EP1441908B1 - Cleaning method and device for a printing roller - Google Patents

Description

The invention relates to a printing press roller cleaning method and a printing press roller cleaning device according to the claims.

A cleaning device of this kind is from the DE-A-198 16 660 known .

Ink rollers of an inking unit in a printing unit for offset printing are moistened by a so-called spray tube for dissolving the paint with liquid, which is sprayed onto one of the rollers and doctored down on another roller. One or more of the inking rollers are driven, while other rollers are not driven, but are rotated only by the contact of their roll shell with the roll shell of an adjacent roll. The cleaning process must be carried out in a short period of time to shorten the downtime for the printing operation. The liquid must therefore be transferred from the roll, which is moistened with the liquid from the spray tube, as quickly and uniformly as possible to all rolls of the compactor. If little liquid is sprayed onto the one roller, it will take a long time for all rollers to be moistened. If a lot of liquid is sprayed onto the one roll, there is a risk that the liquid in the nip or even before it is jammed in the roll winding and thereby runs out laterally in the roll longitudinal direction of the compactor. Furthermore, there is a risk of over-wetting of the first or several subsequent rolls of the compactor, so that the non-driven rollers are no longer rotated due to lack of static friction of adjacent roller or stop and rotate abruptly, thereby spun liquid mixed with dissolved color. The liquid and thus also the color dissolved by it is no longer transferred to the stationary roll and thus also not transferred to the squeegee device of the doctored roller. Thus, the inking is not cleaned enough, so it must be cleaned manually.

The invention enables the problem to be solved in a simple and inexpensive way to achieve a safe cleaning of all rolls of a compactor in a short time.

This object is achieved according to the invention by the features of claim 1 and of claim 7.

Further features of the invention are contained in the subclaims.

Advantages of the invention:

The invention ensures that the liquid is rapidly applied and distributed in a short time to all rollers up to and including the doctored-off roller. The invention prevents over-rolling of rolls and thereby slippage or stagnation of non-driven rolls. Standing rollers prevent the transfer of fluid to other rollers and thereby cause a liquid accumulation in the roller winding, from which liquid is laterally squeezed out. The Nichtbefeuchturigszonen ensure sufficient frictional adhesion between the rollers through which all non-driven rollers are rotated by adjacent rollers and no rollers slip due to over-wetting of the adjacent roller. Furthermore, a fast fluid transfer to all rollers is achieved. The invention uses substantially fewer discharge ports or nozzles than the prior art.

"Liquid" may be solvent, detergent, detergent or solvent-containing water, water with one or more additives which affect the printing process, pure water or any other liquid. Furthermore, the type of liquid can be changed during the washing process. For example, initially detergent or solvent or water containing it may be used to dissolve the paint from the rolls, and then rinsed with clean water. "Rollers" also include press cylinders, but especially inking rollers.

"Driven Roller": A roller may be driven by an electric motor, a pneumatic motor or a hydraulic motor, or by a drive connection from another roller or cylinder of the printing press.

"Non-driven roller" is a roller which rotates only by being in contact with an adjacent roller and being co-rotated by the frictional resistance.

"Dot-shaped cross-section of the liquid jets" means a jet with a small cross-section and distance from each other over the entire jet length from the nozzle to the point of impingement on the roll, in contrast to a spray jet or a very wide flat jet which already on impact with the roll or even before each other touch or mix with each other.

"Scraper device" for stripping the liquid and possibly detached from it roll contamination: This may be a squeegee, a brush or a cloth or other element, with which the liquid and possibly dissolved by her dirt from a roller is removable.

• Fig. 1 schematisch eine Seitenansicht eines Druckwerkes mit einem Farbwerk und einem Feuchtwerk,
• Fig. 2 schematisch eine Draufsicht auf eine besondere Ausführungsform der Erfindung,
• Fig. 3 einen Querschnitt längs der Ebene III-III eines Sprührohres von Fig. 2.

The invention will now be described by way of example with reference to the drawings of preferred embodiments. In the drawings show

• Fig. 1 schematically a side view of a printing unit with an inking unit and a dampening unit,
• Fig. 2 schematically a top view of a particular embodiment of the invention,
• Fig. 3 a cross section along the plane III-III of a spray tube of Fig. 2 ,

Fig. 1 shows schematically and not to scale a printing unit comprising a plate cylinder 2, a blanket cylinder 3 contacting him, a printing cylinder 4 contacting them, an inking unit 6 and a dampening unit 8. Thus, it is a dampening solution liquid offset printing unit. However, the invention can also be used for a dry offset printing unit. The printing unit can be part of a sheet-fed offset printing press (printing of sheets) or a web offset printing press (printing of sheet-like printing material). The invention is also applicable to other types of printing machines (high pressure, gravure printing).

The printing material 10 (sheet or web) passes through the nip 11 between the blanket cylinder 3 and the pressure roller 4. The image is transferred from the plate cylinder 2 on the blanket cylinder and from there to the substrate 10.

The inking unit 6 may be of any type, which contains at least one ink roller driven by a motor and at least one non-driven ink roller, which latter is driven by the frictional resistance of its lateral surface with the lateral surface of another roller.

The inking unit 6 of Fig. 1 includes, as an example, a paint box 14 and a roller train of ink rollers 16-27, of which a roller 16 is a so-called ductor roller for receiving ink from the ink fountain 14 and of which at least one roller is driven by an electric motor or other motor drive and not shown of which one or more rollers have no motor drive, but are driven only by touching their roll shell with an adjacent roll of this adjacent roll, which may also be a roller without motor drive.

To one of the ink rollers, which is removed from the ductor roller 16, a doctor blade 30 is engageable to abzurakeln of this roller 27 paint and other contaminants, preferably in a receptacle 32nd

The dampening unit 8 contains a dampening solution tank 36 from which dampening solution liquid is applied to the peripheral surface of the plate cylinder 2 via a train of dampening rollers 38, 39, 40 and 42 to form ink-repelling areas corresponding to the printed image to be printed.

According to a particular embodiment, a transfer roller 44 or more transfer roller may be provided which on the one hand in circumferential contact with a dampening roller, z. B. dampening roller 42, and on the other hand in circumferential contact with a paint roller, for example, the ink rollers 26 and 27. By such a combination, an optimum printing condition on the plate cylinder 2 can be achieved faster at the beginning of a printing operation.

According to the invention, a printing unit roller cleaning device 46 is provided for cleaning rotating rollers of a compactor, of which at least one roller is driven by a motor, for example, the ink roller 17 after the ductor roller 16, and of which at least one roller, for example 19, only by contact their Mantle surface is drivable with the lateral surface of one of the other rollers, and of which at least one roller is an ink roller for ink transfer. According to the example of Fig. 1 all ink rollers 16-27 of the inking unit 6 and the transfer roller 44 are to be washed.

The cleaning device 46 includes a liquid applicator 48. This includes a manifold 49 having a plurality of liquid dispensing orifices 50 disposed along a first one of the rollers, e.g. B. the ink roller 18, which may be a motor-driven or a motor-driven roller, are positioned at a distance from her or positioned to liquid on the Apply lateral surface of the roller 18. This liquid is transferred by rotation of this roller 18 on the standing in mantle with her other rollers and from these rollers on other rollers in contact with them. The discharge openings 50 may be bores or nozzles used in bores.

"Liquid" may be solvent, detergent, detergent or solvent-containing water, water with one or more additives which affect the printing process, pure water or any other liquid. Furthermore, the type of liquid can be changed during the washing process. For example, initially detergent or solvent or water containing it may be used to dissolve the paint from the rolls, and then rinsed with clean water.

The liquid discharge openings 50 are small in size and shape such that liquid can only be applied to discrete moistening longitudinal zones 52 of this first roller 18, leaving non-moistening longitudinal zones 54 therebetween on this first roller 18. The width of a longitudinal moistening zone 52 is equal to the width of a liquid jet.

Further, the cleaning device 46 includes a liquid supply means 56 for supplying liquid to the discharge openings 50 and from there to the lateral surface of the first roller 18 in such an amount of liquid that the rotation of the rollers, the liquid from the discrete Befeuchtungszonen 52 of the first roller 18th on the lateral surface of the voltage applied to its lateral surface further roller, in the present example, the rollers 17 and 19, is transmitted. As a result of the rotation of the rollers, the liquid is transferred from the longitudinal moistening zones 52 of the first roller 18 to longitudinal moistening zones of the at least one further roller 17 and 19, leaving non-moistening longitudinal zones thereon. In the same way, the Transfer liquid to discrete moistening longitudinal zones 52 from roller to roller on other rollers, in the present example on the rollers 19-27.

The liquid continues to flow on the rotating rolls in the roll longitudinal direction beyond the longitudinal wetting zones 52 from roll to roll, as shown in FIG Fig. 2 is schematically represented by "dot-dot-dash" lines 52-2.

In this way, with each roller revolution, the liquid is more and more distributed to the non-moistening longitudinal zones 54 and thus to the entire length of all rollers 16-27 and 44 to be cleaned.

The amount of liquid per unit time of the discharge ports 50 may be constant or variable.

The jets of liquid should hit the roller "softly". Therefore, they are preferably applied in the form of an arcuate jet on the surface of the roll shell. Fig. 1 shows the liquid jets 51 only schematically.

Fig. 1 shows on the left an applicator 48 whose liquid jets 51 are directed to the roller 18, and on the right another, alternatively or additionally usable application device 48, the liquid jets 51 are directed into the gusset between two rollers, such as the rollers 17 and 18th

According to a preferred embodiment of the invention, the liquid discharge openings 50 are designed to produce liquid jets 51 which have a point-shaped cross-section from the discharge openings 50 to the rolls 17 and 18, respectively.

The applicator 48 is preferably provided at its lower end with a drip tray 64 for catching dripping washing liquid having a drain 66.

Fig. 2 shows a possible embodiment of a liquid supply means 56. A detergent container 70 via a valve 72 fresh water of a fresh water connection 74 can be fed. If desired, an automatic supply of detergent or solvent 76 may be provided in the detergent container 70. From the detergent tank 70 is a line 78, which includes a pump 79 and a valve 80, to the distribution channel 49 of the liquid applicator 48. Furthermore, a fresh water supply line 92, which contains a valve 93, be provided from the fresh water connection 74 to the distribution channel 82. Thus, over all dispensing openings 50 either detergent-containing or solvent-based washing liquid or fresh water can be supplied on the other hand. According to other embodiments of the liquid supply device 56, only the supply of detergent-containing or solvent-containing washing liquid or only the supply of fresh water can be provided. The control of the valves and pumps is performed by an electronic control device 94, preferably in response to a higher-level machine operating program of the printing press.

The invention is not limited to offset printing presses but can also be used for cleaning inking rollers in other types of printing presses.

Instead of a doctor blade 30, it is also possible to use another dirt-wiping element, for example a cloth or a brush, which is applied to one of the rollers to be cleaned in order to strip off paint and washing liquid therefrom.

Claims (11)

1. Printing-press roll cleaning method for cleaning rotating rolls (16-27, 38, 39, 40, 42, 44) in a roll train which contains a plurality of successive rolls resting on one another, comprising at least one driven roll and at least one non-driven roll, which can be driven only by peripheral surface contact with an adjacent roll, in particular inking unit rolls of an inking unit (6) for offset printing, liquid being applied by machine to the peripheral surface of at least a first (17, 18) of these rolls in order to loosen contamination, via discharge openings (50) in a liquid application apparatus (48), which has a plurality of discharge openings (50) distributed over the roll length, in addition the liquid being transferred from peripheral surface to peripheral surface of the rolls by the rotation of the rolls in the nip, and the liquid, together with the dirt loosened by it, in particular ink and paper dust, being wiped off on another of the rolls by a wiping apparatus (30, 32), characterized in that the liquid jets (51) are applied only to individual narrow wetting zones (52) corresponding to their width on the at least one first roll (18), leaving non-wetting zones (54) between them, the liquid being applied to the at least one roll in such a low quantity per unit time that the non-wetting zones (54) extend on the first roll (17, 18) as far as the peripheral surface contact with the adjacent roll, with the result that, between the first roll (17, 18) to which the liquid is applied and the roll resting on it, a sufficient frictional resistance is ensured, for rotational driving, the liquid only flowing away laterally over the entire width of the non-wetting zones during a large number of roll revolutions, and, in the case of at least some of the rolls in the roll train following the one first roll, in the nip of the rolls resting on one another, the liquid is initially likewise transferred only to wetting zones of the respective next roll, leaving non-wetting zones between them, and the liquid then flowing away laterally over the entire width of the non-wetting zones only after a plurality of roll revolutions, so that between the non-driven roll and the roll or rolls resting on it, a sufficient frictional resistance in order to drive it along in rotation is always ensured.
2. Printing-press roll cleaning method according to Claim 1, characterized in that the at least some of the rolls following the first roll (18) include the roll on which the liquid is wiped off.
3. Printing-press roll cleaning method according to at least one of the preceding claims, characterized in that the wetting zones (52) on the at least one first roll (18) are narrower than the non-wetting zones (54) .
4. Printing-press roll cleaning method according to at least one of the preceding claims, characterized in that the liquid jets (51) are sprayed into the pocket between the one first roll (18) and a further roll (17) resting on it.
5. Printing-press roll cleaning method according to at least one of the preceding claims, characterized in that the liquid jets (51) are aimed at the at least one first roll (18) so as to fall in an arc, in order to achieve a soft landing thereon.
6. Printing-press roll cleaning method according to at least one of the preceding claims, characterized in that the liquid jets (51) have a point-like cross section from the discharge openings (50) until they strike the at least one first roll, in order to form narrow wetting zones (52) corresponding to their widths.
7. Printing-press roll cleaning apparatus for cleaning rotating rolls (16-27, 38, 39, 49, 42, 44) in a roll train which contains a plurality of successive rolls resting on one another, comprising at least one driven roll and at least one non-driven roll which can be driven only by peripheral surface contact with an adjacent roll, in particular inking unit rolls of an inking unit (6) for offset printing, the cleaning apparatus containing a liquid application apparatus (48) with a plurality of discharge openings (50) distributed over a roll length, through which liquid can be applied by machine to the peripheral surface of at least one of the first rolls (17, 18) to loosen dirt, in particular ink and paper dust, the liquid being transferred from peripheral surface to peripheral surface in the nip by the rotation of the rolls and it being possible for the liquid, together with the dirt loosened by it, to be wiped off on another of the rolls by a wiping apparatus (30, 32), characterized in that the discharge openings (50) have an opening form and a distance from one another in the roll longitudinal direction such that the liquid jets (51), over their entire length and when they strike the at least one first roll (17, 18), have a spacing from one another in the roll longitudinal direction and, as a result, form individual wetting zones (52) on the first roll (17, 18), corresponding to their jet width, leaving non-wetting zones (54) between them, which no liquid jets strike the non-wetting zones (54) extending on the first roll (17, 18) as far as the peripheral surface contact with the adjacent roll, with the result that, between the first roll (17, 18) to which the liquid is applied and the roll resting on it, a sufficient frictional resistance is ensured for rotational driving.
8. Printing-press roll cleaning apparatus according to Claim 7, characterized in that the spacing of the discharge openings (50) from one another in the roll longitudinal direction is so great, and the liquid jet (51) produced by them on the roll surface is so narrow, that the non-wetting zones (54) lying between them on the first roll (17, 18) are wider than the wetting zones (52).
9. Printing-press roll cleaning apparatus according to Claim 7 or 8, characterized in that the discharge openings (50) aim the liquid jets (51) into the pocket between the one first roll (18) and the further first roll (17) resting on it.
10. Printing-press roll cleaning apparatus according to at least one of Claims 7 to 9, characterized in that the liquid jets (51) fall in an arc.
11. Printing-press roll cleaning apparatus according to one of Claims 7 to 10, characterized in that the liquid jets (51) have a point-like cross section when they strike the at least one first roll (17, 18).

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