DE20002090U1 - Sheet guiding device in a printing press - Google Patents

Description

• * ··■· m · · &igr;

M02G090

February 4, 2000

MAN ROLAND PRINTING MACHINES AG

Mühlheimer Strasse 341

63075 Offenbach am Main

Sheet guiding device in a printing press
10

The invention relates to a sheet guiding device in a printing machine with a guide surface extending along the sheet path with openings for the passage of air and with a chamber adjacent to the guide surface, which is divided by an intermediate wall provided with openings arranged between the guide surface and a chamber floor opposite the guide surface into a first space facing the guide surface and a second space facing away from the guide surface, wherein the second space is connected to an air conveying device for blowing air or suction air.

A curved guide device of the type specified is known from DE 298 19 402 Ul. The guide surface is arranged on a box-shaped flow channel and is separated from the channel section connected to a pneumatic system by a fixed perforated plate extending within the flow channel. This is intended to reduce the occurrence of turbulence in blowing air operation.

The invention is based on the object of creating a sheet guiding device of the type mentioned at the beginning, which can be optimally adjusted to the respective requirements of the printing material.

- 2 - M02G090

This object is achieved according to the invention in that the distance between the intermediate wall and/or the cannon bottom and the guide surface is adjustable.
5

The invention is based on the knowledge that by changing the distances between the guide surface and the partition wall or the chamber floor, the pressure level used to guide the sheet and the pressure distribution on the guide surface can be easily influenced and thus adapted to the requirements of the sheet guide. The adjustability according to the invention is particularly advantageous when it is not possible to regulate the air supply in any other way or only to a limited extent. The adjustment option according to the invention can also be used in conjunction with an adjustable air conveying device to achieve better fine-tuning. In addition, the design according to the invention counteracts the formation of turbulence.

The distances can be changed in various ways. For example, either only the partition wall or only the chamber floor can be adjustable relative to the guide surface; however, the partition wall and the chamber floor can also both be independently adjustable and the partition wall and the chamber floor can also be adjusted together relative to the guide surface. The adjustment of the partition wall and/or the chamber floor is preferably carried out via motor-driven adjusting devices, e.g. linear motors, but manually adjustable adjusting devices can also be provided. If motor-driven adjustment is provided, a setting made in relation to the printing material or the print job can be saved as a data set and automatically read in and adjusted when the same print job is repeated. Furthermore, according to the invention, a

- 3 - M02G090

Pressure-dependent control of the distances between the partition wall or chamber floor should be provided to compensate for pressure fluctuations caused by faults. For pressure control, the pressure in the first room and/or the second room can be measured using pressure sensors.

The inventive design of the sheet guiding device enables a particularly uniform pressure distribution and a very extensive optimization of the sheet guiding to be achieved.

The invention is explained in more detail below using embodiments shown in the drawing.
15

Figure 1 shows a cross-section of a sheet guiding device with adjustable intermediate plate and adjustable chamber floor,

Figure 2 shows a cross section of a sheet guiding device with adjustable intermediate plate and

Figure 3 shows a cross-section through a sheet guiding device with an adjustable unit consisting of an intermediate plate and a chamber floor.

The sheet guiding device shown in Figure 1 has a guide surface 1 extending along a section of the sheet path, which is formed by a cover plate provided with openings 2. The guide surface 1 is attached to the side supports 3 of the printing press at its edges on both sides of the sheet path. On the side of the guide surface 1 facing away from the sheet path, a chamber 4 with a chamber floor 5 and side walls 6 formed by bellows is arranged. Several fans 7 are attached to the chamber floor 5, through which air

- 4 - M02G090

can be blown into the chamber 4 or sucked out of the chamber 4. Instead of the fans 7, another air supply device, e.g. a central air supply, can also be provided. The chamber floor 5 is held by at least 3 linear motors 8 and its distance from the guide surface 1 can be adjusted by these. The chamber 4 is divided by a partition 9 into a space 10 adjacent to the guide surface 1 and a space 11 adjacent to the chamber floor 5. The partition 9 consists of a sheet metal provided with openings 12. It is held outside the chamber 4 by at least three linear motors 13 and can be adjusted by these relative to the guide surface 1. The linear motors 8, 13 are each attached to the machine stand and can be driven pneumatically, hydraulically or electrically. The linear motors 8, 13 can be controlled from the control station of the printing press, whereby the linear motors 8 can be controlled separately from the linear motors 13. Individual control of each linear motor can also be provided.

In the sheet guiding device shown in Figure 1, the distance of the intermediate wall 9 from the guide surface 1 and the distance of the chamber floor 5 from the guide surface 1 or from the intermediate wall 9 can be individually adjusted.

As a result, the pressure level in the chambers 10, 11 and thus the pressure distribution can be varied both during blowing and suction operation of the fans 7 in such a way that a uniform pressure distribution is achieved on the side of the guide surface 1 facing the sheet path, which is optimally adapted to the respective printing material and the respective machine speed.

Figure 2 shows a simplified embodiment of a sheet guiding device in which the chamber 4 is formed by a rigid air box 14, the upper wall of which has the guide surface 1 provided with openings 2 and the

- 5 - M02G090

lower wall forms the chamber floor 5. Fans 7 are in turn attached to the chamber floor 5. The intermediate wall 9, formed by a perforated sheet, is arranged in the air box 14 parallel to the chamber floor 5 and is held by linear motors 13 which are attached to the chamber floor 5. The linear motors 13 can adjust the intermediate wall 9 in the direction of the guide surface 1 or the chamber floor 5 and thus change the pressure level in the space 10 adjacent to the guide surface 1.

In the embodiment shown in Figure 3, the perforated partition wall 9 and the chamber floor 5 form an air box 15, which can be supplied with blowing or suction air using the fans 7 attached to the chamber floor 5. The guide surface 1 is arranged on a hood 16, which surrounds the side walls 18 of the air box 15 with its side walls 17 and is sealed to the side walls 18 by means of sliding seals. Linear motors 13 are attached to the hood 16, which support the air box 15 and can adjust the air box 15 relative to the hood 16 in such a way that the distance between the guide surface 1 and the partition wall 9 becomes larger or smaller.

Claims (6)

1. Sheet guiding device in a printing machine with a guide surface extending along the sheet path with openings for the passage of air and with a chamber adjacent to the guide surface which is divided by an intermediate wall provided with openings arranged between the guide surface and a chamber floor opposite the guide surface into a first space facing the guide surface and a second space facing away from the guide surface, the second space being connected to an air conveying device for blown air or suction air, characterized in that the distance of the intermediate wall ( 9 ) and/or the chamber floor ( 5 ) from the guide surface ( 1 ) is adjustable. 2. Sheet guiding device according to claim 1, characterized in that the intermediate wall ( 9 ) and the chamber floor ( 5 ) are adjustable independently of one another. 3. Sheet guiding device according to one of claims 1 or 2, characterized in that the intermediate wall ( 9 ) and the chamber floor ( 5 ) are connected to one another and are jointly adjustable relative to the guide surface ( 1 ). 4. Sheet guiding device according to one of the preceding claims, characterized in that the adjustment of the intermediate wall ( 9 ) and/or the chamber floor ( 5 ) is carried out via motor-driven adjusting devices, e.g. linear motors. 5. Sheet guiding device according to one of the preceding claims, characterized in that an adjustment of the intermediate wall ( 9 ) and/or the chamber floor ( 5 ) in relation to the printing material or the print job is stored as a data record and is automatically read in and adjusted when the same print job is repeated. 6. Sheet guiding device according to one of the preceding claims, characterized in that the pressure in the first space ( 10 ) and/or the second space ( 11 ) of the chamber ( 4 ) is measured by means of pressure sensors and the distance of the intermediate wall ( 9 ) and/or the chamber floor ( 5 ) from the guide surface ( 1 ) is regulated as a function of pressure.