Abstract: An adjustable optical arrangement includes an optics mount, an optical element held at the optics mount, a holding structure having a ball joint for receiving the optics mount, a ball joint holding the optics mount at the holding structure, a first adjustment device configured to pivot the optics mount with respect to the holding structure about a first axis, and a second adjustment device configured to pivot the optics mount with respect to the holding structure about a second axis. The ball joint is disposed between the optical element and the first and the second adjustment device.

Abstract: A device for controlling substrate web tension includes first and second driving units with respective driving rollers around which the substrate web is partially guided and tensioned. The first and second driving units have different rotational moments of inertia. A measuring unit measures the tension of the substrate web. A control unit has first and a second filtering units with different filtering characteristics for filtering the measured value. The control unit includes a first control device for controlling the first driving unit based on the measured value filtered by the first filtering device, and a second control device for controlling the second driving unit based on the measured value filtered by the second filtering device.

Abstract: A method for detecting errors in individual color separation images of a multi-color printing machine, in particular an electrophotographic printing machine, comprising a plurality of printing units, is described. Using this method, first a plurality of first register lines is printed with a first printing unit, and a plurality of second register lines is printed with a second printing unit in such a manner that each of the first register lines, together with one of said second register lines, is positioned inside a respective registration frame. Then the plurality of the first and second register lines in the respective registration frame are detected with a register sensor, and an output signal of the register sensor relating to the respective second register line is compared with an intensity threshold value in order to determine whether the second register lines can be recognized.

Abstract: A method for calibrating a position of a first register line in a register mark for a multi-color printing machine, said first register line consisting of a first color that does not offer sufficient contrast with respect to a printing material to allow detection above a determined threshold on a register sensor. A plurality of register marks, each consisting of at least one starting line, a background line and a first register line, is printed, said background line consisting of a second color which offers sufficient contrast with respect to the first color for detection above the specified threshold on the register sensor if the first register line is printed on the background line, and said background line having a width that is greater than the first register line, and said starting line, said background line and said first register line being printed with the use of the pre-determined control parameters, which normally cause the first register line to be printed on the background line.

Abstract: A device for controlling substrate web tension includes first and second driving units with respective driving rollers around which the substrate web is partially guided and tensioned. The first and second driving units have different rotational moments of inertia. A measuring unit measures the tension of the substrate web. A control unit has first and a second filtering units with different filtering characteristics for filtering the measured value. The control unit includes a first control device for controlling the first driving unit based on the measured value filtered by the first filtering device, and a second control device for controlling the second driving unit based on the measured value filtered by the second filtering device.

Abstract: A method of preventing a registration error while printing at least one printing image, wherein, in order to control or adjust the correct length of the printing image, the start and/or the distance of the printing image lines of the printing image are controlled by determining the ratio of the number of rotary encoder signals of a transport web counted during a specific time interval to the number of rotary encoder signals of a cylinder of a printing and by taking into account a change of this ratio as a correction, said ratio being a function of a printing sheet located in a printing nip between the transport web and the printing unit, is characterized in that a changed printing material situation occurring in said printing nip between the transport web and the printing unit is used to achieve registration accuracy immediately.

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: A method for detecting errors in individual color separation images of a multi-color printing machine, in particular an electrophotographic printing machine, comprising a plurality of printing units, is described. Using this method, first a plurality of first register lines is printed with a first printing unit, and a plurality of second register lines is printed with a second printing unit in such a manner that each of the first register lines, together with one of said second register lines, is positioned inside a respective registration frame. Then the plurality of the first and second register lines in the respective registration frame are detected with a register sensor, and an output signal of the register sensor relating to the respective second register line is compared with an intensity threshold value in order to determine whether the second register lines can be recognized.

Abstract: Described is a method for calibrating a position of a first register line in a register mark for a multi-color printing machine, said first register line consisting of a first color that does not offer sufficient contrast with respect to a printing material in order to allow a detection above a determined threshold value on a register sensor.

Abstract: A method of preventing a registration error while printing at least one printing image, wherein, in order to control or adjust the correct length of the printing image, the start and/or the distance of the printing image lines of the printing image are controlled by determining the ratio of the number of rotary encoder signals of a transport web counted during a specific time interval to the number of rotary encoder signals of a cylinder of a printing and by taking into account a change of this ratio as a correction, said ratio being a function of a printing sheet located in a printing nip between the transport web and the printing unit, is characterized in that a changed printing material situation occurring in said printing nip between the transport web and the printing unit is used to achieve registration accuracy immediately.