EP0924068A2 - Device for preventing the formation of condensation water in printing machines - Google Patents

Abstract

A device for avoiding condensation in a printing press (1) comprises a protective element (31, 32) which has a heatable surface (31a) located near a printing press roll (1, 2) and a coolable surface (31b) opposite the surface (31a) ), which is separated from the first roller-near surface (31a) by an insulating layer (41). The protective element (31, 32) is further arranged near the surface of the printing press rollers (1, 2) in order to thereby reduce the amount of air enclosed between the surface (31a) near the roller and the roller. <IMAGE>

Description

The present invention relates to a device for avoiding Condensation formation in printing machines according to the preamble of claim 1.

The problem in printers and printing press test equipment is that especially in the case of high-speed printing presses for the protection of the Machine operators very important safety elements, such as hand protection bars, Finger protection spindles and other sections of the printing press, condensation forms. Condensed water can e.g. B. on the surface of a protective shield in the form of Droplets occur that can collect in drops, which then either on the Surface of the material web to be printed or fall into the printing unit itself and Cause printing defects and other undesirable conditions. Condensation under the Material web can also cause printing defects, for example if there are droplets fall onto the surfaces of jack rollers or the like of a lower printing unit.

Even on printing unit components such as signs, rails and frame sections Condensation can form in the form of droplets on the web or on it Components of the inking unit fall and thus pose a risk to the preservation of the Show print quality. For example, condensation on the surface of Printing unit rollers, in particular on the rollers in the dampening unit of a printing press, have a harmful effect on the water / dampening solution supply in the offset printing process, d. H. that the condensation water added to the dampening solution on a roller Capacity of the printing nip can exceed, so that excess Water accumulates in the pressure gap, causing an unsteady water supply and therefore one Decrease in print quality.

Furthermore, condensation water dripping onto the web can cause printing errors cause and condensation on a roller, especially on dampening rollers destabilize the offset printing process.

It is an object of the present invention to detect defects on the one Printing machine to avoid coming printed material that comes on Condensation can be attributed. It is another job of the present invention, the surfaces of components on which Condensation can form, keeping it at a temperature level above the dew point and to create a surface on which condensation can collect without the To influence the print quality of a printing unit.

This object is achieved by the features of claim 1.

According to one embodiment of the present invention, a device for Avoiding condensation in printing machines, in particular Web-fed rotary printing presses, components that are in a processing unit of the Printing machines are arranged and designed in such a way that these Humidity near selected sections of the press reduce, and a mechanism can be provided by which the Temperature differences between the surfaces of the machine sections and the Ambient atmosphere can be changed. For example, the hollow interior a pressure gap protective cover with media such. B. water, oil, air or a Mixture of these, filled with suitable heat transfer properties, which have different temperatures to create a cool and a warm surface to create and thus condensation in the selected areas of the printing press to reduce. A pure liquid with appropriate can also be added to the media Heat transfer properties include, especially a glycol or other Antifreeze mixture. Such mixtures are often used in printing presses Water mixed to counteract corrosion.

There is also the possibility that between the components in which the Surface temperature must be kept above the dew point of the ambient air, or where cool and warm surfaces have to be created closed circuit is established. The closed circuit can e.g. B. a Pipe system with supply and return sections and include a reservoir. The Reservoir can be a heat exchange element and a pumping and stirring device have a uniform temperature distribution in the respective in the Maintain reservoir contained medium. Through a manually operated or remotely controllable flow control mechanism, for example by control valves, can in the components, e.g. B. in pressure gap protective covers, trusses, Boxes, protective shields or lifting rollers, the temperature levels of the media be regulated accordingly.

According to a further embodiment of the present invention, there is a condensate protection device provided near the surface of a plate or Blanket cylinder of the printing press or near a roller, for example one Dampening roller arranged and on the course of the surface portion of the roller is adjusted to the amount of humid air from which condensation forms and on the cylinders or rollers can drip to reduce.

Although the condensate protection device can be a passive device, is in a further embodiment of the present invention a the cylinder or side of the protective device opposite the roller over the ambient temperature can also be heated to prevent condensation on the protective device forms.

In a further embodiment of the present invention, that of the Cylinder or the side of the condensation protection device facing away from the roller the level of the ambient temperature cooled and thus a surface for Condensed water is created, reducing the water content of the atmosphere / air in the area the roller in question is further reduced. The condensate protection device can also be constructed so that the condensed water z. B. collected on the cool side becomes.

The present invention is more preferred in the following description Embodiments in connection with the accompanying, listed below Drawings explained in more detail.

Fig. 1

eine exemplarische Druckspalt-Schutzabdeckung gemäß vorliegender Erfindung, die in ein geschlossenes Kreislaufsystem zweier Medien integriert ist;

Fig. 2

ein Ausführungsbeispiel einer Kondenswasser-Schutzeinrichtung gemäß vorliegender Erfindung; und

Fig. 3

eine Querschnittsansicht eines weiteren Ausführungsbeispiels einer Kondenswasser-Schutzeinrichtung gemäß vorliegender Erfindung.

Show it:

Fig. 1

an exemplary pressure gap protective cover according to the present invention, which is integrated in a closed circulatory system of two media;

Fig. 2

an embodiment of a condensate protection device according to the present invention; and

Fig. 3

a cross-sectional view of another embodiment of a condensate protection device according to the present invention.

Fig. 1 shows a printing unit of a web-fed offset printing press, e.g. B. one Heidelberg Harris M-3000 printing press, with two first top and bottom Printing unit cylinders 1, 2 and two second upper and lower Printing unit cylinders 16, 17, between which a material web 7 on their two Pages is printed. A printing unit component, e.g. B. a pressure gap cover 3, that protects the machine operator or printer from injury has two Surfaces 4 and 5. The pressure gap cover 3 is, for example, with a Pipe system 8 connected, which has a feed section 9 and a return section 10 has, which are both connected to a reservoir 12.

The pipe system 8 includes, for example, a first pipe section 8a and a through an insulating layer 8c separate second pipe section 8b. The first pipe section 8a can e.g. B. the printing unit cylinders 1, 2 or 16, 17 may be arranged facing while the second pipe section 8b from the printing couple cylinders 1, 2 or 16, 17th is arranged facing away. The feed section 9 of the pipe system consists, for. B. from a first feed section 9a connected to the first pipe section 8a and one with the second pipe section 8b connected to the second feed section 9b. In the same Way, the return section 10 of the pipe system 8 z. B. one with the first Pipe section 8a connected first return section 10a and one with the second Have pipe section 8b connected second return section 10b.

In the preferred embodiment of the invention, the first pipe section 8a heated above the temperature of the ambient air by z. B. a heated one Liquid is passed through the first feed section 9a into the first pipe section 8a or the pipe section is heated by an electrically operated heating coil. The second Pipe section 8b can continue to be cooled below the level of the ambient air temperature be by z. B. via the second feed section 9b, a cooling liquid through the second pipe section 8a is passed, whereby through the heated and the cooled side of the pipe system is prevented that on the cylinders 1, 2 or 16, 17th facing side of the pressure gap protective cover 3 forms condensation. A Collecting device 8d, in which the condensed water on the cooled surface of the Pressure gap protective cover 3 collects, e.g. B. with a condensate collection box a drainage system leading into a closed container prevents Condensation in the operative sections of the printing press or on the web 7 drips.

In a reservoir 12, which consists of a first section 12a and one of the first Section separate second section 12b can be a first medium 13a in section 12a and a second medium 13b in section 12b on an im be kept substantially constant temperature level, the first Medium 13a for example hot water and the second medium 13b z. B. cold Can be water. The media 13a and 13b in each Reservoir section 12a, 12b - e.g. B. water, oil, air or a mixture of others Components - can be stirred by a respective pump device 15a, 15b be, whereby a uniform temperature distribution in each medium 13a and 13b in the respective reservoir sections 12a, 12b. In the event that the temperature level of one of the return section 10 of the pipe system 8 through the reservoir 12 directed media 13a, 13b has changed significantly, z. B. by Monitoring the temperature of everyone using a temperature sensor Medium 13a, 13b e.g. B. over each section of the reservoir 12 assigned conventional heat exchangers 14a, 14b can be controlled individually. The pipe system 8 may further include flow control devices 11 around the Flow of media 13a, 13b to cover 3 or generally to the printing unit component to regulate.

In the exemplary embodiment shown in FIG. 1, the condensed water is in the region the printing unit cylinder 1, 2 and 16, 17 reducing component a printing nip protective cover 3 with a hollow interior. When using a closed circuit, however, other components, for example Protective shields, trusses, frames, etc. of a printing unit can be integrated to Avoid droplets of condensation that affect print quality.

Fig. 2 represents an inventive, preferably the above. 3 protective cover Condensate protection device 30, which has an upper protective plate 31 and a lower one Protection plate 32 includes. The plates 31 and 32 are for example with the frame of the Printing unit connected. By the upper protective plate 31 in an area close to the Printing unit cylinders 1, 2 (or close to the printing unit cylinders 16, 17) placed and from the shape of the respective surface sections of the Printing unit cylinder 1, 2 or 16, 17 is adapted, the between the upper Protective plate 31 and the surface portions of the cylinders 1, 2 located amount humid air from which condensation water forms and into which Dampening solution can get on the printing unit cylinders 1, 2. Furthermore, the upper Protective plate 31 may be formed as shown in Fig. 2 and two or more interconnected domed sections have to in the case of a substantially horizontal arrangement of the condensed water on its surface, e.g. B. between the interconnected domed sections. Alternatively, e.g. B. the Surface of the upper protective plate 31 formed flat and with a concave profile be provided to collect the condensed water.

As also shown in FIG. 2, a lower protective plate 32 can be connected to the Upper protective plate 31 are used, which is also one of the surfaces of the Printing unit cylinder 1, 2 or 16, 17 adapted to the volume of the between the protective plate 32 and the surface portions of the cylinders 1, 2 moist air - from which condensation water forms and onto which Printing unit cylinder 1, 2 can drip - further reduce.

According to a further embodiment of the present invention, the Condensate protection device 30 be a passive device and z. B. only be arranged in the area of the printing couple cylinders 1, 2 or 16, 17 by the volume moist air, from which condensation water forms and on the printing couple cylinders 1, 2 or 16, 17 can drop. For example, the protective plates 31 and 32 at 2.54 cm (1 inch) and 0.64 cm (1/4 inch) from the Surface sections of cylinders 1, 2 or 16, 17 are placed away to the Effectively reduce humid air volume.

In a further exemplary embodiment of the invention shown in FIG Condensate protection device 30 is one of the printing unit cylinders or Rolls 1, 2 facing near the surface 31a of the upper protective plate 31 over the Level of ambient air temperature also heated to the formation of Condensed water on the upper protective plate 31 in the area of the printing couple cylinders 1, 2 to avoid while one facing away from the printing unit cylinders or rollers 1, 2 Surface 31b remote from the roller of the upper protective plate 31 below the dew point of the Ambient air can be cooled to remove condensation in the area of the cylinder or To avoid rollers 1, 2, which can cause defects in the printing process. An exemplary arrangement for heating and cooling the condensate protection device 30 is shown in FIG. 3.

For example, the upper protective plate 31 can have an outer wall 40 made of sheet metal or a other suitable material, which by an insulating layer 41 of a Roll near inner wall 43 is separated, the z. B. from a material such as polystyrene, Polyethylene, foam or glass fiber is made. Below the near the roller Surface 31b of outer wall 40 has an opening 40b and above it Surface 31a of the inner wall 43 remote from the roller is an opening 40a, wherein the openings 40a and 40b are separated by the insulating layer 41. Around the roller Heating surface 31a can pump hot water through opening 40a become. For example, the surface 31a close to the roller can be positioned over the Pipe section 8a, the feed section 9a, the return section 10a (including Reservoir section 12a) and the pump device 15a are heated, as with 1 is described. In order to cool the surface 31b remote from the roller, in cold water can be pumped through the opening 40b in the same way. So it can Surface 31b remote from the roller, e.g. B. via the pipe section 8b, the feed section 9b, return section 10b (including reservoir section 12b) and one Pump device 15b are cooled. As shown in Fig. 3, the roller remote Surface 31b be designed (e.g. concave) so that the formed on it Condensed water collects.

The lower protective plate 32 can be constructed in a similar manner so that the Heated cylinder surfaces 1, 2 and the cylinder surfaces 1, 2 opposite side can be cooled, provided that a device under the Lower protective plate 32 is arranged, in which the condensed water collects, for. B. a Condensate collection box 8d with a drainage system, for example with a Drain in a closed container. Alternatively, the lower protective plate 32 can be a Outer wall 50 made of sheet metal or other suitable material and a single one Have opening 50a therebetween, as shown in FIG. 3. In the same way is hot water through the in the preferred embodiment of the invention Pumped opening 50a to heat and protect lower protective plate 32 To keep temperature above the dew point of the ambient temperature, and thereby the Avoid formation of condensation.

Although the condensate protection device 30 according to the present invention previously with regard to the prevention of condensation on printing unit cylinders 1, 2 and 16, 17, it is understood that the condensate protection device 30 with an upper protective plate 31 and / or a lower one Protection plate 32 also for many other systems with condensation problems, such as used for example for rollers of a dampening unit of an offset printing machine can be.

LIST OF REFERENCES

1

upper printing unit cylinder

2nd

lower printing cylinder

3rd

Pressure gap cover

4th

Surface of the pressure gap cover

5

Surface of the pressure gap cover

7

Material web

8th

Pipe system

8a

first pipe section

8b

second pipe section

8c

Insulating layer

8d

Condensate collection box

9

Feed section of the pipe system 8

9a

first feed section

9b

second feed section

10th

Return section of the pipe system 8

10a

first return section

10b

second return section

11a

Flow control device

11b

Flow control device

12th

reservoir

12a

first reservoir section

12b

second reservoir section

13

medium

13a

first medium

13b

second medium

14a

Heat exchanger

14b

Heat exchanger

15

Pumping device

16

lower printing cylinder

17th

lower printing cylinder

30th

Condensate protection device

31

upper protective plate / protective element

31a

surface of the upper protective plate near the roller

31b

Surface of the upper protective plate remote from the roller

32

lower protective plate / protective element

40

Outer wall of the upper protective plate 31

40a

Opening of 31a

40b

Opening of 31b

41

Insulating layer

43

inner wall near the roller

50

Outer wall of the lower protective plate 32

50a

Opening from 32

Claims (15)

Condensation protection device in a printing press, with a first Protective element (31), which has a surface remote from the roller (31b) and one of these opposite, a first surface section of a Printing machine roller (1, 2) facing the roller near surface (31a), in the way that the air volume between the near-roll surface (31a) and the first surface section of the roller (1, 2) is reduced. Device according to claim 1,
characterized by that the surface (31b) remote from the roller forms a condensate collecting surface with a first rounded section and a second rounded section adjoining it, and a collecting area formed between the two sections for the condensed water collecting on the surface (31b) remote from the roller. Device according to one of the preceding claims,
characterized by that at least part of the surface (31a) close to the roller is adapted to the shape of the roller (1, 2). Device according to one of the preceding claims,
characterized by that the distance between the roll-near surface (31a) and the first surface section of the roll (1, 2) is less than 2.5 cm. Device according to one of the preceding claims,
characterized by that the distance between the roller-near surface (31a) and the first surface section of the roller (1, 2) is greater than 0.6 cm. Device according to one of the preceding claims,
characterized by that it comprises a second protective element (32) with a further roller surface (50) which is arranged on a second surface section of the roller (1, 2). Apparatus according to claim 6,
characterized by that the first and the second protective element (31, 32) opposite sides are arranged above and below the roller (1, 2). Device according to one of the preceding claims,
characterized by that an insulating layer (41) is provided between the surface (31b) remote from the roller and the surface (31a) near the roller, and that the surface (31a) close to the roll can be heated and the surface (31b) remote from the roll can be cooled. Device according to claim 8,
characterized by that an opening (40a) through which a heating medium (13a) flows is formed between the insulating layer (41) and the surface (31a) near the roller. Device according to one of claims 8 or 9,
characterized by that an opening (40b) through which a cooling medium (13b) flows is provided between the insulating layer (41) and the surface (31b) remote from the roller. Device according to one of claims 9 or 10,
characterized by that a first supply system (8b, 9b) for supplying the cooling medium (13b) to the opening (40b) and a second supply system (8a, 9a) for supplying the heating medium to the opening (40a) is provided. Device according to claim 11,
characterized by
that the first feed system (8b, 9b) comprises a first feed section (9b) connected to the first opening (40b), a first reservoir section (12b) and a pump device (15b); and that the second feed system (8a) comprises a second feed section (9a) connected to the second opening (40a), a second reservoir section (12a) connected to the second feed section (9a) and a pump device (15a). Device according to claim 12,
characterized by that the first supply system (8b) comprises a first heat exchanger (14b) associated with the first reservoir section (12b) and the pump device (15b); and that the second supply system (8a) comprises a second heat exchanger (14a) assigned to the second reservoir section (12a) and the second pumping device (15a). Device according to one of claims 9 to 13,
characterized by that the cooling medium (13b) and / or the heating medium (13a) consist of water, oil, air or an antifreeze mixture. Apparatus according to claim 6,
characterized by that the second protective element (32) can be heated.

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