datum surface, or in other words, with respect to the closed and smooth-walled assumed cylindrical surface of the ink film roller 09. That vacant space corresponds to the cross-section of the opening of the respective cavity or of the respective depression in the plane of the datum surface. The total vacant space of all of the cavities and/or all of the depressions on the circumferential surface of the film roller 09 forms a vacant space ratio relative to the closed, assumed cylindrical surface, with the maximum vacant space ratio amounting to 35% of this cylindrical surface and with that vacant space ratio preferably lying between 20% and 30%. Depending upon the sizes of their respective vacant spaces and their respective depths, the cavities and/or depressions of the film roller 09 form a vacant volume. The vacant volume of all of the cavities and/or all of the depressions existing per m2 of assumed cylindrical surface amounts to at least 50,000 mm3, preferably amounts to at least 100,000 mm3, especially amounts to at least 150,000 mm3.
The cavities and/or the depressions which are arranged on the circumferential surface of the ink film roller 09 therefore structure the circumferential surface of the ink film roller 09 with their respective vacant space ratio and their respective vacant volume, forming a relief. This relief can be adapted, for example, to the rheological behavior of the ink to be transported, and can be adapted especially to the viscosity and/or to the smoothness of the ink to be transported. The processes of filling and emptying the cavities and/or depressions with the ink to be transported, and an adherence of the ink to be transported, during its respective transport from the ink fountain roller 08 to the ink dividing roller 11, are optimized based upon a rotational speed which is provided for this ink film roller 09 on its circumferential surface. A transport speed of the substrate which is being printed in this rotary printing press, which transport speed conditions the rotational speed of the film roller 09, can range, for example, up to 20 m/s when such a rotary printing press of this type is being used especially in newspaper printing. The beneficial effect of the cavities and/or depressions which have been introduced into the ink film roller 09, comes to bear especially at a higher transport speed of the print substrate which is printed in the rotary printing press, for example at a transport speed of at least 10 m/s, and especially within the transport speed range of between 10 m/s and 15 m/s. The production speed of the printing press can also be indicated by the speed of its printing couple cylinders 01; 02. This speed of the rotating printing couple cylinders 01; 02, which are embodied, for example, as double-circumference cylinders, amounts, for example, to more than 40,000 revolutions per hour. A double-circumference cylinder has two longitudinal sections, which are each preferably equal in length, along its circumference, with each one of the two longitudinal sections corresponding, for example, to the height of one newspaper page to be printed. The two cooperating printing couple cylinders 01; 02 are preferably equal in circumference.
To even out the thickness of the layer of ink on the ink dividing roller 11, and to remove excess ink which is applied by the ink fountain roller 08 to the circumferential surface of that ink dividing roller 11, another roller 14, which may be embodied as a doctor roller 14, can be engaged or at least can be engageable against the ink dividing roller 11. A doctor blade 16 is positioned on the doctor roller 14. The doctor roller 14 is engaged against the ink dividing roller 11 downstream, in the direction of rotation of the ink dividing roller 11, from the point at which the secondary flow C branches off. The excess ink which is doctored off the ink dividing roller 11 by the doctor roller 14, with the use of the doctor blade 16, is returned, for example, to the ink reservoir 07, which is indicated schematically in
Additionally, a stripper roller 17 can be provided. The stripper roller 17 is engaged, or at least can be engaged simultaneously against one of the ink forme rollers 03 and against a roller 18 of a dampening unit that can be also engaged against the forme cylinder 02. The roller 18 of the dampening unit can be embodied, for example, as a dampening forme roller 18. The stripper roller 17 can preferably be engaged against the ink forme roller 03, which is situated in the primary flow B. Stripper roller 17 again smoothes the primary flow B of the ink flow A coming from the ink fountain roller 08 and leading to the forme cylinder 02. The dampening unit is preferably embodied as a dampening unit that applies a dampening agent which is received in the dampening unit in a contactless fashion, for example as a spray dampening unit. The dampening unit has a spray bar 19. A plurality of spray nozzles, which are arranged on the spray bar 19, spray the dampening agent onto a roller 21 of the dampening unit, which roller 21 is embodied, for example, as a dampening distribution roller 21. The dampening agent that is sprayed onto the dampening distribution roller 21 by the spray bar 19 is transferred by a further roller 22 of the dampening unit, which further roller 22 may be embodied, for example, as a smoothing roller 22, to its dampening forme roller 18. From there, the dampening agent is transferred to the forme cylinder 02. With the use of the stripper roller 17, the primary flow B of the ink flow A, which is coming from the ink fountain roller 08 and leading to the forme cylinder 02, can be extended up to the dampening forme roller 18 of the dampening unit. This configuration provides the advantage that the ink being transported in the primary flow B comes into contact with the dampening agent supplied by this dampening unit, in the dampening unit, and is applied to the forme cylinder 02 together with the dampening agent. In this operational case, only a partial flow F of the ink transported in the primary flow B now leads from the ink forme roller 03, which is situated in the primary flow B, directly to the forme cylinder 02. The majority of the ink in the primary flow B is applied to the forme cylinder 02 through the stripping roller 17 and the dampening forme roller 18.
The circumferential surface of the dampening forme roller 18 is preferably made of an elastomeric material, preferably a rubber. The hardness of this circumferential surface, defined according to DIN 53505, preferably ranges from 25 to 30 Shore A, and is therefore relatively soft. Assuming that the circumferential surface of a cooperating smoothing roller 22 is made of chromium, the circumferential surface of the dampening distribution roller 21 is also made of a relatively soft elastomeric material, preferably a rubber. The hardness of this circumferential surface, defined according to DIN 53505, preferably ranges from 25 to 30 Shore A. If, however, the circumferential surface of the smoothing roller 22 is also made of an elastomeric material, then the circumferential surface of the smoothing roller 22 and that of the dampening distribution roller 21 are preferably made of the same elastomeric material, for example a rubber. The hardness of each of these circumferential surfaces, defined according to DIN 53505, preferably ranges from 40 to 60 Shore A. Therefore, the circumferential surface of the dampening distribution roller 21, in the second alternative, in which the smoothing roller 22 has an elastomeric surface, is harder than that of the first alternative in which the smoothing roller 22 has a chromium surface. Whether the first or the second alternative is used depends upon how the rollers 18; 21; 22 of the dampening unit are driven. If the smoothing roller 22 has an independent drive 57, such as, for example, an electric motor 57, which is schematically represented in
In
The uppermost ink forme roller 06 of the inking unit is situated such that, in its operating position, in which it is engaged against the forme cylinder 02, a horizontal tangent T06, which is placed on the periphery of this ink forme roller 06, is located at a vertical distance a06 of at least 50 mm from, and beneath a horizontal tangent T02 which is placed on the periphery of the forme cylinder 02. This vertical distance a06 forms an offset, so to speak, between the uppermost ink forme roller 06 and the forme cylinder 02. This arrangement allows sufficient access to the forme cylinder 02, from an operating side of the printing couple, especially if all of the remaining rollers 03; 04; 08; 09; 11; 12; 13; 14 belonging to the inking unit are positioned substantially below the horizontal tangent T06 placed on the periphery of the uppermost ink forme roller 06. The rollers 18; 21; 22 of the dampening unit are positioned substantially below the forme cylinder 02, and also do not restrict access to the forme cylinder 02. Accessibility of the forme cylinder 02 is necessary, for example, to allow one or more printing formes, which are carried on the circumferential surface of the forme cylinder 02, to be changed within the shortest possible time. A change of printing formes on the forme cylinder 02 can be performed manually by a printing press operator, or can be performed automatically with the help of a printing forme magazine 58, as may be seen in
Despite the relatively low number of ink gap positions in the roller train that transports ink to the printing couple cylinder 02 in accordance with the present invention, the represented inking unit generates an even ink application on the printing couple cylinder 02. This is because more rollers are provided where they are especially needed for smoothing the applied ink, namely in direct contact with the printing couple cylinder 02, where preferably the three ink forme rollers 03; 04; 06 are provided. Particularly, with the provision of the special, stochastic structure of the circumferential surface of the film roller 09, the inking unit in accordance with the present invention is not prone to ghosting. As a result, a high quality printed product can be produced using this inking unit, even in newspaper printing, which accomplishes compliance with the ever-increasing demand for quality in newspaper printing. Even in a high-speed printing press, in which the transport speed of the print substrate exceeds 10 m/s, and preferably ranging from 10 m/s to 15 m/s, as is currently customary in newspaper printing, the undesirable effect of ink misting rarely occurs. This is a result of the use of the short roller train and the use of the film roller 09 in accordance with the present invention. The use of the inking unit described in reference to
All of the rollers 03; 04; 06; 08; 09; 11; 12; 13; 14 of the inking unit, the rollers 18; 21; 22 of the dampening unit, the stripper roller 17 and the printing couple cylinders 01; 02 are rotatably mounted in side frames 47; 48 of the printing press, as may be seen in
With the adjustment of the contact pressure, which is exerted by one of the rollers 03; 04; 06; 09; 11; 18; 21 on its adjacent rotational body, the width of a roller strip that is formed by the direct contact between this roller 03; 04; 06; 09; 11; 18; 21 and the adjacent rotational body is also adjusted. This roller strip is represented as a flattened area on the circumferential surface of the roller 03; 04; 06; 09; 11; 18; 21, alternatively, as a flattened area on the circumferential surface of the cylindrical rotational body that cooperates with the roller 03; 04; 06; 09; 11; 18; 21, or as flattened areas on the circumferential surfaces of both. The width of the roller strip is the chord that is formed as a result of the flattening of the otherwise circular cross-section of the roller 03; 04; 06; 09; 11; 18; 21 or of the rotational body that cooperates with it. The flattening is made possible due to an elastically deformable circumferential surface of the roller 03; 04; 06; 09; 11; 18; 21 or of the circumferential surface of the rotational body that cooperates with it. A roller strip is also referred to as a nip point. In the control unit which controls the actuators 23, values for the respective pressure levels to which the respective actuators 23 are to be adjusted can be stored. This is done in order to form a roller strip of a specific width for a specific roller 03; 04; 06; 09; 11; 18; 21 with its adjacent rotational body, as a result of the contact pressure resulting from the respective adjustment of the actuators for the specific roller and/or its adjacent rotational body.
The printing couple cylinders 01; 02, specifically the transfer cylinder 01 and the forme cylinder 02, are each mounted in a bearing unit 24, according to their respective representation in
In addition to a bearing 26, which may be, for example, a radial bearing 26, and may specifically be, for example, a cylinder roller bearing 26 as is depicted schematically in
One length of the linear bearing, and especially at least one length of the bearing element 27 of the linear bearing, which, when mounted, is fixed to the frame, is smaller than a diameter of the allocated printing couple cylinder 01; 02, as viewed in the direction of the adjustment path S. The bearing block 29 preferably has only a single degree of freedom of motion in the direction of the adjustment path S. That direction of the adjustment path S is depicted by the double-headed arrow in
The bearing unit 24 depicted in
A print-on adjustment is performed by moving the bearing block 29 in the direction of the print position, by the utilization of a force F which is applied to the bearing block 29 by at least one actuator 32, and especially by the use of at least one power-controlled actuator 32. Through the use of such an actuator 32, a defined or a definable force F can be applied to the bearing block 29 in the print-on direction for the purpose of adjustment, as may be seen in
Particularly advantageous is an embodiment of the present invention in which the bearing block 29 is mounted such that it can move in at least one direction away from the print position against a force, such as, for example, against a spring force, and especially against a definable force, even when the printing press is running. In this manner, in contrast to a mere restriction of movement, on one hand a maximum linear force is defined by the cooperation of the cylinders 01; 02, and on the other hand a yielding of one of the cylinders is enabled, which yielding of one of the cylinders may be necessary, for example, in the case of a web tear associated with a paper jam on one of the printing couple cylinders 01; 02.
On its side that faces a print position, the bearing unit 24 has a stop 33. This stop 33 is movable, at least during the adjustment process, and limits the path of adjustment S up to, or towards the print position. The stop 33 can be moved in such a way that a stop surface 34, which stop surface 34 functions as the stop, the reference symbol of which is indicated in
Also provided, in an advantageous embodiment of the present invention, is a holding or a clamping element, which is not specifically illustrated in
Ideally, the applied force F, the restoring force FR and the position of the stop 33 are selected such that between the stop 33 and the stop surface of the bearing block 29, in the engaged position, no substantial force AF is transferred, and such that, for example, |ΔF|<0.1*(F−FR), especially |ΔF|<0.05*(F−FR), ideally |ΔF|≈0. In this case, the engagement force between the printing couple cylinders 01; 02 is essentially determined by the force F that is applied via the actuator 32. The linear force FL at the respective nip point, which linear force FL is decisive for ink transfer and therefore for print quality, among other factors, is therefore defined primarily not by an adjustment path S, but, in the case of a quasi-free stop 33, is defined by the force F and the resulting equilibrium. In principle, once the basic adjustment has been determined with the forces F appropriate for this, a removal of the stop 33 or of a corresponding immobilization element, that is effective only during the basic adjustment, would be conceivable.
In principle, the actuator 32 can be embodied as any actuator 32 that will exert a defined force F. Advantageously, the actuator 32 is configured as a positioning element 32 which can be actuated with pressure medium, and is preferably configured as a piston 32 that can be moved by a fluid. Advantageously with respect to a possible tilting, the assembly comprises multiple actuators 32 of this type, in the embodiment depicted in
To actuate the actuators 32, which are embodied in this embodiment shown in
To prevent excessively long engagement/disengagement paths, while still protecting against web wrap-up, on a side of the bearing block 29 that is distant from the print position, a restriction of movement, by the use of a movable, force-limited stop 39 as an overload protection element 39, such as, for example, in combination with a spring element 39, can be provided. In the operational print-off position, while the pistons 32 are disengaged and/or retracted, this force-limiting stop can serve as a stop 39 for the bearing block 29. In the case of a web wrap-up, or of other excessive forces originating from the print position, the stop will yield and will open up a larger path. A spring force for this overload protection element 39 is therefore selected to be greater than the sum of forces of the spring elements 37. Thus, in operational engagement/disengagement, a very short adjustment path, such as, for example, of only 1 to 3 mm, can be provided.
In the represented embodiment depicted in
The stop 33, which is embodied in the depiction shown in
In principle, the stop 33 can also be embodied differently. For example, it can be embodied as a ram that can be adjusted and affixed in the direction of adjustment, such that it forms a stop surface 34 for the movement of the bearing block 29 in the direction of the print position. This stop surface is variable in the direction of the adjustment path S and, at least during the adjustment process, can be secured in position. In an embodiment which is not specifically illustrated here, the stop 33 is adjusted, for example, directly parallel to the direction of adjustment path S via a drive element, such as, for example, via a cylinder that is actuable with pressure medium, with dual-action pistons, or with an electric motor.
The printing tower 44 is positioned on a base 46. At least one of the pairs of side frames 47; 48 may be capable of moving linearly on the base 46.
While a preferred embodiment of a rotary printing press comprising a film roller, in accordance with the present invention, has been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that various changes in, for example, the type of web being printed, the number of printing couples being used, and the like could be made without departing from the true spirit and scope of the present invention, which is to be limited only by the appended claims.
Number | Date | Country | Kind |
---|---|---|---|
10 2006 024 029 | May 2006 | DE | national |
10 2006 030 057 | Jun 2006 | DE | national |
10 2006 042 590 | Sep 2006 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP2007/053701 | 4/17/2007 | WO | 00 | 11/21/2008 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2007/134919 | 11/29/2007 | WO | A |
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