Abstract:
In accordance with the invention a varnishing unit in a printing machine is provided which simultaneously varnishes and perfects printing sheets. The varnishing unit comprises a rotating impression cylinder in contact with a rotating varnishing cylinder to create a nip between the two cylinders through which sheets are individually drawn. In order to perfect each sheet at the nip, the impression cylinder has at least one plate or a blanket secured to its surface. Depending on whether a plate or a blanket is secured to the impression cylinder, an appropriate dampening and inking means is provided. Similarly, the varnishing cylinder is supplied a controlled quantity of varnish by a varnishing means.
Abstract:
A job strip encoding printing process data is disposed on an indicia-free zone of an associated printing plate. The printing process data include process control data, press presetting data and organization data for the entire print order using the associated printing plate. Preferably, all of the important printing adjustments are computer controlled and the printing machine includes a scanner for automatically reading the job strip when the printing plate is clamped onto the plate cylinder of the printing machine. The job strip is not integral with the printing plate so that the printing process data are easily changed. The job strip, however, is attached to the printing plate and therefore the printing process data and associated printing plates are not mixed up in the print shop. The job strip is elongated and aligned parallel and adjacent to a longitudinal edge portion of the printing plate which is clamped to the plate cylinder. The job strip is circumferentially displaced from but located close to the area of the printing plate which is capable of printing and which engages the blanket cylinder, so that the inking rollers roll over the job strip during printing to keep it clean for scanning.
Abstract:
A system for presetting register and color zone adjusting devices in a multi-color rotary printing machine uses digitally-driven optical scanners axially traversing the plate cylinders under control of at least one numerical computer. Machine-specific characteristics are programmed in non-volatile memory as referenced values. Data processing is not required to be conducted external to the printing machine. The system is compact and requires practically no re-adjustment or entry of desired values from the machine operator. The machine operator, however, may enter coordinates for printing areas on the printing plate in order to speed up the scanning process for determining the initial color zone preset. The scanner multi-functionally scans the printing plate for both register adjustment and for integrating the ratio of printing to non-printing area for each inking zone. The system is easily reprogrammed and the optical scanner is interchangeable with a densitometer in order to provide alternative control functions during printing, such as the regulation of inking and dampening.
Abstract:
A device for monitoring the side lay marks and excess draw of a sheet fed rotary press that further ensures that sheets are at a sufficient distance from the side lay mark prior to transverse conveyance. A lateral sensor is positioned at a predetermined distance from the side lay mark so that when front sensors determine the presence of a sheet at front lay marks, the lateral sensor is evaluated. The sheet will only be conveyed transversely toward the side lay if the lateral sensor has not detected a sheet but the front sensors have, thus ensuring that the side edge of the sheet is at a sufficient distance from the side lay mark. A single sensor can also be used for all side lay mark monitoring, including monitoring for excess draw.
Abstract:
An oscillating form roller in the inking mechanism of a printing press includes a roller casing which is rotatable and axially displaceable relative to a roller shaft. During its axial displacement the roller casing encounters set collars that are fastened to the roller shaft so as to be continuously adjustable. Friction surfaces are provided so that, in this contacting position, the set collars and the roller shaft are caused to rotate in synchronism with the roller casing.
Abstract:
A mechanism for selectively engaging the doctor blade in a washer for the blanket cylinder of a printing press. The mechanism permits independent control of doctor blade engagement and, through the use of a plurality of adjustably mounted fluid pressure actuators spaced along the length of the doctor blade, facilitates accurate blade alignment, thus preventing non-uniform wear of the doctor blade and the washer roller.
Abstract:
Disclosed is an apparatus for a printing press, with means being provided in the press for correcting any out-of-register position of a printing plate, so as to release, after the printing plate has been clamped onto the plate cylinder, initially the tension of a rear tensioning strip, whereupon a forward tensioning strip is canted by a desired degree. Then, rear stops are moved back and the rear tensioning strip is tensioned by way of spring force. The described steps are repeated if required. Means are also proposed to noticeably reduce the sliding friction between the plate cylinder and the printing plate.
Abstract:
A clamping gripper for sheet-fed rotary printing presses wherein tensions produced in the paper by adhesion forces of the blanket do not react in run-on shifts of the center of a main gripper member mounted for rotation with a fit clearance on the gripper shaft. A spring is so disposed, and the bearing plane and the gripper support surface are so inclined relative to one another, that the resultant force due to the spring force, thrust and bearing load intersect the gripper finger at the transfer point.
Abstract:
For the rapid simultaneous engagement, disengagement and adjustment of all the applicator rollers at the plate cylinder of a printing machine, cam discs are mounted on the journals independently of the plate cylinder bearing. In an offset printing machine, the inking and damping rollers are each associated with their own cam discs. The cam discs are pivotable by means of drives, about the journals, with respect to adjustable stops for the engagement positions and end stops for the disengaged positions of the applicator rollers. The applicator rollers are mounted on rocker arms with respect to the stationary axis of the distributors preceding the applicator rollers and are adjustable with respect to the plate cylinder through the agency of adjustment means which co-operate with the cam discs. Adjustment of the applicator rollers during operation is effected by way of the cam discs which, in addition to the disengagement lobes, have cam zones for the roller engagement and adjustment.
Abstract:
An inking system for a lithographic printing press in which the plate has a non-ink accepting column position. Ink from an ink fountain is conveyed to the plate over its full width by a series of roller elements including an ink drum and ending with a form roller which is in rolling engagement with the plate. Water from a water fountain is conveyed to the plate by a series of rollers ending with a water form roller. A sub-frame is positioned at the non-ink accepting column position. The sub-frame mounts a pair of guide rollers supporting a relatively narrow endless belt in an elongated loop, the belt presenting a flat ink-accepting surface. A relatively narrow roller segment couples one end of the loop to the plate while the other end of the loop is coupled to the ink drum so that the belt forms an ink "bridge" on the downstream side of the series of ink rollers. Thus any ink which may become emulsified and which may therefore be deposited on the plate in non-ink accepting areas is picked off of the plate and conveyed by the belt back to the ink drum. In the preferred embodiment the narrow roller segment is journalled in a pair of arms which are swingable on the sub-frame about the axis of the adjacent one of the guide rollers with provision for adjusting the pressure exerted by the roller segment against the plate on the plate cylinder.