Control of powder zones in a printer

Abstract

The invention relates to a device for the regional application of powder in a powder device (6) in a delivery of a sheet-fed printing press, wherein the device has a plurality of powder zones (2) which extend over the width of the printed sheet and has a control computer (7) which has a plurality of data zones (1) for the control of the powder metering, which can be selected and controlled by the operator on a display device (8). The invention is characterized in that the width of one powder zone (2, 4) corresponds to an integer multiple of the width of one or more data zones (1).

Description

Technical Field

[0001] The present invention relates to an apparatus for regionally applying powder in a powder device in a paper receiver of a sheet printing press, and to a paper receiver and the sheet printing press itself for a sheet printing press. Background Technology

[0002] Existing technology discloses a method and apparatus for applying powder to sheets in a printing press, which has multiple powder zones distributed across the width of the sheet-shaped printing material. DE 10 2019 214 114 A1 discloses a method and apparatus for applying powder to sheets in a printing press. Here, for applying powder to sheets in a printing press, there exists an apparatus having a first nozzle row by means of which powder is applied uniformly across the width of the sheet-shaped printing material. Furthermore, the apparatus has a second nozzle row that can simultaneously and similarly apply powder regionally across the entire width of the sheet shape. Here, referring to area units, more powder is applied using the second nozzle row than using the first nozzle row. Here, to control the second nozzle row, printing image data from the prepress stage can be used. The nozzles of the second nozzle row can be partially deactivated. In this way and method, nozzles outside the sheet dimensions being printed can be shut off in particular, so that the dimensions can be adjusted to their respective printing dimensions. This method can avoid powder waste and machine contamination. Summary of the Invention

[0003] The objective of this invention is to provide an apparatus for regionally applying powder in a powder device in the delivery unit of a sheet printing press, which further improves powder metering and allows for further reduction of excess powder.

[0004] According to the invention, the task is solved by a device for regionally applying powder in a powdering apparatus in the delivery unit of a sheet-fed printing press, a delivery unit for a sheet-fed printing press, and a sheet-fed rotary printing press, according to a preferred embodiment of the invention. Advantageous configurations of the invention are derived from alternative embodiments, the description, and the drawings.

[0005] The apparatus of the present invention can be used particularly in all offset rotary sheet printing presses, depending on the printing process, by having a powdering device in the take-up unit to prevent the printed sheets from sticking together and thus to prevent damage to the printed sheets in the take-up unit of the sheet offset rotary printing press. Of course, the apparatus can also be used in all other sheet printing presses with powdering devices, such as in the take-up unit of large-format inkjet printers. Here, for regional application of powder, the apparatus has a powdering device in the take-up unit of the sheet printing press capable of regionally distributing the powder to the corresponding metering device. For this purpose, the apparatus has multiple powder zones that have defined areas when viewed across the width of the printing material. Therefore, the distribution across the width of the printing material results in the sheet-shaped printing material being typically conveyed in the printing press such that the long side is in the sheet transport direction. Of course, the apparatus can also be used in printing presses that transport sheets longitudinally, so that the narrow side is conveyed along the sheet transport direction. However, generally speaking, the powdering zone extends across the width of the printed sheet because it is conveyed forward with the wider side. In addition, a control computer exists, which has multiple data zones for controlling powder metering. This control computer can be part of the printing press computer, but it can also be a separate computer, part of the powder metering device, or part of other peripheral equipment. The multiple data zones for controlling powder metering are displayed on a display device, such as a screen with a touchscreen, allowing the printing press operator to selectively select and control the metering in individual powder zones. Here, individual powder zones can be turned on and off, and metering can be set individually in each powder zone, or multiple powder zones can be selected, each assigned the same metering. Typically, there are fewer powder zones than data zones because a large number of powder zones leads to high structural costs in powder supply and thus very expensive powder equipment. In practice, this results in far fewer powder zones than data zones. However, a large number of data zones is necessary to achieve the most efficient powder distribution possible across the entire width of the printing material, and this powder distribution can be individually adapted to the image content in the respective data zones. Therefore, the high color intensity in the data zones requires a correspondingly higher powder metering to prevent sticking on that part of the printing material due to high ink application. According to the present invention, the width of a powder area is set to be an integer multiple of the width of one or more data areas. By setting this integer multiple, overlapping areas between the data areas and the powder area are avoided. In practice, it has been found that overlapping areas are detrimental to powder consumption because higher powder contamination occurs there. By setting this integer multiple of one or more data areas, it is possible to avoid undesirable overlap and further reduce powder consumption. Here, it is possible for a powder area to be an integer multiple of one or more data areas, but it is also possible for the width of a powder area to be an integer multiple of the width of exactly one data area. Decisively, in both cases, overlapping areas are avoided through integer multiples.

[0006] In the first configuration of the invention, the data zones are configured in number and width to correspond to the ink zones in the ink mechanism of the printing unit of a sheet-fed offset rotary printing press. A typical 102-size sheet-fed offset rotary printing press has 32 ink zones, which are necessary for sufficiently fine and adaptive adjustment of ink metering across the entire width of the substrate according to the printed image. Because the printed image is divided into these ink zones, the press operator also desires to have powder values ​​in the same number and width of the data zones. Therefore, it is highly advantageous that the data zones are consistent in number and width with the ink zones in the ink mechanism of the printing unit, i.e., 32 data zones in this case. In this case, a meaningful number of powder zones is 8 or 16, provided that the widths of the data zones and powder zones are the same. Modern powder equipment has up to 36 powder nozzles, and it is meaningful to also provide 36 data zones in this case. However, it is not necessary to set up 36 powder zones. For example, setting up 18 powder zones is sufficient. In this case, there are always two powder nozzles for each powder zone, so there are always two powder nozzles supplying powder through a common channel.

[0007] In another configuration of the invention, a separate powder value can be input for each data zone via a display device, and the control computer calculates a setpoint for the corresponding powder zone from the input powder value and uses this setpoint to drive the corresponding powder zone. The printing press operator would prefer to be able to adjust the powder value individually for each data zone. However, since there are fewer powder zones than data zones, the control computer of the powder unit must calculate the setpoint for that powder zone from the setpoint of the data zone assigned to it, because each powder zone can only have one setpoint. For this purpose, the control computer could, for example, use the average of the individual powder values ​​for the data zones, but it is also possible to weigh the data zones and thus calculate different powder values ​​for a single powder zone.

[0008] Furthermore, it is advantageous to arrange the width of the powder zone extending across the width of the sheet-shaped printing material to be different. Therefore, it is possible to set wider or narrower powder zones in specific areas of the printing material to allow for more precise measurement of the critical (or key) areas. In particular, the width of the powder zone can be made smaller in the side edge areas of the printing material than in the central area. For example, it is possible to combine three data zones into one powder zone in the edge areas, and three or five data zones into one powder zone in the central area. Because the edge areas are more critical or key when powder is applied, powder issues in the side edge areas can be addressed more specifically or individually.

[0009] Furthermore, advantageously, the data areas are configured to correspond in number and width to each individual powder nozzle. In this case, the data areas are optimally adapted to the width and number of powder nozzles. Attached Figure Description

[0010] The present invention will now be described and explained in detail with reference to the accompanying drawings. In the drawings:

[0011] Figure 1 This illustrates the arrangement of the powder and data areas across the width of the substrate in a sheet-fed printing press. Detailed Implementation

[0012] In sheet-fed printing presses, viewed in the sheet transport direction, the right side is generally referred to as the drive side AS and the left side as the operating side BS. The operating side BS is accessible to the press operator, while the drive motors for peripheral equipment and the printing mechanism are located on the drive side AS. In the accompanying drawings, the number of data zones 1 is shown in the first row, extending across the entire width of the substrate or the printing press. Accordingly, the powder equipment in the press's delivery unit has a control computer 7, into which the press operator can input a set value for metering powder for each data zone 1. The number of data zones 1 here corresponds to the number of ink zones in the ink mechanism of the printing mechanism; that is, 32 ink zones are set in specification 102, and thus 32 data zones 1 are also set.

[0013] The control computer 7 can be part of the control computer of the printing press, or it can be a separate control computer for the powder equipment 6. In any case, the control computer 7 is connected to a display device 8, which is implemented as a touchscreen, allowing not only the display but also the input of powder metering values. The operator can input individual powder values ​​for each data zone 1 via the screen 8. Furthermore, it is possible that the control computer 7 can automatically calculate matching powder values ​​for each data zone 1 based on the printed image and associated data from the prepress stage, thus requiring only the operator to acknowledge receipt of the calculated data.

[0014] The second row of the accompanying diagram shows the arrangement of powder zone 2, as is common in the prior art. Here it can be seen that the width of powder zone 2 is not an integer multiple of the width of data zone 1. This results in a so-called overlapping region 5, in which powder metering via powder zone 2 cannot be well adapted to the overlapping data zone 1. This leads to unnecessarily high powder consumption.

[0015] The third line shows the powder zones 3 of a technically ideal powder apparatus 6, which correspond precisely to the data zones 1 in both number and width. However, this results in a very high number of powder zones, making the powder apparatus 6 very expensive. Therefore, such a large number of powder zones 3 is economically unreasonable.

[0016] The solution of the invention is shown in the fourth line, where the powder area 4 is always an integer multiple of the data area 1. For example, three or four data areas 1 can be configured for a powder area 4. Here, the width of the powder area 4 does not need to be the same across the entire width of the substrate or printing press; it is possible that fewer data areas 1 are configured for the edge regions of the powder area 4 than for the central regions. The decisive factor is that there is no overlap 5, thus ensuring that an integer multiple of a data area 1 is always configured for a powder area 4, where such integer multiple must be at least 1. This avoids the need for fractional data areas 1 configured for the powder area 4, thereby eliminating the disadvantageous overlapping regions 5. Consequently, it is possible to effectively drive the powder area 4 based on the data areas 1 without having to set up an uneconomical, large number of powder areas 3.

[0017] List of reference numerals in the attached diagram:

[0018] 1 Data Area

[0019] 2 Powder Zone

[0020] 3. A large number of powder zones

[0021] 4. Distribution of powder regions according to the present invention

[0022] 5. Overlapping areas

[0023] 6. Powder Equipment

[0024] 7. Control the computer

[0025] 8 screens

[0026] AS drive side

[0027] BS operating side.

Claims

1. An apparatus for regionally applying powder in a powdering device (6) in the paper receiver of a sheet printing press, wherein the apparatus has a plurality of powder zones (2) extending over the width of the printed sheet, and includes a control computer (7) having a plurality of data zones (1) for controlling powder metering, the data zones being selectable and controlled by an operator on a display device (8), characterized in that, The width of a powder area (2, 4) corresponds to an integer multiple of the width of one or more data areas (1); the widths of the powder areas (2, 4) extending across the width of the sheet-shaped printing material are different; and the width of the powder areas (2, 4) is smaller in the side edge areas of the printing material than in the central area of ​​the printing material.

2. The apparatus according to claim 1, characterized in that, The width of a powder region (2, 4) corresponds to an integer multiple of exactly one data region (1).

3. The apparatus according to claim 1 or 2, characterized in that, The data area (1) corresponds in number and width to the ink area in the ink mechanism of the printing mechanism of a sheet offset rotary printing press.

4. The apparatus according to claim 1 or 2, characterized in that, For each data zone (1), a separate powder value can be input by means of the display device (8), and the control computer (7) calculates the set value for the corresponding powder zone (2, 4) from the input powder value and uses the set value to drive the corresponding powder zone (2, 4).

5. The apparatus according to claim 1 or 2, characterized in that, There are 32 or 36 data areas (1).

6. The apparatus according to claim 1 or 2, characterized in that, The data area (1) corresponds to each individual powder nozzle in terms of both number and width.

7. A paper receiver for a sheet printing press, comprising the means according to any one of claims 1 to 6.

8. A sheet-fed rotary printing press having the apparatus according to any one of claims 1 to 6.

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