Abstract:
A printing machine which allows for the economic production of multi-color prints and allows for automation of the printing process is provided. The printing machine according to the collect-run principle in which the multicolor prints are collected on a rubber cylinder. In a single printing unit, the printing machine can also process two different printing inks. To execute the collect-run printing operation, the sheets are fed in a cycle offset to the collection of the images on the rubber cylinder. This enables very compact and simply structured printing machine configurations.
Abstract:
To facilitate the attachment and adjustment of a printing plate on the outer surface of the plate cylinder of a printing machine, a layer of friction-reducing material is applied to the underside of the printing plate or the outer surface of the plate cylinder or both. The friction-reducing, sliding material may be a thermoset material, a thermoplastic material or an inorganic dry lubricant. The sliding material may be burnt into the supporting surface or bonded thereto by an adhesion promoting substrate layer.
Abstract:
A guard mechanism for a printing machine which includes a guard plate that is movable between a first position which impedes access to the interior of the printing machine and a second position which permits access to the interior of the printing machine and the plate cylinder and ink fountain located therein, the guard plate having an articulated connection with to the ink fountains such that upon movement of the ink fountain to a throw-off position the guard plate is simultaneously moved to a position which prevents the possibility of interference between movement of the guard plate and ink fountain.
Abstract:
A resilient sheet gripper for a sheet-fed rotary printing press having a gripper shaft to which is secured a pivoting clamping member in resilient relationship with a pivotable gripper finger having a fulcrum and adjsutable biasing, is provided including a base member mounted loosely around the gripper shaft, a joint on the base member for pivotally securing the finger to the base member, a plurality of compression springs disposed on opposite sides of the gripper shaft with associated stops for adjustably pressing the gripper finger and the base member against the clamping member, and another stop which acts against the cylinder upon closure of the gripper finger thereby moving the fulcrum of the gripper finger from the gripper shaft to the joint so as to change the gripper finger lever transmission which then increases the retaining force.
Abstract:
The invention relates to a process for the production of structured retaining areas on sheet grippers, sheet gripper supports or similar gripper facilities for machines for handling and processing sheets by the formation of a non-etchable dot structure on the base member and the subsequent etching out of intervening areas. To provide structured retaining areas having a smoothly shaped surface, the dot structure is produced by screen printing or pressure pad printing and after the etching-out of unprinted areas, a hard smoothing coating, preferably of chromium or ceramic, is applied to the structural retaining area.
Abstract:
An improved sheet gripper system disposed on the impression cylinder of a printing press having regular sheet grippers mounted on a gripper shaft on the impression cylinder with additional grippers provided in the spaces between the regular grippers, which spaces are intended for cooperating transfer grippers, the additional grippers being adapted to retract into a gripper channel and extend out into the gripper plane only in one zone of the movement of the impression cylinder in which the between-gripper spaces are freed of the cooperating transfer grippers so that the front edge of a sheet is held by both the regular grippers, as it passes through the printing zone, and the additional grippers and the tension to which the printing material is subjected is greatly reduced, and the registry and print quality are improved.
Abstract:
A system for remote sensing, indicating and remote control provides for the non-smear guidance of sheets through a sheet-fed machine and is especially useful for printing machines which print on both sides of the sheets. Sheet guides are adjustable during machine operation from a control panel at a central location outside of the machine. The positions of the sheet guides are preferably displayed in direct comparison with zones of ink application. Also, the sheet guides are adjustable from the control panel so that the guides fall within the gaps between printed areas on the sheet. An immediate and graphic check of the sheet guides is provided. In a preferred embodiment, the positions of the sheet guides are indicated on a linear array of optical indicators, each indicator representing a respective boundary between adjacent inking zones, and two adjacent ones of the optical indicators being simultaneously activated when one of the sheet guides is adjusted approximately at the center of the inking zone defined by the boundaries represented by the two adjacent ones of the optical indicators.
Abstract:
A lithographic sheet fed press having means for clearing a jamming condition in which a plurality of sheets become wedged between the blanket and impression cylinders. The blanket cylinder is journaled in eccentric bushings having respective operating arms. Toggle linkages are respectively interposed between each arm and the associated frame plate and settable in a slightly overcenter operating condition for maintaining normal printing pressure between the blanket cylinder and the impression cylinder. A toggle-breaking power actuator is laterally coupled to the toggle linkages for breaking the same to the opposite side of dead center. A back-off power actuator is coupled to the bushings for imparting substantial rotation to the bushings accompanied by relief of pressure and full collapse of the toggle linkages with scissoring action. The actuators are energized in sequence to secure (a) release of the toggle linkages and (b) backing off of the blanket cylinder from the impression cylinder. The toggle linkages are re-set to their overcenter operating condition following removal of the wedged sheets. The toggle linkages are mirror images of one another and are preferably interconnected by cross shafting to keep the movements at each end of the blanket cylinder in step with one another.
Abstract:
A gap cover of arcuate cross section for covering the longitudinal channel in the cylinder of a printing press, the cover being dimensioned to bridge the gap and held in place by first and second fastening assemblies accommodated below the presented surface. The first fastening assembly includes an axially oriented hook and stirrup, while the second assembly includes a radially oriented shaft having a flat head of oblong profile forming a pair of wings. The cover has a recessed portion radially aligned with the latching element and containing an aperture of mating oblong profile bounded by land surfaces so that the head of the latching element may project therethrough, for locking engagement with the lands upon rotation through 90.degree. by a turning tool. The shaft of the latching element has an associated detent for snapping the head from its free position to its locking position and for securely holding it there until intentionally released by additional turning movement. Preferably the cover has a nominal radius of curvature which is smaller that the radius of the cylinder, and the fastening assemblies are located at a radius which requires manual pressing of the cover into a slightly flattened sprung position as a precondition to engagement.
Abstract:
A device for removing curling tendency in sheets, particularly sheets fed to printing presses, in which the sheets are conveyed over two beam-like supporting members arranged transversely with respect to the direction of sheet movement and presenting supporting surfaces which are spaced parallel to one another on one side of the sheet to define a groove in between them. Suction is applied within the groove to draw a passing sheet downwardly into the groove to produce a relatively sharp concave bend in the sheet thereby to counteract the curling tendency. The cross-sectional profile of the groove is variable by a movable member to vary the profile of the groove and hence the degree of sharpness of the bend, thereby permitting the degree of correction to be varied while keeping the suction substantially constant. The device, in both preferred and alternate embodiments, has provision for removing curling tendency in opposite directions.