Heidelberger Druckmaschinen Ag

Heidelberger Druckmaschinen

Gretag Aktiengesellschaft

Heidelberger Druckmaschinen Aktiegesellschaft

Gretag Atkiengesellschaft

Gretak Aktiengesellschaft

Gerhard Loffler

Helmut Kipphan

Willi Jeschke

Hans Ott

Guido Keller

Anton Rodi

Harald Bucher

Jurgen Reithofer

Norbert Freyer

Hugo Rambausek

Franz Arendt

Rudolf Karl Uhrig

Rolf Boegli

Rudolf-Karl Uhrig

Werner L Giesa

Werner Ewendt

Ulrich Birch

To improve the control of the inking process in an offset printing machine, color measuring fields provided on printed sheets are evaluated not as heretofore densitometrically but colorimetrically by means of spectral measurements. Spectral reflections are used to match colors, or color coordinates are calculated from them and compared with corresponding set reflections or set color coordinates. The color deviations obtained in this manner are used to control the inking process. For the stabilization of printing runs the spectral reflections are converted into filter color densities and the inking process is controlled on the basis of these color densities in a conventional manner. The control of the inking process using color deviations and control using color density may be superposed upon each other. The process makes it possible to adapt color impressions in delicate locations of importance for the image in the print to the corresponding locations of the proof. Color deviations due to different material properties and other error sources may also be equalized to some extent.

Process and apparatus for controlling the inking process in a printing

A method for multicolor printing, wherein stored information from the surface of a printing material obtained from an earlier pass of the printing material is applied to subsequent passes of the printing material through the printing machine, and wherein the image signals obtained by means of an image pickup device from at least one surface of the printed material are stored in a steering-or control device, and wherein the stored image signals are applied to subsequent passes of the printed material through the printing machine. The invention can be applied to other devices for producing printed images.

Method of multicolor printing involving multiple passes through a

Method of controlling imaging of a printing form includes producing on printing material or stock, with a printing press, control patches of an imaged printing form, generating image signals with an image-detecting device from the control patches of the imaged printing form produced on the printing material, and determining with an evaluating device any deviations of the generated image signals from respective reference image signals.

Method and apparatus for monitoring image formation on a printing form

The object of the invention is attained in a manner where is at least one image pickup device is provided for picking up image signals obtained from at least one surface of a printed image, and a steering and control device connected to the pickup device in which the image sequences are stored. Furthermore, the image signals are examined for presence of jumps or transitions in tone values, and the position coordinates of the transitions in tone value jumps are stored. In a further step the frequency of those tone value jumps, in direction of the coordinates, which exceeds a given threshold value, are recorded, and applied to develop a signal for indicating need to replace the dressing.

Method for testing elastic properties of a dressing on a printing

Offset printing method wherein ink in the form of screened half-tone dots or pixels and unscreened printing-image elements is applied to a printing surface of a recording medium by means of a printing device; a printing form being generated from signals reproducing a printed image; the printing form being inked with an inking device; and the ink being transferred to the printing surface, upon transport of the recording medium relative to the printing device; the signals being processed in a control device for the printing device; includes, near the printing device and before the printing form is generated on a screen or monitor, forming a copy of the printed image from the signals reproducing the printed image and from signals containing parameters of the printing device; whenever the copy deviates from a desired printed image, manually inputting correction values for local inking into the control device, until the copy corresponds to the desired printed image; and generating the printing form and adjusting the elements affecting the inking with the signals reproducing the desired printed image and from signals containing fixed printing-press characteristics.

Offset printing method

It is the object of the invention to provide a printing method permitting a high printing quality and reducing the influences of the forces and fields acting on the printing material. The object is achieved in that, by means of two image-detecting arrangements disposed in the transport path of the printing material, image signals are obtained before and behind a device treating the surface of the printing material and are supplied to a control unit, and in that the changes of the outer dimensions are quantitatively determined on the basis of said image signals. The invention may be applied on printing machines.

Method of drying printing material

The wear on printing forms in a printing machine is monitored in that the inking values at certain locations on the printed product are measured. At least two measurement locations are defined on the print image. The first measurement location has a defined tonal value above an upper tonal value, and the second measurement location has a tonal value below a lower tonal value. The printed product is scanned as it leaves the printing unit. The measured inking values at the measurement locations are compared with the setpoint values as defined by the tonal values at the defined locations. If the lower tone signal is below the setpoint signal while the upper tone signal corresponds or exceeds the setpoint inking values, the control unit deduces that the printing plate may be worn. The printed product count may be used as auxiliary information in the wear determination.

Method of monitoring the wear on printing forms in a printing machine

Method of controlling inking in a printing press, wherein the inking is evaluated in non-image areas during printing with a printing form on printing material, includes generating with at least one image-detecting device image signals in the non-image areas on the surface of the printing material, feeding the image signals to a control or regulating device and, with a temperature-controlling device, varying the temperature of ink applied to the printing form in accordance with the image signals.

Method of controlling inking in a printing press

Device for compensating for deviations in register in a printed product produced in a sheet-fed rotary printing press having a plurality of printing units includes at least one opto-electrical sensor device for detecting measured values from at least two image regions of a printed product; a computer/control device connected to the sensor device for receiving therefrom data regarding the measured values, for ascertaining from the data deviations in register between color separations caused by shrunken and/or swollen printing transferred to the printed product in the respective printing units, and for determining corresponding compensating adjustment data; and adjusting devices connected to the computer/control device for compensating for the deviations in register between the color separations in accordance with the determined adjustment data of the computation/control device; and method of compensating.

Device for compensating for deviations in register in printed products

A holding unit for a measuring device having a base carrying an inductive charging input, and a side wall formed with openings for infrared data transmission, includes a two-step cover surface including an upper cover surface and a lower cover surface, the lower cover surface being formed with a recess having a contour corresponding to the contour of the measuring device for receiving the measuring device therein, a side wall of the holding unit partly defining the recess formed in the lower cover surface and being formed with openings for infrared data transmission coinciding with the openings for infrared data transmission formed in the side wall of the measuring device when the measuring device is received in the recess, an output for an inductive power supply disposed in a base of the recess formed in the lower cover surface, the output coinciding with the inductive charging input carried by the measuring device when the measuring device is received in the recess, the upper cover surface being formed with two substantially rectangular recesses, one of the substantially rectangular recesses having a contour corresponding to the outer contour of a printer receivable therein.

Holding unit for a measuring device

To improve the control of the inking process in an offset printing machine, color measuring fields provided on printed sheets are evaluated not as heretofore densitometrically but colorimetrically by means of spectral measurements. Spectral reflections are used to match colors, or color coordinates are calculated from them and compared with corresponding set reflections or set color coordinates. The color deviations obtained in this manner are used to control the inking process. For the stabilization of printing runs the spectral reflections are converted into filter color densities and the inking process is controlled on the basis of these color densities in a conventional manner. The control of the inking process using color deviations and control using color denisty may be superposed upon each other. The process makes it possible to adapt color impressions in delicate locations of importance for the image in the print to the corresponding locations of the proof. Color deviations due to different material properties and other error sources may also be equalized to some extent.

A method of positioning a measuring field of a sensor device on a selected region of an outer cylindrical surface of a cylinder in a rotary printing press, includes directing a light spot of a pilot light source into the selected region; storing the position of the light spot on the outer cylindrical surface of the cylinder in a computing/control device; and controlling the sensor device so that it supplies measured data from the selected region, and a device for performing the method.

Method and device for positioning a sensor device

Color measurement system for offset printing, having a bridge for spanning an original which is to be measured and a color-measuring device movably disposed on the bridge, the color-measuring device comprising a first three-color simultaneous measuring head for densitometric measurement, and a second three-color simultaneous measuring head for colorimetric measurement.

Color measurement system

A method of monitoring dampening-medium feed in an offset printing machine includes scanning non-printed areas in a region of given inked areas by a device of an opto-electric transducer, and evaluating signals generated by the scanning; and a device for performing the foregoing method.

Method of monitoring and/or controlling dampening-medium feed in an

Assembly for influencing inking in printing machines including a color density measuring device, a device for comparing nominal values and actual measured values, at least one electronic computer for linking the measured values with adjustment values, devices for metering ink feed zonewise to a printing plate and having ink metering elements with appertaining adjustment members and feed-back or reply devices, including a plurality of displays assigned to the ink metering elements for representing adjustment values of all ink zone adjustment members, respectively, of a printing unit, said displays providing exact recommendations to an operator of the assembly, before adjustment of the inking zone adjustment members, for adjusting the adjustment members to predetermined positioning nominal values and signaling to the operator absolute adjustment travel thereof both in magnitude and direction and a positioning device having means selective by the operator for following up the ink zone adjustment members individually and of at least one printing unit, respectively, the positioning device being coupled with the displays.

Growing community of inventors

Walldorf, Germany

Gerhard Loffler