DE4206626A1 - METHOD FOR REDUCING DUBLIERS WHEN STARTING A SHEET PRINTING MACHINE - Google Patents

Abstract

A method for reducing doubling in the start-up phase of a sheet-fed printing press provides a start-up operation essentially without any disturbing mechanical effects. In a first step, all units and components needed for printing are put into operation, except for the engagement of the rubber blanket cylinder (17, 18) with the impression cylinder (19, 20) and that in further steps, with the entry of a first sheet (21) into a respective printing unit (6), its rubber blanket cylinder (17, 18) and impression cylinder (19, 20) are uncoupled from all other printing units (5) so as to essentially have no disturbing effect on the latter and are engaged with each other for production printing. <IMAGE>

Description

The invention is applicable to sheetfed presses where Duplication arises from the fact that when the Sheet printing machine needed for production in Operation and these repercussions exercise previous printing units that are already pressurized.

To start up a sheet-fed press, you have to do different things Sub-assemblies of the machine according to one of one Machine control using the specified time regime Actuators are put into operation. The Machine control can include a program according to which the Adjustments are carried out in succession or in parallel (DE-Z .: Maschinenbautechnik 29 (1980), No. 2, p. 6, Figure 8).

In all known sheet printing machines with several Printing units start up so that the printing units in Direction of sheet travel can be put under pressure one after the other. The means that before the first sheet enters the first Printing unit first all necessary for the printing Actuating operations are carried out on the first printing unit, and that then the first sheet is printed in the first printing unit and is transported to the second printing unit. Be further before the first sheet arrives at the second printing unit operations required for printing on the second Printing unit executed, the first printing unit on production remains and printed another sheet. The All other printing units are started in an analog manner Way, with all preceding printing units on Stay in print. The actuations that ever Printing unit made, affect u. a. the  Commissioning of the inking unit and dampening system, the queuing the inking rollers on the blanket cylinder and starting of the blanket cylinder to the impression cylinders. Through the mechanically rigid coupling of the printing units to one another, arise from the mechanical adjustment processes mechanical Vibrations, shocks and the like, which are related to previous ones The printing units located in the printing press and the in the form of duplicating negatively on the printed image impact.

The object of the invention is a method for reduction of duplication when starting a sheet-fed press specify which one mechanically largely reaction-free starting enabled.

The object is achieved in that in one first step down to the position of the rubber cylinder the printing cylinders all others needed for printing Sub-units are put into operation, and that in others Steps when the first sheet arrives at the respective one Printing unit rubber and printing cylinders largely decoupled from the previous ones Printing units are put together for production printing.

With this procedure, duplication during start-up is possible decrease because the number of operations with their disturbing mechanical effects on those already in print existing printing units reduced to the bare minimum will. The only remaining operations, which still The reclining movements can cause repercussions of the blanket cylinder to the impression cylinder, their Repercussions can be further dampened if Appropriate constructional precautions are taken. So it is favorable if the adjusting movements of the rubber cylinder to the pressure cylinder is carried out by an actuator, which has a separate drive, d. H. whose  which has a separate drive, d. H. whose Drive energy not from the actual drive of the printing units is removed. It is also advantageous if the rigid Coupling the printing units with a view to the reduction mechanical feedback is partially canceled.

An embodiment of the invention is based on a Drawing will be explained in more detail.

Show it:

Fig. 1 part units of the printing machine in the starting position,

Fig. 2, the sub-assemblies in their position when starting the printing press.

In Fig. 1, various sub-assemblies of a sheet-fed printing press 1 are shown in excerpt, the actuating devices for the sub-assemblies being in the position before the sheet-fed printing press 1 starts up. For example, the sub-units in the feeder 2 and in the delivery 3 , which are used to transport sheets 4, are switched on, and in the first printing unit 5 and in the second printing unit 6 , the inking rollers 7 , 8 of the inking units 9 , 10 and the dampening roller 11 , 12 of the dampening units 13 , 14 turned off by the plate cylinders 15 , 16 .

Furthermore, the rubber cylinders 17 , 18 are out of contact with the plate cylinders 15 , 16 and the pressure cylinders 19 , 20 .

The method for reducing duplication when starting up the sheet-fed printing press 1 will be described below with reference to FIG. 2:

According to the invention, all of the other sub-assemblies required for printing are to be put into operation in a first step except for the placement of the blanket cylinders 17 , 18 on the impression cylinders 19 , 20 and the plate cylinders 15 , 16 . As shown in FIG. 2, the inking rollers 7 , 8 , the inking units 9 , 10 and the dampening solution rollers 11 , 12 of the dampening units 13 , 14 are then set against the plate cylinders 15 , 16 . Furthermore, after this step, all sub-assemblies used to transport the sheets 4 are put into operation.

When the first sheet 21 arrives in the first printing unit 5 , after a color / moisture mixture suitable for printing has run onto the plate cylinder 15 , the rubber cylinder 17 is set against the plate cylinder 15 and the printing cylinder 19 .

The freshly printed sheet 21 is transported via the transport cylinders 22 , 23 and 24 to the second printing unit 6 , the rubber cylinder 18 being set against the plate cylinder 16 and the printing cylinder 19 when this sheet 21 arrives. The setting of the rubber cylinder 18 is largely decoupled from the first printing unit 5 , which still remains set to continuous printing. Because the positioning movement of the blanket cylinder 18 causes almost no disruptive mechanical effects on the first printing unit 5 , the duplication when starting the sheet-fed printing press 1 can be reduced. The method can be implemented for sheet-fed printing presses 1 , in which more than two printing units 5 , 6 are also arranged one behind the other.

In any case, when the first sheet 21 arrives at the respective printing unit, the rubber and printing cylinders are decoupled from one another, largely without reaction, from all the preceding printing units which are already in production. The control of the actuating devices for the various sub-assemblies takes place from a central machine control, to which signals from sheet travel sensors and sensors for the angle of rotation of the printing press can be fed.

Reference list

1 sheet printing machine
2 feeders
3 outriggers
4 sheets
5 printing unit
6 printing unit
7 inking rollers
8 inking rollers
9 inking unit
10 inking unit
11 fountain solution rollers
12 dampening roller
13 dampening system
14 dampening system
15 plate cylinders
16 plate cylinders
17 rubber cylinders
18 rubber cylinders
19 impression cylinders
20 printing cylinders
21 sheets
22 transport cylinders
23 transport cylinders
24 transport cylinders

Claims (1)

1. A method for reducing duplication when starting a sheet-fed printing machine with several printing units, in which, before passing through the first sheet of a predetermined number of sheets to be printed, the sub-assemblies required for printing are put into operation in a time regime specified by a machine control by means of actuating devices, characterized ,

• - That in a first step up to the employment of the rubber cylinders ( 17 , 18 ) to the printing cylinders ( 19 , 20 ) all other sub-units required for printing are put into operation, and
• - That in further steps upon arrival of the first (sheet ( 4 ) at the respective printing unit ( 6 ) blanket cylinders ( 17 , 18 ) and printing cylinders ( 19 , 20 ) are largely decoupled from the previous printing units ( 5 ) for production printing.