Heidelberger Druckmaschinen Ag

Ernst-Christian Maschler

Karl-Heinz Helmstädter

Thomas Schmidt

Martin Greive

Michael Kohlmann

Markus Wolf

Sibel Korkut Punckt

Gerald Hauptmann

A method for feedback control of ink temperature in inkjet printing includes pumping ink through supply and return lines of an ink distributor and between these lines through print heads supplied in parallel with the ink, comparing a temperature actual value with a predefined temperature setpoint value and calculating a manipulated variable for a setpoint value of an ink heater from a setpoint/actual value deviation. A flow sensor is operated between the supply and return lines in parallel with the print heads and measures the flow of the ink or generates a measurement signal dependent on the flow. The flow or the measurement signal is converted by a predefined characteristic curve into a temperature auxiliary value used as the temperature actual value or temperature setpoint value for feedback control. This enables continuous unimpaired production by inkjet printing, particularly upon changes in viscosity of the ink in industrial inkjet printing.

Method for feedback control of the temperature of an ink in inkjet printing

A printing machine includes an inkjet printing head having separately controllable nozzles for applying ink to a transported printing material, a radiation drier having radiation sources for generating electromagnetic radiation to at least partly dry and/or cure the applied ink on the transported printing material and at least one light trap disposed between the inkjet printing head and the radiation drier in such a way that the light trap forms a barrier for reflected and/or scattered radiation, thus protecting the inkjet printing head from radiation. The light trap includes at least one channel connected to an aspiration device for aspirating contaminated ambient air through the channel and reducing or preventing contamination of the radiation drier.

Printing machine with an inkjet printing head, a radiation drier and at least one light trap

A printing press for printing on both sides of sheets is developed with low expenditure on costs and material, makes it possible to print on both sides of sheets in one pass and which has a small overall size. The printing press for printing on both sides of sheets, has at least one printing unit, in which in each case at least one form cylinder and at least one sheet-guiding impression cylinder are provided. A feeder feeds sheets individually one after another to the printing unit. A delivery guides the sheets away from the printing unit, and grippers convey the sheets individually one after another along a path which runs back and forth, the paths crossing one another.

Printing press for printing on both sides of sheets

A method and a device for converting a mode of operation from straight printing to perfecting in a sheet-processing machine, includes a cam/follower control for operating a gripper system, in which cam followers are maintained in a position in which they are disengaged from control cams before a conversion of the mode of operation is performed. The method and the device convert a gripper system of a reversing drum between a straight or one-sided printing mode and a perfecting or recto-verso printing mode, by controlling pivoting and opening movements of grippers of the gripper system with a control cam. Initially, a cam follower is locked in a position in which it is disengaged from the control cam. Subsequently, a further cam follower is locked in a position in which it is disengaged from a further control cam. Then the gripper system is converted.

Method and device for switching between single-sided or straight printing mode and perfecting or recto/verso printing mode in a sheet-processing machine and reversing drum having the device

In a device for changing over a gripper control in a turning configuration of a sheet-processing machine, there is provided a slide to be guided axially displaceably by radial stops. The device changes over a gripper control from recto printing to verso printing on a transfer device such as a drum or a cylinder of a turning configuration in a sheet-processing machine.

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Heidelberg, Germany

Ernst-Christian Maschler