Abstract: The present invention concerns an inking for a flexographic or a rotogravure press. The inking system uses a very small amount of ink coupled with an ink source made of two tanks with two different inks. Thanks to feedback given by measuring the output directly on the printed support, the system mixes the ink in the optimal proportions to ensure an optimal printing quality at any time. It can compensate any effect due to environmental changes like the humidity or the temperature. This system, coupled with a seven colours press allows for the replacement of spot colours in most cases thereby saving times and costs.

Abstract: A method of inking a substrate in a printing press is provided. The printing press includes a plurality of printing units, each printing unit includes a blanket cylinder, a plate cylinder and an inker. The method includes the steps of running the plate cylinder, blanket cylinder and inker at a press speed, driving the inker independently, printing on a substrate with a desired ink film thickness at the press speed and stopping the press for a press stop event. Stopping the press further includes stopping the inker at a maximum stop rate, stopping the plate cylinder and blanket cylinder at a normal stop rate and moving the plate cylinder and blanket cylinder into an off impression position.

Abstract: A process for controlling the quantity of ink applied to a material being printed includes the stages of: driving an inking roller and a printing roller at first inking and printing speeds, changing the printing speed to a second printing speed, changing the inking speed to a second inking speed on the basis of a speed correction index, measuring a first and a second quantity of ink, calculating the difference in the quantities of ink applied, and altering the speed correction parameter on the basis of the difference in the quantity of ink printed. The process may be applied to offset presses.

Abstract: A method for operating a printing machine in a print operating mode and another operating mode, for example a maintenance mode. In the print operating mode, bringing a vibrating roller periodically into contact with a first roller of an inking unit, driving the first roller rotationally by a first motor, driving a second roller of the inking unit rotationally by a second motor, transmitting no torque from the first motor to the second roller through a clutch therebetween, and activating the first motor by a control device causing the first roller to rotate at a rotational speed in a constant ratio to a rotational speed of the second roller. In the other operating mode, driving the first and second rollers rotationally by the first motor and transmitting torque from the first motor to the second roller through the clutch. A printing machine for carrying out the method Is also provided.

Abstract: The inking system of an offset lithography press incorporates certain rollers running at different speeds. The hard rollers do not oscillate and the form rollers and the soft transfer rollers of the inking system oscillate endways.

Abstract: A printing press contains a distributor roller, an oscillating roller which has a roller axle and a roller barrel, and a switching device for optionally releasing, in a first operating mode, and locking, in a second operating mode, an oscillating movement of the roller barrel. The oscillating movement is driven frictionally by the distributor roller. The switching device is disposed separately from the roller axle and the roller axle is mounted so as to be adjustable relative to the switching device.

Abstract: In a printing press, ink fountain keys are disposed to be movable toward and away from an ink fountain roller of an ink fountain to allow them to have a predetermined gap therebetween and hence the amount of ink to be fed to a downstream roller to be determined. The ink fountain roller is rotated while ink is prevented from being fed to the downstream roller. At least one of the ink fountain keys is moved so as to allow the at least one of the fountain keys to change a position thereof relative to the ink fountain roller of the ink fountain with time. With this arrangement, it is possible to improve an ink kneading effect produced by the rotation of the ink fountain roller without the necessity to manually knead ink in the ink fountain by the operator and the necessity to provide any ink kneading device or unit independently of the printing press.

Abstract: A driving apparatus in a printing press includes a plate cylinder driven by a printing press motor, an inking device drive-coupled to the plate cylinder, and a driving connecting/disconnecting mechanism. The mechanism connects and disconnects transmission of driving from the plate cylinder to the inking device, and includes first and second gears which are engageable with each other, supported rotatably, and constantly drive-coupled to one and the remaining one, respectively, of the plate cylinder and inking device. The second gear has a second engaging portion engageable with a plurality of first engaging portions of the first gear which have the same shape and are equidistantly arranged in a rotational direction of the first gear. When the first and second engaging portions engage, the plate cylinder and inking device are drive-coupled; when they are disengaged, they are disconnected.

Abstract: Keyless inking systems and methods are disclosed which employs a main form roller and a smaller clean-up roller, both in contact with a rotating printing plate. Separate application and subtractive roller systems control the ink film on the form roller. The clean-up roller removes residual ink from non-image areas on the printing plate. The clean-up roller is in ink communication with the main form roller through a vibrating roller. Mechanisms are provided to selectively engage and disengage the various rollers.

Abstract: An inking system for a printing machine which has a relatively simple design and which is adapted for more stable ink transfer to a plate cylinder. The inking system includes an ink supply roller (15), one or more drivable inking unit rollers (14, 19), an adjustment system for establishing a predetermined nip (19) between the ink supply roller and one of the drivable unit inking rollers (14, 19), and at least one movable calender roller (10) in constant contact with one of the drivable inking unit rollers operable for selectively interrupting the ink transfer.

Abstract: A lithographic printing method of supplying emulsion ink to a lithographic printing plate via a form roller, and disrupting emulsion on the form roller. The degree of the emulsion's disruption before printing has started is different from the degree of disruption after printing has started. The duration of an idling mode can be shortened with the added advantage of reducing the development of waste paper right after the start of printing.

Abstract: A printing press includes an inking unit provided with a screen roller having, on a circumference thereof, a pattern formed of depressions fillable with a printing medium, another roller co-operatively engageable with the screen roller, and a drive device, the screen roller and the other roller being drivingly coupled with one another so that, after each revolution of the screen roller, a pattern depicted by the printing medium on the other roller in a form of printing medium accumulations has a slight offset, in circumferential direction, with respect to a pattern depicted on the other roller during a preceding revolution of the screen roller, so that the new printing medium accumulations are positionable on the other roller in at least approximately printing-medium free gaps in, respectively, adjacent printing medium residual accumulations; and a method of operating the printing unit.

Abstract: In a first printing process in Steps S1 through S6, ink supply is controlled so that a measured printed density (Vn) is approximately equal to a first target density (V1). This provides a uniform amount of ink remaining on ink rollers after the first printing process. Thereafter, in a second printing process in Steps S7 through S11, printing is performed using a second target density (V2) lower than the first target density (V1). This provides a slightly reduced, uniform amount of ink remaining on the ink rollers. Thus, a novel method of presetting ink is provided which facilitates the formation of a distribution of the new amount of ink at the beginning of the next printing operation and which stabilizes the early start of printing.

Abstract: A printing apparatus includes an image reader for reading an image on a printed paper sheet to obtain image data, and a controller for controlling the image reader to obtain image data about a color chart including solid patches once for every predetermined number of printed sheets or at every predetermined time interval which is inputted and set. The controller processes the image data to compute a printed density of each solid patch. Measurement data including the printed density are sequentially stored in a storage section in association with the number of printed sheets or time. The measurement data stored in the storage section may be displayed by a display section or outputted to a print section in the form of history data indicating measurement data transitions. Thus, the printing apparatus including a device for measuring printed sheets can perform history management on the measurement data for every predetermined number of printed sheets or at every predetermined time interval.

Abstract: The present invention relates to a method for controlling the ink feed in a printing press which processes printing substrates (12) and features at least one inking unit and one computer and to a device for carrying out the method. The present invention is characterized in that the computer knows at least the physical properties of printing ink and/or printing substrates (12) as data, that the stored data is read into an ink control model which is stored in the computer, and that the optimum settings with regard to the ink feed are made on the basis of this ink control model before the start of printing or during the printing process.

Abstract: A method for controlling a quantity of medium transferable from a screen roller of a printing machine onto a roller that is in contact with the screen roller includes exerting an influence upon a difference in circumferential speed between the screen roller and the roller in contact therewith, and further includes controlling the difference in the circumferential speed as a function of the printing speed of the printing machine, so that printed medium density remains at least approximately constant at least within a wide printing speed range.

Abstract: A method for controlling the ink quantity in an inking unit of a printing machine by a predetermined nominal value, using a vibrator roller oscillating between a fountain roller and the inking unit, and picking up an ink portion and surrendering it to the inking unit with which the vibrator roller is in contact, includes varying the width of an ink stripe on the vibrator roller, depending upon the nominal value, by adjusting the size of the transferred ink portion, for a modification in the nominal value, from a size (FI) corresponding to the nominal value prior to modification, to at least one intermediate size (Fz) lying beyond a size (Fx) corresponding to the modified nominal value and, subsequent to the expiration of a transition time interval ([t1,t2]), adjusting the intermediate size (Fz) of the ink portion back to the size (Fx) thereof corresponding to the modified nominal value.

Abstract: To minimize the presence of roll-to-roll nips in an inking system for a printing plate cylinder, an ink transfer belt transfers ink from an ink transfer roller, which receives ink from a supply, to the ink receiving elements on a printing plate cylinder. A plurality of guide rolls inside the loop of the ink transfer belt contact the drivable surface of that belt. A drive is connected with one of the guide rollers for driving it to rotate at a first velocity, which is the velocity of the ink transfer roll and of the printing plate cylinder. An ink distribution roller is disposed outside the loop of the belt in contact with the opposite, ink transfer surface of the belt and between the ink transfer roller and the printing plate cylinder. The ink distribution roller is driven to rotate at a different speed than the ink transfer belt and is also driven to vibrate or to oscillate axially for ink distribution on the ink transfer surface of the belt.

Abstract: A method for controlling a quantity of medium transferable from a screen roller of a printing machine onto a roller that is in contact with the screen roller includes exerting an influence upon a difference in circumferential speed between the screen roller and the roller in contact therewith, and further includes controlling the difference in the circumferential speed as a function of the printing speed of the printing machine, so that printed medium density remains at least approximately constant at least within a wide printing speed range.