EP1743771A1 - Device for cleaning cylinders of a printing machine - Google Patents

Abstract

The device has a wash roller (2) connected to a cylinder to be cleaned. A collecting tray (6) is mounted movably relative to the wash roller in such a manner that a wiper (4) stays in contact with a surface of the wash roller temporarily by a corresponding movement of the collecting tray or disengaged from the surface of the roller. The wiper is formed as a wiper bar and sits in a retainer (5) attached to the wiper bar or in the collecting tray, where the retainer has two side walls that are provided with through holes.

Description

The invention relates to a device for cleaning cylinders of a printing press according to the preamble of claim 1. Accordingly, this device comprises a driven washing roller, which is engageable with a cylinder to be cleaned. By means of a squeegee, which at least intermittently engages the surface of the rotating washing roller, the dirt removed from the washing cylinder by the cylinder to be cleaned is scraped off. The squeegee is attached to a sump in which the abgerakelte dirt is collected and discharged.

Cleaning devices of this type are used to remove deposits and contaminants on cylinders of printing presses, which arise in particular by the intensive contact with the substrates. When paper is printed, especially paper dust and ink are deposited on the cylinders of the press.

An example of a known cleaning device is in EP-A-1 106 354 described. The set by the engine of this device in rotation, designed as a brush roller washing roller is employed on a cylinder, which may be a blanket cylinder, impression cylinder, plate or forme cylinder, or even a chill roll, ink roller or dampening roller of a printing machine. At the same cleaning liquids are applied to the washing roller, so that the adhering to the cylinder impurities are softened and lifted by the rotating washing roller from the cylinder. The dirt picked up by the washing roller is wiped off by a squeegee, which is clamped in several squeegee holders. These are inserted into a serving as a scaffold of the cleaning device holding profile and fastened there. Below the squeegee a drip tray is provided.

Usually, the direction of rotation of the brush roller is chosen so that its surface travels as short a path as possible between the surface of the cylinder to be cleaned and the doctor blade. Furthermore, the stripping of the brush roller on the doctor blade is known to take place by elastic bending of the individual bristles on the doctor blade and subsequent elastic re-erection of the bristles, wherein the particles of dirt are not only stripped off the doctor blade but also thrown off when the bristles are re-erected. For this reason too, the direction of rotation of the brush roller is usually selected so that the centrifuging of the dirt particles is directed away from the cylinder to be cleaned.

Since the dirt collected by the washing roller, in particular due to the ink contained therein have a high adhesive force, so are sticky, always something dirt hanging on the doctor blade holder of such a known cleaning device, which forms a dirt build-up with increasing operating time. Such a dirt build-up can be avoided by attaching the squeegee directly to the sump rather than to separate brackets. An example of such a cleaning device is known from DE-A-197 02 082 known.

However, direct doctoring of the dirt removed by a brush roller from the surface of the cylinder to be cleaned is not always optimal. Because when doctoring not only the dirt particles are thrown off the brush roller, but also the recorded from the brush roller washing liquid. In the course of the most efficient use of the washing liquids when cleaning cylinders in a printing press, it may be advantageous not to bring the brush roller for a while in contact with the doctor blade. Accordingly, the washing liquid remains on the surface of the brush roller and, after one revolution, re-acts on the surface of the cylinder to be cleaned. The amount of washing liquid used in a cleaning cycle without doctor blade is reduced significantly.

This is particularly important in heat-set presses where the freshly printed substrate enters a dryer. Such a dryer works with heat, and the commonly used washes contain a high proportion of volatile hydrocarbons. Especially in heat-set printing machines is usually required that the cleaning of the cylinder surfaces takes place during production. The printing material running through the printing machine thus absorbs washing liquid and then transports it into the dryer. In the dryer, the volatile hydrocarbons evaporate, and moreover, they are heated so that there is a constant risk that the hydrocarbon concentration in the dryer will rise above a value prescribed for safety reasons. However, since high-quality substrates are being used at the same time in heat-set printing presses, care must be taken to ensure that the cleaning of the cylinder surfaces, which inevitably results in waste, takes place as quickly as possible.

However, these two requirements are contradictory: in order to ensure a high level of protection against too high a concentration of volatile hydrocarbons in the dryer, it is necessary to use as little washing liquid as possible. On the contrary, the requirement to keep the cleaning cycle as short as possible requires the use of relatively much washing liquid, since the time is too short within which the contaminants on the surface of the cylinder to be cleaned can be dissolved. It is therefore important to achieve maximum efficiency when using the washing liquid.

This includes not keeping the squeegee constantly in engagement with the surface of the washing roller but temporarily removing it from this operation. The washing liquid then remains longer on the washing roller surface and accordingly has more time to dissolve the contaminants on the surface of the cylinder to be cleaned. It is then less often necessary to add new washing liquid; the consumption of washing liquid drops accordingly with comparable cleaning performance.

An example of a cleaning device with as needed engageable to the washing roller and off this off blade can be found in the US-A-5,010,819 , There, a squeegee bar is brought by means of individual movable brackets in the region of the washing roller and, if necessary, moved into engagement with the surface of the washing roller.

The present invention has for its object to improve a cleaning device of the type mentioned in terms of their handling.

This object is achieved by a device having the features of claim 1. Preferred embodiments and further developments are laid down in claims 2 to 9.

The device according to the invention thus differs from the previously known devices in particular in that the collecting trough is mounted movably relative to the washing roller such that the squeegee attached to the collecting trough is adjusted to the washing roller as required by a corresponding movement of the collecting trough or out of engagement with the surface the washing roller is moved out. The doctor can therefore be taken out of engagement with the surface of the washing roller in the interest of the most efficient use of washing liquids, so that the washing liquid is not thrown off the washing roller immediately during the cleaning process again. However, this does not require moving squeegee mounts, which form a "bridge" between the squeegee and the frame of the device, a housing wall or a retaining profile, which can lead to dirt build-up, which ultimately also affects the on and off mechanics of the squeegee mounts. Instead, the squeegee, together with the sump to which it is attached, moves into engagement with and out of the surface of the squeegee. The scraped dirt thus gets in any case only in the drip tray; it can not form dirt.

A front wall of the drip pan may be formed as a doctor blade holder; but it may also be appropriate, a doctor blade holder inside the sump to arrange, especially for brush rollers that are scraped off, the dirt is not only thrown off, but partially stalked on the front of the doctor of the bristles so that it runs down the squeegee front. For this reason, it also offers advantages when the doctor blade holder is provided below the doctor with gaps or feedthroughs, so that the running down on the doctor blade front dirt through the gaps or feedthroughs in the drip pan or in the dirt receiving in the main part of the Drip tray arrives.

The doctor blade is preferably designed as a doctor bar and is seated in a receptacle adapted to the doctor bar in or on the drip pan. In this recording, the doctor bar can be used in particular by clamping and is therefore easily replaceable. By means of conventional screws the squeegee can be adjusted within the recording in height, for example, to compensate for signs of wear.

This recording for the doctor bar can be arranged within the doctor blade. In this case, it is advantageous if the receptacle has two side walls, which are provided with openings in their lower area, so that the dirt running down on the squeegee front side can reach the other side of the receptacle.

Very particular advantages are obtained if the drip pan, which is movably arranged according to the invention, preferably pivotably arranged around a rotation axis in the manner of a rocker, is designed to be removable. Because then the sump can be easily removed from the device together with the squeegee or arranged therein, to clean them and optionally replace the squeegee or turn to bring, for example, a fresh edge of the squeegee in operative position.

The pivotable arrangement of the sump in the manner of a rocker is preferably implemented so that the sump sits in a holder which is mounted in the manner of a rocker with two lever arms pivotally mounted on the axis of rotation, wherein one lever arm spring loaded and the other lever arm with a against the Spring-operated actuator, in particular a hydeinem provided against the spring force actuator, in particular a hydraulic or pneumatic piston-cylinder unit is provided. The attachment of the drip pan to this pivotal holder is then preferably by means of releasable connecting elements, such as a latch mechanism. As a result, the pivoting function and the removability of the drip pan can be implemented robustly and simply and safely operable.

The doctor can, as is known, be formed by a profile element with hexagonal cross-section. In connection with a clamping attachment, the squeegee can then be converted by a simple rotation about its longitudinal axis to replace a worn squeegee edge with a new edge.

Figur 1

eine perspektivische Ansicht eines Ausführungsbeispiels einer erfindungsgemäßen Reinigungsvorrichtung (schematisch);

Figuren 2 bis 4

eine Seitenansicht der Vorrichtung aus Figur 1, in unterschiedlichen Arbeitszuständen;

Figur 5

die Auffangwanne der Vorrichtung aus Figur 1 separat.

An embodiment of the invention will be described and explained in more detail below with reference to the accompanying drawings. Show it:

FIG. 1

a perspective view of an embodiment of a cleaning device according to the invention (schematically);

FIGS. 2 to 4

a side view of the device of Figure 1, in different working conditions;

FIG. 5

the drip pan of the device of Figure 1 separately.

In Figure 1, the surface of a cylinder to be cleaned 1 is indicated by a broken line. A washing roller 2 embodied as a brush roller is set against the surface of the cylinder 1 to be cleaned and initially moves in the direction of rotation 3 over the surface of the cylinder 1 to be cleaned, picks up dirt there and transports it further up to a doctor blade 4 which is in a receptacle 5 sits clamped. The receptacle 5 is arranged in a collecting trough 6, which in turn is fastened to a holder 7. A housing of the cleaning device shown here is only hinted at, by means of a partition 8.

At the back of the sump 6, a drain 9 is provided for the mixed with detergent, abgerakelten dirt.

On the (not shown in Figure 1) housing 17 of the device pneumatic elements 10 are fixed, each actuate a piston-cylinder unit 11. This acts on a second lever arm 12 of the pivotable about a pivot axis 13 bracket 7, while a first lever arm 14 is biased by a spring 15.

Figures 2 to 4 show in a side view of the device shown in Figure 1 different working conditions thereof, wherein like parts are given the same reference numerals, so that reference can be made to the above description of Figure 1. In addition to the parts known from FIG. 1, spraying pipes 16 for the washing liquids and a housing 17 are also shown here.

FIG. 2 shows the operating state with doctor 4 engaging in the surface of the washing roller 2. The piston-cylinder unit 11 is extended and presses against the second lever arm 12, so that the holder 7 is pivoted together with the attached collecting tray 6 about the pivot axis 13 against the force of the spring 15. The collecting tray 6 pivoted in this way thus leads via the receptacle 5 arranged in the collecting trough 6 and the squeegee 4 seated in the receptacle 5 to the fact that the squeegee 4 is set against the washing roller 2 and is therefore active. At the collecting trough 6, a pawl 18 is arranged, which is engaged behind by a fastened to the holder 7, spring-loaded latch 19.

FIG. 3 shows the operating state of the device in which the doctor blade 4 is set down from the washing roller 2. By relaxing the piston-cylinder unit 11 of the second lever arm 12 of the force of the spring 15 nothing opposes, so that the holder 7 and with it the drip pan 6 was pivoted about the pivot axis 13 so that in the receptacle 5 of the sump 6 seated doctor blade 4 down out of engagement with the washing roller 2 has been removed.

In Figure 4, the easy removability of the drip pan 6 together with the seated in the receptacle 5 blade 4 is illustrated. By releasing the bolt 19 against the spring force acting on it, the pawl 18 has been released, so that the drip pan 6 could be removed from the holder 7. The seat of the sump 6 in the holder 7 is ensured by on the one hand a guide 20 in the holder 7 and on the other hand a displaceable in this guide, arranged on the drip pan 6 web 21, which continues in the pawl 18. After cleaning the sump 6 and / or the replacement of the squeegee 4, the sump 6 is quite easily inserted back into the guide 20, wherein the latch 19 automatically engages behind the pawl 18.

Finally, FIG. 5 shows the collecting trough 6 removed from the device in a perspective view. Particularly clearly here are the web 21 with the molded thereon pawl 18 and the receptacle 5 for the (not shown here) doctor blade 4 to recognize. On the basis of this figure, it is clear that the receptacle 5 is arranged within the drip pan 6 and is part of the same, so that no dirt build-up is to be feared on any doctor blade holders, which may even be movable. The on and off of the doctor takes place, as described above, by pivoting the entire sump 6. The receptacle 5 has two side walls 22, which are provided in their lower region with openings 23. Through these openings 23 dirt that runs down the front of the squeegee, in the rear part of the sump 6 and thus reach the drain 9.

Claims (9)

Apparatus for cleaning cylinders of a printing machine, comprising a driven washing roller (2) which can be adjusted to a cylinder (1), a doctor blade (4) engaging at least temporarily in the surface of the washing roller (2) and a collecting trough (6) for the cylinder dirt doctored off by the rotary washing roller (2) by means of the doctor blade (4), the doctor blade (4) being fastened to the collecting trough (6),
characterized,
in that the sump (6) is movably mounted relative to the washing roller (2) such that the squeegee (4) is engaged with or removed from the surface of the washing roller (2) by appropriate movement of the sump (6) as required , Device according to claim 1,
characterized,
that the drip pan (6) is designed to be removable. Device according to one of claims 1 or 2,
characterized,
in that the doctor blade (4) is designed as a doctor bar and is seated in or on the drip pan (6) in a receptacle (5) adapted to the doctor bar. Device according to claim 3,
characterized,
that the receptacle (5) has two side walls (22) which are provided in their lower region with openings (23). Device according to claim 4,
characterized,
that the receptacle (5) is provided with adjustment elements for the pitch of the squeegee beam. Device according to at least one of claims 1 to 5,
characterized,
that the drip pan (6) is arranged pivotably about a pivot axis (13) in the manner of a rocker. Device according to claim 6,
characterized,
in that the collecting trough (6) is seated in a holder (7) which is fastened in the manner of a rocker with a first lever arm (14) and a second lever arm (12) pivotably on the pivot axis (13), wherein the first lever arm (14) is spring-loaded and the second lever arm (12) is provided with a working against the spring force actuator, in particular a hydraulic or pneumatic piston-cylinder unit (11). Device according to claim 7,
characterized,
in that the collecting trough (6) is attached to the holder (7) by means of detachable connecting elements (18, 19, 20, 21). Device according to claim 8,
characterized,
in that the releasable connection elements consist of a latch mechanism (18, 19).

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