Patent Application
20060011079
This application claims the priority of German Patent Document No. 10 2004 034 049.8, filed Jul. 13, 2004, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a form cylinder of a web-fed rotary press.
Web-fed printing presses, in particular newspaper presses, have a plurality of printing units, each printing unit having, inter alia, at least one form cylinder and at least one transfer cylinder. Printing plates are fastened on the form cylinders and rubber blankets are fastened on the transfer cylinders, for which reason the form cylinders are also referred to as printing plate cylinders and the transfer cylinders are also referred to as blanket cylinders. A transfer cylinder interacts with every form cylinder in such a way that, during printing, a form cylinder rolls on the respective transfer cylinder. Accordingly, there is rolling contact during printing between the form cylinders and the transfer cylinders. During printing or while the form cylinders are rolling on the respective transfer cylinders, cylinder oscillations can form which impair the printing quality. Accordingly, cylinder oscillations have to be minimized in order to ensure satisfactory printing quality.
Proceeding from this, the present invention is based on the problem of providing a novel, oscillation-minimizing form cylinder of a web-fed rotary press.
According to the invention, a clamping channel of the form cylinder has an effective clamping-channel width of at most 7 millimeters (mm), as seen in the circumferential direction. Cylinder oscillations which occur during printing can be reduced considerably by adapting the clamping-channel width to less than 7 mm.
As seen in the circumferential direction, the clamping channel of the form cylinder has an effective clamping-channel width of from 3 mm to 7 mm. In the context of the invention, the following ranges are preferred for the effective clamping-channel width between 3 mm and 7 mm: from 3 mm to 6 mm; from 3 mm to 5 mm; from 3 mm to 4 mm; from 4 mm to 7 mm; from 4 mm to 6 mm; from 4 mm to 5 mm; from 5 mm to 7 mm; from 5 mm to 6 mm; and from 6 mm to 7 mm.
Preferred developments of the invention result from the following description. Without being restricted thereto, exemplary embodiments of the invention will be explained in greater detail using the drawings, in which:
In the following text, the present invention will be described in greater detail with reference to FIGS. 1 to 4.
In the exemplary embodiment of
In the exemplary embodiment from
In the context of the present invention, it is proposed that the clamping channel 15 be configured in such a way that, in the circumferential direction of the form cylinder 10, the clamping channel 15 has an effective channel width of at most 7 mm or of less than 7 mm. In the event of effective clamping-channel widths of less than 7 mm, no impermissibly high cylinder oscillations occur any more during printing and therefore during the rolling contact between the form cylinder and a corresponding transfer cylinder or blanket cylinder, as a result of which the printing quality can be improved considerably.
In the context of the present invention, the effective clamping-channel width preferably lies between 3 mm and 7 mm, in particular in the following ranges:
From the range of from 3 mm to 7 mm, a very wide variety of partial ranges are accordingly conceivable for the effective clamping-channel width.
As has already been mentioned, the form cylinder 10 in the exemplary embodiment from
According to a first alternative, the form cylinder 10 or the clamping channel 15 has such an axial length that two printing plates can be positioned next to one another in the axial direction. According to a second alternative, the form cylinder 10 or the clamping channel 15 has such an axial length that three printing plates can be positioned next to one another in the axial direction. According to a third alternative, the form cylinder 10 or the clamping channel 15 has such an axial length that four or else six printing plates can be positioned next to one another in the axial direction. Furthermore, it is also conceivable that five or seven or eight printing plates can be positioned on the form cylinder 10 next to one another in the axial direction.
As, in the exemplary embodiment from
Here, the printing plates can have one or more vertical printing pages in the circumferential direction and/or axial direction and/or one or more horizontal printing pages in the circumferential direction and/or axial direction. A printing plate can have, for example, two vertical printing pages one behind another in the circumferential direction. Furthermore, a printing plate can also have, for example, four horizontal printing pages next to one another in the axial direction. It is also possible that a printing plate has a combination of vertical and horizontal pages which are positioned both next to one another in the axial direction and behind one another in the circumferential direction.
In contrast to the exemplary embodiment from
Furthermore, it is conceivable that the form cylinder has a plurality of clamping channels which extend along the form cylinder in the axial direction only in sections. In this case, according to a first alternative, there can be in each case only one clamping channel at every axial position of the form cylinder as seen in the circumferential direction, at least one clamping channel then being offset in the circumferential direction compared with the other clamping channels. According to a second alternative, there can be two clamping channels at each axial position of the form cylinder as seen in the circumferential direction, at least two clamping channels of the form cylinder which extend at the same axial position then being offset in the circumferential direction compared with the other clamping channels of the form cylinder. According to a further alternative, there can be a group of at least two, preferably two or four, clamping channels at each axial position of the form cylinder as seen in the circumferential direction, at least one group of clamping channels which extend at the same axial position being offset in the circumferential direction compared with the other clamping channels of the other groups. Cylinder oscillations can be minimized once again by the configuration of the clamping channels on the form cylinders which are offset in the circumferential direction. In every case, however, the effective clamping-channel width of all the clamping channels is at most 7 mm, the effective clamping-channel width lying between 3 mm and 7 mm, preferably between 4 mm and 5 mm, or alternatively between 6 mm and 7 mm.
With reference to FIGS. 1 to 3, the term “effective clamping-channel width” has been used multiple times, which term is to be defined in the following text with reference to
According to the basic idea of the present invention, the clamping-channel width on form cylinders is limited to an effective clamping-channel width of at most 7 mm, in order to minimize cylinder oscillations which impair the printing quality. This is true both when the form cylinder has only one clamping channel or also has a plurality of clamping channels. If the form cylinder has a plurality of clamping channels which do not extend over the whole axial length of the form cylinder but rather extend along the form cylinder only in sections, the clamping channels can be additionally offset with respect to one another in the circumferential direction, as a result of which cylinder oscillations during printing can be minimized further.
The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 034 049.8 | Jul 2004 | DE | national |
