DE19855156A1 - Device to separate uppermost sheet of paper from stack has rotatable brush roller for keeping back second sheet, and with some bristles located to press from behind and above stack - Google Patents

Abstract

The holding element for keeping back the second sheet of paper in the stack is a rotatable brush roller (23). The brush roller has a rotational pivot (31) which is located at an angle above the rear edge of the stack. The roller is positioned so that one part of the bristles (32a) are located to press from behind against the stack (7) of paper and one part of the bristles (32b) are located to press down on the stack from the top. The brush roller is mounted in a holder which is attached to an axially movable bearing block (28).

Description

The invention relates to a device for separating the uppermost sheet Sheet stack according to the preamble of claim 1.

Such a device is known from DE 19 29 714. This points to Hold the rear end of the subsequent second sheet Separating element in the form of a wiping brush. However, this is not in plant with the sheet stack, but is at a distance above that Arranged stack of sheets so that they only when an unwanted lifting second sheet comes into contact with it.

The invention has for its object a device for restraint of the second sheet, which can be separated with a low tendency to scratch of the first sheet improved.

The object is achieved by the features of claim 1 solved.

In an advantageous embodiment of the invention, the holding element is rotatable stored brush roller trained. This is advantageously so arranged that an axis of rotation of the brush roller obliquely above the Top of the sheet stack is located. With this arrangement, part of the Bristle the brush roll from behind against the sheet stack and another Part of the sheet stack from above. The bristles are bent slightly and apply a holding force to the bow due to their elasticity.  

An embodiment of the invention is shown in the drawings and is described below.

Show it:

Fig. 1 is a schematic side view of the sheet-processing machine with a device for separating the uppermost sheet of a sheet stack,

Fig. 2 is an enlargement of the separating apparatus in a schematic representation according to the invention with the brush roller,

Fig. 3 is a plan view of the separating device with a brush roller.

A sheet processing machine, preferably a rotary printing press 1 , has, inter alia, a sheet feeder 2 , at least one printing unit 3 ; 4 and a boom 6 .

Arranged in the sheet feeder 2 is a sheet stack 7 intended for processing, the top sheet 8 of which is in each case by means of a separating device 9 , this is a so-called suction head, raised from the sheet stack 7 and a further transport device, for. B. a belt table 10 is supplied.

The rear region of the sheet 8 is lifted here by means of a number of lifting-I separating suction devices 11 , which are distributed across the format width of the sheet 8 transversely to the sheet transport direction. A provided feeler foot 16 determines the height of the sheet stack 7 . One or more air blowers 18 are arranged outside the periphery of the sheet stack 7 and blow air under the raised sheet 8 , so that it is transported during the transport movement by means of suction devices 19 provided on an air cushion. In addition, the feeler foot 16 itself can also have a blown air device which is also supplied with blown air in parallel with the air blowers 18 .

Scraper brush rollers 23 , which are axially adjustable, are received on a crossbar 22 fastened to the suction head 9 by means of the holder 21 provided. These are rotatably supported in a fork-shaped holder 24 . The holder 24 has, at one end facing away from the wiping roller 23, a further fork-shaped receptacle 26 , by means of which the holder 24 can be fastened in a longitudinally displaceable manner to a bearing block 28 . The bearing block 28 has a locking screw 27 , by means of which it is displaceably arranged on the crossmember 22 parallel to the trailing edge of the sheet stack. The wiping brush roller 23 consists essentially of a shaft 31 and bristles 32 that come out radially therefrom.

The scraper brush roller 23 is positioned relative to the top of the sheet stack in such a way that part of the bristles 32 a press against the back of the sheet stack 7 under internal tension, with another part of the bristles 32 b pressing onto the sheet stack 7 from above.

When lifting the uppermost sheet 8 from the sheet stack 7 by means of the lifting / separating suction device 11 , the bristles 32 b press from above onto the second sheet and hold it in place so that it is not transported away by the blown air with the first sheet. Depending on the sheet thickness to be processed, different stripping brush rollers 23 can be used, e.g. B. soft or thin bristles with low residual stress for processing thin paper z. B. Bible printing paper or firm, thick bristles with high internal tension or spring force for processing thick sheet thicknesses (e.g. cardboard).

For this purpose, the holders 24 of the scraper brush roller 23 are designed to be easily replaceable.

REFERENCE SIGN LIST

1

Rotary printing press

2nd

Investors

3rd

Printing unit

4th

Printing unit

6

boom

7

Sheet stack

8th

arc

9

Separation unit

10th

Conveyor table

11

Lifting / separating suction

16

Feet

17th

arc

18th

Air blowers

19th

Drag vacuum

21

Holder (

9

)

22

traverse

23

Brush roller

24th

Holder (

23

)

26

Admission (

24th

)

27

Locking screw

28

Bearing block

31

Shaft, axis (

23

)

32

,

32

a,

32

b bristles

32

a bristles

32

b bristles

Claims (6)

1. Device for separating the uppermost sheet of a stack of sheets by means of lifting / separating suction devices lifting the sheet in the region of the sheet stack rear edge and with at least one holding element holding back the second sheet of the sheet stack, characterized in that the holding element is a brush roller ( 23 ). 2. Device according to claim 1, characterized in that the brush roller ( 23 ) is rotatably mounted. 3. Apparatus according to claim 1 or 2, characterized in that the brush roller ( 23 ) has an axis of rotation ( 31 ) which can be arranged obliquely above the trailing edge of the stack. 4. Apparatus according to claim 1, 2 or 3, characterized in that the brush roller ( 23 ) is positioned such that a part of the bristles ( 32 a) are arranged from behind against the sheet stack ( 7 ) and a part of the bristles ( 32nd b) are pressed from above onto the sheet stack ( 7 ). 5. Device according to one of the preceding claims, characterized in that the brush roller ( 23 ) is mounted in a holder ( 24 ) which is releasably attached to an axially displaceably arranged bearing block ( 26 ). 6. Device according to one of the preceding claims, characterized in that the brush roller ( 23 ) is rotatably mounted in the releasable holder ( 24 ).