Patent application number | Description | Published |
20090153889 | METHOD OF PREVENTING A REGISTRATION ERROR WHILE PRINTING - 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. | 06-18-2009 |
20110063634 | METHOD FOR CALIBRATING A MULTI-COLOR PRINTING MACHINE - 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. In this method, first 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 a detection above the specified threshold value on the register sensor if the first register line is printed on the background line, and said background line having a width that is by X mm 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, in the normal case, cause the first register line to be printed on the background line. Subsequently, it is detected whether the first register line has been recognized by the register sensor above the pre-determined threshold value as being completely positioned on the background line. If this is not the case, then, in accordance with the method, at least one pre-determined control parameter for printing the first register line is changed and printing of the register marks and the detection are repeated. Changing of the at least one control parameter may be repeated one or more times, with the first register line being shifted each time with respect to its width with different algebraic signs. The above method is also particularly suitable as a pre-calibration of the first register line for a calibration pass for all colors of the multi-color printing machine. | 03-17-2011 |
20110063643 | METHOD FOR DETECTING ERRORS IN INDIVIDUAL COLOR SEPARATION IMAGES OF A MULTI-COLOR PRINTING MACHINE - 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. In an alternative embodiment of the method, a plurality of the first register lines is printed with a first printing unit in such a manner that each of the first register lines is printed within a respective registration frame. Subsequently, the plurality of the first register lines in the respective registration frames is detected with a register sensor, and an output signal of the register sensor relating to the respective first register lines is compared with a pre-specified intensity threshold value in order to determine whether the first register lines are recognizable. | 03-17-2011 |
20120093524 | METHOD FOR PRINTING AN IMAGE ONTO A SHEET IN A PRINTER - 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. If the sheet matches the frame within predetermined limits, a start of frame signal is issued at a predetermined fixed time following the generation of the frame clock signal in accordance with which the sheet was fed into the frame, wherein the start of frame signal starts generation of a latent toner image in the print module for transfer to the sheet. If the sheet does not match the frame position within predetermined limits, the start of frame signal is issued at a specified time following the generation of the frame clock signal in accordance with which the sheet was fed into the frame, wherein the specified time corresponds to the predetermined fixed time to which a time shift is added, wherein the time shift is determined on the basis of the deviation of the actual sheet. Finally, the sheet is aligned in-track in accordance with the start of frame signal, and the thus aligned sheet is transported through the print module in alignment with the latent toner image to transfer the same to the sheet. | 04-19-2012 |
20130010024 | DEVICE AND METHOD FOR CONTROLLING THE TENSION OF A SUBSTRATE WEB - 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. | 01-10-2013 |