Abstract: A method for detecting a type of one of plurality of devices attached to a graphics machine, each device being one of at least a first type and a second type. The method includes detecting at a controller the type of device attached to or to be attached to the machine. The controller is capable of preadjusting the device or machine as a function of the detection. A graphics machine includes a controller, a first device connected to the controller, the first device being categorizable as one of at least a first type and a second type, the controller detecting the type of the first device, and a memory accessible by the controller, the memory storing information regarding the first type and the second type.

Abstract: The present invention relates to a method for aligning at least two flexographic printing plates on at least one printing cylinder, which provides acquiring an image of a part of a first plate, memorising the acquired image, framing a part of a second plate, at the same time displaying the memorised image and the image relating to the part of the second framed plate in real time; and aligning the image framed in real time with the memorised image.

Abstract: A printing unit of a printing press is comprised of at least two frame parts, the position of at least one of which, relative to the other, can be changed. Cooperating ones of these frame parts are placed against each other along a common joining surface, in a first operational position. These frame parts are separated from each other in a second operational position. An interstice, that is partly defined by these frame parts, is formed between the separated frame parts in the printing unit. At least one of the cooperating frame parts is supported so that it is movable along an adjustment path. At least one sensor is provided and is usable to monitor the interstice. The sensor has orientation characteristics or a sensory range along the joining surface. An aperture width of a first angular aperture of the orientation characteristics or of the sensory range is smaller than a respective aperture width of a second or third angular aperture of the orientation characteristic or sensory range.

Abstract: A printer accessory comprises a base having a top surface and a bottom surface, and an ink absorber having a thickness in accordance with an example of the present disclosure. The ink absorber rests on the top surface and includes an absorbent material to retain excess ink from a printing operation. Furthermore, the accessory includes print media supports connected to the base and extending beyond the thickness of the ink absorber, wherein when print media is present, the print media spans the print media supports without contacting the ink absorber. An attachment clip is connected to the base having a resiliently flexible portion to releasably secure the printer accessory to a printer.

Abstract: A printing plate module is disclosed. The module comprises a printing plate support member (3) having means (5) to locate printing plates (4) in a predetermined position thereon and, engagement means (8) on the plate support member for the releasab a engagement of the printing plate support member (3) with a printing press during a plate loading operation to locate printing plates (4) located on the plate support member (3) in a predetermined position relative to a plate cylinder (7) of the press. The invention also discloses a printing apparatus and, a method of loading printing plates onto a plate cylinder of a printing unit.

Abstract: A machine for in-register mounting of flexographic printing plates with a virtual data-processing system, having a supporting footing for a printing plate cylinder, on which a respective flexographic printing plate is mounted, suitable for printing a predefined image, and at least one television camera, which is connected to a monitor, is trained onto the cylinder and can slide parallel to the cylinder to check correct positioning-mounting of the printing plate, the television camera being associated with position sensors and connected to a device for the real-time processing and display of at least one composite image, for allowing the operator to perform precise position comparisons for optimum plate mounting between a preprocessed graphical reproduction of the image to be printed, provided on a digital memory composed of graphical memory associated with position measurements, and the position of the printing plate.

Abstract: A cartridge device applied to production lines for automatic screen printing is revealed. The cartridge device includes a frame, a plurality of cartridges for loading articles to be printed, two cartridge lifting members for driving the cartridge to move up/down, two cartridge convey member for driving the cartridge move horizontally, two printed substrate (articles) delivery members for delivering the articles to be printed, and two shift mechanisms for taking out or putting in the articles to be printed from the cartridge or the printed substrate delivery members. By one shift mechanism, the article to be printed on a work line is moved from the printed substrate delivery member into the cartridge for running material collection or the article to be printed is moved from the cartridge to the printed substrate delivery member for performing material feeding. Thus the two work lines of the production line can perform automatic material feeding, collection and storage simultaneously or respectively.

Abstract: Disclosed is an image forming apparatus to form an image on a paper, comprising: a main body section including a housing to house an apparatus to perform processing for the paper, and a control circuit to control the apparatus housed in the housing; and a peripheral apparatus provided separately from the main body section, which includes a hardware module having an electric component, and is connected to the control circuit so that communication therebetween is performed, and which is detachably provided to the housing, wherein a position at which the peripheral apparatus is provided to the housing can be changed, wherein the housing and the peripheral apparatus respectively include a conductive material, and the conductive material of the housing is grounded, and wherein when the peripheral apparatus is provided to the housing, the conductive material of the housing is conductive with the conductive material of the peripheral apparatus.

Abstract: A system for checking the loading of a print form magazine, which stores at least two print forms, utilizes at least one code reader to read a code which is carried by the print forms. The code reader reads the coding of the printing forms in a secondary region. The coding of at least two printing forms, which are arranged adjacently, horizontally or vertically together, is read by the code reader. The code reader has an image sensor and an illumination system for lighting the secondary region. A system is also provided for transporting at least one print form stored in the print form magazine to a cylinder. An analytical unit can be connected to the code reader, or to another registration device, and stores information regarding the transport of each printing form, that is stored in the print form magazine, to the cylinder. The analytical unit that may be connected to the code reader is provided with a signaling device.

Abstract: A printing machine is provided with at least one printing unit that is usable for printing an image, in ink, on a printable material. The printing machine includes at least one application device which is usable to apply at least one contactless identification characteristic, in the form of an RFID system or a part thereof, to the printable material. At least one inspection device is also provided in the printing machine. At least one test device, for testing the identification characteristic, or the part thereof, is also provided in the printing machine.

Abstract: A printing machine, in particular a label printing machine or a sheet-fed offset printing press, includes printing units accommodated in a machine support structure that is made at least partially, and preferably entirely, of rock. The rock may be a natural rock, in particular granite, or an artificial rock, in particular concrete.

Abstract: A printing unit of a printing machine is supported by a pair of spaced side frames that are disposed opposite to each other. The printing unit includes at least one printing machine and at least one ink unit. The printing machine is formed by a plurality of printing cylinders. Each of the spaced side frames include a longitudinal crossbar that runs in the direction of transfer of a print substrate traveling through the printing unit. The two longitudinal crossbars form the boundaries of a foot space of the printing unit at two parallel sides. A plurality of pipelines are disposed in the foot space between the two longitudinal crossbars. These pipelines supply flowable media to the printing unit, which flowable media can be either liquid or gaseous. At least one of the pipelines is connected to a user of one of the supplied flowable media in the printing unit or to at least one source of the flowable media. The printing machine can utilize a plurality of printing units.

Abstract: At least several spaced apart storage compartments are provided in a plate storage device. These compartments can receive used printing forms from a printing cylinder or new printing forms that are to be supplied to the printing cylinder. At least one positioning assembly is utilized to adjust at least one mouth region of two of the storage compartments to the same spaced position, with respect to the printing cylinder, at different times in the operating cycle of the plate storage compartments. This mouth region is situated facing the printing cylinder. In another embodiment, at least one printing form, that is being received from the printing cylinder, can be stored in at least one storage compartment. At least one conveying apparatus is provided and includes an entraining mechanism for gripping the printing form that is to be removed.

Abstract: A printer includes a platen roller that is detachably supported on a support section that is formed in a frame, and a head unit that is supported on the frame and can be moved in a direction in which the head unit is brought into pressure-contact with the platen roller, The printer also includes a regulating member that is movably supported on the frame, and the regulating member has a regulating section that regulates a shaft of the platen roller to deviate from the support section and a pressing section that is arranged on the opposite side to the regulating section, with the head unit interposed therebetween. A first plate spring that presses the head unit against the platen roller and a second plate spring that presses the pressing section so as to bias the regulating member in a direction in which the regulating section can regulate the shaft are provided in an area on the opposite to the platen roller, with the head unit interposed therebetween.

Abstract: A plate feeding method includes a suction-holding step for causing suction pads to suck and hold an upper surface adjacent an end edge, remote from nip rollers, of each plate, a moving step, while swinging the suction pads about a moving unit, for moving the moving unit toward the nip rollers, thereby inverting a portion adjacent the end edge of each plate P, and subsequently moving the end edge of the plate inverted to a position to be pinched by the nip rollers, a pinching step for causing the nip rollers to pinch the end edge of the plate having been inverted, a releasing step for canceling suction-holding of the plate by the suction pads, a pressing step for pressing the plate with a support roller, and a transporting step for rotating the nip rollers to transport the plate P.

Abstract: The present invention relates to a safety system comprising at least two stationary detector elements each defining a respective first safety zone, said first safety zones not coinciding, a moving detector element, and a control unit connected to the stationary detector elements. The control unit is adapted to detect the presence of the moving detector element in one of the first safety zones. The invention is applicable to rotary printing presses.

Abstract: A device such as a row of wheels, a row of pressurized air blasts, or guide fingers is attached directly to a UV LED lamp that is mounted into a sheet-fed printing press for curing UV inks and coatings. The device will enable the UV LED lamp to be placed closer to the sheet than previously possible by preventing the trailing edge of the sheet from dragging across the UV LED lamp as the sheet passes by the lamp.

Abstract: A printing unit is comprised of at least two side frame parts whose distance, relative to each other, can be modified in a horizontal direction. Each printing unit receives at least one printing group or parts of a printing group. At least one of the side frame parts can be moved between a closed functional position, in which the side frames are moved together and are fixed relative to one another, and an open position, in which they are spaced from each other. In order to fix or to secure the side frame parts relative to one another, at lease one closure device is provided. The at least one closure device is comprised of a cylinder that can be used to pretension the side frame parts into the closed functional position. The cylinder carries a piston rod that is adapted to carry out a stroke movement. The closure device is configured as a swivel tensioning element.

Abstract: Provided is a printing plate cylinder to which a sleeve printing plate is detachably attached. In the printing plate cylinder, weight reduction and radiation performance can be improved, and generation of rust can be suppressed. The printing plate cylinder (1) includes a shaft portion (3) rotatable about a central axis (O), a tubular portion (5) formed cylindrically, arranged coaxially with the shaft portion (3), and arranged at a distance from an outer circumferential surface (3a) of the shaft portion (3), and a rib (7) fixed integrally to the outer circumferential surface (3a) of the shaft portion (3) and an inner circumferential surface (5b) of the tubular portion (5) and connecting the shaft portion (3) and the tubular portion (5). An air supply channel (31) is formed so as to penetrate from the outer surface of the rib (7) exposed to the outside to the outer circumferential surface (5a) of the tubular portion (5).

Abstract: A printing module provided with a frame (12), an impression roller (13), a plate cylinder assembly (22), an anilox roller and a doctor roller, wherein the printing module comprises two receiving units disposed on opposite sides of the plate cylinder, which are connected with the frame, while fixation means are provided for fixating the plate cylinder assembly in the receiving units, the fixation means (26, 27) being situated substantially under the plate cylinder assembly (22), the fixation means preferably comprising two rods (46,46?) which, at an upwardly directed end, are provided with a hook (47,47?), the two hooks, on opposite sides of the plate cylinder, engaging a stationary shaft of the plate cylinder assembly, while on the rods a pull force is exerted for pressing the plate cylinder assembly into the receiving units.

Abstract: At least two blankets which are removed from the same cylinder of a printing machine one after the other, are stored in a storage device. The blankets are drawn off the cylinder in a longitudinal direction and are stored in the device at an angle of inclination of not more than 15° relative to the horizontal. The second blanket to be drawn off is stored below the previously drawn-off blanket at a distance that is vertical along its length.

Abstract: The present invention relates to a printing system, comprising a print material inlet, where non-imprinted print materials can be supplied to the printing system, and a printed product outlet, where printed products can be conveyed out of the printing system, and comprising at least one printing couple (19, 251) or printing tower in which the print material can be imprinted, and comprising at least one reel changer (18) or sheet feeder for feeding the print material, and comprising at least one unit, particularly a folding unit (22, 255, 256) or sheet delivery, for post-processing and/or removing the printed product, wherein the printing system comprises at least two system levels arranged vertically above each other, and wherein the printing system forms at least one material flow line (12) along which the print material is conveyed through the printing system, wherein in addition to the printing system a transport system is provided which extends parallel to the material flow line across the entire length o

Abstract: Printing plate material supply spool (PMSS) for a printing machine or plate-imaging machine and a method of loading it is provided. An exemplary PMSS can comprise a printing plate material film that is wrapped around a hollow core (HC), wherein the HC is adapted to be engaged with a heavy duty core (HDC) prior to be placed in the printing machine. The method for loading the printing plate material supply spool (PMSS) in a printing machine or plate imaging machine may comprise inserting a heavy-duty core (HDC) inside the HC of the PMSS forming an integrated core. Then the PMSS and the integrated core can be placed in the printing machine.

Abstract: A printing press having inboard cantilevered cylinder supports is disclosed. The press includes a frame with a drive side spaced from a non-drive side, and the press includes a cylinder defining an having an axis and having a drive end and a non-drive end. The drive end includes a drive aperture extending axially into the cylinder and a splined insert mounted within the drive aperture, while the non-drive end includes a non-drive aperture extending axially into the cylinder. A drive shaft is rotatably mounted to the drive side of the frame and is arranged for connection to a power source. The drive shaft includes a spline sized to engage the splined insert and is arranged to a portion of the cylinder, while a mandrel carried by the non-drive side of the frame extends into the non-drive aperture and is arranged to support another portion of the cylinder.

Abstract: An apparatus and method for registering a position of a component of a press is disclosed. The press having a plurality of components that can rotate about a central longitudinal axis, such as a main drive shaft and press cylinders, at least one of these components being assigned at least one position registering device, which registers the angular position of the respective component. The, or each, position registering device is formed as a magnetic rotary encoder.

Abstract: An arrangement for synchronizing printing presses and additional components, in which arrangement a printing press and/or an additional component form/forms a unit and are/is connected to further units, and the drives of the connected units are synchronized, the units having either AC drives and/or DC drives and being synchronized internally via synchronism regulators in the case of an AC drive and via at least one drive shaft in the case of a DC drive. For the synchronization of the units which are to be connected, at least one additional synchronism regulator is attached to at least one unit, all synchronism regulators of all units being connected to one another and being adapted to a setpoint value of the connected units.

Abstract: A sheet feeding device which feeds a sheet by loosening a sheet by loosening sheets by blowing air to the end portions of the sheets, comprising: a sheet tray provided to be capable of lifting up/down supporting the sheets; air blowing means which loosens the sheets by blowing air to the end portion at the topside of the sheets supported by the sheet tray; and a pair of restricting members which restricts both end portions in the direction perpendicular to the sheet feeding direction of the sheet with sheet opposing faces opposing the end portions of the sheets, wherein the interval between the sheet opposing faces at the top side of the pair of the restricting members is set larger than the interval between the sheet opposing faces below the position in which air is blown to the sheets with the air blowing means.

Abstract: An apparatus for imaging a media is able to accommodate, in an imaging position, a drum for loading flat sheets of media or a mandrel for loading sleeve media. The apparatus includes a storage position for locating the drum or mandrel when not in use and provides mechanisms for safe transport of the drum or mandrel between the storage and imaging positions.

Abstract: A rotating body of a printing press includes a barrel that has a base body and an outer body which at least partially surrounds the base body. The external body, or at least one channel which is located in the barrel is traversed by a temperature control medium. The outer body or the at least one channel is thermally insulated with respect to the base body.

Abstract: A removal system for removing an interleaf sheet that is interposed between plate sheets in an imaging system, wherein said removal system contains a substantially horizontal member, at least two roller assemblies, a disposal roller assembly, a rail assembly, and at least one springing roller.

Abstract: A cylinder of a printing unit is received in a bearing structure that includes a bearing block having a rotary bearing and which is movable along an adjustment path in linear bearings. The bearing structure is configured as a bearing unit that can be mounted as a whole. The bearing structure thus includes the rotary bearing, the bearing block and the linear bearings which enable the relative movement of the bearing block.

Abstract: A plate feeding apparatus of this invention includes a storage unit 10 for storing a plurality of plates P with end edges thereof arranged even by a stopper 11, a first and a second nip rollers 12 and 13, a suction device 45 disposed at a distal end of an arm 44 swingable about a moving unit 43 for sucking and holding an upper surface adjacent an end edge of each plate, a moving mechanism for moving the moving unit 43 along the surfaces of the plates, and for swinging the arm 44 about the moving unit 43, thereby to invert a portion adjacent the end edge of each plate sucked and held by the suction device 45, and subsequently to move the portion to a position to be pinched by the first nip roller or second nip roller, and a storage unit moving mechanism 26 for moving the storage unit 10 in directions perpendicular to the axes of the first and second nip rollers 12 and 13.

Abstract: Transportation of a lithographic plate uses an indexer to load plates into pods for delivery to a press cylinder via a pod elevator or a pod cart. The plates are imprinted with a bar code, imaged, punched, bent, sheared, corner notched, and registered to a press cylinder. The plates are loaded into the indexer, which moves the loaded plates into a position in alignment with designated pod compartments, and loads the plates into each of the designated pod compartments by indexed movement of an elevator within the indexer. The pod elevator or the pod cart moves the pods proximate to a press cylinder where the plates are unloaded from the pod and loaded onto a press cylinder. A computing device, such as a PLC, directs the process. A vision system senses information from the indexer, pod, pod elevator, and the plate for feedback to a PLC, which initiates all of the foregoing operations.

Abstract: It is the object to provide a printing press having no fear of interruption of printing operation and also having a structure by which the utilization efficiency thereof is increased. A printing press is provided that includes a plurality of blowers each having an air supply tube for supplying air, a header pipe to which the air supply tubes of all the blowers are connected, and a plurality of air showers for executing predetermined processes using air supplied from the header pipe through pneumatic tubing, by which the respective air showers are connected to the header pipe.

Abstract: Compression-resistant heating frame, comprising an upper plate and a lower plate which are secured to each other, and a heating layer interposed between the two plates. Force-absorption studs are disposed between the two plates in order to protect the heating layer against deformation by compression of the plates against each other. The studs are distributed to permit regular heating of each plate. The force-absorption studs are distributed at the nodes of a rectangular, hexagonal or centered square network. The force-absorption studs preferably include a flange to distribute the compression force on a metal base sheet which is interposed between the upper plate and the heating means. Thermal insulation material is interposed between the heating layer and the upper plate. The heating layer may comprise a film through which an electric circuit passes in order to produce heating by joule effect.

Abstract: A proofing tool including an anilox roll and an impression roll that are shiftable relative to each other between an engaged position and a disengaged position. The invention further includes a positive rotational linkage between the anilox roll and the impression roll whereby a pitch velocity of the anilox roll and a pitch velocity of the impression roll are substantially matched.

Abstract: A method for detecting a type of one of plurality of devices attached to a graphics machine, each device being one of at least a first type and a second type. The method includes detecting at a controller the type of device attached to or to be attached to the machine. The controller is capable of preadjusting the device or machine as a function of the detection. A graphics machine includes a controller, a first device connected to the controller, the first device being categorizable as one of at least a first type and a second type, the controller detecting the type of the first device, and a memory accessible by the controller, the memory storing information regarding the first type and the second type.

Abstract: A proofing tool, including an anilox roll and an impression roll shiftable relative to each other from an engaged position and a disengaged position and a positive stop nip adjustment mechanism. operably connected to the anilox roll and the impression roll and being adjustable whereby when the anilox roll and the impression roll are in the engaged position the positive stop prevents the nip distance from being smaller than a set value.

Abstract: A plate inserting device includes a plate cylinder, roller, and rotation braking unit. The plate cylinder has a groove portion in its outer surface to extend in an axial direction. A plate is to be mounted on the outer surface of a plate cylinder. The roller is rotatably supported to be able to come close to and separate from the outer surface of the plate cylinder. The roller comes into contact with the outer surface of the plate cylinder, when a distal end bent portion of a new plate is to be inserted in the groove portion of the plate cylinder, to press the distal end bent portion of the new plate. The rotation braking unit brakes rotation of the roller in relation to insertion operation of the distal end bent portion of the new plate into the groove portion of the plate cylinder.

Abstract: A press cylinder having at least one drivable device and having a generator assigned to the press cylinder for generating electrical energy for actuating the drivable device is disclosed. A generator housing of the generator is permanently connected to the press cylinder and rotates with the press cylinder. A generator rotor belonging to the generator and enclosed by the generator housing rotates relative to the generator housing, and it being possible for the generator rotor to be driven by an electric motor.

Abstract: A method and apparatus for replacing a printing plate enabling to easily replace the printing plate of a plate cylinder of a printing unit in an easy posture in a variable cutoff rotary press of a web offset press or the like is realized.

Abstract: The invention relates to an electromotive direct drive for one cylinder (1) of a printing press, which cylinder (1) is held in a connecting construction (3) with a journal (2) via a roller bearing (4), a rotor (6.1) of an electric motor (6) being connected fixedly in terms of rotation to the journal (2), and a stator (6.2) being connected to the connecting construction (3). This drive is distinguished by the fact that the rotor (6.1) is connected to an end side of the roller bearing (4), and the stator (6.2) is accommodated by a housing (9) which can be fastened to the connecting construction (3) via a bearing housing (5). The advantage of this direct drive according to the invention lies in the fact that the drive and the bearing are combined as a captive, preassembled structural unit which can be handled in a simple manner.

Abstract: A method for detecting a type of one of plurality of devices attached to a graphics machine, each device being one of at least a first type and a second type. The method includes detecting at a controller the type of device attached to or to be attached to the machine. The controller is capable of preadjusting the device or machine as a function of the detection. A graphics machine includes a controller, a first device connected to the controller, the first device being categorizable as one of at least a first type and a second type, the controller detecting the type of the first device, and a memory accessible by the controller, the memory storing information regarding the first type and the second type.

Abstract: A display device and a display method are provided for printing material processing machines having components disposed relative to a printing material. The display device and method are configured in such a way that changes in a relative position of the components of the machine are displayed on the display device in relation to the printed image and/or the printing material. A printing press having a display device is also provided.

Abstract: A sheet brake for braking sheets made from a printing material contains circulating brake elements and at least one sheet support that is disposed between the brake elements and forms a blowing device. The sheet support contains a first nozzle array having air nozzles and a second nozzle array having air nozzles. The air nozzles of the first nozzle array are configured to produce blown air volumetric flows, which are smaller than blown air volumetric flows from the air nozzles of the second nozzle array.

Abstract: Apparatus for balancing a printing roller having an image producing area thereon, includes a detector for detecting any unbalance of the printing roller during rotation thereof. A computer determines weight adjustments of the printing roller that are required to correct the unbalance, in response to the detection. A laser is controlled by the computer to remove material, in response to the determination, from at least one engraveable plate mounted on the outer surface of the printing roller or from the printing roller itself, in an area outside of the image producing area, in order to balance the printing roller.

Abstract: A platen assembly for a printer comprised of a platen roller assembly and a housing assembly that is structured to rotatably support the platen roller assembly. More particularly, the present invention is directed to a platen roller assembly comprising a platen roller defining first and second ends; a locking pin extending from at least one of the first and second ends of the platen roller; a housing assembly adapted to rotatably support the platen roller; and a drive assembly structured to rotatably engage the locking pin extending from one end of the platen roller. In this regard, the present invention provides a platen roller assembly that is simple, easily alignable, and readily replaceable by a user.

Abstract: An unload table (50) for a plate making machine comprises an unload table proximal segment (194) proximate the cylindrical surface (120) of the imaging drum (110) of the plate making machine. The unload table proximal segment can tilt to receive a printing plate (40) being unloaded from the imaging drum. In a further embodiment the unload table itself can also tilt about another axis, allowing the unload table and unload table proximal segment to remain clear of any fixtures on the rotating imaging drum, thereby allowing a printing plate imaged on the imaging drum while the unload table and unload table proximal segment are moving in to a unloading orientation. This enhances the throughput of the plate making machine by reducing the total time required for bulky unload tables to reposition and re-orient for unloading of printing plates.

Abstract: A method for operating a printing press, which enables a uniform print quality to be achieved during long periods of operation without replacement of the impression cylinder. The printing press comprises several printing units having impression cylinders and a sheet turning device disposed between the printing units. The circumferential surface of the impression cylinder has an ink-repelling surface. The printing press is used to print sheets, until the ink-repelling surface of the circumferential surface of the impression cylinder has been worn away to an extent that the ink-repelling effect is less than a predetermined threshold value, after which a foil, of which the side facing away from the circumferential surface has an ink-repelling surface, is removably placed on the circumferential surface of the impression cylinder.

Abstract: A printing press for processing a web of printing material, in particular for producing labels or packaging, includes a plurality of printing units which are convertible between different printing processes. Each of the convertible printing units includes at least one receiving element to releasably connect and receive a printing unit subassembly or printing unit component in such a way that the printing process can be implemented on the web of printing material passing through the printing unit in a printing nip formed between a cylinder and an impression cylinder. In order to provide diagonal register adjustment, the axis of rotation of the cylinder is tiltable relative to the axis of rotation of the impression cylinder by a linear movement of the at least one receiving element perpendicular to a direction of engagement between the cylinder and the impression cylinder.