Abstract: Sheet inverters and methods for inverting sheets are provided that guide longer length receivers through a 180 degree turn while the receivers are being transported along a transport path while reducing the possibility of jams, the extent of sheet stress experienced during inversion and reducing the risk of creating print artifacts.

Abstract: Sheet inverters and methods for inverting sheets are provided that guide longer length receivers through a 180 degree turn while the receivers are being transported along a transport path while reducing the possibility of jams, the extent of sheet stress experienced during inversion and reducing the risk of creating print artifacts.

Abstract: The invention relates to a method for the alignment of a sheet in a direction transverse (cross-track) to its transport direction in a sheet-printing machine, in particular in a digital printing machine, preferably in an electrographically operating printing machine. The object of the invention is to improve, in a simple manner, a method and a device of the aforementioned generic types in view of a first rough alignment of the individual sheet. Referring to the method, this object is achieved in accordance with the invention in that the individual sheet is flipped about a preferably non-physical, mathematical or imagined flipping axis extending in transport direction, and that this flipping produces a transverse offset of the sheet in transverse direction.

Abstract: A method for printing a multi-color image on a web that is moved in a transport direction along a plurality of printing units for respectively printing one color separation of the multi-color image. A line clock is determined for the printing unit being the first one in transport direction, as a function of the transport speed of the web, and a plurality of synchronization marks is printed with the web, said synchronization marks located in a region of the web that is outside the region of the multi-color image, and printed at a prespecified clock that is formed of a partial set of the line clock. The synchronization marks are detected at a position between the first and the second printing units, and a line clock for the second printing unit in the direction of movement is determined based on the detection of the synchronization marks.

Abstract: A method of printing an image onto a sheet in a printer having at least one print module and a transport arrangement defining a transport path for transporting sheets through the at least one print module is shown. In accordance with the method, a series of constant frame clock signals is generated and a sheet is approximately feed into a frame along the sheet transport path in accordance with the frame clock signal, wherein the frame defines a virtual desired sheet position, which moves with a predetermined speed along the sheet transport path. The sheet is transported along the sheet transport path, an in-track position of the sheet in the sheet transport path is detected and it is determined whether the in-track sheet position matches the frame within predetermined limits.

Abstract: The invention relates to a method for the alignment of a sheet in a direction transverse (cross-track) to its transport direction in a sheet-printing machine, in particular in a digital printing machine, preferably in an electrographically operating printing machine. The object of the invention is to improve, in a simple manner, a method and a device of the aforementioned generic types in view of a first rough alignment of the individual sheet. Referring to the method, this object is achieved in accordance with the invention in that the individual sheet is flipped about a preferably non-physical, mathematical or imagined flipping axis extending in transport direction, and that this flipping produces a transverse offset of the sheet in transverse direction.

Abstract: Color register and/or register errors are detected in a printing machine by using triangles serving as register marks. A first triangle is printed onto a sheet near the leading edge and a second triangle is printed onto a sheet near its trailing edge. The first triangle and the second triangle are detected by a sensor and a displacement of the sheet at right angles to the travel direction of the sheet and/or an angular displacement of the sheet is/are determined.

Abstract: Color register and/or register errors are detected in a printing machine by using triangles serving as register marks. A first triangle is printed onto a sheet near the leading edge and a second triangle is printed onto a sheet near its trailing edge. The first triangle and the second triangle are detected by a sensor and a displacement of the sheet at right angles to the travel direction of the sheet and/or an angular displacement of the sheet is/are determined.

Abstract: A tunnel construction made of tubbings forming a lining or casing for a tunnel includes a plurality of contact points between adjacent tubbings. These contact points comprise adhesive material acting to connect adjacent tubbings to each other at predetermined points. The contact points are distributed around the circumference of the tubbing rings at predetermined locations which depend on the type of the tubbing used and also on the points of pressure application by the driving shield of a tunneling or heading machine. The present tubbings have recesses in their surface facing into the tunnel whereby the recesses have a substantially trapezoidal shape to form three ribs extending substantially in the direction of the longitudinal tunnel axes.