Page printing machine

Abstract

The invention relates to a sheet printing machine, comprising a plate (2) having suction openings (8a, 8b) and associated valves (9), each having a suction duct (10) and a valve body (12), which can be contactlessly switched into a release position (12a) for opening the suction duct (10) and into a closing position (12b) for closing the suction duct (10). A neutral turning position (12c) of the valve body (12) is located between the release position (12a) and the closed position (12b). The plate (2) may be, for example, a so-called tray for conveying pages in an inkjet printer.

Description

Technical Field

[0001] The invention relates to a sheet-fed printing press comprising a plate with a suction opening and associated valves, each of which has a suction channel and a valve body which can be switched contactlessly into a release position for opening the suction channel and into a closed position for closing the suction channel. Background Art

[0002] Printing presses in which the sheets are transported on plates known as trays form the background for the invention.

[0003] DE102016201240A1 shows such a printing press. Here, the valve body is designed as a switching piston.

[0004] DE 10002134 A1 describes a valve for a suction opening, the valve body of which is designed as a diaphragm.

[0005] DE4335051A1 forms further prior art. It describes a tilt lever with a valve. Summary of the invention

[0006] It is an object of the present invention to provide a further sheet-fed printing press.

[0007] According to a first variant, the task is solved by a sheet printing machine, which includes a plate with a suction port and a related valve, which respectively have an air intake duct and a valve body, and the valve body can be switched contactlessly to a release position for opening the air intake duct and a closed position for closing the air intake duct, characterized in that a neutral flip position of the valve body is located between the release position and the closed position; a spring is assigned to the valve body; and the tension of the spring is greater when the valve body is in the neutral flip position than when the valve body is in the release position or the closed position.

[0008] In a development of this first variant of the invention, the valve body is arranged as a slide in a chamber and the chamber has a constriction.

[0009] In a further development, the spring is arranged in the chamber and forms the constriction.

[0010] In a further development, the valve body can be adjusted magnetically.

[0011] In a further development of the first variant, the valve body is a component of a mechanical tilt closure.

[0012] According to a second variant, the task can be solved by a sheet printing machine, which includes a plate with a suction port and an associated valve, which respectively have an intake duct and a valve body, and the valve body can be switched contactlessly to a release position for opening the intake duct and a closed position for closing the intake duct, characterized in that the neutral flip position of the valve body is located between the release position and the closed position; the valve body is elastically constructed; the valve body is elastically deformed in the neutral flip position; and the valve body is a component of a bistable flip closing mechanism, wherein the valve body is a small recess, and the small recess is inverted or turned upside down (umstülpen) when the valve is switched.

[0013] In a further development, the depressions of the valves are formed on a common diaphragm.

[0014] In a further development, the valve body can be adjusted pneumatically.

[0015] The advantage of both variants of the invention is that each plate has a valve with high functional reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Two variant developments emerge from the following description and the accompanying drawings, in which:

[0017] Figure 1 A printing press with a tray is shown;

[0018] Figure 2 Show Figure 1 A first embodiment of a middle tray;

[0019] Figure 3 Show Figure 1 A second embodiment of the middle tray;

[0020] Figure 4 Details of the components of the second embodiment are shown. DETAILED DESCRIPTION

[0021] Figure 1 A printing press with an inkjet print head 1 is shown schematically. During printing, the sheets are transported on plates 2, so-called pallets, which together form an endless chain 4 that rotates in direction 3. As the sheets are transported in direction 5, they are held on the plates 2 by suction air. The vacuum required for this is transferred to the plates 2 via suction boxes 6. For this purpose, the sheets 2 are moved on the straight section of the rotating track of the chain 4 to the side of the suction box 6 that is open to the chain 4.

[0022] Figure 2 and Figure 3: It is shown that the sheet 7 on the plate 2 covers the suction opening 8a, and another suction opening 8b is located outside the specifications of the sheet 7. The suction opening 8a is activated and sucks the sheet 7. The suction opening 8b is not activated and does not suck. In addition to the two suction openings 8a and 8b shown in the figure, the plate 2 can also have more suction openings of this type, which are arranged in several rows and form a regular pattern. Each suction opening 8a and 8b is equipped with a valve 9, which can open and close the suction channel 10 leading to the suction opening 8a or 8b. A section of the suction channel 10 forms a chamber 11, in which a valve body 12 is arranged.

[0023] Figure 2 A first embodiment is shown in which the valve body 12 of the corresponding valve 9 is movable in the chamber 11. In this first embodiment, the chamber 11 is a hollow cylindrical blind hole and the valve body 12 is a slide. The switching device 13 ( Figure 1 ) comprises one or more electromagnets 14, and when the plate 2 passes through the switching device 113, the magnetic force of the electromagnet can selectively shift the valve body 12 to the release position 12a and the closed position 12b. By correspondingly switching the polarity of the electromagnet 14, the electromagnet can be adjusted to whether it attracts the valve body 12 to open the valve 9 or repels the valve body 12 to close the valve 9. For this purpose, the valve body 12 of the corresponding valve 9 is designed as a permanent magnet or is equipped with a permanent magnet.

[0024] A spring 15 is arranged in the chamber 11, which can hold the valve body 12 not only in the release position 12a, but also in the closed position 12b. The spring 15 is a leaf spring and has two legs and an angled portion between the two legs, which forms a constriction 16 of the chamber 11. When the valve body 12 moves from one of its two switching positions (release position 12a, closed position 12b) to the constriction 16, the tension of the spring 15 increases. After passing through the constriction 16, the valve body 12 snaps into another switching position of the valve 9 to be set. Therefore, the closing mechanism of the corresponding valve 9 composed of the valve body 12 and the spring 15 is a mechanical flip mechanism with a bistable valve body 12. The valve body 12 is pressed into the release position 12a or the closed position 12b by the spring 15, depending on which leg of the spring 15 the valve body 12 rests on. The release position 12a and the closed position 12b are stable positions of the valve body 12.

[0025] If the valve body 12 is located in the center of the chamber 12 during its movement and thus in the region of the constriction 16, the valve body 12 is in an unstable intermediate position, which is referred to as the neutral tilt position 12c and is Figure 2In the middle, the spring 15 is in the state of maximum tension and the bent portion of the spring 15 is pressed against the valve body 12. If the force of the switching device 13 does not act on the valve body 12, the valve body 12 can jump ("flip") to any of the two switching positions (release position 12a, closed position 12b). Only the magnetic force of the switching device 13 can predetermine which switching position the valve body 12 moves from the neutral flip position 12c to.

[0026] The following modifications of the first embodiment are possible:

[0027] A longitudinal groove can be introduced in the side wall of the chamber 11, in which the spring 15 is located and fixed to prevent sliding. The spring 15 can be combined with a leaf spring of the same structure (such as Figure 2 The contraction 16 may be formed by a plurality of leaf springs of the same structure evenly distributed along the circumference of the chamber 11 (as shown), or may also be formed together with a plurality of leaf springs of the same structure uniformly distributed along the circumference of the chamber 11. The spring may be arranged outside the chamber (for example as a coil spring) and loaded with a pressure piece (for example a ball) protruding into the chamber 11 and forming the contraction 16. The spring 15 may also be designed as a bushing made of a rubber elastic material, which is in the shape of a hollow double cone (hourglass, hollow hyperbola), wherein the valve body 12 is movably arranged inside the bushing. Instead of a magnetic method, the switching device 13 may move the valve body 12 pneumatically (blowing or suction duct). For this purpose, each valve 9 may also be additionally provided with a control air duct as in the second embodiment. It is also possible that the valve body 12 can be moved to a switching position magnetically and to another switching position pneumatically.

[0028] Figure 3 A second embodiment is shown, in which the valve body 12 is configured as a small recess or cup. These small dimples are formed on an elastic membrane 17, which is arranged between the two layers 2.1 and 2.2 of the plate 2. The chamber 11 has the shape of a hollow ball or lens (or lentil). In addition to the air intake duct 10, there is also a control air duct 18 leading to the chamber 11. The control air duct 18 leads to the chamber 11 on the side of the membrane 17 opposite to the air intake duct 10. The membrane 17 divides the chamber 11 of the corresponding valve 9 into a half introduced into the layer 2.1 and a half introduced into the layer 2.2, and completely separates the two halves. The small dimples forming the valve body 12 of the corresponding valve 9 can be inverted pneumatically in order to move the valve body 12 from the release position 12a to the closed position 12b and then back. For pneumatic regulation, interfaces A, B, C for applying air to the chamber 11 are used. Interfaces A and C are the mouth of the air intake duct 10 and are located on opposite sides of the plate 2. The interface C is the same as the suction port 8 a or 8 b , and the interface B is the mouth of the control airway 18 and is located on the same side of the plate 2 as the interface A.

[0029] The valve body 12 can be adjusted from the release position 12a to the closed position 12b by applying an overpressure (blowing) to the port B, or applying a negative pressure (vacuum) to the port A when the port C is closed, or applying a negative pressure to the port C when the port A is closed, or applying a negative pressure to the ports A and C at the same time. The valve body 12 can be adjusted from the closed position 12b to the release position 12a by applying a negative pressure to the port B, or applying an overpressure to the port A when the port C is closed, or applying an overpressure to the port C when the port A is closed, or applying an overpressure to the two ports A and C at the same time. When the ports A, B, and C pass through the switching device 13, the ports A, B, and / or C are pneumatically loaded in the switching device 13 to switch the corresponding valve 9.

[0030] In the release position 12a, the small pit is turned downward, that is, away from the suction opening 8, and the diaphragm 17 is against the half shell of the chamber 11 introduced into the layer 2.2, so that the two openings of the suction channel 10 into the chamber 11 are open. In the closed position 12b, the small pit is turned upward, that is, toward the suction opening 8, and the diaphragm 17 is against the half shell of the chamber 11 introduced into the layer 2.1, so that the two openings of the suction channel 10 into the chamber 11 are covered by the diaphragm 17. Due to the elastic properties of the diaphragm 17, the diaphragm 17 stably maintains its small pit shape in the release position 12a and the closed position 12b. During the inversion of the diaphragm 17 or its small pit from one switching position to another switching position, the diaphragm 17 passes through an unstable neutral flip position 12c. Starting from this neutral flip position 12c, if there is no vacuum or blast loading the diaphragm, the diaphragm 17 may jump or "flip" into any of the two stable switching positions due to its inherent elasticity. The switching direction is determined by the pneumatic loading direction of the diaphragm 17 or its corresponding small depression.

[0031] Figure 4 A partial view of a diaphragm 17 with a plurality of small recesses forming a valve body 12 is shown in a three-dimensional view. The small recesses are arranged in several rows and together form a regular pattern, specifically a square grid here. All the small recesses are turned up toward one side of the diaphragm 17. Next to each small recess, a hole 19 is introduced into the diaphragm 17. The corresponding hole 19 forms a section of the air intake duct 16. When the plate 2 is installed, the diaphragm 17 is arranged between the layers 2.1 and 2.2, wherein each small recess is precisely placed in another chamber 11. In this second embodiment, the valve body 12 (here the small recess) is also a component of a bistable flip sealing mechanism with a neutral flip position 12c.

[0032] List of reference numerals:

[0033] 1 Printing head

[0034] 2 boards

[0035] 2.1 Layer

[0036] 2.2 Layer

[0037] 3 Directions

[0038] 4 Chain

[0039] 5 Directions

[0040] 6 Suction box

[0041] 7 pages

[0042] 8a Suction port

[0043] 8b Suction port

[0044] 9 valves

[0045] 10 Inspiratory tract

[0046] 11 Chamber

[0047] 12 Valve body

[0048] 12a Release position

[0049] 12b Closed position

[0050] 12c Flip position

[0051] 13 Switching device

[0052] 14 Electromagnet

[0053] 15 Spring

[0054] 16 Contraction

[0055] 17 Diaphragm

[0056] 18 Control of the airway

[0057] 19 holes

[0058] A interface

[0059] B-Mount

[0060] C interface.

Claims

1. A sheet-fed printing press, comprising a plate (2) with suction openings (8a, 8b) and associated valves (9), each of which has a suction channel (10) and a valve body (12), which can be switched contactlessly into a release position (12a) for opening the suction channel (10) and a closed position (12b) for closing the suction channel (10), characterized in that: The neutral flip position (12c) of the valve body (12) is located between the release position (12a) and the closed position (12b); The valve body (12) is provided with a spring (15); and When the valve body (12) is in the neutral flip position (12c), the tension of the spring (15) is greater than when the valve body (12) is in the release position (12a) or the closing position (12b).

2. The sheet-fed printing press according to claim 1, characterized in that The valve body (12) is arranged as a slide in the chamber (11); and The chamber (11) has a constriction (16).

3. The sheet-fed printing press according to claim 2, characterized in that The spring (15) is arranged in the chamber (11) and forms the constriction (16).

4. The sheet-fed printing press according to claim 1, characterized in that The valve body (9) can be adjusted magnetically.

5. A sheet-fed printing press, comprising a plate (2) with suction openings (8a, 8b) and associated valves (9), each of which has a suction channel (10) and a valve body (12), which can be switched contactlessly into a release position (12a) for opening the suction channel (10) and a closed position (12b) for closing the suction channel (10), characterized in that The neutral flip position (12c) of the valve body (12) is located between the release position (12a) and the closed position (12b); The valve body (12) is elastically constructed; The valve body (12) is elastically deformed in the neutral flip position (12c); and The valve body (12) is a component of a bistable flip sealing mechanism, wherein the valve body (12) is a small recess which is inverted when the valve (9) is switched.

6. The sheet-fed printing press according to claim 5, characterized in that The depressions of the valves (9) are formed on a common membrane (17).

7. The sheet-fed printing press according to claim 5, characterized in that The valve body (12) can be adjusted pneumatically.

Images