Dusting apparatus

Abstract

The invention relates to a device for powdering (11) a sheet (1) in a printing press, said device having a nozzle (5) which is movable relative to a suction device (17), said nozzle (5) being fixed on a powder bar (4) and the nozzle opening (10) of said nozzle (5) being movable relative to said powder bar (4) in the direction of transport (T) of the sheet (1) and against the direction of transport (T) of the sheet (1).

Description

Technical Field

[0001] This invention relates to an apparatus for sprinkling powder onto sheets in a printing press. Background Technology

[0002] DE 196 43 987 C1 describes a powder-spreading device having a row of nozzles extending across the width of the printing substrate, the nozzles being configured as perforations or slits. The powder-spreading device is arranged linearly movable relative to a suction device.

[0003] Its disadvantage is that the entire powder-spreading equipment must be in motion. Due to the large inertia of the powder-spreading equipment, its dynamic performance will be adversely affected. Summary of the Invention

[0004] The objective of this invention is to provide a powder-spreading device that operates with high dynamics.

[0005] This task is accomplished by a device for applying powder to sheets in a printing press, the device having nozzles movable relative to a suction device, characterized in that these nozzles are fixed to a powder bar, and the nozzle orifices are movable relative to the powder bar in both the direction of sheet transport.

[0006] The advantage of the device according to the invention is that only a portion of the device must move, and because the moving portion has low inertia, this movement can be performed at a high frequency in a sheet transport cycle. The relatively heavy powder bar does not need to move and can be arranged stationary. Therefore, the device according to the invention is most suitable for printing presses operating at high printing speeds.

[0007] An additional advantage is that, because the moving part has low inertia, it avoids strong vibrations that could otherwise be transmitted to other components and cause complications. Since the device vibrates less during operation, it is also relatively quiet, which is beneficial for noise protection. Attached Figure Description

[0008] Advantageous extensions will be derived from the following description of embodiments and accompanying drawings, which illustrate:

[0009] Figures 1 to 4 In the first embodiment, the nozzle is composed of a flexible hose, and

[0010] Figure 5 and 6 In the second embodiment, the nozzle is composed of pipes that are hingedly connected to each other. Detailed Implementation

[0011] Figure 1 As shown, the printed sheets 1 in the printing press are firmly held on the front edge by the clamping bridge 2 and dragged in the conveying direction T to the take-up stack. These sheets 1 travel past the powdering device 3, where the powdering device 3 sprinkles powder onto these sheets 1.

[0012] Figure 2 The powder-spreading device 3 is shown separately in the side view. The powder-spreading device 3 includes a powder rod 4, which, according to… Figure 1 The powder rod 4 is not shown in the top view. It is equipped with nozzles 5 for spraying powder 11, these nozzles 5 arranged in an arrangement extending transversely to the conveying direction T. The powder rod 4 is a hollow profile and houses a piping system through which the nozzles 5 are supplied with a mixture of powder and pressurized air. This piping system is not shown in the accompanying drawings. For the reasons explained, the powder rod 4 is relatively heavy. The powder rod 4 is stationary between and fixedly connected to the side walls 6 and 7 of the printing press, for example, by screwing them on.

[0013] The guide rod 8 runs parallel to the powder rod 4 and engages with the free end of the nozzle 5 (i.e., the end not connected to the powder rod 4). These nozzles 5 are constructed as hollow conduits, specifically as flexible, bendable hoses 9. Each nozzle 5 has an orifice 10 at its free end from which powder 11 is ejected. The guide rod 8 has an array of orifices 12 arranged at the same intervals as the nozzles 5. The nozzles 5 are inserted into the orifices 12 and thus guided by the guide rod 8. The guide rod 8 is movably supported in the linear guide sections 13 and 14 in a direction parallel to the conveying direction T and performs a reciprocating motion B in that direction. Figure 1 In the diagram, the guide rod 8 is shown as a solid line in one phase of motion and as a dashed line in another phase of motion.

[0014] A servo drive 15 is engaged with the guide rod 8 to drive the motion B of the guide rod 8. The servo drive 15 may be a pneumatic cylinder or an electric linear drive. The motion B is transmitted from the guide rod 8 to the nozzles 5 through a plug-in connection between the nozzles 5 and the guide rod 8, thereby causing the nozzles 5 to oscillate together in a conveying rhythm of page 1.

[0015] Figure 3The figure shows the movement B at its front end position in the conveying direction T, where the flexible hoses 9 are bent to the left, as shown in the figure. In this front end position, the nozzle 5 sprays powder 11 onto the area of ​​the sheet 1 near the clamp bridge 2.

[0016] Figure 2 The diagram shows the intermediate position of the movement B, where the nozzle 5 is not swung out from the vertical direction, and the hose 9 is therefore not bent. In this intermediate position, the nozzle 5 applies powder to the middle area of ​​the sheet and the rear area of ​​the sheet 1 in the conveying direction T.

[0017] Figure 4 An operating state is shown in which, instead of the powder-spreading device 3, the gap 16 between successive sheets 1 is positioned opposite to the powder-spreading device 3. In this operating state, the nozzles 5 are swung out at an angle +α against the conveying direction T. The nozzles 5 are in the rear end position of the movement B, and the flexible hose 9 is bent to the right with reference to the accompanying drawings. Here, the nozzle orifice 10 of the nozzle 5 faces the suction device 17, which is connected to a negative pressure generator. This negative pressure generator permanently generates [something] on the attached [something]. Figure 2 , 3 The suction airflow 18 is indicated by the arrow in section 4. The suction device 17 captures the powder airflow ejected from the nozzle 5, which is then deflected into the suction device 17. In this way, the powder airflow cannot pass through the gap 16 and will not contaminate the surrounding environment of the powder spreading device 3.

[0018] Since the motion B can be performed at a high frequency, there is no need to activate and deactivate the nozzle 5 at the conveying cycle of page 1, thereby reducing technical costs.

[0019] Alternatively, an operating mode can be set in which the front end position of nozzle 5 is disabled. Figure 3 ), and these nozzles 5 are only in the middle position ( Figure 2 ) and the location of the rear terminal ( Figure 4 It swings back and forth between ) .

[0020] Figure 5 and Figure 6 An embodiment is shown, which is consistent with the embodiment according to Figures 1 to 4 The difference in this embodiment lies only in that each nozzle 5 is composed of two tubular components 19 and 20 connected to each other by a hinge 21, instead of the aforementioned flexible hose 9. Powder 11 flows from the upper tubular component 19, which is fixed to the powder rod 4, through the hinge 21 into the lower tubular component 20, which has the nozzle 10. Because... Figure 5 and Figure 6The powder rod 4 and the nozzle 5 are shown as a single unit, so the tube 20 with the nozzle 10 inserted into the orifice 12 of the guide rod 8 is not visible. The guide rod 8 engages with the lower tube 20 so that the lower tube 20 swings relative to the upper tube 19 about the hinge 21. Thus, the lower tube 19 of the nozzle 5 also performs the movement B.

[0021] Figure 5 The text shows the relationship with... Figure 2 The corresponding, extended, straight nozzle orientation, and Figure 6 The text shows the relationship with... Figure 4 The corresponding bend nozzle orientation. (Not shown in the attached diagram.) Figure 3 The orientation of the nozzle 5, which is assembled from two pipe fittings 19 and 20 respectively.

[0022] Both of the above embodiments have advantages: the guide rod 8 is much lighter than the powder rod 4 and therefore has less inertia. The guide rod 8 can be, for example, an aluminum strip or a plastic strip.

[0023] List of reference numerals

[0024] 1 page

[0025] 2. Clamping bridge

[0026] 3. Powder Spreading Equipment

[0027] 4 Powder rod

[0028] 5 nozzles

[0029] 6. Sidewalls

[0030] 7. Sidewalls

[0031] 8 guide rods

[0032] 9. Flexible hose fittings

[0033] 10 nozzles

[0034] 11 Powder

[0035] 12-hole opening

[0036] 13 Linear Guide Section

[0037] 14 Linear Guide Section

[0038] 15 Servo Drivers

[0039] 16 gaps

[0040] 17. Suction device

[0041] 18. Suction airflow

[0042] 19 Pipe fittings

[0043] 20 Pipe Fittings

[0044] 21. Hinge

[0045] α angle

[0046] B Sports

[0047] T conveying direction

Claims

1. An apparatus for sprinkling powder (11) onto a sheet (1) in a printing press, said apparatus having a nozzle (5) movable relative to a suction device (17), Its features are, The nozzle (5) is fixed to the powder rod (4), and The nozzle (5) ejects powder (11) through a nozzle (10) that can reciprocate relative to the powder rod (4) in the direction (T) of the sheet (1) conveying process, both in the direction and against the direction (T) of the sheet (1) conveying process, at the conveying rhythm of the sheet (1).

2. The device according to claim 1, Its features are, A guide rod (8) is attached to the nozzle (5), and the guide rod extends parallel to the powder rod (4).

3. The device according to claim 2, Its features are, The guide rod (8) has an arrangement of orifices (12) in which the nozzle (5) is guided.

4. The device according to claim 2 or 3, Its features are, A servo driver (15) is provided to drive the reciprocating motion (B) of the guide rod (8).

5. The device according to any one of claims 1 to 3, Its features are, The nozzles (5) are each configured as flexible hoses (9).

6. The device according to any one of claims 1 to 3, Its features are, The nozzles (5) are assembled from the pipe fittings (20).

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