DE102018201606A1 - Method for operating a printing press during printing pauses - Google Patents

Abstract

The invention relates to a method for operating a printing machine (100) during a printing pause, the printing press (100) having a transport device (1) with a rotating transport element (10) for moving a printing material (1000) through a printing station (13), with subsequent printing Steps: a) Driving the printing machine (100) in a disengaging position and separating a drive connection between a main drive (2) and the transport element (10) b) operatively connecting a drive connection between an auxiliary drive (3) and the transport element (10) c) Permanent Driving the transport element (10) by the auxiliary drive (3) to equalize the heat distribution on the transport element. The invention also relates to a printing machine (100) for carrying out the method. It can be advantageously prevented uneven heating of the transport element.

Description

The invention relates to a method for operating a printing press having the features of claim 1 and to a printing press for carrying out the method having the features of claim 8.

State of the art

The DE 10 2016 205 769 A1 shows a digital printing machine with a printing station with inkjet printing unit and Jettingzylinder. The jetting cylinder is used for transporting sheets to be printed under the inkjet printing unit.

To quickly dry the printed ink on the sheet and prevent smudging, powerful dryers are used downstream of the inkjet printing unit. Although a high print quality can be achieved due to the short distance between the print head and the dryer, on the other hand the dryer emits a lot of heat to the jetting cylinder as a heat source. In a machine standstill, the Jettingzylinder warms up on one side, which affects the print quality at a resumption of the printing process, as an uneven heat distribution on the jetting cylinder adversely affects the print quality.

task

The object of the present invention is to describe a method for operating a printing machine and to provide a printing press which prevent uneven heating of the transport element and at least partially overcome the disadvantages of the prior art.

Technical solution

This object is achieved by a method for operating a printing press with the features of claim 1 and a printing press for carrying out the method with the features of claim 8.

The method according to the invention serves to operate a printing press, for example a digital printing press, during a printing pause. The printing press has a transport device with a rotating transport element, in particular in the region of the printing station, for moving a printing material, for example a sheet of paper or cardboard, through a printing station. Meanwhile, the substrate is printed. The method according to the invention has the following steps:

In a first method step, the printing machine is moved with the transport elements of their transport device in a Auskuppelposition and there is a separation of a drive connection between a main drive and the transport element. This is done in particular by the transport element is separated from the main drive or its gear train by pressing a switchable coupling.

In a next step, a drive connection between an auxiliary drive and the transport element takes place. In this case, either the auxiliary drive can be switched on, for example by extending a pinion of the auxiliary drive, or the auxiliary drive can rotate continuously during printing and before disconnecting the drive connection between the main drive and transport element, for example using a freewheel, and only after the separation the drive connection main drive-transport element take effect.

In a subsequent step, the transport element is permanently driven by the auxiliary drive to equalize the heat distribution on the transport element.

Advantageously, the method according to the invention is used only for a longer printing pause, in particular for a pause of a duration of more than one minute, in any case only during a pause, which has a duration that is greater than the time required for the separation of the Drive connection and in operative connection of the drive connection with the auxiliary drive.

In a particularly advantageous and therefore preferred development of the method according to the invention, the main drive is stopped in an angular position in which the rotating transport element is freely rotatable, without it being possible for a collision with upstream or downstream transport elements such as, for example, cylinders equipped with gripper bridges. This special angular position defines the disengaging position.

In an alternative embodiment of the method according to the invention are between the separation of the drive connection main drive-transport element and the operative connection of the drive connection auxiliary drive transport element the rotating transport element directly upstream and / or directly downstream transport elements spent in a spaced apart from the rotating transport element position, in particular pivoted. The directly upstream and / or directly downstream transport elements can be, for example, with gripper bridges equipped transport cylinders act. The drive connection of the directly upstream and / or directly downstream transport elements with the main drive remains. This makes it possible that the printing press including the directly upstream and / or directly downstream transport elements can be driven in the printing pauses, for example, to clamp coating plates or to clean cylinders.

In a further alternative variant of the method, a drive connection between the main drive and the transport element directly upstream and / or downstream of the rotating transport element is also separated before the auxiliary drive transport element is actively connected to the drive connection. For switchable couplings can be provided. The directly upstream and / or directly downstream transport elements can be fixed in their disengaged position. Thus, collisions with the rotating transport element can be avoided.

The invention also relates to a printing machine for carrying out the method described above. The printing machine according to the invention has a transport device with a rotating transport element, optionally the rotating transport element directly upstream or directly downstream transport elements, a main drive for driving the transport device, at least one switchable clutch for separating a drive connection between the main drive and the rotating transport element and an auxiliary drive for driving of the rotating transport element in printing breaks.

In an advantageous embodiment, the rotating transport element either as a so-called jetting cylinder, d. H. be designed as a sheet transport cylinder below an inkjet head, or as a conveyor belt, in particular as a circulating suction belt. The switchable coupling is advantageously designed as a spring-loaded multi-tooth clutch. The multi-toothed design enables an angle-precise engagement when restarting the press. The spring preload prevents disengagement in the event of a power failure and consequent collisions in the area of the transport device, in particular a collision of grippers.

The invention described and the described advantageous developments of the invention are also in combination with each other - as far as is technically feasible - advantageous developments of the invention.

With regard to further advantages and constructive and functional advantageous embodiments of the invention, reference is made to the dependent claims and the description of exemplary embodiments with reference to the accompanying figures.

embodiment

The invention will be explained in more detail with reference to attached figures. Corresponding elements and components are provided in the figures with the same reference numerals. In favor of a better clarity of the figures was waived a true to scale representation.

• 1 eine erste Ausführungsvariante einer erfindungsgemäßen Druckmaschine
• 2 eine erste Ausführungsvariante einer Antriebsverbindung des Jettingzylinders
• 3 eine zweite Ausführungsvariante einer erfindungsgemäßen Druckmaschine
• 4 eine zweite Ausführungsvariante einer Antriebsverbindung des Jettingzylinders und von vor- und nachgelagertem Zylinder

It show in a schematic representation

• 1 a first embodiment of a printing machine according to the invention
• 2 a first embodiment of a drive connection of the Jettingzylinders
• 3 a second embodiment of a printing machine according to the invention
• 4 a second embodiment of a drive connection of the Jettingzylinders and upstream and downstream cylinder

1 shows a printing press 100 for printing on sheets 1000 in a printing station 13 with inkjet printheads. bow 1000 be from a sheet pile 1001 in the area of an investor coming in the transport direction T using a transport device 1 through the printing press 100 transported through, thereby printed and in the range of a boom back to a sheet pile 1001 stored. The transport device 1 has a jetting cylinder 10 on, which is mounted as a rotating transport element below a printing station 13 with inkjet printheads. The jetting cylinder 10 serves the bow 1000 to move through under the inkjet printheads, leaving a print on the sheet 1000 can be done. The jetting cylinder 10 is a cylinder 11 directly in front of which arch 1000 to the jetting cylinder 10 passes. From the jetting cylinder 10 become the printed sheets 1000 to a directly downstream cylinder 12 to hand over. The cylinders 11 . 12 thus serve as transport elements and can, as in 1 indicated with grippers 8th be equipped. To the transport device 1 and in particular the jetting cylinder 10 as well as upstream and downstream cylinders 11 . 12 Driving is a major driver 2 intended. About one in 1 not shown gear train 5 becomes the rotational movement of the main drive 2 on the various transport elements 10 . 11 . 12 the transport device 1 transfer. To the on the bow 1000 A drier 14 is provided downstream of the printing station 13, to dry the applied ink and to prevent smearing of the ink upon further transport.

In printing breaks, in which no bow 1000 be printed, the printing machine 100 is usually quiet. At standstill, a strong unilateral heat input from the dryer 14 in the jetting cylinder 10 respectively. Since this is to be regarded as disadvantageous, an auxiliary drive is advantageously 3 intended, which for permanent rotation of the Jettingzylinders 10 used in the printing breaks. To the jetting cylinder 10 to be able to rotate permanently in the printing pauses, the printing press 100 in a like in 1 stopped disengaged position. In this Auskuppelposition are the grippers 8th from upstream and downstream cylinder 11 . 12 spaced apart from the jetting cylinder 10 and upstream or downstream cylinder 11 . 12 each have no contact with the jetting cylinder 10 ,

Then - as in 2 shown - the jetting cylinder 10 from the gear train 5 of the main drive 2 be separated. This is a switchable coupling 4 intended. Upon actuation of the switchable coupling 4 becomes the driving connection between Jettingzylinder 10 and the main drive 2 separated. Subsequently, a drive connection between an auxiliary drive 3 and the jetting cylinder 10 be brought into operative connection. For this purpose, the auxiliary drive 3 via a switchable, in particular movable, pinion 3.1 feature. In the presentation of 2 became the movable pinion 3.1 already shifted so that a drive connection between the auxiliary drive 3 and the jetting cylinder 10 over the pinion 3.1 and a toothed ring fixed to the jetting cylinder 10 with toothing 3.2 was produced.

By means of the auxiliary drive 3 can the jetting cylinder 10 be rotated permanently during the printing pauses and the heat distribution in the area of the Jettingzylinders 10 can be made uniform.

In the in 3 illustrated embodiment of the printing press 100 Both the upstream cylinder 11 as well as the downstream cylinder 12 by a pivoting movement v in one to the jetting cylinder 10 Spaced position spent. For this purpose, a not shown eccentric bearing of upstream and downstream cylinder 11 . 12 intended. In the pivoted position of upstream and downstream cylinder 11 . 12 are the grippers 8th the cylinder 11 . 12 so far from the jetting cylinder 10 spaced that a collision of the gripper 8th with the jetting cylinder 10 is excluded. This makes it possible for the main drive 2 disengaged jetting cylinder 10 also upstream and downstream cylinders 12 by means of the main drive 2 can be rotated, for example, for adjustment or cleaning. Upstream and downstream cylinders 11 . 12 be through the pivoting movement v So only so far from the jetting cylinder 10 spaced apart, that a collision is excluded, the gearing 5.1 the cylinder 11 . 12 with the gear train 5 remains engaged.

In a further embodiment of the printing machine 100 as they are in 4 is not only the jetting cylinder 10 a switchable clutch 4 but also each of the upstream cylinder 11 and the downstream cylinder 12. This allows upstream and downstream cylinders 11 . 12 and the jetting cylinder 10 from the gear train 5 of the main drive 2 can be decoupled. To the jetting cylinder 10 To be able to rotate in the uncoupled state in the printing pauses, is an auxiliary drive 3 provided, as it has already been described above. To both the upstream and the downstream cylinder 11 . 12 locked in disengaged state, are on the machine frame 7 activatable fixing bolts 6 intended. Unlike the in 1 and 2 illustrated embodiment, the other transport elements so by the gear train 5 of the main drive 2 be rotated, which allows, for example, assembly and cleaning activities.

LIST OF REFERENCE NUMBERS

1

transport means

2

main drive

3

auxiliary drive

3.1

pinion

3.2

gearing

4

switchable coupling

5

Gear train (gear train)

5.1

Gearing engaged

6

Bolt Fixing

7

machine frame

8th

grab

9

pivot bearing

10

Jetting cylinder (rotating transport element)

11

upstream cylinder (transport element)

12

downstream cylinder (transport element)

100

press

1000

bow

1001

sheet pile

v

swiveling

T

transport direction

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102016205769 A1 [0002]

Claims (10)

Method for operating a printing press (100) during a printing pause, the printing press (100) having a transport device (1) with a rotating transport element (10) for moving a printing material (1000) through a printing station (13), with the following steps: a) driving the printing machine (100) into a disengaging position and disconnecting a drive connection between a main drive (2) and the transport element (10) b) in operative connection of a drive connection between an auxiliary drive (3) and the transport element (10) c) Permanent driving of the transport element (10) by the auxiliary drive (3) to equalize the heat distribution. Method for operating a printing press according to Claim 1 , wherein in step b) the auxiliary drive (3) is switched on. Method for operating a printing press according to Claim 1 , wherein the auxiliary drive (3) continuously rotates before step a). Method for operating a printing press (100) according to one of the preceding claims, wherein the method is used only for a longer printing pause, in particular for a pause of a duration of more than one minute. Method for operating a printing press according to one of the preceding claims, wherein in step a) the main drive (2) is stopped in an angular position in which the rotating transport element (10) is freely rotatable. Method for operating a printing press according to one of Claims 1 to 4 in which, between the steps a) and b), directly upstream and / or directly downstream transport elements (11, 12) are brought into a position spaced from the rotating transport element (10) from the rotating transport element (10). Method for operating a printing press according to one of Claims 1 to 4 , wherein prior to step b) also a drive connection between the main drive (2) and transport elements (11, 12), which are directly upstream of the rotating transport element (10) and / or directly downstream, is separated. Printing machine (100) for carrying out the method according to one of the preceding claims, comprising a printing station (13), a transport device (1) with a rotating transport element (10), with a main drive (2) for driving the transport device (1), at least one shiftable clutch (4) for separating a drive connection between the main drive (2) and the rotating transport element (10) and with an auxiliary drive (3) for driving the rotating transport element (10). Printing press after Claim 8 , characterized in that the rotating transport element is designed as Jettingzylinder (10) or as a conveyor belt. Printing press after Claim 8 or 9 , characterized in that the switchable coupling (4) is designed as a spring-biased multi-tooth clutch.

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