JPH0366151B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention comprises first and second groups of tension rolls for moving a web without perforations or registration holes, The present invention relates to a printing unit for a web-fed rotary printing press for subsequently changing to another paper format and printing on the web.

[Prior Art] A rotary printing press capable of changing the paper size is known from West German Patent Application No. 2617418, and in this case there is no need to change the printing cylinder to change the paper size. . The web to be printed is advanced and retracted through the printing gap between the printing cylinders and stopped. However, this known printing press requires a printing carrier with perforations because a belt conveyor with pins is arranged before and after the printing unit, respectively. However, such perforated printing carriers are not desirable for all printing orders.

In the specification of West German Patent Application No. 2213531,
A web rotary printing press is disclosed for printing carton webs that do not have any perforations or registration holes. The known web-fed rotary printing press is constructed in such a way that it is possible to print a carton web from one paper format to another. In order to adapt the running path of the carton web to the printing format, two pairs of transport rolls are used which can move the carton web with variable speed and direction. The provision of two transport roll pairs makes it impossible to properly maintain carton tension. This is because the two transport roll pairs act alternately on the carton web.

[Problem to be Solved by the Invention] The problem of the present invention is to be able to print continuously and accurately no matter what paper size is chosen, and to do so without having to move forward or backward only a very short section of the web. It is an object of the present invention to provide a printing unit for a web-fed rotary printing press which does not require any reciprocating components for moving the web through the printing gap.

[Means for Solving the Problems] The configuration means of the present invention for solving the above problems is such that the first and second tension roll groups are arranged in front of the printing gap.
Also provided behind the printing gap are third and fourth tension roll groups, respectively between said first and second tension roll groups and between said third and fourth tension roll groups. , a web store for tensioning the web is provided, and a controlled transmission drive is provided in each case as a drive for the second and third pulling roll groups for forward and backward movement of the web. At the point.

[Function] The effect achieved by the invention is particularly significant because the web transport device consisting of the pulling roll group and the web store can be arranged directly in front of the printing cylinder and directly behind the printing cylinder, so that the web Only short segments need to be reciprocated, thereby
Furthermore, neither the registration of subsequent printing nor the registration of cutting is adversely affected. The production speed and noise-free running performance of the printing press are significantly increased. This is because there is no need for conventional reciprocating mechanical parts. Switching paper formats becomes significantly simpler. The web tension of the web running through the printing unit can be easily varied by controlled tension rolls.

[Example] Next, an example of the present invention will be described based on the drawings.

A web 1 unwound from a supply web roll (not shown) is fed to the printing unit 2 by a first pull roll group 4 driven by a main drive 3. From this first group of pulling rolls 4 the web 1 is led to a first web store 6 . The web store 6 consists of a roller 7 suspended on two arms 8, said arms 8 being fixedly engaged with shafts rotatably supported on both side frames of the printing unit 2. has been done. A drive pin of the rotating electromagnet 5 is connected to one end of the shaft. The casing of the rotating electromagnet 5 is fixed to the side frame. The torque of the rotating electromagnet 5 is infinitely adjustable in a known manner and is adapted to keep the web 1 taut with a predetermined force between the first pulling roll group 4 and the rollers 7 of the web store 6. It acts on The web tension is adjusted and kept constant between the rollers 7 and the first tension roll group 4.

The web 1 is wound around the roller 7 for about 180 degrees from the apex of the roller, and then two webs are placed at a distance from each other at the lower right and lower left of the roller and are pivotally supported by both side frames. It travels while being wound around direction change guide rollers 9 and 11. From the deflection guide roller 11, the web 1 is fed to a second electrically driven pulling roll group 12. web 1
First, the pressure roll 13 of the second tension roll group 12
The tension 14 is then wound virtually without slip. From the tension roll 14 the web 1 passes through a deflection guide roller 16 and through a printing gap between two horizontally opposite printing cylinders 17 and 18 to a third printing cylinder.
The tension roll group 19 is reached. This third tension roll group 19 includes an electrically driven tension roll 2
1, and a pressure roll 22 that is in contact with the circumferential surface of the tension roll. After passing through the crimping roll 22, the web 1 passes through a second web store 23. This second web store 23 consists of the same components as the first web store 6 described above, namely a roller 24, two arms 26 and a rotating electromagnet 27. The web 1 from the second web store 23 is transferred to a fourth web driven from the main drive 3 of the printing press.
28 and from there to a subsequent printing unit or processing stations. The post-printing unit or processing station subjects the web 1, running at constant speed, to further processing, for example printing or cutting during running.

Each pulling roll 14 and 21 of the second and third pulling roll groups 12, 19 is each driven by a DC motor and is equipped with an ordering disc as an actual value signal generator. The encoder disk is connected to the shaft of each DC motor for driving the pulling rolls 14, 21 or to the pulling rolls 14, 21.
It is configured as a scale disc which is fixedly mounted on the shaft of the scale and is equipped with a sensor for detecting the scale increments. The encoder disk has the task of transmitting the actual angular position values of the tension rolls 14, 21 in the form of pulses to a digital comparator circuit.

An encoder is connected to one of the printing cylinders 17, 18 as a setpoint value signal generator. The encoder has a high resolution and transmits the angular position of the printing cylinder in the form of pulses to a digital comparison circuit.
The angular position in this case is used as a target value when comparing the angular position of the printing cylinders 17, 18 with the angular position of the tension rolls 14, 21. Since the second and third pulling roll groups 12, 19 each have their own control circuit for the DC motor, the second and third pulling roll groups 12, 19
The desired web tension is adjusted and maintained between the tension rolls 12 and 19 of.

During printing, the web 1 is transferred to a printing cylinder 1 that performs double-sided printing.
Through printing gaps 7 and 18, the web is conveyed as long as the printing plate acts on it. Both printing cylinders 17,
When the 18 tension member receiving grooves 10 pass through the printing gap, the second and third tension roll groups 12, 19 take over the further transport of the web 1 in the following manner.

First step: the web 1 is brought to a stop from the production speed over a distance section of, for example, 60.0 mm with a constant deceleration or by braking on the basis of a certain sinusoidal function.

Second stage: the web 1 is moved backward from a standstill over a distance section of, for example, 60.0 mm with a constant acceleration or on the basis of a certain sine function.

3rd stage: Reverse movement of web 1 by 60.0mm, for example.
The web 1 is stopped by braking at a constant deceleration or based on a certain sine function over a distance section of .

Fourth stage: Returning the web 1 to the production speed by moving it forward over a distance section of, for example, 60.0 mm from a stationary state with a constant acceleration or on the basis of a certain sinusoidal function.

Therefore, when the web 1 is transported in a normal conveyance format when the tightening member storage groove 10 passes through the printing gap, the unprinted blank area that inevitably occurs is also
The four-step operation described above not only completely eliminates web loss, but also allows the web to be fed to suit the desired paper format by appropriately selecting the acceleration/deceleration of the web and the distance section. can get.

The tension rolls 14 and 21 provided for conveying the web cooperate with one pressure roll 13; 22 in each case to convey the web virtually without slipping. During printing, printing cylinders 17, 18 and tension rolls 14, 21
have equal circumferential velocity. The constant circumferential speed is ensured by comparing the setpoint value of the pulses generated by the encoder with the actual value.

In the case of the largest paper size, the durations for the four stages are all equal; in the case of the smallest paper size, the durations for the first and fourth stages are equal, and the lengths are also the same for the largest paper size. However, the second
The time required for the third stage is the same, but it is correspondingly longer than for the largest paper format. Note that one of the printing cylinders 17 and 18 is rotatably supported in a fixed position, and the other printing cylinder is rotatably supported so that it can approach and move away from the other printing cylinder, that is, the printing gap can be adjusted. The printing gap is adjusted in advance for each predetermined printing. It is also known per se that the paper format can be changed without replacing the printing cylinders 17, 18 by widening or shortening the underlay under the printing cylinder bracket.

Alternatively, it is also possible to do as follows. In other words, the time required for the first stage and the second stage is equal,
Further, although the required time for the third stage and the fourth stage is the same, it is also possible to make the time required for the third stage and the fourth stage longer than the time required for the first stage and the second stage.

However, in the case of relatively small paper formats, instead of stopping the web 1 while the clamping member receiving groove 10 passes through the printing gap, the end of the paper format is The non-printing surface, which is limited by the sheet starting edge, is
It is also possible to stop the web 1 while passing through the printing gap between 7 and 18. In short, if the paper format is relatively small and a shortened underlay is used under the bracket of the printing cylinder, the surface involved in printing becomes smaller, and the total area not involved in printing (= tightening member accommodation groove + blanket portion without underlay) ) is enlarged, making it possible to pull back the web 1 even in blanket areas that are not required for printing. Note that in order to change to various paper formats, the paper format can be input into the control computer, ie, the digital comparison circuit.

A first web store 6 in front of the printing unit 2 and a second web store 23 in the rear of the printing unit 2 continuously feed the web 1 from the supply web roll and, after printing, to a downstream processing station. This is to enable continuous supply to the tank.

[Brief explanation of drawings]

The drawing is a schematic representation of a printing unit equipped with the device according to the invention. DESCRIPTION OF SYMBOLS 1... Web, 2... Printing unit, 3... Main drive, 4... First pulling roll group, 5... Rotating electromagnet, 6... First web storage device, 7... Roller, 8 ...Arm, 9...Direction changing guide roller,
DESCRIPTION OF SYMBOLS 10...Tightening member accommodation groove, 11...Direction changing guide roller, 12...2nd tension roll group, 13...Crimping roll, 14...Tension roll, 16...Direction changing guide roller, 17, 18... ...Print cylinder, 19...Third tension roll group, 21...Tension roll, 22...
...Crimping roll, 23...Second web storage device, 2
4...Roller, 26...Arm, 27...Rotating electromagnet, 28...Fourth tension roll group.

Claims (1)

[Claims] 1 comprising a first and a second pulling roll group 4, 12 for moving a web 1 without feed holes or registration holes, changing from one paper format to another paper format; In a printing unit 2 for a web rotary printing press for printing the web 1, a first and a second tension roll group 4, 1 are arranged in front of the printing gap.
However, also behind the printing gap there are third and fourth pulling roll groups 19, 28, between said first and second pulling roll groups 4 and 12 and between said third and fourth pulling roll groups. a web store 6; 2 for tensioning the web 1 between pulling rolls 19 and 28 respectively;
3 and for the forward and backward movement of the web 1 second and third pulling roll groups 12; 1;
Printing unit for a web-fed rotary printing press, characterized in that a controlled electric drive is provided as each of the 9 drives.